Alzheimer’s disease (AD), which is the most major cause of dementia, is a progressive neurodegenerative disease that affects cognitive functions. Even though the prevalence of AD is continuously increasing, few drugs including cholinesterase inhibitors and N-methyl D-aspartate-receptor antagonists were approved to treat AD. Because the clinical trials of AD drugs with single targets, such as β-amyloid and tau, have failed, the development of multi-target drugs that ameliorate many of the symptoms of AD is needed. Thus, recent studies have investigated the effects and underlying mechanisms of herbal formulae consisting of various herb combinations used to treat AD. This review discusses the results of clinical and nonclinical studies of the therapeutic efficacy in AD and underlying mechanisms of the herbal formulae of traditional Oriental medicines and bioactive compounds of medicinal plants.
Age-associated chronic inflammation is characterized by unresolved and uncontrolled inflammation with multivariable low-grade, chronic and systemic responses that exacerbate the aging process and age-related chronic diseases. Currently, there are two major hypotheses related to the involvement of chronic inflammation in the aging process: molecular inflammation of aging and inflammaging. However, neither of these hypotheses satisfactorily addresses age-related chronic inflammation, considering the recent advances that have been made in inflammation research. A more comprehensive view of age-related inflammation, that has a scope beyond the conventional view, is therefore required. In this review, we discuss newly emerging data on multi-phase inflammatory networks and proinflammatory pathways as they relate to aging. We describe the age-related upregulation of nuclear factor (NF)-κB signaling, cytokines/chemokines, endoplasmic reticulum (ER) stress, inflammasome, and lipid accumulation. The later sections of this review present our expanded view of age-related senescent inflammation, a process we term “senoinflammation”, that we propose here as a novel concept. As described in the discussion, senoinflammation provides a schema highlighting the important and ever-increasing roles of proinflammatory senescence-associated secretome, inflammasome, ER stress, TLRs, and microRNAs, which support the senoinflammation concept. It is hoped that this new concept of senoinflammation opens wider and deeper avenues for basic inflammation research and provides new insights into the anti-inflammatory therapeutic strategies targeting the multiple proinflammatory pathways and mediators and mediators that underlie the pathophysiological aging process.
Metformin is currently the most effective treatment for type-2 diabetes. The beneficial actions of metformin have been found even beyond diabetes management and it has been considered as one of the most promising drugs that could potentially slow down aging. Surprisingly, the effect of metformin on brain function and metabolism has been less explored given that brain almost exclusively uses glucose as substrate for energy metabolism. We determined the effect of metformin on locomotor and cognitive function in normoglycemic mice. Metformin enhanced locomotor and balance performance, while induced anxiolytic effect and impaired cognitive function upon chronic treatment. We conducted in vitro assays and metabolomics analysis in mice to evaluate metformin’s action on the brain metabolism. Metformin decreased ATP level and activated AMPK pathway in mouse hippocampus. Metformin inhibited oxidative phosphorylation and elevated glycolysis by inhibiting mitochondrial glycerol-3-phosphate dehydrogenase (mGPDH) in vitro at therapeutic doses. In summary, our study demonstrated that chronic metformin treatment affects brain bioenergetics with compound effects on locomotor and cognitive brain function in non-diabetic mice.
Oxidative stress is defined as an imbalance between production of free radicals and reactive metabolites or [reactive oxygen species (ROS)] and their elimination by through protective mechanisms, including (antioxidants). This Such imbalance leads to damage of cells and important biomolecules and cells, with hence posing a potential adverse impact on the whole organism. At the center of the day-to-day biological response to oxidative stress is the Kelch-like ECH-associated protein 1 (Keap1) - nuclear factor erythroid 2-related factor 2 (Nrf2)- antioxidant response elements (ARE) pathway, which regulates the transcription of many several antioxidant genes that preserve cellular homeostasis and detoxification genes that process and eliminate carcinogens and toxins before they can cause damage. The redox-sensitive signaling system Keap1/Nrf2/ARE plays a key role in the maintenance of cellular homeostasis under stress, inflammatory, carcinogenic, and pro-apoptotic conditions, which allows us to consider it as a pharmacological target. Herein, we review and discuss the recent advancements in the regulation of the Keap1/Nrf2/ARE system, and its role under physiological and pathophysiological conditions, e.g. such as in exercise, diabetes, cardiovascular diseases, cancer, neurodegenerative disorders, stroke, liver and kidney system, etc. and such.
Mesenchymal stem cells (MSCs) are an attractive cell source for regenerative medicine. However, MSCs age rapidly during long-term ex vivo culture and lose their therapeutic potential before they reach effective cell doses (ECD) for cell therapy. Thus, a prerequisite for effective MSC therapy is the development of cell culture methods to preserve the therapeutic potential during long-term ex vivo cultivation. Resveratrol (RSV) has been highlighted as a therapeutic candidate for bone disease. Although RSV treatment has beneficial effects on bone-forming cells, in vivo studies are lacking. The current study showed that long-term (6 weeks from primary culture date)-cultured MSCs with RSV induction retained their proliferative and differentiation potential despite reaching ECD. The mechanism of RSV action depends entirely on the SIRT1-SOX2 axis in MSC culture. In a rat calvarial defect model, RSV induction significantly improved bone regeneration after MSC transplantation. This study demonstrated an example of efficient MSC therapy for treating bone defects by providing a new strategy using the plant polyphenol RSV.
Despite increasing research efforts, there is a lack of consensus on defining aging or health. To understand the underlying processes, and to foster the development of targeted interventions towards increasing one’s health, there is an urgent need to find a broadly acceptable and useful definition of health, based on a list of (molecular) features; to operationalize features of health so that it can be measured; to identify predictive biomarkers and (molecular) pathways of health; and to suggest interventions, such as nutrition and exercise, targeted at putative causal pathways and processes. Based on a survey of the literature, we propose to define health as a state of an individual characterized by the core features of physiological, cognitive, physical and reproductive function, and a lack of disease. We further define aging as the aggregate of all processes in an individual that reduce its wellbeing, that is, its health or survival or both. We define biomarkers of health by their attribute of predicting future health better than chronological age. We define healthspan pathways as molecular features of health that relate to each other by belonging to the same molecular pathway. Our conceptual framework may integrate diverse operationalizations of health and guide precision prevention efforts.
