Differential Epigenetic Changes in the Dorsal Hippocampus of Male and Female SAMP8 Mice: A Preliminary Study

Alzheimer’s disease (AD) is the most common age-related neurodegenerative disease characterized by memory loss and cognitive impairment. The causes of the disease are not well understood, as it involves a complex interaction between genetic, environmental, and epigenetic factors. SAMP8 mice have been proposed as a model for studying late-onset AD, since they show age-related learning and memory deficits as well as several features of AD pathogenesis. Epigenetic changes have been described in SAMP8 mice, although sex differences have never been evaluated. Here we used western blot and qPCR analyses to investigate whether epigenetic markers are differentially altered in the dorsal hippocampus, a region important for the regulation of learning and memory, of 9-month-old male and female SAMP8 mice. We found that H3Ac was selectively reduced in male SAMP8 mice compared to male SAMR1 control mice, but not in female mice, whereas H3K27me3 was reduced overall in SAMP8 mice. Moreover, the levels of HDAC2 and JmjD3 were increased, whereas the levels of HDAC4 and Dnmt3a were reduced in SAMP8 mice compared to SAMR1. In addition, levels of HDAC1 were reduced, whereas Utx and Jmjd3 were selectively increased in females compared to males. Although our results are preliminary, they suggest that epigenetic mechanisms in the dorsal hippocampus are differentially regulated in male and female SAMP8 mice

Physical Exercise Affects Adipose Tissue Profile and Prevents Arterial Thrombosis in BDNF Val66Met Mice

Adipose tissue accumulation is an independent and modifiable risk factor for cardiovascular disease (CVD). The recent CVD European Guidelines strongly recommend regular physical exercise (PE) as a management strategy for prevention and treatment of CVD associated with metabolic disorders and obesity. Although mutations as well as common genetic variants, including the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism, are associated with increased body weight, eating and neuropsychiatric disorders, and myocardial infarction, the effect of this polymorphism on adipose tissue accumulation and regulation as well as its relation to obesity/thrombosis remains to be elucidated. Here, we showed that white adipose tissue (WAT) of humanized knock-in BDNFVal66Met (BDNFMet/Met) mice is characterized by an altered morphology and an enhanced inflammatory profile compared to wild-type BDNFVal/Val. Four weeks of voluntary PE restored the adipocyte size distribution, counteracted the inflammatory profile of adipose tissue, and prevented the prothrombotic phenotype displayed, per se, by BDNFMet/Met mice. C3H10T1/2 cells treated with the Pro-BDNFMet peptide well recapitulated the gene alterations observed in BDNFMet/Met WAT mice. In conclusion, these data indicate the strong impact of lifestyle, in particular of the beneficial effect of PE, on the management of arterial thrombosis and inflammation associated with obesity in relation to the specific BDNF Val66Met mutation

Effect of clotting duration and temperature on BDNF measurement in human serum

Brain-derived neurothrophic factor (BDNF) is a neurotrophin expressed in different tissues and cells, including neurons, endothelial cells, leukocytes, megakaryocytes and platelets. Modifications of BDNF in plasma and/or in serum are associated with neurodegenerative and psychiatric disorders, cardiovascular diseases, metabolic syndrome and with mortality risk. Indeed, changes in blood levels of BDNF may reflect those of its tissue of origin and/or promote pathological dysfunctions. The measurement of BDNF amount in plasma or in serum has been characterized with particular attention in the impact of different anti-coagulants, clotting duration, temperature (\ue2\u89\ua421 \ue2\u97\ua6C) and delay in blood sample centrifugation as well as in stability of storage. However, the influences of normothermic conditions (37 \ue2\u97\ua6C) and of clotting duration on BDNF levels in human serum have not been investigated yet. Here, we showed that time and temperature during serum preparation could be taken into consideration to assess the association and/or impact of BDNF levels in the occurrence of pathological conditions

Apocynin Prevents Abnormal Megakaryopoiesis and Platelet Activation Induced by Chronic Stress

