Canagliflozin regulates metabolic reprogramming in diabetic kidney disease by inducing fasting-like and aestivation-like metabolic patterns.

AIMS/HYPOTHESIS: Sodium-glucose co-transporter 2 (SGLT2) inhibitors (SGLT2i) are antihyperglycaemic drugs that protect the kidneys of individuals with type 2 diabetes mellitus. However, the underlying mechanisms mediating the renal benefits of SGLT2i are not fully understood. Considering the fuel switches that occur during therapeutic SGLT2 inhibition, we hypothesised that SGLT2i induce fasting-like and aestivation-like metabolic patterns, both of which contribute to the regulation of metabolic reprogramming in diabetic kidney disease (DKD). METHODS: Untargeted and targeted metabolomics assays were performed on plasma samples from participants with type 2 diabetes and kidney disease (n=35, 11 women) receiving canagliflozin (CANA) 100 mg/day at baseline and 12 week follow-up. Next, a systematic snapshot of the effect of CANA on key metabolites and pathways in the kidney was obtained using db/db mice. Moreover, the effects of glycine supplementation in db/db mice and human proximal tubular epithelial cells (human kidney-2 [HK-2]) cells were studied. RESULTS: Treatment of DKD patients with CANA for 12 weeks significantly reduced HbA1c from a median (interquartile range 25-75%) of 49.0 (44.0-57.0) mmol/mol (7.9%, [7.10-9.20%]) to 42.2 (39.7-47.7) mmol/mol (6.8%, [6.40-7.70%]), and reduced urinary albumin/creatinine ratio from 67.8 (45.9-159.0) mg/mmol to 47.0 (26.0-93.6) mg/mmol. The untargeted metabolomics assay showed downregulated glycolysis and upregulated fatty acid oxidation. The targeted metabolomics assay revealed significant upregulation of glycine. The kidneys of db/db mice undergo significant metabolic reprogramming, with changes in sugar, lipid and amino acid metabolism; CANA regulated the metabolic reprogramming in the kidneys of db/db mice. In particular, the pathways for glycine, serine and threonine metabolism, as well as the metabolite of glycine, were significantly upregulated in CANA-treated kidneys. Glycine supplementation ameliorated renal lesions in db/db mice by inhibiting food intake, improving insulin sensitivity and reducing blood glucose levels. Glycine supplementation improved apoptosis of human proximal tubule cells via the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway. CONCLUSIONS/INTERPRETATION: In conclusion, our study shows that CANA ameliorates DKD by inducing fasting-like and aestivation-like metabolic patterns. Furthermore, DKD was ameliorated by glycine supplementation, and the beneficial effects of glycine were probably due to the activation of the AMPK/mTOR pathway.

Characteristics of metabolic inflammatory syndrome among inpatients with type 2 diabetes: A cross-sectional study in China.

BACKGROUND: As meta-inflammation is a common feature for obesity, type 2 diabetes (T2D), nonalcoholic fatty liver disease and atherosclerosis, we have proposed a new concept, metabolic inflammatory syndrome (MIS), to cluster such diseases. We aimed to characterize MIS and explore its association with coronary heart disease (CHD) among T2D inpatients in China. METHODS: A total number of 8344 T2D participants were enrolled. Each component of MIS and metabolic syndrome (MS) was analyzed. Their association with the risk of CHD was assessed using a binary logistic analysis. RESULTS: Among the T2D inpatients, the detection rate of MIS was much higher than that of MS (93.6 % vs. 53.2 %). Among all the components of MIS and MS, carotid atherosclerosis (71.9 %) was most commonly detected, which increased with aging in subgroups. Surprisingly, the most common combination of MIS was with all 4 components in T2D patients, with a constituent ratio of 30.9 %. According to the odds ratios (ORs), MIS was a better predictor of CHD than MS, especially after adjustment for age, sex, smoking, and alcohol consumption (adjusted OR for MIS: 3.083; for MS: 1.515). The presence of more components of MIS was associated with a higher detection rate of CHD (P < 0.001). Among all the components of MIS and MS, carotid atherosclerosis best predicted the risk of CHD (adjusted OR: 1.787). CONCLUSIONS: MIS is an independent risk factor for CHD, with a bigger OR value than MS. Carotid atherosclerosis, with the highest detection rate, was the best individual predictor of CHD and thus a critical component of MIS. The concept of MIS represents the understanding of metabolic diseases from the perspective of holistic integrative medicine.

Compound Danshen Dripping Pills moderate intestinal flora and the TLR4/MyD88/NF-κB signaling pathway in alleviating cognitive dysfunction in type 2 diabetic KK-Ay mice.