Diabetes mellitus (DM) is well-known to exert complications such as retinopathy, cardiomyopathy and neuropathy. However, in recent years, an elevated osteoarthritis (OA) complaints among diabetics have been observed, portending the risk of diabetic OA. Since formation of advanced glycation end products (AGE) is believed to be the etiology of various diseases under hyperglycemic conditions, we firstly established that streptozotocin-induced DM could potentiate the development of OA in C57BL/6J mouse model, and further explored the intra-articularly administered adipose-derived stem cell (ADSC) therapy focusing on underlying AGE-associated mechanism. Our results demonstrated that hyperglycemic mice exhibited OA-like structural impairments including a proteoglycan loss and articular cartilage fibrillations in knee joint. Highly expressed levels of carboxymethyl lysine (CML), an AGE and their receptors (RAGE), which are hallmarks of hyperglycemic microenvironment were manifested. The elevated oxidative stress in diabetic OA knee-joint was revealed through increased levels of malondialdehyde (MDA). Further, oxidative stress-activated nuclear factor kappa B (NF-κB), the marker of proinflammatory signalling pathway was also accrued; and levels of matrix metalloproteinase-1 and 13 were upregulated. However, ADSC treatment attenuated all OA-like changes by 4 weeks, and dampened levels of CML, RAGE, MDA, NF-κB, MMP-1 and 13. These results suggest that during repair and regeneration, ADSCs inhibited glycation-mediated inflammatory cascade and rejuvenated cartilaginous tissue, thereby promoting knee-joint integrity in diabetic milieu.
Alzheimer’s disease (AD) is the most common neurodegenerative disease characterized by irreversible decline in cognition with unclear pathogenesis. Recently, accumulating evidence has revealed that CD2 associated protein (CD2AP), a scaffolding molecule regulates signal transduction and cytoskeletal molecules, is implicated in AD pathogenesis. Several single nucleotide polymorphisms (SNPs) in CD2AP gene are associated with higher risk for AD and mRNA levels of CD2AP are decreased in peripheral lymphocytes of sporadic AD patients. Furthermore, CD2AP loss of function is linked to enhanced Aβ production, Tau-induced neurotoxicity, abnormal neurite structure modulation and reduced blood-brain barrier integrity. This review is to summarize the recent discoveries about the genetics and known functions of CD2AP. The recent evidence concerning the roles of CD2AP in the AD pathogenesis is summarized and CD2AP can be a promising therapeutic target for AD.
Although aging is a physiological process, it has raised interest in the science of aging and rejuvenation because of the increasing burden on the rapidly aging global population. With advanced age, there is a decline in homeostatic maintenance and regenerative responsiveness to the injury of various tissues, thereby contributing to the incidence of age-related diseases. The primary cause of the functional declines that occur along with aging is considered to be the exhaustion of stem cell functions in their corresponding tissues. Age-related changes in the systemic environment, the niche, and stem cells contribute to this loss. Thus, the reversal of stem cell aging at the cellular level might lead to the rejuvenation of the animal at an organismic level and the prevention of aging, which would be critical for developing new therapies for age-related dysfunction and diseases. Here, we will explore the effects of aging on stem cells in different tissues. The focus of this discussion is on pro-youth interventions that target intrinsic stem cell properties, environmental niche component, systemic factors, and senescent cellular clearance, which are promising for developing strategies related to the reversal of aged stem cell function and optimizing tissue repair processes.
Aging is characterized by a progressive loss of skeletal muscle mass and function (sarcopenia). Obesity exacerbates age-related decline and lead to frailty. Skeletal muscle fat infiltration increases with aging and seems to be crucial for the progression of sarcopenia. Additionally, skeletal muscle plasticity modulates metabolic adaptation to different pathophysiological situations. Thus, cellular bioenergetics and mitochondrial profile were studied in the skeletal muscle of overweight aged people without reaching obesity to prevent this extreme situation. Overweight aged muscle lacked ATP production, as indicated by defects in the phosphagen system, glycolysis and especially mostly by oxidative phosphorylation metabolic pathway. Overweight subjects exhibited an inhibition of mitophagy that was linked to an increase in mitochondrial biogenesis that underlies the accumulation of dysfunctional mitochondria and encourages the onset of sarcopenia. As a strategy to maintain cellular homeostasis, overweight subjects experienced a metabolic switch from oxidative to lactic acid fermentation metabolism, which allows continued ATP production under mitochondrial dysfunction, but without reaching physiological aged basal levels. This ATP depletion induced early signs of impaired contractile function and a decline in skeletal muscle structural integrity, evidenced by lower levels of filamin C. Our findings reveal the main effector pathways at an early stage of obesity and highlight the importance of mitochondrial metabolism in overweight and obese individuals. Exploiting mitochondrial profiles for therapeutic purposes in humans is an ambitious strategy for treating muscle impairment diseases.
Alzheimer’s disease (AD) is a complex, multifactorial disease involving many pathological mechanisms. Nonetheless, single pathogenic mutations in amyloid precursor protein (APP) or presenilin 1 or 2 can cause AD with almost all of the clinical and neuropathological features, and therefore, we believe an important mechanism of pathogenesis in AD could be revealed from examining pathogenic APP missense mutations. A comprehensive review of the literature, including clinical, neuropathological, cellular and animal model data, was conducted through PubMed and the databases of Alzforum mutations, HGMD, UniProt, and AD&FTDMDB. Pearson correlation analysis combining the clinical and neuropathological data and aspects of mutant APP processing in cellular models was performed. We find that an increase in Aβ42 has a significant positive correlation with the appearance of neurofibrillary tangles (NFTs) and tends to cause an earlier age of AD onset, while an increase in Aβ40 significantly increases the age at death. The increase in the α-carboxyl terminal fragment (CTF) has a significantly negative correlation with the age of AD onset, and β-CTF has a similar effect without statistical significance. Animal models show that intracellular Aβ is critical for memory defects. Based on these results and the fact that amyloid plaque burden correlates much less well with cognitive impairment than do NFT counts, we propose a “snowball hypothesis”: the accumulation of intraneuronal NFTs caused by extracellular Aβ42 and the increase in intraneuronal APP proteolytic products (CTFs and Aβs) could cause cellular organelle stress that leads to neurodegeneration in AD, which then resembles the formation of abnormal protein “snowballs” both inside and outside of neurons.
