Measuring hypertrophy in neonatal rat primary cardiomyocytes and human iPSC-derived cardiomyocytes.

In the heart, left ventricular hypertrophy is initially an adaptive mechanism that increases wall thickness to preserve normal cardiac output and function in the face of coronary artery disease or hypertension. Cardiac hypertrophy develops in response to pressure and volume overload but can also be seen in inherited cardiomyopathies. As the wall thickens, it becomes stiffer impairing the distribution of oxygenated blood to the rest of the body. With complex cellular signalling and transcriptional networks involved in the establishment of the hypertrophic state, several model systems have been developed to better understand the molecular drivers of disease. Immortalized cardiomyocyte cell lines, primary rodent and larger animal models have all helped understand the pathological mechanisms underlying cardiac hypertrophy. Induced pluripotent stem cell-derived cardiomyocytes are also used and have the additional benefit of providing access to human samples with direct disease relevance as when generated from patients suffering from hypertrophic cardiomyopathies. Here, we briefly review in vitro and in vivo model systems that have been used to model hypertrophy and provide detailed methods to isolate primary neonatal rat cardiomyocytes as well as to generate cardiomyocytes from human iPSCs. We also describe how to model hypertrophy in a "dish" using gene expression analysis and immunofluorescence combined with automated high-content imaging.

A mixed blessing for liver transplantation patients - Rapamycin.

BACKGROUND: Liver transplantation (LT) is an effective treatment option for end-stage liver disease. Mammalian target of rapamycin (mTOR) inhibitors, such as rapamycin, are widely used post LT. DATA SOURCES: In this review, we focused on the anti-cancer activities and metabolic side effects of rapamycin after LT. The literature available on PubMed for the period of January 1999-September 2022 was reviewed. The key words were rapamycin, sirolimus, liver transplantation, hepatocellular carcinoma, diabetes, and lipid metabolism disorder. RESULTS: Rapamycin has shown excellent effects and is safer than other immunosuppressive regimens. It has exhibited excellent anti-cancer activity and has the potential in preventing hepatocellular carcinoma (HCC) recurrence post LT. Rapamycin is closely related to two long-term complications after LT, diabetes and lipid metabolism disorders. CONCLUSIONS: Rapamycin prevents HCC recurrence post LT in some patients, but it also induces metabolic disorders. Reasonable use of rapamycin benefits the liver recipients.

Prognostic implication of early posttransplant hypercholesterolemia in liver transplantation for patients with hepatocellular carcinoma.

BACKGROUND: Hyperlipidemia is a common complication after liver transplantation (LT) and develops mostly in the early posttransplant period. Recently, some studies have reported a positive correlation between hyperlipidemia and favorable prognosis in patients with hepatocellular carcinoma (HCC) undergoing hepatectomy. This study aimed to evaluate the possibility of predicting prognosis in HCC patients receiving LT by early posttransplant dyslipidemia. METHODS: From January 2015 to December 2017, a total of 806 HCC patients from China Liver Transplant Registry database were retrospectively enrolled. The prognostic relevance of early posttransplant hypertriglyceridemia or hypercholesterolemia was examined using survival analysis, and subgroup analysis was implemented based on LT criteria. RESULTS: Early posttransplant hypercholesterolemia (EPHC) was independently inversely associated with the risk of recurrence [hazard ratio (HR) = 0.630; P = 0.022], but was not significantly correlated with the mortality. However, early posttransplant hypertriglyceridemia was not related to prognosis. Intriguingly, with further classification, we found that borderline EPHC (B-EPHC), instead of significant EPHC, was a predictor of lower risk for both recurrence (HR = 0.504; P = 0.006) and mortality (HR = 0.511; P = 0.023). Compared with non-EPHC patients, B-EPHC patients achieved significantly superior 1-year and 3-year tumor-free survival (89.6% and 83.7% vs. 83.8% and 72.7% respectively; P = 0.023), and 1-year and 3-year overall survival (95.8% and 84.8% vs. 94.6% and 77.6% respectively; P = 0.039). In the subgroup analysis, B-EPHC remained an independent predictor of better prognosis in patients beyond Milan criteria and those within Hangzhou criteria; whereas there was no significant relationship between B-EPHC and prognosis in patients within Milan criteria and those beyond Hangzhou criteria. More interestingly, patients beyond Milan criteria but within Hangzhou criteria were identified as the crucial subpopulation who benefited from B-EPHC (recurrence HR = 0.306, P = 0.011; mortality HR = 0.325, P = 0.031). CONCLUSIONS: B-EPHC could assist transplant teams in dynamically evaluating prognosis after LT for HCC as a postoperative non-oncological biomarker, especially in patients beyond Milan criteria but within Hangzhou criteria.

