Aminotransferase activity in the liver of diabetic mice

Pharmacological and Pathological Effects of Mulberry Leaf Extract on the Treatment of Type 1 Diabetes Mellitus Mice

This study investigated the pharmacological and pathological effects of aqueous mulberry leaf extract on type 1 diabetes mellitus mice induced with an intraperitoneal injection of streptozotocin (STZ). Diabetic mice were randomized into six groups: control (normal group), model, metformin-treated mice, and high-dose, medium-dose, and low-dose mulberry. The mulberry-treated mice were divided into high-, medium-, and low-dose groups based on the various doses of aqueous mulberry leaf extract during gavage. The efficacy of the six-week intervention was evaluated by measuring levels of fasting plasma glucose, alkaline phosphatase, alanine aminotransferase, aspartate transaminase, blood urea nitrogen, gamma-glutamyl transferase, glucose, high-density lipoprotein cholesterol, lactate dehydrogenase, and low-density lipoprotein cholesterol and recording body weight. Results revealed that mulberry leaf extract exhibited an ideal hypoglycemic effect, and the high-dose group was the most affected. Histology analysis, glycogen staining and apoptosis detection were used to study the extract's effects on the liver, kidney, and pancreatic cells of diabetic mice, enabling the assessment of its effectiveness and complications on a clinical and theoretical basis. It was shown that a certain concentration of aqueous mulberry leaf extract repaired the islet cells of type 1 diabetes mellitus mice, promoting normal insulin secretion. Herein, it was confirmed that mulberry leaf could be used to develop new hypoglycemic drugs or functional health food with broad applicability.

Evaluating the Effects of Low Carbohydrate and High Protein Diet on Erectile Function in Rats

Introduction

Carbohydrate restriction in diet is becoming a popular means of losing weight nowadays, although it has been reported that excessive intake of low-carbohydrate and high-protein (LCHP) diet causes an adverse effect on cardiovascular function.

Aim

To investigate the influence of LCHP on erectile function in rats.

Methods

A total of 48, 12-week-old rats were divided into 2 groups and either fed a LCHP diet (LCHP group) or a normal diet (Control group). Hematological examination, blood pressure evaluation, erectile function assessments as well as evaluations of the relaxation and contractile responses of corpus cavernosum were carried out in these rats by using standardized methods. Statistical analysis using 2-way ANOVA and Welch's t-test was conducted to examine the obtained data.

Main Outcome Measure

At the end of the study period, the evaluated outcomes to assess erectile function were intracavernosal pressure , mean arterial pressure , endothelial functions, nitric oxide (NO)-operated nerve functions and the expressions of endothelial nitric oxide synthase (eNOS), neuronal nitric oxide synthase (nNOS), and sphingosine-1-phosphate receptor 1 (S1P1).

Results

The intracavernosal pressure / mean arterial pressure ratio was significantly lower in the LCHP group (P < .05) at 4 weeks. Compared to the Control group, the LCHP group exhibited significantly lower responses to ACh and EFS and a decreased nNOS mRNA expression. The results based on this animal model indicate that extreme carbohydrate restricted diet may affect erectile function. Our study identified that LCHP decreased erectile function in rats. A major limitation of this study is, due to the extreme condition of completely replacing carbohydrates with protein, that carbohydrate intake will be gradually increased in the future.

Conclusion

Extreme carbohydrate restriction and high protein in diet may cause ED with vascular endothelial dysfunction and a decrease in the relaxation response of the corpus cavernosum smooth muscle via NO-operated nerves.

Kataoka T, Hidaka J, Suzuki J, et al. Evaluating the Effects of Low Carbohydrate and High Protein Diet on Erectile Function in Rats. Sex Med 2021;10:100500.

