Adiponectin deficiency-induced diabetes increases TNFα and FFA via downregulation of PPARα

Enhanced hepatoprotective effects of empagliflozin and vitamin D dual therapy against metabolic dysfunction-associated steatohepatitis in mice by boosted modulation of metabolic, oxidative stress, and inflammatory pathways

Although single treatment with sodium-glucose cotransporter-2 inhibitors (SGLT2i) or vitamin D3 (VD3) inhibited metabolic dysfunction-associated steatohepatitis (MASH) development in diabetic patients, their combination has not been explored previously. Hence, this study investigated the hepatoprotective effects of SGLT2i (empagliflozin) and/or VD3 against MASH in type 2 diabetic mice. Forty Mice were assigned into negative (NC) and positive (PC) controls, SGLT2i, VD3, and SGLT2i + VD3 groups. All animals, except the NC group, received high-fructose/high-fat diet (8 weeks) followed by diabetes induction. Diabetic mice then received another cycle of high-fructose/high-fat diet (4 weeks) followed by 8 weeks of treatment (five times/week) with SGLT2i (5.1 mg/kg/day) and/or VD3 (410 IU/Kg/day). The PC group demonstrated hyperglycaemia, dyslipidaemia, elevated liver enzymes, and increased non-alcoholic fatty liver disease activity score (NAS) with fibrosis. Hepatic glucose transporting molecule (SGLT2) with lipogenesis (SREBP-1/PPARγ), oxidative stress (MDA/H2O2), inflammation (IL1β/IL6/TNF-α), fibrosis (TGF-β1/α-SMA), and apoptosis (TUNEL/Caspase-3) markers alongside the PI3K/AKT/mTOR pathway increased in the PC group. Conversely, hepatic insulin-dependent glucose transporter (GLUT4), lipolytic (PPARα/INSIG1), antioxidant (GSH/GPx1/SOD1/CAT), and anti-inflammatory (IL-10) molecules with the inhibitor of PI3K/AKT/mTOR pathway (PTEN) decreased in the PC group. Whilst SGLT2i monotherapy outperformed VD3, their combination showed the best attenuation of hyperglycaemia, dyslipidaemia, and fibrosis with the strongest modulation of hepatic glucose-transporting and lipid-regulatory molecules, PI3K/AKT/mTOR pathway, and markers of oxidative stress, inflammation, fibrosis, and apoptosis. This study is the first to reveal boosted hepatoprotection for SGLT2i and VD3 co-therapy against diabetes-induced MASH, possibly via enhanced metabolic control and modulation of hepatic PI3K/AKT/mTOR, anti-inflammatory, anti-oxidative, and anti-fibrotic pathways.

Influence of diet and body weight in treatment-resistant acquired partial lipodystrophy after hematopoietic stem cell transplantation and its potential for metabolic improvement

Lipodystrophy is a rare disease characterized by various metabolic complications resulting from the complete or partial loss of adipose tissues and abnormal fat accumulation. Acquired lipodystrophy may occur due to certain drugs, autoimmunity or for unknown reasons. Recently, cases of acquired lipodystrophy after hematopoietic stem cell transplantation (HSCT) have been reported. Leptin administration, used recently to treat generalized lipodystrophy, effectively controlled metabolic complications; however, few reports demonstrated the effectiveness of leptin for acquired partial lipodystrophy. In this report, we present the case of a 17-year-old woman who developed insulin resistance, hypertriglyceridemia, and fatty liver after HSCT. Due to her thin gluteal fat and low blood adiponectin levels, her metabolic abnormalities were attributed to partial lipodystrophy. While both leptin and pemafibrate administration partially attenuated metabolic abnormalities, its effects were relatively limited, probably because the serum leptin levels were maintained, which is not likely in generalized lipodystrophy. Nevertheless, after she developed adjustment disorder and experienced weight loss, along with decreased food intake, her metabolic markers significantly improved. This case suggests the modest effect of leptin and permafibrate in partial lipodystrophy after HSCT, highlighting the importance of diet therapy in metreleptin treatment for acquired partial lipodystrophy.