Environmental chronic stress (ECS) has been identified as a trigger of acute coronary syndromes (ACS). Changes in redox balance, enhanced reactive oxygen species (ROS) production, and platelet hyperreactivity were detected in both ECS and ACS. However, the mechanisms by which ECS predisposes to thrombosis are not fully understood. Here, we investigated the impact of ECS on platelet activation and megakaryopoiesis in mice and the effect of Apocynin in this experimental setting. ECS induced by 4 days of forced swimming stress (FSS) treatment predisposed to arterial thrombosis and increased oxidative stress (e.g., plasma malondialdehyde levels). Interestingly, Apocynin treatment prevented these alterations. In addition, FSS induced abnormal megakaryopoiesis increasing the number and the maturation state of bone marrow megakaryocytes (MKs) and affecting circulating platelets. In particular, a higher number of large and reticulated platelets with marked functional activation were detected after FSS. Apocynin decreased the total MK number and prevented their ability to generate ROS without affecting the percentage of CD42d+ cells, and it reduced the platelet hyperactivation in stressed mice. In conclusion, Apocynin restores the physiological megakaryopoiesis and platelet behavior, preventing the detrimental effect of chronic stress on thrombosis, suggesting its potential use in the occurrence of thrombosis associated with ECS

Association between Obesity and Circulating Brain-Derived Neurotrophic Factor (BDNF) Levels: Systematic Review of Literature and Meta-Analysis

Reduction in brain-derived neurotrophic factor (BDNF) expression in the brain as well as mutations in BDNF gene and/or of its receptor are associated to obesity in both human and animal models. However, the association between circulating levels of BDNF and obesity is still not defined. To answer this question, we performed a meta-analysis carrying out a systematic search in electronic databases. Ten studies (307 obese patients and 236 controls) were included in the analysis. Our data show that obese patients have levels of BDNF similar to those of controls (SMD: 0.01, 95% CI: -0.28, 0.30, p = 0.94). The lack of difference was further confirmed both in studies in which BDNF levels were assessed in serum (MD: -0.93 ng/mL, 95% CI: -3.34, 1.48, p = 0.45) and in plasma (MD: 0.15 ng/mL, 95% CI: -0.09, 0.39, p = 0.23). Data evaluation has shown that some bias might affect BDNF measurements (e.g., subject recruitment, procedures of sampling, handling, and storage), leading to a difficult interpretation of the results. Standardization of the procedures is still needed to reach strong, affordable, and reliable conclusions

Sub-Chronic Stress Exacerbates the Pro-Thrombotic Phenotype in BDNFVal/Met Mice: Gene-Environment Interaction in the Modulation of Arterial Thrombosis

Brain-Derived Neurotrophic Factor (BDNF) Val66Met polymorphism has been associated with increased susceptibility to develop mood disorders and recently it has been also linked with cardiovascular disease (CVD). Interestingly, stressful conditions unveil the anxious/depressive-like behavioral phenotype in heterozygous BDNFVal66Met (BDNFVal/Met) mice, suggesting an important relationship in terms of gene-environment interaction (GxE). However, the interplay between stress and BDNFVal/Met in relation to CVD is completely unknown. Here, we showed that BDNFVal/Met mice display a greater propensity to arterial thrombosis than wild type BDNFVal/Val mice after 7 days of restraint stress (RS). RS markedly increased the number of leukocytes and platelets, and induced hyper-responsive platelets as showed by increased circulating platelet/leukocyte aggregates and enhanced expression of P-selectin and GPIIbIIIa in heterozygous mutant mice. In addition, stressed BDNFVal/Met mice had a greater number of large and reticulated platelets but comparable number and maturation profile of bone marrow megakaryocytes compared to BDNFVal/Val mice. Interestingly, RS led to a significant reduction of BDNF expression accompanied by an increased activity of tissue factor in the aorta of both BDNFVal/Val and BDNFVal/Met mice. In conclusion, we provide evidence that sub-chronic stress unveils prothrombotic phenotype in heterozygous BDNF Val66Met mice affecting both the number and functionality of blood circulating cells, and the expression of key thrombotic molecules in aorta. Human studies will be crucial to understand whether this GxE interaction need to be taken into account in risk stratification of coronary artery disease (CAD) patients

Influenza and pneumococcal vaccinations are not associated to COVID-19 outcomes among patients admitted to a university hospital

In order to reduce the burden on healthcare systems and to support differential diagnosis with COVID-19, influenza and pneumococcal vaccinations were strongly recommended during the COVID-19 pandemic, especially in vulnerable groups. However, no univocal and conclusive evidence on the relationship between influenza and pneumococcal vaccinations and COVID‐19 outcomes exists. We evaluated the association between such vaccinations, COVID-19 hospitalization, intensive care unit admissions and deaths in a cohort (N = 741) of COVID-19 patients who had access to the emergency room of a large Italian University hospital between March 1, 2020 and June 1, 2020. Results show that influenza and pneumococcal vaccinations did not affect hospitalization, intensive care unit admission and deaths in COVID-19 patients in the overall sample and in those ≥65 years. The same pattern of results was confirmed considering timing of influenza vaccine administration, vaccination type, and number of uptakes in the last five vaccination campaigns. In conclusion, our study does not support an impact of influenza and pneumococcal vaccinations on COVID-19 outcomes