miR-150-PTPMT1-cardiolipin signaling in pulmonary arterial hypertension

Circulating levels of endothelial miR-150 are reduced in pulmonary arterial hypertension (PAH) and act as an independent predictor of patient survival, but links between endothelial miR-150 and vascular dysfunction are not well understood. We studied the effects of endothelial miR-150 supplementation and inhibition in PAH mice and cells from patients with idiopathic PAH. The role of selected mediators of miR-150 identified by RNA sequencing was evaluated in vitro and in vivo. Endothelium-targeted miR-150 delivery prevented the disease in Sugen/hypoxia mice, while endothelial knockdown of miR-150 had adverse effects. miR-150 target genes revealed significant associations with PAH pathways, including proliferation, inflammation, and phospholipid signaling, with PTEN-like mitochondrial phosphatase (PTPMT1) most markedly altered. PTPMT1 reduced inflammation and apoptosis and improved mitochondrial function in human pulmonary endothelial cells and blood-derived endothelial colony-forming cells from idiopathic PAH. Beneficial effects of miR-150 in vitro and in vivo were linked with PTPMT1-dependent biosynthesis of mitochondrial phospholipid cardiolipin and reduced expression of pro-apoptotic, pro-inflammatory, and pro-fibrotic genes, including c-MYB, NOTCH3, transforming growth factor β (TGF-β), and Col1a1. In conclusion, we are the first to show that miR-150 supplementation attenuates pulmonary endothelial damage induced by vascular stresses and may be considered as a potential therapeutic strategy in PAH.

Accuracy of Noninvasive Fibrosis Scores to Detect Advanced Fibrosis in Patients With Type-2 Diabetes With Biopsy-proven Nonalcoholic Fatty Liver Disease

BACKGROUND

Recent guidelines have recommended screening for nonalcoholic fatty liver disease (NAFLD) and case finding of advanced disease with fibrosis in patients with type-2 diabetes (T2D). The aim of this study is to assess the accuracy of commonly used noninvasive scores to predict the presence of advanced fibrosis (AF) in a large cohort of diabetics in real-life settings.

PATIENTS AND METHODS

Using International Classification of Diseases, Ninth Revision (ICD-9) codes, all patients with the diagnosis of T2D who had a liver biopsy for suspected NAFLD between January 2000 and December 2015, were identified and analyzed. Patients with secondary causes of hepatic steatosis were excluded. AST/ALT ratio, aspartate aminotransferase to platelet ratio index (APRI), fibrosis-4 (FIB-4) index, and Nonalcoholic fatty liver disease Fibrosis Score (NFS) were calculated to predict advanced disease. Sensitivity, specificity, and area under the receiver operator curve were calculated and compared with liver biopsies to predict the overall accuracy of each score.

RESULTS

A total of 1319 patients with T2D underwent liver biopsy for suspected NAFLD. After exclusions, 1,157 subjects were included in the final analysis. Our cohort consisted of 64.6% females and 88.4% were whites. Overall, 85% of the population was overweight or obese (body mass index>25 kg/m). Liver biopsy showed 31.7% with AF [Nonalcoholic Steatohepatitis Clinical Research Network (NASH-CRN) stage 3 to 4]. In comparison to liver biopsy, for the diagnosis of AF, AST/ALT>1.4, APRI>1.5, FIB-4>2.67, and NFS>0.676 had reasonable specificities of 84.2%, 97.4%, 69.9%, and 93% but poor sensitivities of 27.4%, 16.5%, 6.7%, and 44.1%, respectively. Even at lower cutoff values of AST/ALT≥1, APRI≥1, and FIB-4≥1.45 sensitivities remained low at 60.7%, 27.9%, and 72.6%, respectively, except for NFS ≥-1.455 with sensitivity of 94.6%, but at this cutoff, its specificity decreased to 16.9%. The area under the receiver operator curve to detect AF was 0.62, 0.74, 0.77, and 0.72, respectively.

CONCLUSIONS

In this large cohort of adult patients with T2D and NAFLD, commonly used fibrosis scores had reasonable specificity, but poor sensitivity for detecting AF in diabetics. The development of reliable biomarkers for NAFLD/NASH in diabetics is urgently needed.

Investigation of endoplasmic reticulum stress and sonic hedgehog pathway in diabetic liver injury in mice

AIMS

Diabetes is a common metabolic disease which damages many organs including the liver and causes endoplasmic reticulum (ER) stress, which originates from non-folded proteins. Sonic hedgehog (Shh) pathway plays a role in liver regeneration and repair. To our knowledge, there is no study showing the relation between ER stress and Shh pathway in the liver in diabetes. Thus, the aim of this study was to investigate the interaction between ER stress and Shh pathway in the liver of diabetic mice.

