COVID-19 causes neuronal degeneration and reduces neurogenesis in human hippocampus.

Recent investigations of COVID-19 have largely focused on the effects of this novel virus on the vital organs in order to efficiently assist individuals who have recovered from the disease. In the present study we used hippocampal tissue samples extracted from people who died after COVID-19. Utilizing histological techniques to analyze glial and neuronal cells we illuminated a massive degeneration of neuronal cells and changes in glial cells morphology in hippocampal samples. The results showed that in hippocampus of the studied brains there were morphological changes in pyramidal cells, an increase in apoptosis, a drop in neurogenesis, and change in spatial distribution of neurons in the pyramidal and granular layer. It was also demonstrated that COVID-19 alter the morphological characteristics and distribution of astrocyte and microglia cells. While the exact mechanism(s) by which the virus causes neuronal loss and morphology in the central nervous system (CNS) remains to be determined, it is necessary to monitor the effect of SARS-CoV-2 infection on CNS compartments like the hippocampus in future investigations. As a result of what happened in the hippocampus secondary to COVID-19, memory impairment may be a long-term neurological complication which can be a predisposing factor for neurodegenerative disorders through neuroinflammation and oxidative stress mechanisms.

Severe Acute Respiratory Syndrome Coronavirus 2 Induces Hepatocyte Cell Death, Active Autophagosome Formation and Caspase 3 Up-Regulation in Postmortem Cases: Stereological and Molecular Study.

This research investigated the histopathological changes in the tissue of the lung, heart and liver, hepatocyte cell death, autophagy, and the apoptosis inductions in the postmortem cases. Since December 2019, coronavirus disease 2019 (COVID-19) has become a significant global health concern. In order to clarify the changes in tissues of the lung, heart and liver by COVID-19, samples were taken from five patients who died of COVID-19 and five control cases, and the pathological changes in the lung, liver, and heart tissue were studied by X-ray, computed tomography, histological studies, and stereological analysis. The formation of hyaline membranes, alveolar wall edema, and fibrin exudate was seen on histological analysis of the lungs in the COVID-19 group. Stereological analysis illustrated the number of hepatocytes, volume of the sinusoid, and volume of the liver have been decreased, however the pathological changes in the heart tissue were not observed. Serum levels of alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, and angiotensin-converting enzyme significantly increased. Real-time PCR results showed that the Bcl2, Caspase3, ATG5, and LC3 decreased while the Bax increased. COVID-19 causes fibrotic changes in the lung tissue and hepatocyte mortality in the liver tissue. Besides, it elevates the level of apoptosis and autophagy markers.

Methamphetamine can induce alteration of histopathology and sex determination gene expression through the oxidative stress pathway in the testes of human post-mortem.

Methamphetamine is a recreational drug that can be taken ingestion orally, injected, smoked or snorted. Methamphetamine abuse may lead to male infertility. The purpose of this study was to evaluate the long-term effects of methamphetamine abuse on the sex reprogramming of human post-mortem testis. Testes were collected from the autopsies of methamphetamine users (n = 10) and healthy males (reference group) (n = 10). They were then taken for stereological studies and RNA extraction to evaluate the expressions of PCNA, DMRT1, SOX8, c-Kit, TNF-α, IL6 and FOXL2 genes. In addition, Reactive Oxygen Species (ROS) level and Glutathione Disulfide (GSH) were assessed. Autopsied testicular samples of methamphetamine revealed a significant reduction in stereological parameters and histopathological findings, suggesting methamphetamine as a practical approach to prevention strategies in reproductive medicine that can disrupt spermatogenesis. Moreover, the results indicated the expressions of the genes involved in testis function and male-to-female genetic reprogramming (PCNA, DMRT1, SOX8, c-Kit, TNF-α, IL6 and FOXL2) (16) as well as in increasing inflammation (TNF-α and IL-6). The results also showed a high level of ROS and a decrease in GSH activity. The results of SOX9 immunohistochemistry indicated a significant decrease in the expression of SOX9 as well as in the number of Sertoli cells in the methamphetamine group. Overall, the results suggested that methamphetamine abuse caused spermatogenesis disruption and genetic reprogramming, probably through oxidative stress and changes in the expression of sex-determining genes.

COVID-19 disrupts spermatogenesis through the oxidative stress pathway following induction of apoptosis.

