Atrial fibrillation (AF) is the most prevalent arrhythmia in the world, due both to its tenacious treatment resistance, and to the tremendous number of risk factors that set the stage for the atria to fibrillate. Cardiopulmonary, behavioral, and psychological risk factors generate electrical and structural alterations of the atria that promote reentry and wavebreak. These culminate in fibrillation once atrial ectopic beats set the arrhythmia process in motion. There is growing evidence that chronic stress can physically alter the emotion centers of the limbic system, changing their input to the hypothalamic-limbic-autonomic network that regulates autonomic outflow. This leads to imbalance of the parasympathetic and sympathetic nervous systems, most often in favor of sympathetic overactivation. Autonomic imbalance acts as a driving force behind the atrial ectopy and reentry that promote AF. Careful study of AF pathophysiology can illuminate the means that enable AF to elude both pharmacological control and surgical cure, by revealing ways in which antiarrhythmic drugs and surgical and ablation procedures may paradoxically promote fibrillation. Understanding AF pathophysiology can also help clarify the mechanisms by which emerging modalities aiming to correct autonomic imbalance, such as renal sympathetic denervation, may offer potential to better control this arrhythmia. Finally, growing evidence supports lifestyle modification approaches as adjuncts to improve AF control.
Flavonoids are known to trigger the intrinsic genetic adaptive programs to hypoxic or oxidative stress via estrogen receptor engagement or upstream kinase activation. To reveal specific structural requirements for direct stabilization of the transcription factors responsible for triggering the antihypoxic and antioxidant programs, we studied flavones, isoflavones and catechols including dihydroxybenzoate, didox, levodopa, and nordihydroguaiaretic acid (NDGA), using novel luciferase-based reporters specific for the first step in HIF1 or Nrf2 protein stabilization. Distinct structural requirements for either transcription factor stabilization have been found: as expected, these requirements for activation of HIF ODD-luc reporter correlate with in silico binding to HIF prolyl hydroxylase. By contrast, stabilization of Nrf2 requires the presence of 3,4-dihydroxy- (catechol) groups. Thus, only some but not all flavonoids are direct activators of the hypoxic and antioxidant genetic programs. NDGA from the Creosote bush resembles the best flavonoids in their ability to directly stabilize HIF1 and Nrf2 and is superior with respect to LOX inhibition thus favoring this compound over others. Given much higher bioavailability and stability of NDGA than any flavonoid, NDGA has been tested in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-animal model of Parkinson’s Disease and demonstrated neuroprotective effects.
Danggui-Shaoyao-San (DSS), also called Toki-shakuyaku-san (TJ-23) or Dangguijakyak-san (DJS), is a well-known herbal formula (Angelica sinensis (Oliv.) Diels., Ligusticum chuanxiong Hort., Paeonia lactiflora pall., Poria cocos (Schw.) Wolf, Alisma orientalis (Sam.) Juzep., Atractylodes macrocephala Koidz.), which has been widely used in oriental countries for the treatment of various gynecological diseases. Recent studies show that DSS has an effect on free radical-mediated neurological diseases and exhibits anti-inflammatory and antioxidant activities and reduces cell apoptosis in the hippocampus. In addition, DSS mediates the modulation of central monoamine neurotransmitter systems and ameliorates dysfunction of the central cholinergic nervous system and scopolamine-induced decrease in ACh levels. DSS improves the function of the dopaminergic, adrenergic, and serotonergic nervous systems. Interestingly, DSS can alleviate cognitive dysfunction of Alzheimer's disease (AD) patients, suggesting that it is a useful therapeutic agent for AD. This paper reviews the mechanism of DSS for the treatment of AD.
Cellular senescence can be described as a complex stress response that leads to irreversible cell cycle arrest. This process was originally described as an event that primary cells go through after many passages of cells during cell culture. More recently, cellular senescence is viewed as a programmed process by which the cell displays a senescence phenotype when exposed to a variety of stresses. Cellular senescence has been implicated in tumor suppression and aging such that senescence may contribute to both tumor progression and normal tissue repair. Here, we review different forms of cellular senescence, as well as current biomarkers used to identify senescent cells in vitro and in vivo. Additionally, we highlight the role of senescence-associated long noncoding RNAs (lncRNAs).