Neurological and metabolic related pathophysiologies and treatment of comorbid diabetes with depression

BACKGROUND

The comorbidity between diabetes mellitus and depression was revealed, and diabetes mellitus increased the prevalence of depressive disorder, which ranked 13th in the leading causes of disability-adjusted life-years. Insulin resistance, which is common in diabetes mellitus, has increased the risk of depressive symptoms in both humans and animals. However, the mechanisms behind the comorbidity are multi-factorial and complicated. There is still no causal chain to explain the comorbidity exactly. Moreover, Selective serotonin reuptake inhibitors, insulin and metformin, which are recommended for treating diabetes mellitus-induced depression, were found to be a risk factor in some complications of diabetes.

AIMS

Given these problems, many researchers made remarkable efforts to analyze diabetes complicating depression from different aspects, including insulin resistance, stress and Hypothalamic-Pituitary-Adrenal axis, neurological system, oxidative stress, and inflammation. Drug therapy, such as Hydrogen Sulfide, Cannabidiol, Ascorbic Acid and Hesperidin, are conducive to alleviating diabetes mellitus and depression. Here, we reviewed the exact pathophysiology underlying the comorbidity between depressive disorder and diabetes mellitus and drug therapy.

METHODS

The review refers to the available literature in PubMed and Web of Science, searching critical terms related to diabetes mellitus, depression and drug therapy.

RESULTS

In this review, we found that brain structure and function, neurogenesis, brain-derived neurotrophic factor and glucose and lipid metabolism were involved in the pathophysiology of the comorbidity. Obesity might lead to diabetes mellitus and depression through reduced adiponectin and increased leptin and resistin. In addition, drug therapy displayed in this review could expand the region of potential therapy.

CONCLUSIONS

The review summarizes the mechanisms underlying the comorbidity. It also overviews drug therapy with anti-diabetic and anti-depressant effects.

Vitamin D3 enhances the effects of omega-3 oils against metabolic dysfunction-associated fatty liver disease in rat

This study investigated the effects of omega-3 oils (OM) and/or vitamin D₃ (VD) against metabolic dysfunction-associated fatty liver disease (MAFLD). Forty rats were divided into negative (NC) and positive (PC) controls, OM, VD, and OM + VD groups, and MAFLD was induced by high-fat/high-fructose diet (12 weeks). Oral OM (415 mg/kg/day) and/or intramuscular VD (290 IU/kg/day) were given for 4 weeks (5 times/week). The PC animals were markedly obese and had hyperglycemia, insulin resistance, dyslipidemia, elevated liver enzymes, abnormal hepatic histology, and increased caspase-3 with apoptosis than the NC group. The expression of hepatic peroxisome proliferator-activated receptor-α (PPAR-α; 5.3-fold), insulin induced gene-1 (INSIG1; 7.8-fold), adiponectin receptor-1 (AdipoR1; 4.4-fold), and leptin receptor (LEPR; 6-fold) declined, while PPAR-γ (3.7-fold) and sterol regulatory element-binding protein-1 (SREBP1; 2.4-fold) increased, in the PC than the NC group. Leptin (2.2-fold), malondialdehyde (2.1-fold), protein carbonyl groups (17.3-fold), IL-1β (4.4-fold), IL-6 (2.1-fold), TNF-α (1.8-fold) also increased, whereas adiponectin (2.8-fold) glutathione (2.1-fold), glutathione peroxidase-1 (2.4-fold), glutathione reductase (2.2-fold), catalase (1.4-fold), and IL-10 (2.8-fold) decreased, in the PC livers. Both monotherapies attenuated obesity, metabolic profiles, and PPAR-γ/SREBP1/leptin/Caspase-3/apoptosis, while induced PPAR-α/adiponectin/AdipoR1/LEPR/INSIG1. The monotherapies also reduced the oxidative stress and pro-inflammatory markers and increased the antioxidant and anti-inflammatory molecules. However, the OM effects were better than VD monotherapy. Alternatively, the co-therapy group showed the greatest ameliorations in liver functions, lipid-regulatory molecules, oxidative stress, inflammation, and apoptosis. In conclusion, while OM monotherapy was superior to VD, the co-therapy protocol displayed the best alleviations against MAFLD, possibly by enhanced modulation of metabolic, antioxidant, and anti-inflammatory pathways.