MAIN METHODS

Six groups of male mice were formed as control, diabetes (streptozotocine-treated), Shh activator (SAG-treated), Shh inhibitor (SANT1-treated), diabetes + SAG and diabetes + SANT1. At the end of the experiment, mice were weighed, anaesthetized and euthanized. Blood samples were collected, livers were excised and weighed. Thereafter, blood glucose, serum ALT and AST levels, TOS and TAC levels in liver tissue were measured. ER stress marker (GRP78) and Shh pathway molecules (Gli1 and Smo) were evaluated by immunohistochemistry, H-score and western blot analyses. Besides, histopathological examination was performed.

KEY FINDINGS

Results showed that GRP78, Gli1 and Smo were increased in liver due to Type 1 diabetes. The SAG agent decreased GRP78 and increased Gli1 and Smo, leading to liver repair, while the inhibitor SANT1 increased GRP78 and decreased Gli1and Smo, causing progression of the liver stress induced by diabetes.

SIGNIFICANCE

In conclusion, the Shh pathway is related to ER stress and may provide a new strategy for its treatment, especially liver stress induced by diabetes.

Diabetes impacts prediction of cirrhosis and prognosis by non-invasive fibrosis models in non-alcoholic fatty liver disease

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) patients with diabetes are at increased risk of cirrhosis and liver-related death, and thus accurate fibrosis assessment in these patients is important. We examined the ability of non-invasive fibrosis models to determine cirrhosis and outcomes in NAFLD patients with and without diabetes.

METHODS

Non-alcoholic fatty liver disease patients diagnosed between 2006 and 2015 had Hepascore, NAFLD fibrosis score (NFS), APRI and FIB-4 scores calculated at baseline and were followed up for outcomes of overall and liver-related mortality/liver transplantation, hepatic decompensation and hepatocellular carcinoma (HCC). Model accuracy was determined by Harrell's C-index and by Kaplan-Meier analysis.

RESULTS

A total of 284 patients (53% diabetic, 15% cirrhotic) were followed up for a median of 51.4 months, (range 6.1-146). During follow-up, diabetic patients had a greater risk of liver-related death/transplantation, HR 3.4 (95% CI 1.2-9.1) decompensation, HR 4.7 (95% CI 2.0-11.3) and HCC, HR 2.9 (95% CI 1.2-7.3). Among 241 subjects with a baseline liver biopsy, the accuracy of Hepascore, APRI and FIB-4 for predicting cirrhosis was lower amongst diabetics compared to non-diabetics (P < .005 for all). Model accuracy apart from Hepascore, was also significantly lower for predicting liver death/transplantation in patients with diabetes. No patient with a low fibrosis score and without diabetes developed liver decompensation or HCC, whereas up to 21% of diabetic patients with a low fibrosis score developed liver decompensation and up to 27% developed HCC at 5 years.

CONCLUSIONS

Non-invasive scoring systems are less accurate at predicting cirrhosis and liver-related outcomes in patients with NAFLD and diabetes.

Diabetes escalates knee osteoarthritis in rats: Evidence of adaptive mechanism

Clinical reports on the coexistence of diabetes mellitus (DM) and osteoarthritis (OA) dated back to the 1960 s. Therefore, the study investigated the effects of induced DM and/or knee osteoarthritis (KOA) on known biomarkers in male Wistar rats. Twenty rats of five animals per group were induced with DM and/or knee OA using streptozotocin plus nicotinamide and sodium monoiodoacetate. Afterwards, they were left untreated for four weeks.The results showed that pro-inflammatory and pro-oxidative events were most significantly expressed in D + OA group and least in OA group. In contrast to the other experimental groups, there was a decreased bone formation in DM group.Unexpectedly, there were significant increases in bone and cartilage degradation markers in diabetic group, relative to D + OA group. In conclusion, diabetic-osteoarthritic state is characterised by more altered biochemical profile, relative to what is probable in either disease condition. Nevertheless, this situation remains subject to the influence of endogenous homeostatic mechanisms.

