Volume 11 · Issue 04 · 2019

Sodium-glucose co-transporter 2 (SGLT-2) inhibitor is a new type of oral hypoglycemic drugs that have appeared in recent years. Its brand-new mode of action and pathophysiological effects on the body have attracted great attention in diabetes and related disciplines. This article briefly reviews the development history and mechanism of SGLT-2 inhibitors, briefly describes their clinical efficacy and safety, and introduces relevant evidence-based medical research results, especially the evidence and related theories of cardiovascular and renal benefits of SGLT-2 inhibitors in diabetic patients.

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are a novel class of oral hypoglycemic drugs that reduce glucose reabsorption in raw urine and reduce blood glucose by inhibiting renal proximal convoluted tubule sodium-glucose cotransporter 2. This class of drugs also has the benefits of reducing uric acid, body weight, blood pressure and the risk of cardiovascular events. However, reports of adverse reactions of such drugs are increasing day by day, especially ketoacidosis caused by SGLT2i (including normoglycemic ketoacidosis) deserves great attention. The role of kidney in blood glucose regulation, the mechanism of action of SGLT2i, the relationship between SGLT2i and metabolic acidosis, and the prevention and treatment of acidosis caused by SGLT2i are reviewed.

The prevalence of diabetes in children and adolescents is increasing year by year worldwide. Because of the early onset age, the disease course is more serious than that of adult diabetes, and it is easy to lead to diabetic complications such as renal failure, blindness and amputation, diabetes in children and adolescents should get more attention. There are three main types of diabetes in children and adolescents: type 1 diabetes (T1DM), type 2 diabetes (T2DM), and single gene mutation diabetes. The accurate classification of three types of diabetes is the basis of clinical diagnosis and treatment, but the current clinical problem is that the clinical data are insufficient to make differential diagnosis of these three types of diabetes in children and adolescents. Juvenile, non-obese diabetic patients are often diagnosed with T1DM, and some of them are actually T2DM or single gene mutation diabetes. Because T1DM is far lower in Chinese children and adolescents than in the Caucasus population, the problem of misdiagnosis may be more serious, and the precision medicine approach based on genetic testing provides a way to solve this problem.

Diabetic foot is one of the main causes of disability and death of diabetic patients. Based on the principle of "Chinese practice, Chinese evidence and Chinese guidelines", the Diabetology Branch of Chinese Medical Association, together with the Infectious Diseases Branch of Chinese Medical Association, the Tissue Repair and Regeneration Branch and other multidisciplinary experts in related fields, jointly formulated this clinical guideline adapting to the current situation of diabetic foot in China, aiming at standardizing the prevention, diagnosis and treatment of diabetic foot in China. This guideline has the following features: (1) highlighting clinical practicality; (2) Chinese evidence fully incorporated in the field of diabetic foot; (3) Pay attention to early screening and management, emphasizing that prevention of diabetic foot is better than treatment; (4) Emphasize the importance of standardized and comprehensive management; (5) Emphasize the multidisciplinary collaborative diagnosis and treatment of diabetic foot. In addition, with reference to the requirements of the 2017 version of China's Type 2 Diabetes Prevention and Treatment Guidelines, key points and evidence levels have been added, and the evidence levels are divided into three levels: A, B and C according to evidence quality, clinical significance, universality and applicability. Grade A: Evidence based on multiple randomized clinical trials or meta-analyses. Grade B: Evidence based on a single randomized clinical trial or multiple non-randomized controlled studies. Grade C: Expert consensus opinion only and/or based on results from small-scale studies, retrospective studies, and registered studies.

To evaluate post-marketing safety of sodium-glucose cotransporter 2 inhibitors (SGLT2i), including dapagliflozin, canagliflozin and empagliflozin.

Reporting odds ratio (ROR) algorithm was adopted to investigate signals of all adverse drug event (ADE) reports submitted to Food and Drug Administration adverse event reporting system from 2012 Q4 to 2017 Q2.