Astrocytes, the largest and most numerous glial cells in the central nervous system (CNS), play a variety of important roles in regulating homeostasis, increasing synaptic plasticity and providing neuroprotection, thus helping to maintain normal brain function. At the same time, astrocytes can participate in the inflammatory response and play a key role in the progression of neurodegenerative diseases. Reactive astrocytes are strongly induced by numerous pathological conditions in the CNS. Astrocyte reactivity is initially characterized by hypertrophy of soma and processes, triggered by different molecules. Recent studies have demonstrated that neuroinflammation and ischemia can elicit two different types of reactive astrocytes, termed A1s and A2s. However, in the case of astrocyte reactivity in different neurodegenerative diseases, the recently published research issues remain a high level of conflict and controversy. So far, we still know very little about whether and how the function or reactivity of astrocytes changes in the progression of different neurodegenerative diseases. In this review, we aimed to briefly discuss recent studies highlighting the complex contribution of astrocytes in the process of various neurodegenerative diseases, which may provide us with new prospects for the development of an excellent therapeutic target for neurodegenerative diseases.
The innate immune system is an ancient and primary component system that rapidly reacts to defend the body against external pathogens. C1 is the initial responder of classical pathway of the innate immune system. C1 is comprised of C1q, C1r, and C1s. Among them, C1q is known to interact with diverse ligands, which can perform various functions in physiological and pathophysiological conditions. Because C1q participates in the clearance of pathogens, its interaction with novel receptors is expected to facilitate apoptosis induction, which could prevent the onset or progression of neurodegenerative diseases and could delay the aging process. Because senescence-associated secreting phenotype determinants are generally inflammatory cytokines or immune factors to activate immune cells. In the central nervous system, C1q has diverse neuroprotective roles against pathogens and inflammation. Most of neurodegenerative diseases show region specific pathology feature in the brain. It has been suggested the evidences that the active site and amount of C1q may be disease specific. This review considers currently the emerging and under-recognized roles of C1q in neurodegeneration and highlights the need for further research to clarify these roles. Future studies on the roles of C1q in regulating disease progression should consider these aspects, including the age-dependent onset time of each neurodegenerative disease progression.
Mitochondrial creatine kinase (MtCK) is vital in the process of mitochondrial energy metabolism, and mitochondrial dysfunction has been implicated in the pathogenesis of Parkinson’s disease (PD). Therefore, we speculated that MtCK activity could be altered in the serum of PD patients. However, no studies to date have investigated this specific topic, so we sought to investigate the serum MtCK activities among a cohort of PD patients. 50 patients with PD and 30 age-matched controls were recruited for this study. Serum ubiquitous MtCK (uMtCK) and sarcomeric MtCK (sMtCK) activities were assayed using an immunoinhibition method. Correlations between serum uMtCK/sMtCK activities and clinical features/parameters were explored in the PD group. Our study revealed a significant decrease in the uMtCK activity in the PD group when compared with the control group. No significant difference was found in the serum sMtCK activity between the PD and control groups. There was a significant correlation between serum uMtCK activities and the disease progression rate, duration, and age at onset in PD patients. While no significant relationship was found between the serum uMtCK activities and the Hoehn & Yahr stage or main non-motor symptoms scale. There was a significant decrease in the uMtCK activity in the serum of PD patients, which was associated with the rate of disease progression, duration, and age at onset of disease. Therefore, uMtCK activity in serum offers a useful clue for identification of PD biomarkers.
Societies in developed countries are aging at an unprecedented rate. Considering that aging is the most significant risk factor for many chronic lung diseases (CLDs), understanding this process may facilitate the development of new interventionist approaches. Skeletal muscle dysfunction is a serious problem in older adults with CLDs, reducing their quality of life and survival. In this study, we reviewed the possible links between handgrip strength (HGS)—a simple, noninvasive, low-cost measure of muscle function—and CLDs in the elderly. Different mechanisms appear to be involved in this association, including systemic inflammation, chronic hypoxemia, physical inactivity, malnutrition, and corticosteroid use. Respiratory and peripheral myopathy, associated with muscle atrophy and a shift in muscle fiber type, also seem to be major etiological contributors to CLDs. Moreover, sarcopenic obesity, which occurs in older adults with CLDs, impairs common inflammatory pathways that can potentiate each other and further accelerate the functional decline of HGS. Our findings support the concept that the systemic effects of CLDs may be determined by HGS, and HGS is a relevant measurement that should be considered in the clinical assessment of the elderly with CLDs. These reasons make HGS a useful practical tool for indirectly evaluating functional status in the elderly. At present, early muscle reconditioning and optimal nutrition appear to be the most effective approaches to reduce the impact of CLDs and low muscle strength on the quality of life of these individuals. Nonetheless, larger in-depth studies are needed to evaluate the link between HGS and CLDs.
Pharmacological studies have indirectly shown that necroptosis participates in ischemic neuronal death. However, its mechanism has yet to be elucidated in the ischemic brain. TNFα-triggered RIPK1 kinase activation could initiate RIPK3/MLKL-mediated necroptosis under inhibition of caspase-8. In the present study, we performed middle cerebral artery occlusion (MCAO) to induce cerebral ischemia in rats and used immunoblotting and immunostaining combined with pharmacological analysis to study the mechanism of necroptosis in ischemic brains. In the ipsilateral hemisphere, we found that ischemia induced the increase of (i) RIPK1 phosphorylation at the Ser166 residue (p-RIPK1), representing active RIPK1 kinase and (ii) the number of cells that were double stained with P-RIPK1 (Ser166) (p-RIPK1+) and TUNEL, a label of DNA double-strand breaks, indicating cell death. Furthermore, ischemia induced activation of downstream signaling factors of RIPK1, RIPK3 and MLKL, as well as the formation of mature interleukin-1β (IL-1β). Treatment with necrostatin-1 (Nec-1), an inhibitor of necroptosis, significantly decreased ischemia-induced increase of p-RIPK1 expression and p-RIPK1+ neurons, which showed protection from brain damage. Meanwhile, Nec-1 reduced RIPK3, MLKL and p-MLKL expression levels and mature IL-1β formation in Nec-1 treated ischemic brains. Our results clearly demonstrated that phosphorylation of RIPK1 at the Ser166 residue was involved in the pathogenesis of necroptosis in the brains after ischemic injury. Nec-1 treatment protected brains against ischemic necroptosis by reducing the activation of RIPK1 and inhibiting its downstream signaling pathways. These results provide direct in vivo evidence that phosphorylated RIPK1 (Ser 166) plays an important role in the initiation of RIPK3/MLKL-dependent necroptosis in the pathogenesis of ischemic stroke in the rodent brain.