Long non-coding RNA H19 (lncRNA H19) was found to be upregulated by hypoxia, its expression and function have never been tested in cerebral ischemia and reperfusion (I/R) injury. This study intended to investigate the role of lncRNA H19 and H19 gene variation in cerebral I/R injury with focusing on its relationship with autophagy activation. Cerebral I/R was induced in rats by middle cerebral artery occlusion followed by reperfusion. SH-SY5Y cells were subjected to oxygen and glucose deprivation and reperfusion (OGD/R) to simulate I/R injury. Real-time PCR, flow cytometry, immunofluorescence and Western blot were used to evaluate the level of lncRNA H19, apoptosis, autophagy and some related proteins. The modified multiple ligase reaction was used to analyze the gene polymorphism of six SNPs in H19, rs217727, rs2067051, rs2251375, rs492994, rs2839698 and rs10732516 in ischemic stroke patients. We found that the expression of lncRNA H19 was upregulated by cerebral I/R in rats, as well as by OGD/R in vitro in the cells. Inhibition of lncRNA H19 and autophagy protected cells from OGD/R-induced death, respectively. Autophagy activation induced by OGD/R was prevented by H19 siRNA. Autophagy inducer, rapamycin, abolished lncRNA H19 effect. Furthermore, we found that lncRNA H19 inhibited autophagy through DUSP5-ERK1/2 axis. The result from blood samples of ischemic patients revealed that the variation of H19 gene increased the risk of ischemic stroke. Taken together, the results of present study suggest that LncRNA H19 could be a new therapeutic target of ischemic stroke.
Muscle power is a strong predictor of functional status in the elderly population and is required to perform different daily activities. To compare the effects of different weekly training frequencies on muscle power and muscle quality induced by concurrent training (resistance + aerobic) in previously trained elderly men. Twenty-four trained elderly men (65 ± 4 years), previously engaged in a regular concurrent training program, three times per week, for the previous five months, were randomly allocated to concurrent training programs in which training was performed either twice a week (2·week-1, n = 12) or three times per week (3·week-1, n = 12). The groups trained with an identical exercise intensity and volume per session for 10 weeks. Before and after the exercise training, we examined muscle power, as estimated by countermovement jump height; knee extensor isokinetic peak torque at 60 and 180o.s-1; and muscle quality, a quotient between the one-repetition maximum of the knee extensors and the sum of quadriceps femoris muscle thickness determined by ultrasonography. Additionally, as secondary outcomes, blood pressure and reactive hyperemia were evaluated. Two-way ANOVA with repeated measures were used and statistical significance was set at α = 0.05. Muscular power (2·week-1: 7%, and 3·week-1: 10%) and muscle quality (2·week-1: 15%, and 3·week-1: 8%) improved with the concurrent exercise training (p < 0.001) but with no differences between groups. The isokinetic peak torque at 60 (2·week-1: 4%, and 3·week-1: 2%) and 180o.s-1 (2·week-1: 7%, and 3·week-1: 1%) increased in both groups (p = 0.036 and p=0.014, respectively). There were no changes in blood pressure or reactive hyperemia with the concurrent training. Concurrent training performed twice a week promotes similar adaptations in muscular power and muscle quality when compared with the same program performed three times per week in previously trained elderly men.
The objective of this study is to systematically review the relationship between lower-extremity peripheral nerve function and mobility in older adults. The National Library of Medicine (PubMed) was searched on March 23, 2015 with no limits on publication dates. One reviewer selected original research studies of older adults (≥65 years) that assessed the relationship between lower-extremity peripheral nerve function and mobility-related outcomes. Participants, study design and methods of assessing peripheral nerve impairment were evaluated and results were reported and synthesized. Eight articles were identified, including 6 cross-sectional and 2 longitudinal studies. These articles investigated 6 elderly cohorts (4 from the U.S. and 2 from Italy): 3 community-dwelling (including 1 with only disabled women and 1 without mobility limitations at baseline), 1 with both community-dwelling and institutionalized residents, 1 from a range of residential locations, and 1 of patients with peripheral arterial disease. Mean ages ranged from 71-82 years. Nerve function was assessed by vibration threshold (n=2); sensory measures and clinical signs and symptoms of neuropathy (n=2); motor nerve conduction (n=1); and a combination of both sensory measures and motor nerve conduction (n=3). Each study found that worse peripheral nerve function was related to poor mobility, although relationships varied based on the nerve function measure and mobility domain assessed. Six studies found that the association between nerve function and mobility persisted despite adjustment for diabetes. Evidence suggests that peripheral nerve function impairment at various levels of severity is related to poor mobility independent of diabetes. Relationships varied depending on peripheral nerve measure, which may be particularly important when investigating specific biological mechanisms. Future research needs to identify risk factors for peripheral nerve decline beyond diabetes, especially those common in late-life and modifiable. Interventions to preserve nerve function should be investigated with regard to their effect on postponing or preventing disability in older adults.