Effect of apoptosis in neural stem cells treated with sevoflurane

BACKGROUND: At present, sevoflurane inhalation anesthesia used on infants is well-known. But long-time exposure to inhalation anesthetic could cause neurologic disorder, especially nerve degeneration in infant and developing brain. The central nervous system degeneration of infants could affect the memory and cognitive function. γ-Aminobutyric acid (GABA) is a known inhibitory neurotransmitter in central nervous system. Inhalation anesthetic sevoflurane may activate GABA(A) receptor to inhibit central nervous system, leading to apoptosis of neural degeneration, cognitive dysfunction in the critical period of brain development. METHODS: Neural stem cells were derived from Wistar embryos, cultured in vitro. Third generation of neural stem cells were randomly divided into four groups according to cultured suspension: Sevoflurane group (Group S), GABA(A) receptor antagonists, Bicuculline group (Group B), Sevoflurane + GABA(A) receptor antagonists, Bicuculline group (Group S + B), dimethyl sulphoxide (DMSO) group (Group D). Group B and Group D did not receive sevoflurane preconditioning. Group S and Group S + B were pretreated with 1 minimum alveolar concentration (MAC) sevoflurane for 0 h, 3 h, 6 h, and 12 h. Group S + B and Group B were pretreated with bicuculline (10 uM). Group D was treated with DMSO (10 uL/mL). After treatments above, all groups were cultured for 48 h. Then we measured the cells viability by Cell Counting Kit (CCK-8) assay, cytotoxicity by Lactate Dehydrogenase (LDH) assay, apoptosis ratio with Annexin V/propidium iodide (PI) staining by flow cytometry, and the expression of GABA(A)R, anti-apoptotic protein Bcl-2, pro-apoptotic protein Bax and Caspase-3 by western blotting. RESULTS: After exposing to sevoflurane for 0 h, 3 h, 6 h, and 12 h with 1MAC, we found that cell viability obviously decreased and cytotoxicity increased in time-dependent way. And Annexin V/PI staining indicated increased apoptosis ratio by flow cytometry. The protein level of GABA(A) receptor, pro-apoptotic protein Bax and apoptosis protein Caspase-3 increased; while anti-apoptotic protein Bcl-2 decreased. And bicuculline could reverse all detrimental results caused by sevoflurane. CONCLUSION: Sevoflurane can inhibit the central nervous system by activating GABA(A), resulting in apoptosis of neural stem cells, thus leading to the NSCs degeneration

Nicotinamide Inhibits Alkylating Agent-Induced Apoptotic Neurodegeneration in the Developing Rat Brain

BACKGROUND: Exposure to the chemotherapeutic alkylating agent thiotepa during brain development leads to neurological complications arising from neurodegeneration and irreversible damage to the developing central nerve system (CNS). Administration of single dose of thiotepa in 7-d postnatal (P7) rat triggers activation of apoptotic cascade and widespread neuronal death. The present study was aimed to elucidate whether nicotinamide may prevent thiotepa-induced neurodegeneration in the developing rat brain. METHODOLOGY/PRINCIPAL FINDINGS: Neuronal cell death induced by thiotepa was associated with the induction of Bax, release of cytochrome-c from mitochondria into the cytosol, activation of caspase-3 and cleavage of poly (ADP-ribose) polymerase (PARP-1). Post-treatment of developing rats with nicotinamide suppressed thiotepa-induced upregulation of Bax, reduced cytochrome-c release into the cytosol and reduced expression of activated caspase-3 and cleavage of PARP-1. Cresyl violet staining showed numerous dead cells in the cortex hippocampus and thalamus; post-treatment with nicotinamide reduced the number of dead cells in these brain regions. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling (TUNEL) and immunohistochemical analysis of caspase-3 show that thiotepa-induced cell death is apoptotic and that it is inhibited by nicotinamide treatment. CONCLUSION: Nicotinamide (Nic) treatment with thiotepa significantly improved neuronal survival and alleviated neuronal cell death in the developing rat. These data demonstrate that nicotinamide shows promise as a therapeutic and neuroprotective agent for the treatment of neurodegenerative disorders in newborns and infants