Evidence has been accumulating that zinc ions can trigger β-amyloid (Aβ) deposition and senile plaque formation in the brain, a pathological hallmark of Alzheimer’s disease (AD). Chelating zinc inhibits Aβ aggregation and may hold promise as a therapeutic strategy for AD. S100A6 is an acidic Ca2+/Zn2+-binding protein found only in a small number of astrocytes in the normal brain. However, in the AD brain, S100A6 is highly expressed in astrocytes around Aβ plaques. The role of the astrocytic S100A6 upregulation in AD is unknown. In the present study, we examined the effects of S100A6 on Aβ plaques and intracellular zinc levels in a mouse model of AD. Chronic exposure to zinc increased Aβ deposition and S100A6 expression, both reversible by the zinc chelator clioquinol, in the brains of amyloid precursor protein/presenilin 1 (APP/PS1) transgenic mice. To examine whether exogenous S100A6 could induce Aβ plaque disaggregation through competition for zinc in vitro, we incubated APP/PS1 mouse brain sections with recombinant human S100A6 protein or co-incubated them with human S100A6-expressing cells. Both treatments efficiently reduced the Aβ plaque burden in situ. In addition, treatment with exogenous S100A6 protected cultured COS-7 cells against zinc toxicity. Our results show for the first time that increased S100A6 levels correlate with both Aβ disaggregation and decrease of Aβ plaque-associated zinc contents in brain sections with AD-like pathology. Astrocytic S100A6 in AD may protect from Aβ deposition through zinc sequestration.
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease mainly affecting upper and lower motor neurons in the brain and spinal cord. Pathogenesis of ALS is still unclear, and a multifactorial etiology is presumed. The remarkable clinical heterogeneity between different phenotypes of ALS patients suggests that environmental and lifestyle factors could play a role in onset and progression of ALS. We analyzed a cohort of 117 ALS patients and 93 controls. ALS patients and controls were compared regarding physical activity, dietary habits, smoking, residential environment, potentially toxic environmental factors and profession before symptom onset and throughout the disease course. Data were collected by a personal interview. For statistical analysis descriptive statistics, statistical tests and analysis of variance were used. ALS patients and controls did not differ regarding smoking, diet and extent of physical training. No higher frequency of toxic influences could be detected in the ALS group. ALS patients lived in rural environment considerably more often than the control persons, but this was not associated with a higher percentage of occupation in agriculture. There was also a higher percentage of university graduates in the ALS group. Patients with bulbar onset were considerably more often born in an urban environment as compared to spinal onset. Apart from education and environment, ALS phenotypes did not differ in any investigated environmental or life-style factor. The rate of disease progression was not influenced by any of the investigated environmental and life-style factors. The present study could not identify any dietary habit, smoking, physical activity, occupational factor as well as toxic influences as risk factor or protective factor for onset or progression of ALS. Living in rural environment and higher education might be associated with higher incidence of ALS.
Aging is a complex and integrated gradual deterioration of cellular activities in specific organs of the body, which is associated with increased mortality. This deterioration is the primary risk factor for major human pathologies, including cancer, diabetes, cardiovascular disorders, neurovascular disorders, and neurodegenerative diseases. There are nine tentative hallmarks of aging. In addition, several of these hallmarks are increasingly being associated with acute brain injury conditions. In this review, we consider the genes and their functional pathways involved in brain aging as a means of developing new strategies for therapies targeted to the neuropathological processes themselves, but also as targets for many age-related brain diseases. A single microRNA (miR), which is a short, non-coding RNA species, has the potential for targeting many genes simultaneously and, like practically all other cellular processes, genes associated with many features of brain aging and injury are regulated by miRs. We highlight how certain miRs can mediate deregulation of genes involved in neuroinflammation, acute neuronal injury and chronic neurodegenerative diseases. Finally, we review the recent progress in the development of effective strategies to block specific miR functions and discuss future approaches with the prediction that anti-miR drugs may soon be used in the clinic.
Owing to excellent therapeutic potential, mesenchymal stem cells (MSCs) are gaining increasing popularity with researchers worldwide for applications in tissue engineering, and in treatment of inflammation-related and age-related disorders. However, the senescence of MSCs over passaging has limited their clinical application owing to adverse effect on physiological function maintenance of tissues as well as disease treatment. An inflammatory microenvironment is one of the key contributors to MSC senescence, resulting in low regeneration efficiency. Therefore, MSCs with high resistance to cellular senescence would be a benefit for tissue regeneration. Toward this end, we analyzed the senescence properties of different types of stem cells during culture and under inflammation, including dental pulp stem cells (DPSCs), periodontal ligament stem cells (PDLSCs), bone marrow mesenchymal stem cells (BMMSCs), and adipose-derived stem cells (ADSCs). Overall, the DPSCs had higher proliferation rates, lower cellular senescence, and enhanced osteogenesis maintenance compared to those of non-dental MSCs cultured from passage three to six. The expression profiles of genes related to apoptosis, cell cycle, and cellular protein metabolic process (contributing to the cell self-renewal ability and metabolic processes) significantly differed between DPSCs and BMMSCs at passage three. Moreover, DPSCs were superior to BMMSCs with regards to resistance to lipopolysaccharide-induced apoptosis and senescence, with enhanced osteogenesis in vitro, and showed improved periodontal regeneration after injection in a miniature pig periodontitis model in vivo. Overall, the present study indicates that DPSCs show superior resistance to subculture and inflammation-induced senescence and would be suitable stem cells for tissue engineering with inflammation.
