The Protective Effect of Low-Dose Ethanol on Myocardial Fibrosis through Downregulating the JNK Signaling Pathway in Diabetic Rats

Beer production potentiality of some non-Saccharomyces yeast obtained from a traditional beer starter emao

The recent realisation regarding the potentiality of the long-neglected non-Saccharomyces yeasts in improving the flavour profile and functionality of alcoholic beverages has pushed researchers to search for such potent strains in many sources. We studied the fungal diversity and the rice beer production capability of the fungal strains isolated from emao-a traditional rice beer starter culture of the Boro community. Fifty distinct colonies were picked from mixed-culture plates, of which ten representative morphotypes were selected for species identification, and simultaneous saccharification and beer fermentation (SSBF) assay. The representative isolates were identified as Hyphopichia burtonii (Hbur-FI38, Hbur-FI44, Hbur-FI47 & Hbur-FI68), Saccharomyces cerevisiae (Scer-FI51), Wickerhamomyces anomalus (Wano-FI52), Candida carpophila (Ccar-FI53), Mucor circinelloides (Mcir-FI60), and Saccharomycopsis malanga (Smal-FI77 and Smal-FI84). The non-Saccharomyces yeast strains Hbur-FI38, Hbur-FI44, Ccar-FI53, and Smal-FI77 showed SSBF capacity on rice substrate producing beer that contained 7-10% (v/v) ethanol. A scaled-up fermentation assay was performed to assess the strain-wise fermentation behaviour in large-scale production. The nutritional, functional, and sensory qualities of the SSBF strain fermented beer were compared to the beer produced by emao. All the strains produced beer with reduced alcohol and energy value while compared to the traditional starter emao. Beer produced by both the strains of H. burtonii stood out with higher ascorbic acid, phenol, and antioxidant property, and improved sensory profile in addition to reduced alcohol and energy value. Such SSBF strains are advantageous over the non-SSBF S. cerevisiae strains as the former can be used for direct beer production from rice substrates.

Fibrosis of the diabetic heart: Clinical significance, molecular mechanisms, and therapeutic opportunities

In patients with diabetes, myocardial fibrosis may contribute to the pathogenesis of heart failure and arrhythmogenesis, increasing ventricular stiffness and delaying conduction. Diabetic myocardial fibrosis involves effects of hyperglycemia, lipotoxicity and insulin resistance on cardiac fibroblasts, directly resulting in increased matrix secretion, and activation of paracrine signaling in cardiomyocytes, immune and vascular cells, that release fibroblast-activating mediators. Neurohumoral pathways, cytokines, growth factors, oxidative stress, advanced glycation end-products (AGEs), and matricellular proteins have been implicated in diabetic fibrosis; however, the molecular links between the metabolic perturbations and activation of a fibrogenic program remain poorly understood. Although existing therapies using glucose- and lipid-lowering agents and neurohumoral inhibition may act in part by attenuating myocardial collagen deposition, specific therapies targeting the fibrotic response are lacking. This review manuscript discusses the clinical significance, molecular mechanisms and cell biology of diabetic cardiac fibrosis and proposes therapeutic targets that may attenuate the fibrotic response, preventing heart failure progression.

Protection of retinal function and morphology in MNU-induced retinitis pigmentosa rats by ALDH2: an in-vivo study

Background

Retinitis pigmentosa (RP) is a kind of inherited retinal degenerative diseases characterized by the progressive loss of photoreceptors. RP has been a conundrum without satisfactory countermeasures in clinic until now. Acetaldehyde dehydrogenase 2 (ALDH2), a major enzyme involved in aldehyde detoxification, has been demonstrated to be beneficial for a growing number of human diseases, such as cardiovascular dysfunction, diabetes mellitus and neurodegeneration. However, its protective effect against RP remains unknown. Our study explored the impact of ALDH2 on retinal function and structure in N-methyl-N-nitrosourea (MNU)-induced RP rats.