BACKGROUD: Bidirectional communications between the gut microbiota and the brain may play a critical role in diabetes-related cognitive impairment. Compound Danshen Dripping Pills (CDDP) treatment has shown remarkable improvement in cognitive impairment in people with type 2 diabetes mellitus (T2DM) in clinical settings, but the underlying mechanisms remain unknown. PURPOSE: An extensive detailed strategy via in vivo functional experiments, transcriptomics, metabolomics, and network pharmacology was adopted to investigate the CDDP-treatment mechanism in diabetic cognitive dysfunction. METHODS: For 12 weeks, KK-Ay mice, a spontaneous T2DM model, were intragastrically administered various doses of CDDP solution or an equivalent volume of water, and the nootropic drug piracetam was orally administered as a positive control. At the 12th week, cognition was assessed using Morris water maze tests and brain magnetic resonance imaging (MRI). Furthermore, transcriptomics, metabolomics, and network pharmacology analyses were applied to reveal novel molecular mechanisms of CDDP-treatment in diabetic cognitive dysfunction of KK-Ay mice, which were then validated using quantitative real-time polymerase chain reaction and Western blot. RESULTS: Here we verified that CDDP can suppress inflammatory response and alleviate the cognitive dysfunction in KK-Ay mice. Also, as demonstrated by 16S rRNA sequencing and short-chain fatty acids (SCFAs) analysis, CDDP attenuated intestinal flora disorder as well as increases of metabolites including butyric acid, hexanoic acid, and isohexic acid. Given the integrated analyses of network pharmacology, transcriptomic, metabolomic data, and molecular biology, the TLR4/MyD88/NF-κB signaling pathway was activated in diabetes, which could be reversed by CDDP. CONCLUSIONS: Our findings demonstrate that CDDP restructures the gut microbiota composition and increased the intestinal SCFAs in KK-Ay mice, which might inhibit neuroinflammation, and thus improve diabetic mice cognitive disorder.

Vitamin D3 Activates Phosphatidylinositol-3-Kinase/Protein Kinase B via Insulin-Like Growth Factor-1 to Improve Testicular Function in Diabetic Rats.

OBJECTIVE: In diabetes mellitus, vitamin D3 deficiency affects sex hormone levels and male fertility; however, the mechanism leading to the disorder is unclear. This research was designed to investigate the mechanism of vitamin D3 deficiency and hypogonadism in diabetic rats. Our aim was to assess serum vitamin D3 levels and the relationship among vitamin D3, insulin-like growth factor-1 (IGF-1), and testicular function. MATERIALS AND METHODS: Rats with streptozotocin-induced diabetes were randomly divided into four groups and treated with different doses of vitamin D3: no vitamin D3, low (0.025 µg/kg/day), high (0.1 µg/kg/day), and high (0.1 µg/kg/day) with JB-1 (the insulin-like growth factor-1 receptor inhibitor group, 100 µg/kg/day). The groups were compared with wild-type rats, which function as the control group. Various parameters such as vitamin D3 and IGF-1 were compared between the experimental and wild-type groups, and their correlations were determined. RESULTS: Twelve weeks of vitamin D3 supplementation improved the testosterone levels, as shown by the increase in the level of serum IGF-1 in diabetic rats. Phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT), which was a downstream of the signaling pathway of IGF-1, was significantly increased after vitamin D3 treatment. CONCLUSIONS: The study shows that vitamin D3 may promote the expression of testosterone and improve testicular function in diabetic rats by activating PI3K/AKT via IGF-1.

Vitamin D3 supplementation improves testicular function in diabetic rats through peroxisome proliferator-activated receptor-γ/transforming growth factor-beta 1/nuclear factor-kappa B.

AIMS/INTRODUCTION: Vitamin D3 deficiency can lead to male hypogonadism in diabetes mellitus, but the target organs and the mechanism driving the disorder are unclear. This experiment was designed to study the relationship between vitamin D3 deficiency and hypogonadism in diabetes mellitus. MATERIALS AND METHODS: Rats with streptozotocin-induced diabetes were randomly divided into four groups and treated with different doses of vitamin D3 : blank (no vitamin D3 ), low (0.025 µg/kg/day), high (0.1 µg/kg/day), high (0.1 µg/kg/day) and with bisphenol A diglycidyl ether (peroxisome proliferator-activated receptor gamma inhibitor 30 mg/kg/day). They were compared with wild-type rats. RESULTS: After 12 weeks, the vitamin D3 supplements had partially restored testicular pathological changes, as shown by reduced testicular fibrosis related to downregulation transforming growth factor beta 1 and apoptosis related to downregulation of nuclear factor kappa B, but not the pituitary gland. The expression of peroxisome proliferator-activated receptor gamma, which can inhibit transforming growth factor beta 1 and nuclear factor kappa B, was significantly increased after treatment with vitamin D3 . CONCLUSIONS: These results suggest that treatment with vitamin D3 can improve testicular function in diabetic rats through the peroxisome proliferator-activated receptor gamma/transforming growth factor beta 1/nuclear factor kappa B signaling pathway.

Involvement of the TGFß1- ILK-Akt signaling pathway in the effects of hesperidin in type 2 diabetic nephropathy.