The inflammatory response is an unavoidable process and contributes to the destruction of cerebral tissue during the acute ischemic stroke (AIS) phase and has not been addressed fully to date. Insightful understanding of correlation of inflammatory mediators and stroke outcome may provide new biomarkers or therapeutic approaches for ischemic stroke. Here, we prospectively recruited 180 first-ever AIS patients within 72 hrs after stroke onset. We used the National Institutes of Health Stroke Scale (NIHSS) to quantify stroke severity and modified Rankin scale (mRS) to assess the 3-month outcome for AIS patients. Initially, we screened 35 cytokines, chemokines, and growth factors in sera from 75 AIS patients and control subjects. Cytokines that were of interest were further investigated in the 180 AIS patients and 14 heathy controls. We found that IL-1RA, IL-1β, IL-4, IL-5, IL-6, IL-7, IL-9, IL-10, IL-13, IL-15, EGF, G-CSF, Flt-3L, GM-CSF and Fractalkine levels were significantly decreased in severe stroke patients. In particular, IL-1β, IL-4, IL-5, IL-7, IL-9, IL-10, IL-15, G-CSF and GM-CSF were significantly reduced in AIS patients with poor outcome, compared to those with good prognosis. IL-6 was notably higher in the poor outcome group. Only IL-9 level decreased in the large infarct volume group. After adjusting for confounders, we found that IL-5 was an independent protective factor for prognosis in AIS patients with an adjusted OR of 0.042 (P = 0.007), whereas IL-6 was an independent risk predictor for AIS patients with an adjusted OR of 1.293 (P = 0.003). Our study suggests the levels of serum cytokines are related to stroke severity, short-term prognosis and cerebral infarct volume in AIS patients.
The global incidence of age-associated neurological diseases is expected to rise with increasingly greying societies. In the aged brain, there is a dramatic decrease in the number of stem cells, which is a main cause for the decrease in brain function. Intrinsic factors, such as cell metabolism, have been studied but its role in neurogenesis is still unknown. Therefore, this study sought to establish whether AMP-activated protein kinase (AMPK) signaling does indeed regulate hippocampal neurogenesis in the aged brain. We found that i) AMPKα2 was the predominant catalytic subunit in the subgranular and subventricular zones; ii) AMPK activation was at a significantly higher level in the aged vs. young hippocampus; iii) short term (7 days) treatment with selective AMPK signaling inhibitor Compound C (10 mg/kg/day, i.p.) significantly increased the numbers of newborn (BrdU+), Type 2 (MCM2+), and Type 3 (DCX+) neural stem cells, but not Type 1 (GFAP+/Sox2+) cells, in the aged hippocampus. Taken together, our results demonstrate that AMPK signaling plays a critical role in the age-related decline of hippocampal neurogenesis.
The longitudinal association between glycated hemoglobin (HbA1c) and different courses of depressive symptoms is understudied. This study aimed to identify different trajectories of depressive symptoms and investigate the relation of HbA1c with the risk of increasing and high-stable depressive symptoms. In the China Health and Retirement Longitudinal Study, depressive symptoms were measured using the 10-item Center for Epidemiological Studies-Depression scale in three visits (years: 2011, 2013 and 2015) among 9804 participants (mean age 60.0 ± 9.0 years). Group-based trajectory modeling was used to identify trajectories of depressive symptoms. HbA1c was measured at baseline and categorized five groups according to the respective quintile. Multinomial logistic regression was fitted to examine this relationship. Four distinct trajectories of depressive symptoms were identified: low symptoms (n=6401, 65.29%); decreasing symptoms (n=1362, 13.89%); increasing symptoms (n=1452, 14.81%); and high symptoms (n=1452, 14.81%). Adjusting for demographic, health-related, and cognitive factors, the risk ratio (95% confidence interval) pertaining to the highest HbA1c (Quintile 5) for decreasing, increasing, and high symptoms of depression versus low symptoms was 1.01 (0.82-1.25), 1.12 (0.92-1.36), and 1.39 (1.04-1.86) compared with the lowest HbA1c (Quintile 1), respectively. We observed a J-shaped relationship between HbA1c and high depressive symptoms, with the lowest risk at a HbA1c concentration of 5.0%. In summary, in this large population-based cohort, high levels of glycated hemoglobin concentrations were associated with a higher risk of increasing and high-stable symptoms of depression.
Advanced chronic liver disease (aCLD) represents a major public health concern. aCLD is more prevalent and severe in the elderly, carrying a higher risk of decompensation. We aimed at understanding how aging may impact on the pathophysiology of aCLD in aged rats and humans and secondly, at evaluating simvastatin as a therapeutic option in aged animals. aCLD was induced in young (1 month) and old (16 months) rats. A subgroup of aCLD-old animals received simvastatin (5 mg/kg) or vehicle (PBS) for 15 days. Hepatic and systemic hemodynamic, liver cells phenotype and hepatic fibrosis were evaluated. Additionally, the gene expression signature of cirrhosis was evaluated in a cohort of young and aged cirrhotic patients. Aged animals developed a more severe form of aCLD. Portal hypertension and liver fibrosis were exacerbated as a consequence of profound deregulations in the phenotype of the main hepatic cells: hepatocytes presented more extensive cell-death and poorer function, LSEC were further capillarized, HSC over-activated and macrophage infiltration was significantly increased. The gene expression signature of cirrhosis significantly differed comparing young and aged patients, indicating alterations in sinusoidal-protective pathways and confirming the pre-clinical observations. Simvastatin administration for 15-day to aged cirrhotic rats improved the hepatic sinusoidal milieu, leading to significant amelioration in portal hypertension. This study provides evidence that aCLD pathobiology is different in aged individuals. As the median age of patients with aCLD is increasing, we propose a real-life pre-clinical model to develop more reliable therapeutic strategies. Simvastatin effects in this model further demonstrate its translational potential.
The complement system is an essential part of innate immunity, typically conferring protection via eliminating pathogens and accumulating debris. However, the defensive function of the complement system can exacerbate immune, inflammatory, and degenerative responses in various pathological conditions. Cumulative evidence indicates that the complement system plays a critical role in the pathogenesis of ischemic brain injury, as the depletion of certain complement components or the inhibition of complement activation could reduce ischemic brain injury. Although multiple candidates modulating or inhibiting complement activation show massive potential for the treatment of ischemic stroke, the clinical availability of complement inhibitors remains limited. The complement system is also involved in neural plasticity and neurogenesis during cerebral ischemia. Thus, unexpected side effects could be induced if the systemic complement system is inhibited. In this review, we highlighted the recent concepts and discoveries of the roles of different kinds of complement components, such as C3a, C5a, and their receptors, in both normal brain physiology and the pathophysiology of brain ischemia. In addition, we comprehensively reviewed the current development of complement-targeted therapy for ischemic stroke and discussed the challenges of bringing these therapies into the clinic. The design of future experiments was also discussed to better characterize the role of complement in both tissue injury and recovery after cerebral ischemia. More studies are needed to elucidate the molecular and cellular mechanisms of how complement components exert their functions in different stages of ischemic stroke to optimize the intervention of targeting the complement system.