Efficacy and safety of sirolimus early conversion protocol in liver transplant patients with hepatocellular carcinoma: A single-arm, multicenter, prospective study.

Mammalian target of rapamycin (mTOR) inhibitor as an attractive drug target with promising antitumor effects has been widely investigated. High quality clinical trial has been conducted in liver transplant (LT) recipients in Western countries. However, the pertinent studies in Eastern world are paucity. Therefore, we designed a clinical trial to test whether sirolimus can improve recurrence-free survival (RFS) in hepatocellular carcinoma (HCC) patients beyond the Milan criteria after LT. This is an open-labeled, single-arm, prospective, multicenter, and real-world study aiming to evaluate the clinical outcomes of early switch to sirolimus-based regimens in HCC patients after LT. Patients with a histologically proven HCC and beyond the Milan criteria will be enrolled. The initial immunosuppressant regimens are center-specific for the first 4-6 weeks. The following regimens integrated sirolimus into the regimens as a combination therapy with reduced calcineurin inhibitors based on the condition of patients and centers. The study is planned for 4 years in total with a 2-year enrollment period and a 2-year follow-up. We predict that sirolimus conversion regimen will provide survival benefits for patients particular in the key indicator RFS as well as better quality of life. If the trial is conducted successfully, we will have a continued monitoring over a longer follow-up time to estimate indicator of overall survival. We hope that the outcome will provide better evidence for clinical decision-making and revising treatment guidelines based on Chinese population data. Trial register: Trial registered at http://www.chictr.org.cn: ChiCTR2100042869.

Hangzhou criteria as downstaging criteria in hepatocellular carcinoma before liver transplantation: A multicenter study from China.

BACKGROUND: The downstaging of hepatocellular carcinoma (HCC) has been confirmed to benefit liver transplantation (LT) patients whose tumors are beyond the transplantation criteria. Milan criteria (MC), a tumor size and number-based assessment, is currently used as the endpoint in these patients. However, many studies believe that tumor biological behavior should be added to the evaluation criteria for downstaging efficacy. Hence, this study aimed to explore the feasibility of Hangzhou criteria (HC), which introduced tumor grading and alpha-fetoprotein in addition to tumor size and number, as an endpoint of downstaging. METHODS: We performed a multicenter and retrospective study of 206 patients accepted locoregional therapy (LRT) as downstaging/bridge treatment prior to LT in three centers of China. RESULTS: Recipients were divided into four groups: failed downstaging to the HC (group A, n = 46), successful downstaging to the HC (group B, n = 30), remained within the HC all the time (group C, n = 113), and tumor progressed (group D, n = 17). The 3-year HCC recurrence probabilities of groups B and C were not significantly different (10.3% vs. 11.6%, P = 0.87). The HCC recurrent rate was significantly higher in group A (52.3%) compared with that in group B/C (P < 0.05). Seven patients (7/76, 9.2%) whose tumor exceeded the the HC were successfully downstaged to the MC, and 39.5% (30/76) to the the HC. In group B, 23 patients remained beyond the MC and their survivals were as well as those of patients within the MC. CONCLUSIONS: Compared to the MC, HC downstaging criteria can give more HCC patients access to LT and furthermore, the outcome of these patients is the same as those matching MC downstaging criteria. Hangzhou downstaging criteria therefore is applicable in clinical practice.

Role of surgical treatments in high-grade or advanced gastroenteropancreatic neuroendocrine neoplasms.