Among various therapeutic approaches for stroke, treatment with human umbilical cord mesenchymal stem cells (hUC-MSCs) has acquired some promising results. However, the underlying mechanisms remain unclear. We analyzed the protein expression spectrum of the cortical peri-infarction region after ischemic stroke followed by treatment with hUC-MSCs, and found 16 proteins expressed differentially between groups treated with or without hUC-MSCs. These proteins were further determined by Gene Ontology term analysis and network with CD200-CD200R1, CCL21-CXCR3 and transcription factors. Three of them: Abca13, Grb2 and Ptgds were verified by qPCR and ELISA. We found the protein level of Abca13 and the mRNA level of Grb2 consistent with results from the proteomic analysis. Finally, the function of these proteins was described and the potential proteins that deserve to be further studied was also highlighted. Our data may provide possible underlying mechanisms for the treatment of stroke using hUC-MSCs.
To study whether focal angiogenesis is induced in aged rodents after permanent distal middle cerebral artery occlusion (MCAO), young adult (3-month-old) and aged (24-month-old) Fisher 344 rats underwent MCAO and sacrificed up to two months after MCAO. Immunohistochemistry and synchrotron radiation microangiography were performed to examine the number of newly formed blood vessels in both young adult and aged rats post-ischemia. We found that the number of capillaries and small arteries in aged brain was the same as young adult brain. In addition, we found that after MCAO, the number of blood vessels in the peri-infarct region of ipsilateral hemisphere in aged ischemic rats was significantly increased compared to the aged sham rats (p<0.05). We also confirmed that ischemia-induced focal angiogenesis occurred in young adult rat brain while the blood vessel density in young adult ischemic brain was significantly higher than that in the aged ischemic brain (p<0.05). Our data suggests that focal angiogenesis in aged rat brain can be induced in response to ischemic brain injury, and that aging impedes brain repairing and remodeling after ischemic stroke, possible due to the limited response of angiogenesis.
Accumulating evidence has shown that the lung is one of the target organs for microangiopathy in patients with either type 1 or type 2 diabetes mellitus (DM). Diabetes is associated with physiological and structural abnormalities in the diabetic lung concurrent with attenuated lung function. Despite intensive investigations in recent years, the pathogenic mechanisms of diabetic lung injury remain largely elusive. In this review, we summarize currently postulated mechanisms of diabetic lung injury. We mainly focus on the pathogenesis of diabetic lung injury that implicates key pathways, including oxidative stress, non-enzymatic protein glycosylation, polyol pathway, NF-κB pathway, and protein kinase c pathway. We also highlight that while numerous studies have mainly focused on tissue or cell damage in the lung, studies focusing on mitochondrial dysfunction in the diabetic lung have remained sketchy. Hence, further understanding of mitochondrial mechanisms of diabetic lung injury should provide invaluable insights into future therapeutic approaches for diabetic lung injury.
The extracellular matrix (ECM) is an environment that has various enzymes attended in regeneration and restoration processes which is very important to sustain physiological and biological functions of central nervous system (CNS). One of the participating enzyme systems in ECM turnover is matrix metalloproteinases. A disintegrin-like and metalloproteinase with thrombospondin type 1 motifs (ADAMTS) is a unique family of ECM proteases found in mammals. Components of this family may be distinguished from the ADAM (A Disintegrin and Metalloproteinase) family based on the multiple copies of thrombospondin 1-like repeats. The considerable role of the ADAMTS in the CNS continues to develop. Evidences indicate that ADAMTS play an important role in neuroplasticity as well as nervous system pathologies such as Alzheimer’s disease (AD). It is hopeful and possible that ADAMTS family members may be utilized to develop therapies for CNS pathologies, ischemic injuries, neurodegenerative and neurological diseases. To understand and provide definitive data on ADAMTS to improve structural and functional recovery in CNS injury and diseases, this review aimed to enlighten the subject extensively to reach certain information on metalloproteinases and related molecules/enzymes. It will be interesting to examine how ADAMTS expression and action would affect the initiation/progression of above-mentioned clinical situations, especially AD.
Subclinical hyperthyroidism is known to be associated with the risk of fractures in elderly people. However, there are few studies assessing whether low normal thyroid-stimulating hormone (TSH) levels affect bone density and geometry. Here, we aimed to assess the influence of the TSH level on bone mineral density (BMD) and geometry in elderly euthyroid subjects. This was a cross-sectional cohort study. A total of 343 men and 674 women with euthyroidism were included and analyzed separately. The subjects were divided into tertiles based on the serum TSH level. The BMD and geometry were measured using dual-energy X-ray absorptiometry and a hip structural analysis program. Multiple regression analysis was used to compute the odds ratios of osteoporosis in the lower TSH tertile group and the association between geometry parameters and the TSH level. We found that the femoral neck and total hip BMDs were lower in the lower TSH tertile group. In women, the cross-sectional area and cortical thickness of the femur were negatively associated with the TSH level in all three regions (the narrow neck, intertrochanter, and femoral shaft); however, in men, these geometry parameters were significantly associated with the TSH level only in the intertrochanter region. The buckling ratio, a bone geometry parameter representing cortical instability, was significantly higher in the lower TSH tertile group in all three regions in women, but not in men. Our results indicated that lower TSH levels in the euthyroid range are related to lower BMD and weaker femoral structure in elderly women.