Decrease in Serum Levels of Adiponectin and Increase in 8-OHdG: a Culprit for Cognitive Impairment in the Elderly Patients with Type 2 Diabetes

BACKGROUND

Adiponectin and 8-Hydroxy-2'-deoxyguanosine (8-OHdG) are identified as important biomarkers in the pathogenesis process of type 2 diabetes mellitus (T2DM). Whether adiponectin and 8-OHdG have a relation to cognitive decline in the elderly T2DM patients has been poorly understood. The aim of this study was to evaluate the effects of adiponectin and 8-OHdG in the elderly patients with T2DM and to determine the role of adiponectin and 8-OHdG in the cognitive impairment of the elderly patients with T2DM.

METHODS

57 individuals were recruited and analyzed , with 26 cases of T2DM without cognitive impairment and 31 cases of T2DM with cognitive impairment. All of them underwent an examination of diabetes scales and blood glucose at different times. A primary diagnosis of diabetes was in line with the diagnosis criteria set by the American Diabetes Association (ADA). Statistical significance was defined as a P-value of less than 0.05.

RESULTS

The variables of sex, age, body mass index (BMI), hypertension, diabetes, metabolic syndrome, lacunar cerebral infarction, smoking and drinking in T2DM patients without cognitive impairment and with cognitive impairment showed no difference according to the univariate analysis exploring each variable separately (p>0.05). A significant difference was observed in the serum levels of adiponectin and 8-OHdG and the scales of MMSE and MoCA (p<0.05). Therefore, it was inferred that there is no correlation between glucose metabolic value and cognitive outcome of T2DM patients. Serum levels of adiponectin and 8-OHdG could act as biomarkers of cognitive impairment degree in the elderly T2DM patients.

CONCLUSION

Serum levels of adiponectin and 8-OHdG could act as specific and sensitive biomarkers for the early diagnosis and treatment of cognitive impairment in elderly T2DM patients. Serum levels of adiponectin and 8-OHdG have a close relation to the neurological cognitive outcome of the elderly T2DM patients.

The effect of adiponectin in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) and the potential role of polyphenols in the modulation of adiponectin signaling

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide, as it affects up to 30 % of adults in Western countries. Moreover, NAFLD is also considered an independent risk factor for cardiovascular diseases. Insulin resistance and inflammation have been identified as key factors in the pathophysiology of NAFLD. Although the mechanisms associated with the development of NAFLD remain to be fully elucidated, a complex interaction between adipokines and cytokines appear to play a crucial role in the development of this condition. Adiponectin is the most common adipokine known to be inversely linked with insulin resistance, lipid accumulation, inflammation and NAFLD. Consequently, the focus has been on the use of new therapies that may enhance hepatic expression of adiponectin downstream targets or increase the serum levels of adiponectin in the treatment NAFLD. While currently used therapies show limited efficacy in this aspect, accumulating evidence suggest that various dietary polyphenols may stimulate adiponectin levels, offering potential protection against the development of insulin resistance, inflammation and NAFLD as well as associated conditions of metabolic syndrome. As such, this review provides a better understanding of the role polyphenols play in modulating adiponectin signaling to protect against NAFLD. A brief discussion on the regulation of adiponectin during disease pathophysiology is also covered to underscore the potential protective effects of polyphenols against NAFLD. Some of the prominent polyphenols described in the manuscript include aspalathin, berberine, catechins, chlorogenic acid, curcumin, genistein, piperine, quercetin, and resveratrol.

Adiponectin Expression and Genotypes in Italian People with Severe Obesity Undergone a Hypocaloric Diet and Physical Exercise Program

Adiponectin exerts positive effects on metabolic and inflammatory processes. Adiponectin levels and some single-nucleotide polymorphisms (SNPs) seem to be associated with obesity. Here, we investigated the effects of a 4-week Hypocaloric diet and Physical exercise Program (HPP) on 268 young people with severe obesity. We evaluated the relationship between adiponectin levels and anthropometric and biochemical parameters, at baseline and after a 4-week HPP. Finally, we investigated some adiponectin gene variants and their correlation to biochemical parameters. Adiponectin levels were statistically lower in people with severe obesity than in controls. At the end of the HPP, all the people with severe obesity showed a Body Mass Index (BMI) reduction with a statistically significant increase in adiponectin levels. Genotyping, the adiponectin gene demonstrated a significant difference in 3 polymorphisms within the people with severe obesity. Besides, c.11377C>G and c.11391G>A homozygous subjects experienced more advantages by HPP. Furthermore, c.268G>A heterozygous subjects showed an enhancement in lipid profile as well in adiponectin levels. The best predictor of the changes in adiponectin levels was represented by the c.268G>A WT allele. Our study confirmed that a 4-weeks HPP in people with severe obesity results in metabolic amelioration associated with a significant increase of adiponectin levels. Importantly, we found that a specific genetic background in the ADIPOQ gene can predispose toward a more significant weight loss.