Methods

Rats were gavaged with 5 mg/kg Alda-1, an ALDH2 agonist, 5 days before and 3 days after MNU administration. Assessments of retinal function and morphology as well as measurement of specific proteins expression level were conducted.

Results

Electroretinogram recordings showed that Alda-1 administration alleviated the decrease in amplitude caused by MNU, rendering protection of retinal function. Mitigation of photoreceptor degeneration in MNU-treated retinas was observed by optical coherence tomography and retinal histological examination. In addition, Western blotting results revealed that ALDH2 protein expression level was upregulatedwith increased expression of SIRT1 protein after the Alda-1 intervention. Besides, endoplasmic reticulum stress (ERS) was reduced according to the significant downregulation of GRP78 protein, while apoptosis was ameliorated as shown by the decreased expression of PARP1 protein.

Conclusions

Together, our data demonstrated that ALDH2 could provide preservation of retinal function and morphology against MNU-induced RP, with the underlying mechanism at least partly related to the modulation of SIRT1, ERS and apoptosis.

Effect of Irbesartan on AGEs-RAGE and MMPs systems in rat type 2 diabetes myocardial-fibrosis model

IMPACT STATEMENT

There are about 425 million diabetes patients (20-79 years) in the world according to the International Diabetes Federation Diabetes Atlas - 8th Edition. The cardiovascular complication is one of the major causes of death in diabetes patients. Myocardial fibrosis is one of the serious pathological changes, so investigating the pathogenesis of myocardial fibrosis has the significant value. Our study aims to investigate the effect of Irbesartan (the angiotensin II receptor antagonist) on the changes of AGE-RAGE system and MMP family components, and analyzes the potential mechanisms in type 2 diabetes-induced myocardial fibrosis. Our results provide the theoretical base for better understanding the pathogenesis in type 2 diabetes-induced myocardial complication. It is useful for clinicians to select the effective therapeutic measures for treatment of type 2 diabetes-induced organ fibrosis.

Spleen tyrosine kinase‑induced JNK‑dependent NLRP3 activation is involved in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a leading contributor to the increased morbidity and mortality rates associated with diabetes. Persistent inflammation has previously been reported to be involved in the pathogenesis of DCM. However, the exact underlying molecular mechanisms remain to be fully elucidated. In the present study, the role of spleen tyrosine kinase (Syk) and c‑Jun N‑terminal kinase (JNK) in NLR family pyrin domain‑containing 3 (NLRP3 inflammasome) activation in DCM were investigated in vivo and in vitro. Streptozotocin (65 mg/kg) was injected intraperitoneally into Sprague‑Dawley rats to induce a rat model of diabetes. Neonatal rat cardiomyocytes and H9c2 cells were cultured to detect the expression of JNK, NLRP3 and its associated downstream molecules, following treatment with Syk/JNK inhibitor or Syk/JNK‑small interfering (si)RNA in high glucose (HG) conditions. It was revealed that the protein and mRNA expression levels of phospho (p)‑Syk, p‑JNK, NLRP3 and its associated downstream molecules, including interleukin (IL)‑1β, were upregulated in vivo and in vitro. The JNK inhibitor significantly decreased the expression of NLRP3 and its downstream molecules in neonatal rat cardiomyocytes and H9c2 cells treated with HG. Furthermore, Syk‑siRNA and the Syk inhibitor markedly inhibited the HG‑induced activation of JNK, followed by the downregulation of NLRP3 and its downstream molecules at the mRNA and protein levels in cells. Therefore, it was demonstrated that the HG‑induced activation of NLRP3 was mediated by the activation of Syk/JNK, which subsequently increased the protein expression levels of mature IL‑1β, suggesting that the Syk/JNK/NLRP3 signaling pathway serves a critical role in the pathogenesis of DCM.