Transient forebrain ischemia induces delayed death of the hippocampal pyramidal neurons, particularly in the CA2 and medial CA1 area. Early pharmacological inhibition of inflammatory response can ameliorate neuronal death, but it also inhibits processes leading to tissue regeneration. Therefore, research efforts are now directed to modulation of post-ischemic inflammation, with the aim to promote beneficial effects of inflammation and limit adverse effects. Transcription factor NF-κB plays a key role in the inflammation and cell survival/apoptosis pathways. In the brain, NF-κB is predominantly found in the form of a heterodimer of p65 (RelA) and p50 subunit, where p65 has a transactivation domain while p50 is chiefly involved in DNA binding. In this study, we subjected middle-aged Nfkb1 knockout mice (lacking p50 subunit) and wild-type controls of both sexs to 17 min of transient forebrain ischemia and assessed mouse performance in a panel of behavioral tests after two weeks of post-operative recovery. We found that ischemia failed to induce clear memory and motor deficits, but affected spontaneous locomotion in genotype- and sex-specific way. We also show that both the lack of the NF-κB p50 subunit and female sex independently protected CA2 hippocampal neurons from ischemia-induced cell death. Additionally, the NF-κB p50 subunit deficiency significantly reduced ischemia-induced microgliosis, astrogliosis, and neurogenesis. Lower levels of hippocampal microgliosis significantly correlated with faster spatial learning. We conclude that NF-κB regulates the outcome of transient forebrain ischemia in middle-aged subjects in a sex-specific way, having an impact not only on neuronal death but also specific inflammatory responses and neurogenesis.
Degenerative diseases often strike older adults and are characterized by progressive deterioration of cells, eventually leading to tissue and organ degeneration for which limited effective treatment options are currently available. Acid-sensing ion channels (ASICs), a family of extracellular H+-activated ligand-gated ion channels, play critical roles in physiological and pathological conditions. Aberrant activation of ASICs is reported to regulate cell apoptosis, differentiation and autophagy. Accumulating evidence has highlighted a dramatic increase and activation of ASICs in degenerative disorders, including multiple sclerosis, Parkinson’s disease, Huntington’s disease, intervertebral disc degeneration and arthritis. In this review, we have comprehensively discussed the critical roles of ASICs and their potential utility as therapeutic targets in degenerative diseases.
Post-stroke depression (PSD) is a common psychiatric complication of stroke that is associated with a poor outcome in stroke patients. Our aim was to assess the association between the serum magnesium levels and the presence of PSD in Chinese patients. Two hundred nine stroke patients were included in the study. Depressive symptoms were measured by the 17-Hamilton Rating Scale for Depression at 3 months after stroke. Based on the depressive symptoms, diagnoses of depression were made in line with the DSM-IV criteria for PSD. Serum magnesium levels were evaluated using the dimethyl aniline blue colorimetric method at admission. Multivariate analyses were conducted using logistic regression models. Further, 120 normal subjects were recruited, and their serum magnesium levels were also measured as control. At 3 months, fifty-nine patients (28.2%) were diagnosed as PSD. The serum magnesium levels were significantly lower in both PSD patients and non-PSD patients than in normal subjects (p < 0.001). Indeed, patients with PSD showed lower serum magnesium levels (p < 0.001) than did non-PSD patients at admission. In the multivariate analyses, after adjusting for potential variables, we found that an increased risk of PSD was associated with serum magnesium levels ≤ 0.84mmol/L (OR 2.614, 95% CI 1.178-5.798, p=0.018). Low serum magnesium levels at admission were found to be associated with the presence of PSD at 3 months after stroke.