Over the last 40 years, the incidence and prevalence of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) have continued to increase. Compared to other epithelial neoplasms in the same organ, GEP-NENs exhibit indolent biological behavior, resulting in more chances to undergo surgery. However, the role of surgery in high-grade or advanced GEP-NENs is still controversial. Surgery is associated with survival improvement of well-differentiated high-grade GEP-NENs, whereas poorly differentiated GEP-NENs that may benefit from resection require careful selection based on Ki67 and other tissue biomarkers. Additionally, surgery also plays an important role in locally advanced and metastatic disease. For locally advanced GEP-NENs, isolated major vascular involvement is no longer an absolute contraindication. In the setting of metastatic GEP-NENs, radical intended surgery is recommended for patients with low-grade and resectable metastases. For unresectable metastatic disease, a variety of surgical approaches, including cytoreduction of liver metastasis, liver transplantation, and surgery after neoadjuvant treatment, show survival benefits. Primary tumor resection in GEP-NENs with unresectable metastatic disease is associated with symptom control, prolonged survival, and improved sensitivity toward systemic therapies. Although there is no established neoadjuvant or adjuvant strategy, increasing attention has been given to this emerging research area. Some studies have reported that neoadjuvant therapy effectively reduces tumor burden, improves the effectiveness of subsequent surgery, and decreases surgical complications.

Effect of Kisspeptin-54 immunization on performance, carcass characteristics, meat quality and safety of Yiling goats.

This study aimed to evaluate the effects of kisspeptin-54 immunocastration vaccine on performance, carcass characteristics, meat quality, and safety of Yiling goats. Thirty buck goats were randomly assigned into three groups: PVAX-B2L-Kisspeptin-54-asd immunized (PBK-asd), control, and surgically castrated. PBK-asd immunization significantly stimulated serum anti-kisspeptin antibody production and reduced testosterone hormone compared with the control group (p < .05). Interestingly, PBK-asd plasmid did not integrate into the host genome and had no significant effect on growth hormone, body weight, and average daily gain (ADG). Conversely, surgical castration significantly reduced ADG and carcass weight compared to the control group. Furthermore, PBK-asd immunization did not affect carcass characteristics (dressing percentage, loin area, and fat thickness) and meat quality traits (pH, color, cooking loss, drip loss, and shearing force). These results indicate that the Kisspeptin-54 DNA vaccine is safe and has potential to be used as an alternative to surgical castration for goats without negatively affecting carcass and meat quality.

Acute and chronic effects of intravitreally injected beta-amyloid on the neurotransmitter system in the retina.

The potential cytotoxic effect of aggregated Abeta(1-42) to neurons that express classical neurotransmitters, including acetylcholine, gamma-amino butyric acid, catecholamines and serotonin was assessed. The cholinergic system has been the central focus of the therapeutic drug strategies in amyloid-depositing pathologies such as Alzheimer's disease. Aggregated Abeta(1-42) has a multisystem cytotoxic effect causing non-specific reduction in immunoreactivity, dysfunction, or loss of retinal nerve cells. The extent of this was investigated using immunocytochemistry, TUNEL staining for apoptosis, and measurement of cell density as well as retinal surface area. There was a differential acute and/or chronic effect of Abeta on choline acetyltransferase, gamma-aminobutyric acid and 5-tryptamine hydroxylase systems, observed with the increasing time course of 6h to 5 months, and a bilateral/systemic effect. In contrast, the overall pattern of catecholaminergic system, as revealed by tyrosine hydroxylase immunoreactivity of the retina, appears to have remained relatively unaffected by Abeta (however this may reflect neuronal loss due to reduction in the retinal surface). This is the first in vivo evidence in a CNS model to show that not only all major neurotransmitter systems are differentially affected by Abeta aggregates but the effect may vary from one transmitter system to another under the same experimental conditions in situ and in a dose- and time-dependent manner.

Protective effects of acarbose against vascular endothelial dysfunction through inhibiting Nox4/NLRP3 inflammasome pathway in diabetic rats.