[Importance of an Aldehyde Dehydrogenase 2 Polymorphism in Preventive Medicine]

Unlike genetic alterations in other aldehyde dehydrogenase (ALDH) isozymes, a defective ALDH2 polymorphism (rs671), which is carried by almost half of East Asians, does not show a clear phenotype such as a shortened life span. However, impacts of a defective ALDH2 allele, ALDH2*2, on various disease risks have been reported. As ALDH2 is responsible for the detoxification of endogenous aldehydes, a negative effect of this polymorphism is predicted, but bidirectional effects have been actually observed and the mechanisms underlying such influences are often complex. One reason for this complexity may be the existence of compensatory aldehyde detoxification systems and the secondary effects of these systems. There are many issues to be addressed with regard to the ALDH2 polymorphism in the field of preventive medicine, including the following concerns. First, ALDH2 in the fetal stage plays a role in aldehyde detoxification; therefore, prenatal health effects of environmental aldehyde exposure are of concern for ALDH2*2-carrying fetuses. Second, ALDH2*2 carriers are at high risk of drinking-related cancers. However, their drinking habits result in less worsening of physiological findings, such as energy metabolism index and liver functions, compared with non-ALDH2*2 carriers, and therefore opportunities to detect excessive drinking can be lost. Third, personalized medicine such as personalized prescriptions for ALDH2*2 carriers will be required in the clinical setting, and accumulation of evidence is awaited. Lastly, since the ALDH2 polymorphism is not considered in workers' limits of exposure to aldehydes and their precursors, efforts to lower exposure levels beyond legal standards are required.

Comparison of serological assessments in the diagnosis of liver fibrosis in bile duct ligation mice

Liver fibrosis assessment is essential to make a prognosis and to determine the appropriate anti-fibrosis treatment. Non-invasive serum markers are widely studied in patients to assess liver fibrosis due to the limitations of liver biopsy. When using animal models to study the mechanism and intervention of hepatic fibrosis, serum markers might be useful for the continuous assessment of liver fibrosis in individual animals, which could avoid the influence of biological differences between individuals. However, it is unclear whether serum markers can assess hepatic fibrosis in the animal model. In the present study, we evaluated and compared the ability of four serum markers to assess liver fibrosis in bile duct ligation mice. According to the stages of liver fibrosis assessed by pathological changes, mice in this study were divided into five groups (F0, F1, F2, F3, and F4). Subsequently, four serum markers, aspartate aminotransferase-to-alanine aminotransferase ratio (AAR), aspartate aminotransferase-to-platelet ratio index (APRI), fibrosis index based on the 4 factors (FIB-4), and Forns Index, were calculated for each group. Furthermore, the correlations between serum markers and pathological stages and the ability of serological markers to evaluate liver fibrosis were analyzed. AAR, APRI, FIB-4, and Forns Index could significantly distinguish F0-2 from F3-4 mice. APRI, FIB-4, and Forns Index could detect F0-3 from F4 mice. Among these four markers, FIB-4 was the best able to distinguish ≥F2 and ≥F3, with area under the curve values of 0.882 and 0.92, respectively. Forns Index was best for diagnosing F4 with area under the curve value of 0.879. These results demonstrated that serum markers could be used for assessing liver fibrosis in bile duct ligation mice, and therefore, these markers might lead to more accurate diagnostic and therapeutic studies through continuous monitoring in individual animals. Impact statement The assessment of liver fibrosis is essential for making a prognosis and determining the appropriate anti-fibrosis treatment. In studies focusing on the mechanism and treatment of liver fibrosis using animal models, it would be more accurate to continuously evaluate liver fibrosis in a single animal to avoid individual biological differences. Unfortunately, it is difficult to perform continuous assessment through liver biopsy in the most commonly used rodent models. It is unclear whether serum markers, which have been used in hepatic fibrosis patients, could be used in animal models. Our results demonstrate that serum markers could be used for assessing liver fibrosis in bile duct ligation mice. This study might contribute to more accurate diagnostic and therapeutic studies through continuous monitoring in individual animals.