The study was designed to investigate the clinical application and significance of the bulbocavernosus reflex (BCR) test for diagnosing diabetic neurogenic bladder (DNB) in female subjects. In this study, 68 female patients with DNB and 40 female normal controls were subjected to a nerve conduction study (NCS) of all four limbs and the BCR test. The data were analyzed and compared, and the corresponding diagnostic sensitivities were discussed. Mean BCR latency for female DNB patients was significantly prolonged, compared to that of the control group, suggesting pudendal nerve injuries in female DNB patients. Moreover, DNB patients were categorized according to the diabetes course. Compared to that of Group A (diabetes course < 5 y), the mean BCR latency was significantly prolonged in Group B (diabetes course between 5 and 10 y) and then further prolonged in Group C (diabetes course > 10 y), which were all longer than the control group. Furthermore, compared with that of the controls, the mean BCR latency was prolonged in DNB patients with or without NCS abnormalities in limbs. Nevertheless, no significant difference was observed in BCR latency between DNB patients with and without NCS abnormalities. Significantly increasing trends were also observed in the NCS and BCR abnormality rates along with increased diabetes course. Most importantly, compared with the NCS of limbs, the BCR test was more sensitive in diagnosing DNB in the female subjects. Overall, our findings suggest that the BCR test would help to assess the pudendal nerve injury in female DNB patients, which might be a potential diagnostic tool in the clinic.
Genetic and environmental protective factors and risks modulate brain structure and function in neurodegenerative diseases and their preclinical stages. We wanted to investigate whether the years of formal education, a proxy measure for cognitive reserve, would influence hippocampal structure in Alzheimer’s disease patients, and whether apolipoprotein Eε4 (APOE4) carrier status and a first-degree family history of the disease would change a possible association. Fifty-eight Alzheimer’s disease patients underwent 3T magnetic resonance imaging. We applied a cortical unfolding approach to investigate individual subregions of the medial temporal lobe. Among patients homozygous for the APOE4 genotype or carrying both APOE4 and family history risks, lower education was associated with a thinner cortex in multiple medial temporal regions, including the hippocampus. Our data suggest that the years of formal education and genetic risks interact in their influence on hippocampal structure in Alzheimer’s disease patients.
In the adult bone marrow, osteoblasts and adipocytes share a common precursor called mesenchymal stem cells (MSCs). The plasticity between the two lineages has been confirmed over the past decades, and has important implications in the etiology of bone diseases such as osteoporosis, which involves an imbalance between osteoblasts and adipocytes. The commitment and differentiation of bone marrow (BM) MSCs is tightly controlled by the local environment that maintains a balance between osteoblast lineage and adipocyte. However, pathological conditions linked to osteoporosis can change the BM microenvironment and shift the MSC fate to favor adipocytes over osteoblasts, and consequently decrease bone mass with marrow fat accumulation. This review discusses the changes that occur in the BM microenvironment under pathological conditions, and how these changes affect MSC fate. We suggest that manipulating local environments could have therapeutic implications to avoid bone loss in diseases like osteoporosis.
Guanosine is a purine nucleoside with important functions in cell metabolism and a protective role in response to degenerative diseases or injury. The past decade has seen major advances in identifying the modulatory role of extracellular action of guanosine in the central nervous system (CNS). Evidence from rodent and cell models show a number of neurotrophic and neuroprotective effects of guanosine preventing deleterious consequences of seizures, spinal cord injury, pain, mood disorders and aging-related diseases, such as ischemia, Parkinson’s and Alzheimer’s diseases. The present review describes the findings of in vivo and in vitro studies and offers an update of guanosine effects in the CNS. We address the protein targets for guanosine action and its interaction with glutamatergic and adenosinergic systems and with calcium-activated potassium channels. We also discuss the intracellular mechanisms modulated by guanosine preventing oxidative damage, mitochondrial dysfunction, inflammatory burden and modulation of glutamate transport. New and exciting avenues for future investigation into the protective effects of guanosine include characterization of a selective guanosine receptor. A better understanding of the neuromodulatory action of guanosine will allow the development of therapeutic approach to brain diseases.
A promising strategy for the prevention of Alzheimer’s disease (AD) is the identification of age-related changes that place the brain at risk for the disease. Additionally, AD is associated with chronic dehydration, and one of the significant changes that are known to result in metabolic dysfunction is an increase in the endogenous formaldehyde (FA) level. Here, we demonstrate that the levels of uric formaldehyde in AD patients were markedly increased compared with normal controls. The brain formaldehyde levels of wild-type C57 BL/6 mice increased with age, and these increases were followed by decreases in their drinking frequency and water intake. The serum arginine vasopressin (AVP) concentrations were also maintained at a high level in the 10-month-old mice. An intravenous injection of AVP into the tail induced decreases in the drinking frequency and water intake in the mice, and these decreases were associated with increases in brain formaldehyde levels. An ELISA assay revealed that the AVP injection increased both the protein level and the enzymatic activity of semicarbazide-sensitive amine oxidase (SSAO), which is an enzyme that produces formaldehyde. In contrast, the intraperitoneal injection of formaldehyde increased the serum AVP level by increasing the angiotensin II (ANG II) level, and this change was associated with a marked decrease in water intake behavior. These data suggest that the interaction between formaldehyde and AVP affects the water intake behaviors of mice. Furthermore, the highest concentration of formaldehyde in vivo was observed in the morning. Regular water intake is conducive to eliminating endogenous formaldehyde from the human body, particularly when water is consumed in the morning. Establishing good water intake habits not only effectively eliminates excess formaldehyde and other metabolic products but is also expected to yield valuable approaches to reducing the risk of AD prior to the onset of the disease.