The cardiovascular efficacy of glucose-lowering drugs is needed due to the cardiovascular complication in type 2 diabetes mellitus (T2DM). Acarbose is an α-glucosidase inhibitor that suppresses postprandial hyperglycemia, however, the cardiovascular protection of acarbose has still remained controversial. NLRP3 inflammasome activation mediated tight junction disruption, a hallmark event of endothelial barrier dysfunction leading to endothelial hyperpermeability in diabetes. Given the anti-inflammatory property of acarbose, it was investigated that acarbose protected against vascular endothelial barrier dysfunction through inhibiting NLRP3 inflammasome in vascular endothelial cells in T2DM rats. The rat aortic endothelial cells (RAECs) were incubated with high glucose (HG, 30 mM) for 24 h in vitro. It was found that HG significantly induced the formation and activation of NLRP3 inflammasome, which was markedly blocked by acarbose treatment. Furthermore, acarbose blocked the Nox4-dependent superoxide (O2.-) generation, which regulated NLRP3 inflammasome in RAECs. Importantly, we found that acarbose remarkably enhanced the junction protein expression of ZO-1 and VE-Cadherin and consequently abolished vascular hyperpermeability, which was associated with inhibiting NLRP3 inflammasome in RAECs. In vivo, acarbose intervention relieved vascular leakage in the heart of diabetic rats injected with Evans blue dye and the vasodilatory response to acetylcholine, which was accompanied with the restoration of ZO-1, VE-Cadherin, Nox4 and NLRP3 inflammasome in the aortal endothelium of diabetic rats. Taken together, our data indicated that acarbose ameliorated endothelial barrier dysfunction by directly inhibiting NLRP3 inflammasome which was dependent on inhibiting Nox4 oxidase-dependent O2.- production. These properties might carry a potential significance for acarbose in cardiovascular protection in diabetic patients.

Analysis of neural potential of human umbilical cord blood-derived multipotent mesenchymal stem cells in response to a range of neurogenic stimuli.

We investigated the neurogenic potential of full-term human umbilical cord blood (hUCB)-derived multipotent mesenchymal stem cells (MSCs) in response to neural induction media or coculture with rat neural cells. Phenotypic and functional changes were assessed by immunocytochemistry, RT-PCR, and whole-cell patch-clamp recordings. Naive MSCs expressed both mesodermal and ectodermal markers prior to neural induction. Exposure to retinoic acid, basic fibroblast growth factor, or cyclic adenosine monophosphate (cAMP) did not stimulate neural morphology, whereas exposure to dibutyryl cAMP and 3-isobutyl-1-methylxanthine stimulated a neuron-like morphology but also appeared to be cytotoxic. All protocols stimulated increases in expression of the neural precursor marker nestin, but expression of mature neuronal or glial markers MAP2 and GFAP was not observed. Nestin expression increases were serum level dependent. Electrophysiological properties of MSCs were studied with whole-cell patch-clamp recordings. The MSCs possessed no ionic currents typical of neurons before or after neural induction protocols. Coculture of hUCB-derived MSCs and rat neural cells induced some MSCs to adopt an astrocyte-like morphology and express GFAP protein and mRNA. Our data suggest hUCB-derived MSCs do not transdifferentiate into mature functioning neurons in response to the above neurogenic protocols; however, coculture with rat neural cells led to a minority adopting an astrocyte-like phenotype.

Changes in endothelial function and its association with plasma osteoprotegerin in hypothyroidism with exercise-induced silent myocardial ischaemia.

OBJECTIVE: Hypothyroidism is associated with an increased risk for cardiovascular disease. Exercise-induced silent myocardial ischaemia (SI) is an early stage of coronary artery disease. Recently, many studies have shown that endothelial dysfunction is an early physiological event in atherosclerosis, and osteoprotegerin (OPG) acts as an important regulatory molecule in the vasculature. The aim of this study was to investigate the alteration of endothelial function and its association with plasma OPG in hypothyroidism with SI. METHODS: Forty-eight female postmenopausal hypothyroid patients with normal rest electrocardiography (ECG) were selected. Of these, 19 cases had SI. Twenty healthy females without SI were selected as controls. High-resolution ultrasound was used to measure brachial artery diameter at rest, after reactive hyperaemia and after sublingual glyceryltrinitrate (GTN). Plasma OPG concentration was measured in duplicate by a sandwich enzyme-linked immunosorbent assay (ELISA). RESULTS: Flow-mediated arterial dilation (FMD) in the total hypothyroid group, the hypothyroidism with SI group and the hypothyroidism without SI group was 3.51 +/- 0.62%, 3.20 +/- 0.54% and 3.72 +/- 0.60%, respectively, significantly lower than that in the controls (5.08 +/- 0.61%) (P < 0.01). Compared with the hypothyroidism without SI group, FMD in the hypothyroidism with SI group was significantly lower (P < 0.05). Plasma OPG levels in the total hypothyroid group, patients with SI and patients without SI were significantly higher than in the control group (P < 0.05). Compared with patients without SI, OPG levels were significantly higher in patients with SI (P < 0.05). On multiple regression analysis, low density lipoprotein cholesterol (LDL-C), lipoprotein (a) [Lp(a)], C-reactive protein (CRP), OPG, TSH, free T3 (FT3) and thyroid peroxidase antibody (TPO-Ab) were found to be significant factors that were associated with FMD. Logistic analysis also showed that LDL-C, TSH, OPG, CRP and FMD were independently and significantly associated with SI in hypothyroidism. CONCLUSION: Impaired endothelial function and increased levels of OPG exist in hypothyroid patients, especially those with SI. These findings support the growing concept that endothelial dysfunction may be associated with vascular disease, and subsequently elevated plasma OPG may have a role in the development of vascular dysfunction in hypothyroid patients.