Cataract is a major cause of blindness worldwide, its complicated and unclear etiopathogenesis limit effective therapy. Here, we found that Yap, a downstream effector of the Hippo pathway, is specifically expressed in lens epithelial cells and Yap conditional knockout (cKO) in the lens leads to cataract. Histologically, Yap deficient lens show fewer epithelial cells, retention of nuclei and accumulation of morgagnian globules in the transitional zone and the posterior area. Mechanistically, GFAP-mediated Yap cKO leads to the reduced proliferation of epithelial cells, delayed fiber cell denucleation and increased cellular senescence in lens. Further RNA profiling analysis reveals Yap cKO results in a significant alteration in gene transcription that is involved in eye development, lens structure, inflammation, cellular proliferation and polarity. Collectively, our data reveal a novel function of Yap in the lens and links Yap deficiency with the development of cataract, making Yap a promising target for cataract therapy.
Positron emission tomography (PET) scan with tracer [18F]-fluorodeoxy-glucose (18F-FDG) is widely used to measure the glucose metabolism in neurodegenerative disease such as Idiopathic Parkinson’s disease (IPD). Previous studies using 18F-FDG PET mainly focused on the motor or non-motor symptoms but not the severity of IPD. In this study, we aimed to determine the metabolic patterns of 18F-FDG in different stages of IPD defined by Hoehn and Yahr rating scale (H-Y rating scale) and to identify regions in the brain that play critical roles in disease progression. Fifty IPD patients were included in this study. They were 29 men and 21 women (mean±SD, age 57.7±11.1 years, disease duration 4.0±3.8 years, H-Y 2.2±1.1). Twenty healthy individuals were included as normal controls. Following 18F-FDG PET scan, image analysis was performed using Statistical Parametric Mapping (SPM) and Resting-State fMRI Data Analysis Toolkit (REST). The metabolic feature of IPD and regions-of-interests (ROIs) were determined. Correlation analysis between ROIs and H-Y stage was performed. SPM analysis demonstrated a significant hypometabolic activity in bilateral putamen, caudate and anterior cingulate as well as left parietal lobe, prefrontal cortex in IPD patients. In contrast, hypermetabolism was observed in the cerebellum and vermis. There was a negative correlation (p=0.007, r=-0.412) between H-Y stage and caudate metabolic activity. Moreover, the prefrontal area also showed a negative correlation with H-Y (P=0.033, r=-0.334). Thus, the uptake of FDG in caudate and prefrontal cortex can potentially be used as a surrogate marker to evaluate the severity of IPD.
Statins belong to the most pre-scribed cholesterol lowering drugs in western countries. Their competitive inhibition of the HMG-CoA reductase causes a reduction in the mevalonate pool, resulting in reduced cholesterol biosynthesis, impaired protein prenylation and glycosylation. Recently, a cohort study showed a decreased mortality rate in humans between age 78-90 going along with statin therapy, which is independent of blood cholesterol levels. As C. elegans harbors the mevalonate pathway, but is cholesterol-auxotroph, it is particularly suitable to study cholesterol-independent effects of statins on aging-associated phenotypes. Here, we show that low doses of lovastatin or a mild HMG-CoA reductase knockdown via hmgr-1(RNAi) in C. elegans substantially attenuate aging pigment accumulation, which is a well-established surrogate marker for biological age. Consistently, for two statins we found dosages, which prolonged the lifespan of C. elegans. Together with an observed reduced fertility, slower developmental timing and thermal stress resistance this complex of outcomes point to the involvement of DAF-16/hFOXO3a, the master regulator of stress resistance and longevity. Accordingly, prolonged low-dose statin exposure leads to an increased expression of jnk-1, a known activator of DAF-16. Moreover, the beneficial effects of statins on aging pigments and lifespan depend on DAF-16 and JNK-1, as shown in epistasis analyses. These effects can be reverted by mevalonate supplementation. In conclusion, we describe a lifespan extension in C. elegans, which is conferred via two well-conserved stress-related factors (JNK-1, DAF-16) and results from mevalonate depletion.
Although autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus, are frequently associated with premature aging of the thymus, a direct link is missing between autoimmunity and thymic atrophy. Here we monitored the progression of thymic involution in Aire-deficient mice, in which defective negative selection causes spontaneous and progressive development of autoimmunity. In young and middle-aged mice, Aire deficiency appeared to be protective as supported by the reduced β-gal+ epithelial cells and the enhanced thymic output. However, once the autoimmune phenotype was fully developed in aged Aire-deficient mice, their thymuses underwent accelerated involution. In comparison to the age-matched wildtype littermates, old Aire-deficient mice showed lower numbers of total thymocytes and recent thymic emigrants but more β-gal+ thymic epithelial cells. This phenomenon may partly be attributable to the increased number of activated Th1 cells homing to the thymus. This speculation was further supported by the enhanced thymic aging following repeated challenges with complete Freund’s adjuvant immunization. Taken together, the present study highlights a unique mechanism by which autoimmunity facilitates the senescence of thymic epithelial cells through returning Th1 cells.
In recent years, cation-chloride cotransporters (CCCs) have drawn attention in the medical neuroscience research. CCCs include the family of Na+-coupled Cl- importers (NCC, NKCC1, and NKCC2), K+-coupled Cl- exporters (KCCs), and possibly polyamine transporters (CCC9) and CCC interacting protein (CIP1). For decades, CCCs have been the targets of several commonly used diuretic drugs, including hydrochlorothiazide, furosemide, and bumetanide. Genetic mutations of NCC and NKCC2 cause congenital renal tubular disorders and lead to renal salt-losing hypotension, secondary hyperreninemia, and hypokalemic metabolic alkalosis. New studies reveal that CCCs along with their regulatory WNK (Kinase with no lysine (K)), and SPAK (Ste20-related proline-alanine-rich kinase)/OSR1(oxidative stress-responsive kinase-1) are essential for regulating cell volume and maintaining ionic homeostasis in the nervous system, especially roles of the WNK-SPAK-NKCC1 signaling pathway in ischemic brain injury and hypersecretion of cerebrospinal fluid in post-hemorrhagic hydrocephalus. In addition, disruption of Cl- exporter KCC2 has an effect on synaptic inhibition, which may be involved in developing pain, epilepsy, and possibly some neuropsychiatric disorders. Interference with KCC3 leads to peripheral nervous system neuropathy as well as axon and nerve fiber swelling and psychosis. The WNK-SPAK/OSR1-CCCs complex emerges as therapeutic targets for multiple neurological diseases. This review will highlight these new findings.