Diabetic nephropathy is one of the manifestations of systemic microangiopathy in diabetes. Hesperetin, a natural flavanone glycoside compound in citrus fruits, has been demonstrated to exert hypoglycemic effects and protect kidney in experimental diabetic animals. The current study was aimed to investigate the mechanisms underlying the hypoglycemic effects of hesperetin in high-fat/streptozocin (STZ)-induced diabetic nephropathy. The results showed that mice in whom hesperetin was administered for 4 weeks attenuated the increased fasting blood glucose and impaired glucose tolerance ability that was observed in high-fat/STZ mice. In addition, we found that hesperetin ameliorated the abnormalities of biochemical parameters in serum, liver, and kidney of mice with diabetic nephropathy. Hesperetin also rescued the irregular distortions in glomerular basement membrane and expanded mesangial regions. Moreover, hesperetin repaired the function of podocyte by increasing renal nephrin expression and decreasing renal alpha-smooth muscle actin expression. Furthermore, hesperetin inhibited the expression of transforming growth factor-ß1 (TGF-ß1) and its downstream effectors integrin-linked kinase (ILK) and Akt. In conclusion, our study implies that hesperetin produced protective effects in diabetic nephropathy possibly by suppressing TGF-ß1-ILK-Akt signaling.

Vitamin D supplement ameliorates hippocampal metabolism in diabetic rats.

Vitamin D deficiency induced by diabetes mellitus is tightly associated with neurodegenerative diseases, but the mechanism is still unknown. Endoplasmic reticulum stress (ER stress) is involved in hippocampal lesion and promote diabetic neuropathy, so we focus on the effects of 1, 25-dihydroxy vitamin D3 on ER stress in hippocampus of diabetic rats. Streptozotocin (STZ)-induced diabetic rats were administrated with different doses of vitamin D and divided into 3 groups: high, low, and blank, compared to wild-type rats which were received the same treatment. At the end of 12 weeks of treatment, the brains of the rats were analyzed by proton magnetic resonance spectroscopy (1H-MRS). Rats were then weighed, tested for blood glucose, serum Ca, P, and vitamin D3, and sacrificed for histopathological analysis of the hippocampus. Neuronal nitric oxide synthase (nNOS) and vitamin D receptor (VDR) expression were measured, as well as ER stress markers, including glucose-regulated protein78 (GRP78), protein kinase-like endoplasmic reticulum kinase (PERK) phosphorylation, eukaryotic initiation factor 2α(eIF-2α) phosphorylation, and CCAAT enhancer-binding protein homologous protein (CHOP). Our study showed that treated with appropriate concentration of active vitamin D could decrease the number of pathological pyramidal neurons, improve hippocampal nerve metabolism, and reduce the over-expression of nNOS, along with the relieved activation of ER stress in hippocampus of diabetic rats. These results suggest that 1,25-dihydroxy vitamin D3 treatment can ameliorate hyperglycemia-induced damage on hippocampal metabolism, possibly through alleviating the aberrant activation of ER stress.

Vitamin D supplement improved testicular function in diabetic rats.

This study was designed to investigate the role that 1,25(OH)2D3 plays against testicular lesion in diabetic rats and try to find its possible mechanism of the steroidogenesis and the spermatogenesis. In diabetic rats, prolonged hyperglycemia evaluated inflammatory cytokines, damaged sperm production function and redox balance, diminished serum testosterone. After treated with 1,25(OH)2D3 at two different doses respectively for 12 months, all the alternations were effectively normalized. 1,25(OH)2D3 showed inhibitory effect on excessive inflammatory biomarkers and adjusted the expression reproductive genes and testicular androgen synthesis. It also upregulated Bcl-2 expression, decreased Bax and COX-2 expression and inhibited active caspase cascade (caspase 8 and caspase 3), which may preserved the testicular cells under diabetic condition. It revealed that vitamin D supplement may protect the cells through suppressing inflammation factors and alleviating cell apoptotic death, as well as upregulating the expression of genes related to reproductive and testosterone synthesis.

Whole exome sequencing of insulinoma reveals recurrent T372R mutations in YY1.

Functional pancreatic neuroendocrine tumours (PNETs) are mainly represented by insulinoma, which secrete insulin independent of glucose and cause hypoglycaemia. The major genetic alterations in sporadic insulinomas are still unknown. Here we identify recurrent somatic T372R mutations in YY1 by whole exome sequencing of 10 sporadic insulinomas. Further screening in 103 additional insulinomas reveals this hotspot mutation in 30% (34/113) of all tumours. T372R mutation alters the expression of YY1 target genes in insulinomas. Clinically, the T372R mutation is associated with the later onset of tumours. Genotyping of YY1, a target of mTOR inhibitors, may contribute to medical treatment of insulinomas. Our findings highlight the importance of YY1 in pancreatic ß-cells and may provide therapeutic targets for PNETs.