Synergistic and non-synergistic effects of salmon calcitonin and omega - 3 fatty acids on antioxidant, anti-inflammatory, and haematological indices in diabetic rats

The optimum therapy for the management of diabetes mellitus (DM) has been a controversial issue. Therefore, the study investigated the effects of salmon calcitonin (Sct) and/or omega-3 fatty acids {eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); EPA/DHA ratio?=?3/2} relative to metformin in diabetic male Wistar rats. Forty rats were used for this study. They were randomly divided into 8 groups of five (5) rats each, which were treated with single or combined administration of salmon calcitonin, N-3 and metformin. DM was induced by the administration of streptozotocin (65?mg/kg b.w., i.p.), 15?min after the administration of nicotinamide (110?mg/kg b.w., i.p.). Nine days afterwards, treatments started, and they lasted for 28 days. Sct was administered at 2.5 and 5.0 IU/kg b.w./day (i.m.), while, N-3 and metformin were administered at 200 and 180?mg/kg b.w./day (p.o.) respectively. The results showed that the induced DM significantly increased pro-inflammatory markers, and significantly altered antioxidant and haematological indices. The combined administration of Sct and N-3 had synergistic effects on total bilirubin and total antioxidant capacity, but, non-synergistic actions on malondialdehyde, uric acid, interleukin-6, lactate dehydrogenase, superoxide dismutase, catalase, glutathione peroxidase, and the haematological parameters. These effects were comparable to that of metformin which showed a more or less therapeutic action than N-3. The study concluded that the antioxidant, anti-inflammatory, and haematological effects of the combined administration of Sct and N-3 is comparable to that of metformin. Nevertheless, the latter showed more or less therapeutic effects relative to N-3.

Diabetes mellitus reduces the clearance of atorvastatin lactone: results of a population pharmacokinetic analysis in renal transplant recipients and in vitro studies using human liver microsomes

BACKGROUND AND OBJECTIVE

Patients with diabetes mellitus might be at a higher risk of HMG-CoA reductase inhibitor (statin)-induced myotoxicity, possibly because of reduced clearance of the statin lactone. The present study was designed to investigate the effect of diabetes on the biotransformation of atorvastatin acid, both in vivo in nondiabetic and diabetic renal transplant recipients, and in vitro in human liver samples from nondiabetic and diabetic donors.

SUBJECTS AND METHODS

A total of 312 plasma concentrations of atorvastatin acid and atorvastatin lactone, from 20 nondiabetic and 32 diabetic renal transplant recipients, were included in the analysis. Nonlinear mixed-effects modelling was employed to determine the population pharmacokinetic estimates for atorvastatin acid and atorvastatin lactone. In addition, the biotransformation of these compounds was studied using human liver microsomal fractions obtained from 12 nondiabetic and 12 diabetic donors.

RESULTS

In diabetic patients, the plasma concentration of atorvastatin lactone was significantly higher than that of atorvastatin acid throughout the 24-hour sampling period. The optimal population pharmacokinetic model for atorvastatin acid and atorvastatin lactone consisted of a two- and one-compartment model, respectively, with interconversion between atorvastatin acid and atorvastatin lactone. Parent drug was absorbed orally with a population estimate first-order absorption rate constant of 0.457 h(-1). The population estimates of apparent oral clearance (CL/F) of atorvastatin acid to atorvastatin lactone, intercompartmental clearance (Q/F), apparent central compartment volume of distribution after oral administration (V(1)/F) and apparent peripheral compartment volume of distribution after oral administration (V(2)/F) for atorvastatin acid were 231 L/h, 315 L/h, 325 L and 4910 L, respectively. The population estimates of apparent total clearance of atorvastatin lactone (CL(M)/F), apparent intercompartmental clearance of atorvastatin lactone (Q(M)/F) and apparent volume of distribution of atorvastatin lactone after oral administration (V(M)/F) were 85.4 L/h, 166 L/h and 249 L, respectively. The final covariate model indicated that the liver enzyme lactate dehydrogenase was related to CL/F and alanine aminotransferase (ALT) was related to Q/F. Importantly, diabetic patients have 3.56 times lower CL(M)/F than nondiabetic patients, indicating significantly lower clearance of atorvastatin lactone in these patients. Moreover, in a multivariate population pharmacokinetics model, diabetes status was the only significant covariate predicting the values of the CL(M)/F. Correspondingly, the concentration of atorvastatin acid remaining in the microsomal incubation was not significantly different between nondiabetic and diabetic liver samples, whereas the concentration of atorvastatin lactone was significantly higher in the samples from diabetic donors. In vitro studies, using recombinant enzymes, revealed that cytochrome P450 (CYP) 3A4 is the major CYP enzyme responsible for the biotransformation of atorvastatin lactone.