Huntington’s disease (HD) is an autosomal dominant inherited neurodegenerative disorder caused by CAG triplet repeats expansion in exon 1 of the Huntingtin gene (HTT). In China, HD is considered to have a low prevalence. The goal of this study was to describe the clinical characteristic and genetic profiles of HD in a Chinese cohort. A total of 322 individuals with expanded CAG repeats were consecutively recruited from the neurologic clinics of three medical centers in Southeastern China between 2008 and 2018. Among them, 80 were pre-symptomatic mutation carriers and 242 were symptomatic patients. The mean age at onset (AAO), defined here as the age at motor symptom onset, of the 242 manifest HD individuals was 40.3 ± 11.9 years and the mean CAG repeat length was 46.1 ± 7.5 in the group of symptomatic patients. Initial symptoms were abnormal movements in 88.8% of the patients with psychiatric symptoms in 6.2%, cognitive impairment in 3.3% and others in 1.7%. The AAO of motor was negatively correlated with the CAG repeat length in an exponential regression analysis (R 2 = 0.74, P<0.001). Analysis of 46 parent-child pairs showed that the CAG repeat length was longer in the offspring group (45.8 ±7.6) than in the parent group (43.8 ±3.0) (p=0.005). Overall, this study provides clinical and genetic profiles in a cohort of Chinese patients with HD, which should contribute to a better understanding of this disorder.
Liuwei Dihuang (LWDH), a famous traditional Chinese medicine, is widely used in the clinical treatment of aging-related diseases in China. However, its pharmacological mechanisms are not clear. In the present study, we evaluated the lifespan extension effect of LWDH in C. elegans and mice and revealed its underlying mechanisms. The results showed that LWDH significantly extended the lifespan of C. elegans in a dose-dependent manner. LWDH also conferred protection to nematodes against oxidative stress and reduced their fat storage. Genetics analysis and microarray data showed that the longevity effect of LWDH was attributed to the regulation of the innate immune response, proteolysis, lipid metabolism, and the oxidation-reduction process and was dependent on daf-16. Among the six herbs in the formula, Radix Rehmanniae Preparata and Fructus Macrocarpii contributed most to the longevity effect of this medicine, while the other four components had a synergistic effect on the longevity effect of the prescription. The lack of any single herb reduced the efficacy of the complete formula. LWDH also extended the lifespan and reduced both the weight and oxidant stress status in aged mice. Taken together, these results suggested that LWDH might function in a multi-target manner to extend the lifespan in both C. elegans and aged mice, and the best effect was achieved with the complete formula.
Aging promotes a range of degenerative pathologies characterized by progressive losses of tissue and/or cellular function. Fibrosis is the hardening, overgrowth and scarring of various tissues characterized by the accumulation of extracellular matrix components. Aging is an important predisposing factor common for fibrotic heart and respiratory disease. Age-related processes such as senescence, inflammaging, autophagy and mitochondrial dysfunction are interconnected biological processes that diminish the regenerative capacity of the aged heart and lung and have been shown to play a crucial role in cardiac fibrosis and idiopathic pulmonary fibrosis. This review focuses on these four processes of aging in relation to their role in fibrosis. It has long been established that the heart and lung are linked both functionally and anatomically when it comes to health and disease, with an ever-expanding aging population, the incidence of fibrotic disease and therefore the number of fibrosis-related deaths will continue to rise. There are currently no feasible therapies to treat the effects of chronic fibrosis therefore highlighting the importance of exploring the processes of aging and its role in inducing and exacerbating fibrosis of each organ. The focus of this review may help to highlight potential avenues of therapeutic exploration
Aging is the progressive decline of physiological functions necessary for survival and reproduction. In gaining a better understanding of the inevitable aging process, the hope is to preserve, promote, or delay healthy aging through the treatment of common age-associated diseases. Although there are theories that try to explain the aging process, none of them seem to fully satisfy. Microcirculation describes blood flow through the capillaries in the circulatory system. The main functions of the microcirculation are the delivery of oxgen and nutrients and the removal of CO2, metabolic debris, and toxins. The microcirculatory impairment or dysfunction over time will result in the accumulation of toxic products and CO2 and loss of nutrition supplementation and O2 in corresponding tissue systems or internal organs, which eventually affect normal tissue and organ functions, leading to aging. Therefore, I propose a microcirculatory theory of aging: aging is the process of continuous impairment of microcirculation in the body.
Although age is a dominant risk factor for Alzheimer’s disease (AD), epidemiological studies have shown that physical activity may significantly decrease age-related risks for AD, and indeed mitigate the impact in existing diagnosis. The aim of this study was to perform a narrative review on the preventative, and mitigating, effects of physical activity on AD onset, including genetic factors, mechanism of action and physical activity typology. In this article, we conducted a narrative review of the influence physical activity and exercise have on AD, utilising key terms related to AD, physical activity, mechanism and prevention, searching the online databases; Web of Science, PubMed and Google Scholar, and, subsequently, discuss possible mechanisms of this action. On the basis of this review, it is evident that physical activity and exercise may be incorporated in AD, notwithstanding, a greater number of high-quality randomised controlled trials are needed, moreover, physical activity typology must be acutely considered, primarily due to a dearth of research on the efficacy of physical activity types other than aerobic.