SGLT2i were recorded in 24 956 reports as suspects (4 699 reports were attributed to dapagliflozin, 15 980 to canagliflozin and 4 277 to empagliflozin), among which 13 905 (55.72%) were serious adverse events and the most frequently reported ADE was diabetes ketoacidosis (2 594, 10.39%). Statistically significant ROR emerged for the following ADEs renal impairment (acute kidney injury, decrease of glomerularfiltration rate, increase of blood creatinine), ketoacidosis (diabetes ketoacidosis), genital infection (genital mycotic infection, balanoposthitis, vulvovaginal mycotic infection, vaginal infection), urinary tract infection (pyelonephritis, urosepsis), hypoglycemia. Furthermore, several new ADE signals for dapagliflozin, canagliflozin and empagliflozin were detected: lactic acidosis (ROR=3.52, 95%CI 2.18-5.67; ROR=3.74, 95%CI 2.90-4.81; ROR=3.41, 95%CI 2.05-5.66, respectively), pancreatitis (ROR=4.07, 95%CI 3.04-5.44;ROR=6.37, 95%CI 5.60-7.24; ROR=6.06, 95%CI 4.72-7.80, respectively). Potential signals of hyperkalaemia (ROR=3.82, 95%CI 2.56-5.72; ROR=3.15, 95%CI 1.98-5.00, respectively) and toe amputation (ROR=7.37, 95%CI 3.06-17.77; ROR=13.02, 95%CI 6.48-26.16, respectively) were also discovered for dapagliflozin and empagliflozin (labeled in canagliflozin instructions). No fracture associated with SGLT2i agents was identified.

In addition to known safety issues such as urinary/genital tract infections, renal impairment, ketoacidosis and hypoglycemia, potential risks of lactic acidosis and pancreatitis should also be noted during the clinical application of SGLT2i.

To investigate the potential pathogenesis and therapeutic targets for diabetic kidney disease (DKD) using renal genomic expression profile and the bioinformatics methods.

Genomic data of kidney from diabetic kidney disease patients and diabetic kidney disease mice model were selected from NCBI-GEO database. The data was analyzed by bioinformatics software to find differentially expressed genes (DEG). Gene ontology and ingenuity pathway analysis (IPA) were performed to find potential targets for DKD for elucidating the possible molecular mechanisms in DKD.

Eighty-nine common DEG were identified from the human and mouse diabetic kidney disease database. Most of the DEG were mainly enriched in metabolism-related enzymes, transporters, nucleic acid binding proteins, and cell proliferation and extracellular matrix. The bioinformatics analysis of IPA showed that the common differentially expressed genes were mainly concentrated in the complement system, the primary immunodeficiency signaling and the B cell development, among them, the complement system is one of important regulatory pathways in diabetic kidney disease. Disease and biological function enrichment analysis showed that DKD was closely related to diabetes mellitu, glucose metabolism disorder, cell movement of blood cells, activation of blood cells and leukocyte migration. IPA regulatory network analysis revealed that proto-oncogene ETS1 and integrin β2 (ITGB) were two crucial sites identified by IPA bioinformatics analysis.

The potential site of diabetic kidney disease can be screened by using different species genomic data of diabetic kidney disease. Bioinformatics analysis shows that transcription factor ETS1 and ITGB might play a role in the pathogenesis of diabetic kidney disease.

To investigate the expression levels of circRNAs in peripheral blood leucocytes and identify the correlation of circRNAs and inflammation factors in type 2 diabetes mellitus (T2DM) patients.

The fresh blood samples of 5 patients with T2DM and 5 healthy controls were collected for RNA sequencing (RNAseq). The peripheral blood from 62 patients with T2DM, 56 age-and gender-matched healthy controls (collected at the Beijing Hospital from June 2017 to December 2017) were chosen and collected. Then RNA of peripheral leukocytes was extracted and performed with reverse transcription PCR to detect the level of circRNA. The protein levels of interleukin 6 (IL-6), C-reactive protein (CRP) and tumor necrosis factor (TNF)-α inflammatory factors were detected by enzyme-linked immunosorbent assay. The correlation of circRNA level and the inflammatory factor level was identified. Data were analyzed using Mann-Whitney test, Student′st-test and Pearson correlation accordingly.