CONCLUSIONS

These studies provide compelling evidence that the clearance of atorvastatin lactone is significantly reduced by diabetes, which leads to an increased concentration of this metabolite. This finding can be clinically valuable for diabetic transplant recipients who have additional co-morbidities and are on multiple medications.

Prevention and treatment of diabetes with resveratrol in a non-obese mouse model of type 1 diabetes

AIMS/HYPOTHESIS

We recently found that activation of the type III histone deacetylase sirtuin 1 suppresses T cell immune responses. Here we sought to determine the therapeutic potential of the sirtuin 1 activator resveratrol in the treatment of diabetes in the NOD mouse model of type 1 diabetes and the mechanisms underlying such potential.

METHODS

NOD mice were fed or subcutaneously injected with resveratrol and evaluated for development of diabetes. Splenocytes from resveratrol-treated and control mice were analysed by gene array. The altered expression of inflammatory genes induced by resveratrol was validated and the role of changed gene expression in prevention of diabetes was determined.

RESULTS

Resveratrol administration potently prevented and treated type 1 diabetes in NOD mice. Gene array analysis indicated a dramatic decrease in expression of Ccr6, which encodes chemokine (C-C motif) receptor (CCR) 6, in the splenocytes from resveratrol-treated mice. CCR6 abundance on IL-17-producing cells and CD11b(+)F4/80(hi) macrophages was inhibited by resveratrol treatment. Interestingly, CCR6(+) IL-17-producing cells and CD11b(+)F4/80(hi) macrophages accumulated in the spleens and pancreatic lymph nodes, but their presence in the pancreas was reduced, suggesting that resveratrol blocks their migration from peripheral lymphoid organs to the pancreas. Indeed, the migration of splenocytes toward media containing chemokine (C-C motif) ligand 20 (CCL20) was impaired by resveratrol treatment. CCL20 peptides, which block CCR6 binding to CCL20, inhibited development of type 1 diabetes.

CONCLUSIONS/INTERPRETATION

Inhibition of CCR6-mediated migration of inflammatory cells by resveratrol may provide a powerful approach for treatment of type 1 diabetes and possibly of other inflammatory diseases.

Restoration of chaperone-mediated autophagy in aging liver improves cellular maintenance and hepatic function

Chaperone-mediated autophagy (CMA), a selective mechanism for degradation of cytosolic proteins in lysosomes, contributes to the removal of altered proteins as part of the cellular quality-control systems. We have previously found that CMA activity declines in aged organisms and have proposed that this failure in cellular clearance could contribute to the accumulation of altered proteins, the abnormal cellular homeostasis and, eventually, the functional loss characteristic of aged organisms. To determine whether these negative features of aging can be prevented by maintaining efficient autophagic activity until late in life, in this work we have corrected the CMA defect in aged rodents. We have generated a double transgenic mouse model in which the amount of the lysosomal receptor for CMA, previously shown to decrease in abundance with age, can be modulated. We have analyzed in this model the consequences of preventing the age-dependent decrease in receptor abundance in aged rodents at the cellular and organ levels. We show here that CMA activity is maintained until advanced ages if the decrease in the receptor abundance is prevented and that preservation of autophagic activity is associated with lower intracellular accumulation of damaged proteins, better ability to handle protein damage and improved organ function.

Changes on levels of B6 vitamin and aminotransferase in the liver of diabetic animals

We measured aminotransferase activity and vitamin B6 content in the livers of diabetic mice. Two different types of mice were used for the measurements, spontaneously non-obese diabetic (NOD) or alloxan-induced diabetic (Allo) mice, and control mice were either non-diabetic NOD or Institute of Cancer Research (ICR). The liver of diabetic mice had more aspartate aminotransferase (AST) activity than those of normal mice. The diabetic livers also had more vitamin B6 than did normal livers, and pyridoxamine (PM) levels were particularly high but pyridoxal (PL) levels were not. ICR livers showed hepatic alanine aminotransferase activities inversely correlated with blood glucose concentrations, while diabetic livers did not. The abundance of AST and B6 in the diabetic liver is consistent with the great need for gluconeogenic substrate there. This is understandable in that most aminotransferases require B6 vitamins, and especially the correlation between s-AST and PM levels was recognized in the diabetic liver. Conversely, the AST and PM levels were negatively correlated in normal mice. A metabolic shift towards gluconeogenesis apparently produces more B6 and PM while it induced holo-AST synthesis.