Parkinson's disease (PD) is a progressive neurodegenerative disorder with complicated pathophysiologic mechanisms. Endoplasmic reticulum (ER) stress appears to play a critical role in the progression of PD. We demonstrated that basic fibroblast growth factor (bFGF), as a neurotropic factor, inhibited ER stress-induced neuronal cell apoptosis and that 6-hydroxydopamine (6-OHDA)-induced ER stress was involved in the progression of PD in rats. bFGF administration improved motor function recovery, increased tyrosine hydroxylase (TH)-positive neuron survival, and upregulated the levels of neurotransmitters in PD rats. The 6-OHDA-induced ER stress response proteins were inhibited by bFGF treatment. Meanwhile, bFGF also increased expression of TH. The administration of bFGF activated the downstream signals PI3K/Akt and Erk1/2 in vivo and in vitro. Inhibition of the PI3K/Akt and Erk1/2 pathways by specific inhibitors partially reduced the protective effect of bFGF. This study provides new insight towards bFGF translational drug development for PD involving the regulation of ER stress.
Population ageing is one of the major social and economic challenges of our contemporary societies. With the advent of the information society, new research and technological developments have been promoted in the field of assistive technologies and information and communication technologies of benefit to elderly people. This article examines the potentialities of new informatics developments in generating solutions to better address elderly people’s daily-life, especially those with chronic illness and/or low autonomy. The authours attempt to propose a research agenda, by exposing various strengts and weaknesses of eHealth innovations for elderly, mainly grounded in secondary sources analysis.
Metformin is an oral anti-diabetic used as first-line therapy for type 2 diabetes. Because benefits of metformin extend beyond diabetes to other age-related pathology, and because its effect on gene expression profiles resembles that of caloric restriction, metformin has a potential as an anti-aging intervention and may soon be assessed as an intervention to extend healthspan. However, beneficial actions of metformin in the central nervous system have not been clearly established. The current study examined the effect of chronic oral metformin treatment on motor and cognitive function when initiated in young, middle-aged, or old male mice. C57BL/6 mice aged 4, 11, or 22 months were randomly assigned to either a metformin group (2 mg/ml in drinking water) or a control group. The mice were monitored weekly for body weight, as well as food and water intake and a battery of behavioral tests for motor, cognitive and visual function was initiated after the first month of treatment. Liver, hippocampus and cortex were collected at the end of the study to assess redox homeostasis. Overall, metformin supplementation in male mice failed to affect blood glucose, body weights and redox homeostasis at any age. It also had no beneficial effect on age-related declines in psychomotor, cognitive or sensory functions. However, metformin treatment had a deleterious effect on spatial memory and visual acuity, and reduced SOD activity in brain regions. These data confirm that metformin treatment may be associated with deleterious effect resulting from the action of metformin on the central nervous system.
We previously demonstrated that serotonin (5-HT) and 5-HT2A receptor (5-HT2AR) levels in platelets were up- or down-regulated after myocardial infarction (MI) associated with depression. In this study, we further evaluated the effects of pretreatment with ginseng fruit saponins (GFS) on the expression of 5-HT and 5-HT2AR in MI with or without depression. Eighty Sprague-Dawley (SD) rats were treated with saline and GFS (n=40 per group). The animals were then randomly divided into four subgroups: sham, MI, depression, and MI + depression (n=10 per subgroup). Protein levels of 5-HT and 5-HT2AR in the serum, platelets and brain tissues were determined with ELISA. The results demonstrated that serum 5-HT levels was significantly increased by GFS pretreatment in all subgroups (except the sham subgroup) when compared with saline-treated counterparts (p<0.01). In platelets, GFS pretreatment significantly increased 5-HT levels in all subgroups when compared with their respective saline-treated counterparts (p<0.01). Brain 5-HT levels also declined with GFS pretreatment in the MI-only and depression-only subgroups (p<0.05 vs. saline pretreatment). With respect to 5-HT2AR levels, platelet 5-HT2AR was decreased in GFS pretreated MI, depression and MI + depression subgroups (p<0.01 vs. saline pretreatment). Similarly, brain 5-HT2AR levels decreased in all four subgroups pretreated with GFS (p<0.01 vs. saline pretreatment). We conclude that GFS plays a clear role in modulating 5-HT and 5-HT2AR expressions after MI and depression. Although the effects of GFS on brain 5-HT remain to be elucidated, its therapeutic potential for comorbidities of acute cardiovascular events and depression appears to hold much promise.