Isolation, Structure elucidation, and antimycobacterial properties of dimeric naphtho-gamma-pyrones from the marine-derived fungus Aspergillus carbonarius.

Two new dimeric naphtho-gamma-pyrones, compounds 1 and 2, were isolated from the AcOEt extract of the fungal strain WZ-4-11 of Aspergillus carbonarius, together with eight known analogues, including 10,10'-bifonsecin B (3), 6'-O-demethylnigerone (4), nigerone (5), isonigerone (6), fonsecin (7), rubrofusarin B (8), TMC 256A1 (9), and flavasperone (10). Their structures were elucidated by means of UV, CD, IR, and 1D- and 2D-NMR spectroscopy, in combination with HR-MS analysis. The fully assigned (1)H- and (13)C-NMR data of 3, and the (13)C-NMR data of 6 are reported for the first time. Compounds 1 and 2 showed weak antimycobacterial activities against Mycobacterium tuberculosis H37Rv, with MIC values of 43.0 and 21.5 microM, resp.

Alterations in presenilin 1 processing by amyloid-beta peptide in the rat retina.

Accumulating evidence indicates that mutations in the presenilin 1 (PS1) gene are responsible for most cases of familial Alzheimer's disease (AD). Although its biological functions are not yet fully understood, it appears that PS1 plays a role in the processing and trafficking of the amyloid precursor protein (APP). However, little is known about factors that are involved in regulating the metabolism of PS1 especially in relation to AD pathology. In this study, we have examined the effect of optic nerve crush, intravitreal injection of the inflammatory agent lipopolysaccharide (LPS) or injection of amyloid beta(1-42) (A beta(1-42)) on the expression and processing of PS1 in the rat retina. We found that 48 h after injection of A beta(1-42) there was a dramatic alteration in the banding pattern of PS1 on Western blots, as indicated by marked changes in the levels of expression of some of its C- and N-terminal fragments in retinal homogenates. These results suggest an A beta(1-42)-induced potentiation of a non-specific stress-related but inflammation-independent alteration of processing of PS1 in this in vivo model.

[Surveillance of schistosomiasis in People's Republic of China in 2015].

OBJECTIVE: To analyze the investigation data of the national schistosomiasis surveillance sites in 2015, so as to provide scientific evidences for schistosomiasis control, elimination and surveillance. METHODS: According to National Schistosomiasis Surveillance Programme (version 2014), 457 surveillance sites were selected, and the investigation data in residents, floating population, domestic animals and Oncomelania hupensis snails were collected and analyzed from four types of endemic counties. RESULTS: A total of 4 468 seropositive cases were detected from 133 350 residents, among which 4 457 residents with seropositive results received the etiological tests, and 71 of them were identified with positive results. Most of them were fishermen and farmers in the middle and old-aged group. The schistosomiasis infection rate was 0.05% in local population. Totally 977 seropositive cases were examined from 85 047 migrant individuals, and 16 positive cases were found out from 966 individuals who took etiological tests, which showed the schistosomiasis infection rate was 0.02% in floating population. Imported cases were found among floating people in four provinces, namely Zhejiang, Hunan, Hubei and Anhui provinces. No acute schistosomiasis cases were reported. A total of 13 406 head of cattle received examinations and only 5 were determined as stool positives. The cattle infection rate was 0.04%. The snail survey covered an area of 22 295.13 hm2 and snails were found in an area of 7 426.63 hm2, including 3.47 hm2 newly detected area with snails. No schistosome-infected snails were found. CONCLUSIONS: Based on the collected data from 457 national schistosomiasis surveillance sites of China, the Schistosoma japonicum infection rate is 0.05% in local population which maintains a stably descending trend. In floating population, there are imported schistosome-in-fected persons. Cattle are still a vulnerable species infected with schistosome. Although no infected snails are found, snails are widely distributed in endemic areas. Some provinces detect areas with snails for the first time or the reproduction of snails. The staff in endemic provinces should carry out the surveillance work according to National Schistosomiasis Surveillance Programme (version 2014) to improve the surveillance system, and enhance the sensibility and effectiveness of surveillance work.