Role of adiponectin/peroxisome proliferator-activated receptor alpha signaling in human chorionic gonadotropin-induced estradiol synthesis in human luteinized granulosa cells

Impaired steroid production in polycystic ovary syndrome (PCOS) may result from adiponectin system dysfunction. However, adiponectin's role in ovulatory dysfunction remains unclear. We aimed to determine whether human chorionic gonadotropin (hCG) and adiponectin affect progesterone and estradiol secretion by granulosa cells (GCs) from overweight or obese women with PCOS or normal ovulation. ADIPOR2 expression was higher in hCG-treated GCs from PCOS patients than in those from normovulatory women. hCG may upregulate ADIPOR2 expression through cAMP/PKA signaling in GCs. GCs from both groups expressed PPARA. Estradiol levels were lower in hCG + adiponectin-treated GCs from PCOS patients than in those from normovulatory women. hCG + adiponectin decreased P450 aromatase expression through adiponectin/PPARα signaling in GCs. Adiponectin downregulates hCG-induced estradiol levels in GCs from overweight or obese women through gonadotropin-adiponectin crosstalk. Changes in gonadotropin and adiponectin signaling in the ovarian microenvironment may improve symptoms in women with PCOS.

Effects of Piceatannol and Resveratrol on Sirtuins and Hepatic Inflammation in High-Fat Diet-Fed Mice

Piceatannol (PIC) is a natural hydroxylated analog of resveratrol (RSV) and considered as a potential metabolic regulator. The purpose of this study was to compare the effects of PIC and RSV on parameters affecting inflammation, oxidative stress, and sirtuins (Sirt). Male C57BL/6J mice, 20 weeks old, were assigned to the following groups; (1) lean control, (2) high-fat diet control (HF), (3) HF_PIC, and (4) HF_RSV. Oral administration of PIC and RSV (10 mg/kg/day) for 4 weeks improved glucose control as shown by decreasing levels of area under the curve (AUC) during the oral glucose tolerance test compared with HF group. PIC improved glycemic control by increasing hepatic levels of insulin receptor and AMP-activated protein kinase. PIC increased the levels of Sirt1, Sirt3, and Sirt6 and also increased two downstream targets of Sirt, peroxisome proliferator-activated receptor gamma coactivator 1-alpha and forkhead box O1, in the liver. The inflammatory markers, interleukin (IL)-1 and IL-6, in the liver were downregulated by RSV treatment. Exposure to PIC and RSV significantly lowered hepatic levels of tumor necrosis factor-alpha. However, PIC and RSV treatments showed minimal effects on hepatic markers of oxidative stress. The levels of antioxidant enzyme, NAD(P)H:quinone oxidoreductase 1 (NQO1), were only increased in livers of RSV-treated mice compared with HF control mice. In conclusion, PIC was superior to an equal concentration of RSV in the regulation of Sirt and its downstream targets as well as insulin signaling-related parameters, while RSV potentially suppressed levels of proinflammatory markers and increased NQO1 protein levels.

Development of blastocyst complementation technology without contributions to gametes and the brain

In Japan, it is possible to generate chimeric animals from specified embryos by combining animal blastocysts with human pluripotent stem (PS) cells (animal-human PS chimera). However, the production of animal-human PS chimeras has been restricted because of ethical concerns, such as the development of human-like intelligence and formation of humanized gametes in the animals, owing to the contributions of human PS cells to the brain and reproductive organs. To solve these problems, we established a novel blastocyst complementation technology that does not contribute to the gametes or the brain. First, we established GFP-expressing mouse embryonic stem cells (G-mESCs) in which the Prdm14 and Otx2 genes were knocked out and generated chimeric mice by injecting them into PDX-1-deficient blastocysts. The results showed that the G-mESCs did not contribute to the formation of gametes and the brain. Therefore, in the PDX-1-deficient mice complemented by G-mESCs without the Prdm14 and Otx2 genes, the germline was not transmitted to the next generations. This approach could address concerns regarding the development of both human gametes and a human-like brain upon mouse blastocyst complementation using human stem cells.