MicroRNA-181 (miR-181) is highly expressed in the brain, and downregulated in miRNA expression profiles of acute ischemic stroke patients. However, the roles of miR-181c in stroke are not known. The clinical relevance of miR-181c in acute stroke patients was evaluated by real-time PCR and correlation analyses. Proliferation and apoptosis of BV2 microglial cells and Neuro-2a cells cultured separately or together under oxidative stress or inflammation were assessed with the Cell Counting Kit-8 and by flow cytometry, respectively. Cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in C57/BL6 mice, and cerebral infarct volume, microglia activation, and expression of pro-apoptotic factors were evaluated by 2,3,5-triphenyl-2H-tetrazolium chloride staining, immunocytochemistry, and western blotting, respectively. Plasma levels of miR-181c were decreased in stroke patients relative to healthy individuals, and were positively correlated with neutrophil number and blood platelet count and negatively correlated with lymphocyte number. Lipopolysaccharide (LPS)/hydrogen peroxide (H2O2) treatment inhibited BV2 microglia proliferation without inducing apoptosis, while miR-181c reduced proliferation but increased the apoptosis of these cells with or without LPS/H2O2 treatment. LPS/H2O2 induced apoptosis in Neuro-2a cells co-cultured with BV2 cells, an effect that was potentiated by miR-181c. In the MCAO model, miR-181c agomir modestly increased infarct volume, markedly decreased microglia activation and B cell lymphoma-2 expression, and increased the levels of pro-apoptotic proteins in the ischemic brain. Our data indicate that miR-181c contributes to brain injury in acute ischemic stroke by promoting apoptosis of microglia and neurons via modulation of pro- and anti-apoptotic proteins.
Vision, hearing, olfaction, and cognitive function are essential components of healthy and successful aging. Multiple studies demonstrate relationship between these conditions with cognitive function. The present article focuses on hearing loss, visual impairment, olfactory loss, and dual sensory impairments in relation to cognitive declination and neurodegenerative disorders. Sensorineural organ impairment is a predictive factor for mild cognitive impairment and neurodegenerative disorders in the elderly. We recommend early detection of sensorineural dysfunction by history, physical examination, and screening tests. Assisted device and early cognitive rehabilitation may be beneficial. Future research is warranted in order to explore advanced treatment options and method to slow progression for cognitive declination and sensorineural organ impairment.
This pilot study examined the status of the master iron regulatory peptide, hepcidin, and peripheral related iron parameters in Alzheimer’s disease (AD) and mild cognitive impairment patients, and evaluated the relationship between iron dyshomeostasis and amyloid-beta (Aβ), cognitive assessment tests, neuroimaging and clinical data. Frozen serum samples from the Oregon Tissue Bank were used to measure serum levels of hepcidin, ferritin, Aβ40, Aβ42 using enzyme-linked immunosorbent assay. Serum transferrin levels were determined indirectly as total iron binding capacity, serum iron was measured and the percent saturation of transferrin calculated. The study variables were correlated with the patients’ existing cognitive assessment tests, neuroimaging, and clinical data. Hepcidin, and iron-related proteins tended to be higher in AD patients than controls, reaching statistical significance for ferritin, whereas Aβ40, Aβ42 serum levels tended to be lower. Patients with pure AD had three times higher serum hepcidin levels than controls; gender differences in hepcidin and iron-related proteins were observed. Patient stratification based on clinical dementia rating-sum of boxes revealed significantly higher levels of iron and iron-related proteins in AD patients in the upper 50% as compared to controls, suggesting that iron dyshomeostasis worsens as cognitive impairment increases. Unlike Aβ peptides, iron and iron-related proteins showed significant association with cognitive assessment tests, neuroimaging, and clinical data. Hepcidin and iron-related proteins comprise a group of serum biomarkers that relate to AD diagnosis and AD disease progression. Future studies should determine whether strategies targeted to diminishing hepcidin synthesis/secretion and improving iron homeostasis could have a beneficial impact on AD progression.