Comparative Pharmacokinetics of Ginsenoside Rg3 and Ginsenoside Rh2 after Oral Administration of Ginsenoside Rg3 in Normal and Walker 256 Tumor-bearing Rats.

BACKGROUND: Ginseng is Chinese traditional herbal medicine, and the ginsenoside Rg3 is the main bioactive ingredient for the anti-tumor effect. However, there is no study on pharmacokinetics (PKs) of ginsenoside Rg3 and its main metabolite after oral ginsenoside Rg3 in tumor-bearing plasma. The aim of this study was to investigate the PK profiles of ginsenoside Rg3 and ginsenoside Rh2 after oral administration of pure ginsenoside Rg3 were administered, and compare the difference of the PK profiles between normal and Walker 256 tumor-bearing rats. MATERIALS AND METHODS: The concentrations of two ginsenosides in plasma were determined by using a simple and rapid high-performance liquid chromatography. All the rats were divided randomly into two groups (Walker 256 tumor-bearing and normal groups). Each group received oral administration of 50 mg/kg ginsenoside Rg3. RESULTS: The results showed that ginsenoside Rh2, possibly as a glycosylation hydrolysis product of ginsenoside Rg3, were found in plasma after oral administration of ginsenoside Rg3 to rats. Ginsenoside Rg3 had shown better absorption than ginsenoside Rh2, whether the oral administration of ginsenoside Rg3, normal rats showed better absorption than tumor-bearing rats. DISCUSSION AND CONCLUSION: The PKs properties of the ginsenoside Rg3 and ginsenoside Rh2 differed between tumor-bearing rats and normal rats, including area under the plasma level/time curve and concentration maximum (P < 0.05). SUMMARY: Ginsenoside Rh2 was found in plasma after oral administration of ginsenoside Rg3 to ratsHPLC could be used to determine simultaneously, the concentration of ginsenoside Rg3 and ginsenoside Rh2 in rat plasma after oral administration of ginsenoside Rg3Normal rats showed better absorption than tumor-bearing rats after oral administration of ginsenoside Rg3.0.

Changes in plasma concentrations of osteoprotegerin before and after levothyroxine replacement therapy in hypothyroid patients.

CONTEXT: Recent study has shown that overt hypothyroidism (oHT) is associated with increased plasma osteoprotegerin (OPG) levels. OBJECTIVE: Our objective was to examine the plasma OPG level alteration before and after levothyroxine (L-T4) treatment in oHT and subclinical hypothyroidism (sHT). PATIENTS: The study subjects included oHT and sHT patients and healthy individuals (20 subjects in each group). METHODS: All patients were given L-T4 therapy to maintain a euthyroid state. Plasma OPG concentration was measured in duplicate by a sandwich ELISA. RESULTS: Plasma OPG levels in oHT and sHT before treatment were significantly higher than levels in controls (P < 0.01). After normalization of thyroid function, OPG levels in both groups decreased markedly (P < 0.01). The absolute changes in OPG showed a significant positive correlation with the changes in TSH (P < 0.05) and negative correlation with the changes in endothelium-dependent arterial dilation (P < 0.01) in hypothyroid patients during the course of treatment. CONCLUSION: OPG may be involved in the development of vascular dysfunction in hypothyroid patients.

Ergothioneine rescues PC12 cells from beta-amyloid-induced apoptotic death.