To evaluate the incidence of apoptosis within the testes of patients who died from severe acute respiratory syndrome coronavirus 2 (COVID-19) complications, testis tissue was collected from autopsies of COVID-19 positive (n = 6) and negative men (n = 6). They were then taken for histopathological experiments, and RNA extraction, to examine the expression of angiotensin-converting enzyme 2 (ACE2), transmembrane protease, serine 2 (TMPRSS2), BAX, BCL2 and Caspase3 genes. Reactive oxygen species (ROS) production and glutathione disulfide (GSH) activity were also thoroughly examined. Autopsied testicular specimens of COVID-19 showed that COVID-19 infection significantly decreased the seminiferous tubule length, interstitial tissue and seminiferous tubule volume, as well as the number of testicular cells. An analysis of the results showed that the Johnsen expressed a reduction in the COVID-19 group when compared to the control group. Our data showed that the expression of ACE2, BAX and Caspase3 were remarkably increased as well as a decrease in the expression of BCL2 in COVID-19 cases. Although, no significant difference was found for TMPRSS2. Furthermore, the results signified an increase in the formation of ROS and suppression of the GSH activity as oxidative stress biomarkers. The results of immunohistochemistry and TUNEL assay showed that the expression of ACE2 and the number of apoptotic cells significantly increased in the COVID-19 group. Overall, this study suggests that COVID-19 infection causes spermatogenesis disruption, probably through the oxidative stress pathway and subsequently induces apoptosis.

COVID-19 disrupts the blood-testis barrier through the induction of inflammatory cytokines and disruption of junctional proteins.

OBJECTIVE: Junctional proteins are the most important component of the blood-testis barrier and maintaining the integrity of this barrier is essential for spermatogenesis and male fertility. The present study elucidated the effect of SARS-CoV-2 infection on the blood-testis barrier (BTB) in patients who died from severe acute respiratory syndrome coronavirus 2 (COVID-19) complications. METHODS: In this study, lung and testis tissue was collected from autopsies of COVID-19 positive (n = 10) and negative men (n = 10) and was taken for stereology, immunocytochemistry, and RNA extraction. RESULTS: Evaluation of the lung tissue showed that the SARS-CoV-2 infection caused extensive damage to the lung tissue and also increases inflammation in testicular tissue and destruction of the testicular blood barrier. Autopsied testicular specimens of COVID-19 showed that COVID-19 infection significantly changes the spatial arrangement of testicular cells and notably decreased the number of Sertoli cells. Moreover, the immunohistochemistry results showed a significant reduction in the protein expression of occluding, claudin-11, and connexin-43 in the COVID-19 group. In addition, we also observed a remarkable enhancement in protein expression of CD68 in the testes of the COVID-19 group in comparison with the control group. Furthermore, the result showed that the expression of TNF-α, IL1ß, and IL6 was significantly increased in COVID-19 cases as well as the expression of occludin, claudin-11, and connexin-43 was decreased in COVID-19 cases. CONCLUSIONS: Overall, the present study demonstrated that SARS-CoV-2 could induce the up-regulation of the pro-inflammatory cytokine and down-regulation of junctional proteins of the BTB, which can disrupt BTB and ultimately impair spermatogenesis.

Exploring amygdala structural changes and signaling pathways in postmortem brains: consequences of long-term methamphetamine addiction.

Methamphetamine (METH) can potentially disrupt neurotransmitters activities in the central nervous system (CNS) and cause neurotoxicity through various pathways. These pathways include increased production of reactive nitrogen and oxygen species, hypothermia, and induction of mitochondrial apoptosis. In this study, we investigated the long-term effects of METH addiction on the structural changes in the amygdala of postmortem human brains and the involvement of the brain- cAMP response element-binding protein/brain-derived neurotrophic factor (CREB/BDNF) and Akt-1/GSK3 signaling pathways. We examined ten male postmortem brains, comparing control subjects with chronic METH users, using immunohistochemistry, real-time polymerase chain reaction (to measure levels of CREB, BDNF, Akt-1, GSK3, and tumor necrosis factor-α [TNF-α]), Tunnel assay, stereology, and assays for reactive oxygen species (ROS), glutathione disulfide (GSSG), and glutathione peroxidase (GPX). The findings revealed that METH significantly reduced the expression of BDNF, CREB, Akt-1, and GPX while increasing the levels of GSSG, ROS, RIPK3, GSK3, and TNF-α. Furthermore, METH-induced inflammation and neurodegeneration in the amygdala, with ROS production mediated by the CREB/BDNF and Akt-1/GSK3 signaling pathways.

NUPR1- CHOP experssion, autophagosome formation and apoptosis in the postmortem striatum of chronic methamphetamine user.