The relationship between recurrent intracerebral hemorrhage (ICH) and total burden of cerebral small vessel disease (CSVD) is not completely investigated. We aimed to study whether recurrent intracerebral hemorrhage (ICH) had higher CSVD score than first-ever ICH. Lacunes, white matter hyperintensities (WMH), cerebral microbleeds (CMBs), enlarged perivascular spaces (EPVS), cortical superficial siderosis (cSS) and CSVD score were rated on brain magnetic resonance imaging (MRI) in primary ICH patients. Recurrent ICHs were confirmed by reviewing the medical records and MRI scans. Mixed hematomas were defined as follows: deep + lobar, deep + cerebellar, or deep + lobar + cerebellar. Of the 184 patients with primary ICH enrolled (mean age, 61.0 years; 75.5% men), recurrent ICH was present in 45 (24.5%) patients; 26.1% (48/184) had ≥2 hematomas, 93.8% (45/48) of which exhibited recurrent ICH. Mixed hematomas were identified in 8.7% (16/184) of patients and bilateral hematomas in 17.9% (33/184). All mixed hematomas and bilateral hematomas were from cases of recurrent ICH. Patients with mixed etiology-ICH were more likely to have recurrent ICH than patients with cerebral amyloid angiopathy (CAA) or hypertensive angiopathy (HA)-related ICH (36.8% vs17.8%, p=0.008). Multivariate ordinal regression analysis showed that the presence of recurrent ICH (p=0.001), ≥2 hematomas (p=0.002), mixed hematomas (p<0.00001), and bilateral hematomas (p=0.002) were separately significantly associated with a high CSVD score. Recurrent ICH occurs mostly among patients with mixed etiology-ICH and is associated with a higher CSVD burden than first-ever ICH, which needs to be verified by future larger studies.
In searching for the drainage route of the interstitial fluid (ISF) in the deep brain, we discovered a regionalized ISF drainage system as well as a new function of myelin in regulating the drainage. The traced ISF from the caudate nucleus drained to the ipsilateral cortex along myelin fiber tracts, while in the opposite direction, its movement to the adjacent thalamus was completely impeded by a barrier structure, which was identified as the converged, compact myelin fascicle. The regulating and the barrier effects of myelin were unchanged in AQP4-knockout rats but were impaired as the integrity of boundary structure of drainage system was destroyed in a demyelinated rat model. We thus proposed that the brain homeostasis was maintained within each ISF drainage division locally, rather than across the brain as a whole. A new brain division system and a new pathogenic mechanism of demyelination are therefore proposed.
Induced pluripotent stem cells (iPSCs)-derived dopaminergic neurons might be reset back to the fetal state due to reprogramming. Thus, it is a compelling challenge to reliably and efficiently induce disease phenotypes of iPSCs-derived dopaminergic neurons to model late-onset Parkinson’s disease (PD). Here, we applied a small molecule, hydroxyurea (HU), to promote the manifestation of disease relevant phenotypes in iPSCs-based modeling of PD. We established two iPS cell lines derived from two sporadic PD patients. Both patients-iPSCs-derived dopaminergic neurons did not display PD relevant phenotypes after 6 weeks culture. HU treatment remarkably induced ER stress on patients-iPSCs-derived dopaminergic neurons. Moreover, HU treatment significantly reduced neurite outgrowth, decreased the expression of p-AKT and its downstream targets (p-4EBP1 and p-ULK1), and increased the expression level of cleaved-Caspase 3 in patients-iPSCs-derived dopaminergic neurons. The findings of the present study suggest that HU administration could be a convenient and reliable approach to induce disease relevant phenotypes in PD-iPSCs-based models, facilitating to study disease mechanisms and test drug effects.
Phenotypic transformation of vascular smooth muscle cells (VSMCs) contributes to vascular remodeling in hypertension. High mobility group box-1 (HMGB1) has been reported to be involved in several pathogenic processes including VSMC proliferation and migration. The present study was designed to determine the role of HMGB1 in VSMC phenotypic transformation in hypertension. First, we demonstrated that HMGB1 was elevated in a model of Ang II-induced VSMC phenotypic transformation, which showed down-regulation of contractile proteins and up-regulation of synthetic proteins. Knockdown of HMGB1 and losartan could block the phenotypic transformation. Next, we identified three potential miRNAs for upstream regulation of HMGB1 by bioinformatic analysis; only miR-181b-5p was significantly down-regulated in Ang II-treated cells. Co-treating the cells with miR-181b-5p mimics suppressed HMGB1 expression as well as the phenotypic transformation, migration, and proliferation. Furthermore, the luciferase reporter gene assay confirmed the direct interaction between miR-181b-5p and HMGB1. Finally, to extend these cell-based studies to clinical patients, we demonstrated that plasma miR-181b-5p levels were decreased, while Ang II and HMGB1 levels, as well as the intima-media thickness (IMT) were increased in hypertensive patients; these effects were reversed following the administration of angiotensin receptor blockers. Based on these observations, we conclude that the down-regulation of miR-181b-5p leads to the elevation of HMGB1 levels in hypertensive patients, which accounts, at least partially, for VSMCs phenotypic transformation and vascular remodeling. Our findings also highlight that the plasma levels of miR-181b-5p and HMGB1 may serve as novel biomarkers for vascular remodeling in the hypertensive patients.
The APOE and fibroblast growth factor 1 (FGF1) have both been associated with amyloid β accumulation and neurodegeneration. Investigation the effect of APOE-FGF1 interactions on episodic memory (EM) deficits and hippocampus atrophy (HA) might elucidate the complex clinical-pathological relationship in Alzheimer’s disease (AD). EM performance and hippocampal volume (HV) were characterized in patients with mild AD based on APOE-ε4 carrier status (APOE-ε4 carriers versus non-carriers) and FGF1 single nucleotide polymorphism (FGF1-rs34011-GG versus FGF1-rs34011-A-allele carriers). The clinical-pathological relationships within each genotypic group (ε4+/GG-carrier, ε4+/A-allele-carrier, ε4-/GG-carrier and ε4-/A-allele-carrier) were analyzed. There were no significant differences between the FGF1-rs34011-GG and FGF1-rs34011-A-allele carriers for the level of EM performance or HV (p> 0.05). The bilateral HV was significantly smaller and EM impairment was significantly worse in ε4+/GG-carrier than in ε4-/A-allele-carrier, and an interaction effect of APOE (APOE-ε4 carriers versus non-carriers) with FGF1 (FGF1-rs34011-GG versus FGF1-rs34011-A-allele carriers) predicted EM impairment (F4,92= 3.516, p= 0.018) and structural changes in voxel-based morphometry. Our data shows that concurrent consideration of APOE and FGF1 polymorphisms might be required to understand the clinical-pathological relationship in AD.