Beta-amyloid (Abeta) peptide is the major component of senile plaques and considered to have a causal role in the development and progression of Alzheimer's disease. There has been compelling evidence that Abeta-induced cytotoxicity is mediated through oxidative and/or nitrosative stress. Recently, considerable attention has been focused on dietary manipulation of oxidative and/or nitrosative damage. l-Ergothioneine (EGT; 2-mercaptohistidine trimethylbetaine) is a low-molecular-weight naturally occurring thiol compound of dietary origin that exists in the brain, liver, kidney, erythrocytes, ocular tissues, and seminal fluids of mammals. This water-soluble antioxidant has the ability to scavenge hydroxyl and peroxynitrite radicals as well as activated oxygen species, such as singlet oxygen. In this study, we investigated the effects of EGT on Abeta-induced oxidative and/or nitrosative cell death. Rat pheochromocytoma (PC12) cells treated with Abeta underwent apoptotic death as determined by positive in situ terminal end-labeling (TUNEL staining), decreased mitochondrial transmembrane potential, increased ratio of proapoptotic Bax to antiapoptotic Bcl-XL, elevated caspase-3 activity, and cleavage of poly(ADP-ribose) polymerase. EGT pretreatment attenuated Abeta-induced apoptosis in PC12 cells. Compared to N-acetyl-l-cysteine, which mainly scavenges reactive oxygen species, EGT effectively inhibited Abeta-induced cell death by suppressing peroxynitrite formation and subsequent nitration of protein tyrosine residues. The effects of EGT on the cytotoxicity induced by the nitric oxide donor sodium nitroprusside (SNP) and the peroxynitrite-generating 3-morpholinosydnonimine chlorhydrate (SIN-1) were compared. Whereas EGT significantly protected against SIN-1-mediated cell death, it barely affected the cytotoxicity induced by SNP. Thus EGT may attenuate apoptosis caused by Abeta, preferentially by eliminating peroxynitrite derived from the neurotoxic peptide. The importance of diet-derived antioxidants in the management of Alzheimer's disease and other neurodegenerative disorders is discussed.

Up-regulation of soluble amyloid precursor protein fragment secretion in the rat retina in vivo by metabotropic glutamate receptor stimulation.

Using the novel rat retinal-vitreal model we have investigated the effect of metabotropic glutamate receptor activation on amyloid precursor protein (APP) metabolism. The release of low mol. wt fragments of APP, at 15-23 kDa in particular, was markedly up-regulated by the metabotropic glutamate receptor agonist (1S,3R)-1-amino-1,3-cyclopentane dicarboxylic acid ((1S,3R)-ACPD) in a concentration- and time-dependent manner, and this response was blocked by the receptor antagonist (S)-alpha-methyl-4-caboxyphenylglycine ((S)-MCPG). These results, together with the observation of a lack of deleterious effects of (1S,3R)-ACPD on the retinal neurons, support a physiological role of metabotropic glutamate receptors in mediating the release of soluble APP fragments, an action which may have important functional and therapeutic implications for Alzheimer's disease.

Ergothioneine treatment protects neurons against N-methyl-D-aspartate excitotoxicity in an in vivo rat retinal model.

Injection of the glutamate agonist N-methyl-D-aspartate into the vitreous body of the rat eye resulted in a number of morphological changes in the retina. Most apparent was a dramatic reduction in the density and sizes of neurons accompanied by a decrease in amyloid precursor protein and glial fibrillary acidic protein immunoreactivity. Cell counts revealed that 81% of ganglion cells and 43% of non-ganglion cells were lost as a result of the treatment. However, in animals treated with the antioxidant ergothioneine, these figures dropped to 44 and 31%, respectively. Thus, ergothioneine appears to be neuroprotective in this system and the data suggest that antioxidants may provide a useful means of modulating glutamate-based toxicity.

The antioxidant cocktail, effective microorganism X (EM-X), protects retinal neurons in rats against N-methyl-D-aspartate excitotoxicity in vivo.

Injection of the glutamate agonist N-methyl-D-aspartate (NMDA) into the vitreous body of rats resulted in severe degeneration of neurons in the retina, with a loss of 81% of ganglion cells and 43% of non-ganglion cells. The cocktail EM-X is a novel antioxidant drink derived from ferment of unpolished rice, papaya and sea-weeds with effective microorganisms (EM-X). In animals treated with an intraperitoneal injection of EM-X, the loss of ganglion cells was reduced to 55% and that of non-ganglion cells to 34% when compared to untreated NMDA-injected retinas. Cell degeneration resulting from NMDA excitotoxicity, is thought to be mediated via oxidative stress mechanisms. The neuroprotective effect of the EM-X in this system is therefore likely to be due, at least in part, to its flavonoids, saponins, vitamin E and ascorbic content.