Methamphetamine (Meth) is a neuro-stimulator substrate which might lead to neural cell death and the activation of several interconnected cellular pathways as well. However, the precise molecular mechanisms underlying Meth-induced neural cell death remained unclear yet. The current study aimed to assess the specific relationship between long-term Meth exposure and several endoplasmic reticulum stress, autophagy, and apoptosis associated markers including C/EBP homologous protein (CHOP), Tribbles homolog 3(Trib3), Nuclear protein 1(NUPR1), and Beclin-1 expression in postmortem human striatum. Therefore, the effects of long-term Meth exposure on autophagy and apoptosis in the striatum of postmortem users were evaluated and molecular, immunehistochemical, and histological examinations were performed on 10 control and 10 Meth-addicted brains. The level of CHOP, Trib3, NUPR1, and Beclin-1, Microtubule-associated proteins 1A/1B light chain 3B(LC3), Caspase 3, and Autophagy protein 5 (ATG5) were measured by using qPCR and immunohistochemistry. Stereological neural cell counting, Hematoxylin and Eosin, Nissl and Tunel staining were also performed. Based on our findings, the expression level of CHOP, Trib3, NUPR1, and Beclin-1 in the striatum of Meth group were significantly higher than the control group. Besides, the neuronal cell death was substantially increased in the striatum based on data obtained from the Tunel assay and the stereological analysis. Long-term presence of Meth in the brain can induce ER stress and overexpression of NUPR1 which is associated with the upregulation of CHOP, a pro-apoptotic transcription factor. Moreover, an increase in Trib3 expression is implicated in CHOP-dependent autophagic cell death during Meth-induced ER stress accompanied by an increase in neuronal cell death in the striatum of the postmortem human brains. Beclin 1 expression was also upregulated which may due to the activation of autophagic mechanisms upon prolonged Meth exposure.

Inflammatory Response Leads to Neuronal Death in Human Post-Mortem Cerebral Cortex in Patients with COVID-19.

The recent coronavirus disease of 2019 (COVID-19) pandemic has adversely affected people worldwide. A growing body of literature suggests the neurological complications and manifestations in response to COVID-19 infection. Herein, we explored the inflammatory and immune responses in the post-mortem cerebral cortex of patients with severe COVID-19. The participants comprised three patients diagnosed with severe COVID-19 from March 26, 2020, to April 17, 2020, and three control patients. Our findings demonstrated a surge in the number of reactive astrocytes and activated microglia, as well as low levels of glutathione along with the upregulation of inflammation- and immune-related genes IL1B, IL6, IFITM, MX1, and OAS2 in the COVID-19 group. Overall, the data imply that oxidative stress may invoke a glial-mediated neuroinflammation, which ultimately leads to neuronal cell death in the cerebral cortex of COVID-19 patients.

LC3 and ATG5 overexpression and neuronal cell death in the prefrontal cortex of postmortem chronic methamphetamine users.

Methamphetamine (METH) abuse is accompanied by oxidative stress, METH-induced neurotoxicity, and apoptosis. Oxidative stress has devastating effects on the structure of proteins and cells. Autophagy is an evolutionarily conserved intracellular regulated mechanism for orderly degradation of dysfunctional proteins or removing damaged organelles. The precise role of autophagy in oxidative stress-induced apoptosis of dopaminergic neuronal cells caused by METH has not clarified completely. In this study, we sought to evaluate the effects of METH abuse on autophagy in the prefrontal cortex of postmortem users, mainly focusing on the ATG5 and LC3 during neuroinflammation. Postmortem molecular and histological examination was done for two groups containing 12 non-addicted and 14 METH addicted cases. ATG5 and LC3 expression were analyzed by real-time PCR and immunohistochemistry (IHC) methods. Histopathological analysis was performed by stereological cell counting of neuronal cells using Hematoxylin and Eosin (H & E) staining technique. In order to detect DNA damage in the prefrontal lobe, Tunnel staining was performed. Real-time PCR and IHC assay showed overexpression of ATG5 and LC3 protein in the prefrontal cortex of Meth users. The cell death and neuronal degeneration were increased significantly based on Tunel assay and the stereological analysis in the Prefrontal cortex. Chronic METH exposure probably induces ATG5 and LC3 overexpression and neuronal cell death in the Prefrontal cortex of the postmortem cases.

Postmortem Study of Molecular and Histological Changes in the CA1 Hippocampal Region of Chronic Methamphetamine User.

Methamphetamine (Meth) is recognized as one of the most important new distributed abused drug that causes severe damage to the different parts of the brain, especially hippocampus. Previous studies have demonstrated that Meth can induce apoptosis and cell death in the brain. In this study, we evaluated the long-term effects of Meth abuse in the CA1 region of postmortem hippocampus. Postmortem molecular and histological analysis was performed for five non-addicted subjects and five Meth addicted ones. Iba-1 (microglia) and glial fibrillary acidic protein, GFAP (astrocytes) expression were assayed by western blotting and immunohistochemistry (IHC) methods. Histopathological assessment was done with stereological counts of hippocampal cells stained with hematoxylin and eosin (H and E). Tunel staining was used to detect DNA damage in human brains. In addition, protein-protein interaction analysis network was investigated. Western blotting and immunohistochemistry assay showed overexpression of GFAP and Iba-1 protein in the CA1 hippocampal region of Meth users' brain. Stereological analysis in the CA1 region revealed increased neuron degeneration. Furthermore, significant apoptosis and cell death were confirmed by Tunel assay in the hippocampus. The prominent role of TLR4, IL1B, CASP1, and NLRP3 in the molecular mechanism of Meth was highlighted via PPI network analysis. Chronic Meth use can induce GFAP and Iba-1 upregulation and neuronal apoptosis in the CA1 region of the postmortem hippocampus.