As the population ages, the occurrence of chronic pathologies becomes more common. Leukocyte telomere shortening associates to ageing and age-related diseases. Recent studies suggest that environmental chemicals can affect telomere length. Persistent organic pollutants (POPs) are most relevant, since they are ingested with foods, and accumulate in the body for a long time. This longitudinal study was undertaken to test if circulating POPs predict telomere length and shortening in elderly people. We studied 1082 subjects belonging to the Helsinki Birth Cohort Study (born 1934-1944), undergoing two visits (2001-2004 and 2011-2014). POPs (oxychlordane, trans-nonachlor, p, p’-DDE, PCB 153, BDE 47, BDE 153) were analysed at baseline. Relative telomere length was measured twice, ’10 years apart, by quantitative real-time PCR. Oxychlordane, trans-nonachlor and PCB-153 levels were significant predictors of telomere length and shortening. In men, we did not find a linear relationship between POPs exposure and telomere shortening. In women, a significant reduction across quartiles categories of oxychlordane and trans-nonachlor exposure was observed. Baseline characteristics of subjects in the highest POPs categories included higher levels of C-reactive protein and fasting glucose, and lower body fat percentage. This is one of few studies combining POPs and telomere length. Our results indicate that exposure to oxychlordane, trans-nonachlor and PCB 153 predicts telomere attrition. This finding is important because concentrations of POPs observed here occur in contemporary younger people, and may contribute to an accelerated ageing.
To investigate the changes of circulating endothelial progenitor cells (EPCs) and stromal cell-derived factor-1α (SDF-1α)/CXCR4 expression in patients with mild traumatic brain injury (TBI) and the correlation between EPC level and the prognosis of mild TBI. 72 TBI patients (57 mild TBI, 15 moderate TBI patients) and 25 healthy subjects (control) were included. The number of circulating EPCs, CD34+, and CD133+ cells and the percentage of CXCR4+ cells in each cell population at 1,4,7,14,21 days after TBI were counted by flow cytometer. SDF-1α levels in serum were detected by ELISA assay. The patients were divided into poor and good prognosis groups based on Extended Glasgow Outcome Scale and Activity of Daily Living Scale at 3 months after TBI. Correlation analysis between each detected index and prognosis of mild TBI was performed. Moderate TBI patients have higher levels of SDF-1α and CXCR4 expression than mild TBI patients (P < 0.05). The percentage of CXCR4+ EPCs at day 7 post-TBI was significantly higher in mild TBI patients with poor prognosis than the ones with good prognosis (P < 0.05). HAMA and HAMD scores in mild TBI patients were significantly lower than moderate TBI patients (P < 0.05) in early term. The percentage of CXCR4+ EPCs at day 7 after TBI was significantly correlated with the prognosis outcome at 3 months. The mobilization of circulating EPCs can be induced in mild TBI. The expression of CXCR4+ in EPCs at 7 days after TBI reflects the short-term prognosis of brain injury, and could be a potential biological marker for prognosis prediction of mild TBI.
Interleukin-33 (IL-33), a newly recognized IL-1 family member, is expressed in various tissues and cells, and involved in pathogenesis of many human diseases. For example, IL-33 plays a protective role in cardiovascular diseases. However, the role of IL-33 in acute ischemic stroke (AIS) remains unclear. This study aims to investigate whether IL-33 level in AIS patient serum can be used as a potential diagnostic and prognostic marker. The study included two hundred and six patients with first-ever ischemic stroke, who were admitted within 72 hours after stroke onset. The serum level of IL-33 was measured with ELISA and the severity of AIS patients on admission was evaluated based on the National Institutes of Health Stroke Scale (NIHSS) score. The functional outcome at 3 months was determined using the Barthel index (BI). We found that serum IL-33 was significantly higher (P < 0.001) in patients with AIS [57.68 ng/L (IQR, 44.95-76.73)] compared with healthy controls [47.48 ng/L (IQR, 38.67-53.78)]. IL-33 was an independent diagnostic biomarker for AIS with an OR of 1.051 (95%Cl, 1.018-1.085; P=0.002). Serum IL-33 was higher (P < 0.05) in the stroke patients with small cerebral infarction volume compared to AIS patients with large cerebral infarction. In addition, serum IL-33 was also significantly higher (P = 0.001) in the patients with mild stroke, compared to the patients with severe stroke. Furthermore, serum IL-33 level in AIS patients with a worse outcome was higher (P < 0.001) compared to AIS patients with a better outcome. IL-33 was also an independent predictor for the functional outcome with an adjusted OR of 0.932 (95% CI, 0.882-0.986). Our results suggest that the lower level of serum IL-33 is associated with large infarction volume and greater stroke severity in AIS patients. Thus, IL-33 can be used as a novel and independent diagnostic and predicting prognostic marker in AIS.