A total of 970 circRNAs were found to be differentially expressed in T2DM patients compared with the normal individuals (428 circRNAs were significantly up-regulated, 542 circRNAs were significantly down-regulated). The high expression level of hsa_circ_0007240 was further identified in the RNAseq samples. The basic RNA level of hsa_circ_0007240 in peripheral leukocytes was also significantly higher in T2DM patients compared to healthy controls in large sample test (Z=-3.422, P<0.001). The protein levels of IL-6, CRP and TNF-α were also significantly different between T2DM group and control group [(12.33±3.96) vs (9.72±2.92) μg/L, (13.34±3.99) vs (9.91±2.75) μg/L, (18.37±4.64) vs (13.73±3.07) μg/L,t=2.370, 3.167, 3.731, respectively, all P<0.05]. The expression level of hsa_circ_0007240 was positive correlated with IL-6 (r=0.596, P=0.006).

The expression level of hsa_circ_0007240 is significantly up-regulated and positive correlated with IL-6 inflammatory factor in peripheral blood leucocytes T2DM patients. Hsa_circ_0007240 can be used as potential biomarker of inflammatory T2DM.

To investigate whether the visceral adiposity content is associated with impaired glucose regulation (IGR), independent of insulin resistance and hyperandrogenism in women with polycystic ovary syndrome (PCOS).

A total of 401 PCOS patients [177 patients with normal glucose tolerance (NGT), 224 patients with IGR] and 200 healthy women matched with age, body mass index, waist circumference and waist to hip ratio in the Department of Endocrinology and Metabolism of Renji Hospital affiliated to Shanghai Jiaotong University School of Medicine from January 2015 to December 2017 were included. All subjects received 75 g oral glucose tolerance test. Insulin and sex hormone levels were measured by radioimmunoassay. Visceral adiposity content was determined by visceral adiposity index (VAI). Logistic regression was used to analyze the association between VAI and IGR.

(1) The VAI level in PCOS patients with IGR group was higher than that in NGT group (3.7±2.6 vs 1.5±0.7, t=-11.019, P<0.05). (2) VAI was positively related with the homeostasis model assessment of insulin resistance (HOMA-IR), the glucose and insulin area under the curve (AUC_glu and AUC_ins) (r=0.416, 0.542, 0.329, respectively, all P<0.05), but negatively related with the Matsuda index (r=-0.458, P<0.05). (3) The prevalence of IGR increased with VAI quartiles after adjustment for age, free androgen index and HOMA-IR in multivariate Logistic regression [the first quartile as a reference, the ORs of the second, third and fourth quartiles were 5.50 (95%CI: 1.15-10.47), 29.74(95%CI: 12.74-69.43) and 70.31(95%CI: 25.35-195.98), respectively; all P<0.05]. (4) The cut-off value of VAI in predicting the high risk of IGR was 1.94 (AUC=0.890, 95%CI: 0.858-0.922, sensitivity=0.826, specificity=0.853, P<0.05).

High visceral adiposity content is independently and positively related with high risk of IGR in PCOS patients. VAI>1.94 can predict the increased risk of IGR in PCOS women.

To investigate the effects of growth differentiation factor-11 (GDF-11) on bone marrow endothelial progenitor cells (BM-EPC) cultured with high glucose and its possible mechanism.

BM-EPC were cultured in vitro and divided into the following groups: normal glucose (NG) group, high glucose (HG) group, HG+recombinant GDF-11 (rGDF-11) group and HG+rGDF-11+TGF-β receptor Ⅰ inhibitor SB431542 group. Proliferation was assessed by MTT, and apoptosis of EPC were stained with Annexin Ⅴ-FITC and propidium iodide (PI), and assessed by flow cytometry. The expression of Bcl-2, Bax and Cleaved-caspase 3 were detected by western blot. The phosphorylation of Smad were assessed by immunofluorescence. Data among multiple groups were compared by using one-way ANOVA and the least significant differencet test.

Compared with the vehicle control group, Bcl-2/Bax ratio decreased, the protein levels of Cleaved-caspase 3 increased and the percentage of apoptotic EPC elevated in those groups cultured with HG [0.45±0.09 vs 1.21±0.23, 0.28±0.02 vs 0.07±0.00, (18.63±3.02)% vs (2.82±0.46)%, t=3.04, -68.06, -7.60, all P<0.05]. However, the effects were blocked by pretreated with rGDF-11. Treatment of EPC with TGF-β receptor Ⅰ inhibitor SB431542 partially abolished the pro-proliferation and anti-apoptotic effects of GDF-11 (0.56±0.11 vs 1.14±0.07,t=4.33, P<0.05). Immunofluorescence analyses showed that Smad2/3 phosphorylation decreased in high glucose culturing. Pre-incubation with rGDF-11 restored p-Smad2/3 expression, however, GDF-11 mediated Smad2/3 activation was partially blocked by SB431542 (0.89±0.12 vs 1.21±0.12, t=-3.20, P<0.05).

GDF-11 may prevent high glucose-induced EPC apoptosis and improve proliferation through activation of TGF-β/Smad2/3 signaling pathway.

To explore the effect of diabetes on circadian expression of clock gene Per2 and its mechanism.

A total of fifty healthy adult male Sprague-Dawley rats were randomly divided into non-diabetic (NDM) group and DM group. The rats were randomly divided into 5 sub-groups: NDM+A, DM+A, NDM+P, DM+P and DM+A+PF (n=10 for each). At the same time, a circadian rhythm model was established and the rats were given 12 h light/12 h dark cycle environment. Hematoxylin-eosin (HE) staining was used to observe the morphological changes of myocardium; Immunohistochemistry was used to analyze the pathological changes of myocardium and the expression of Per2; Real-time PCR was used to detect the gene expressions of CK1ε and Per2, and Western blot was used to detect the expressions of CK1ε and Per2 at the protein level. Single factor variance analysis andt-test were used for statistical analysis.

Both CK1ε and Per2 expressions increased at mRNA and protein levels in DM+A group than those in NDM+A group (t=2.84, 4.63; t=4.00, 5.32, respectively, all P<0.05); Compared with NDM+P group, the mRNA and protein expressions of CK1ε increased in DM+P group (t=6.04, 3.60, all P<0.05), while the mRNA expression of Per2 decreased (t=3.90, P<0.05) and the protein expression of Per2 increased (t=2.55, P<0.05); Compared with NDM + A group, the protein expression of Per2 decreased in NDM + P group (t=3.54, P<0.05), while the mRNA expression of Per2 increased (t=5.35, P<0.05); Compared with DM+A group, the expressions of CK1ε and Per2 at the mRNA and protein levels decreased in DM+P group (t=3.24, 4.32, all P<0.05); Compared with DM+A group, in PF-670462 intervention subgroup both CK1ε and Per2 expressions at the protein levels decreased (bothP<0.05); Compared with each NDM sub-groups, HE staining showed myocardial arrangement disorder, interstitial edema and inflammatory cell infiltration in each DM subgroups, and the results of immunohistochemistry showed more positive of Per2 expression displayed at diabetic myocardiopathy.

Diabetes mellitus affects the diurnal expression of clock gene Per2 injury possibly by upregulated CK1ε signal which may be related to diabetic myocardial injury.

To observe the effect of dipeptidyl peptidase-Ⅳ (DPP-4) inhibitor sitagliptin on the apoptosis and p38 mitogen activated protein kinase (p38MAPK) signaling pathway in renal tubular epithelial cells induced by high glucose.

In vitro cultured rat renal tubular epithelial cell line (NRK-52E) was divided into normal glucose control group (NG), hypertonic control group (MG), high glucose stimulation group (HG), high glucose plus p38MAPK blocker (SB202190) group (HG+SB), and high glucose plus sitagliptin group (HG+ST). Trypan blue experiment was conducted to find out the appropriate concentration of sitagliptin. The activation of p38MAPK signaling pathway was detected by western blot. The relative amount of pro-apoptosis factor anti-apoptotic factor B-cell lymphoma-2 (bcl-2) mRNA and Bcl-2 associated X protein (bax) mRNA was detected by real-time fluorescence quantitative PCR and the ratio of the two was determined. The cell apoptosis rate, was detected by flow cytometry. Transforming growth factor beta (TGF-β) and fibronectin (FN) released into media were quantitatively analyzed by enzyme-linked immunosorbent assay (ELISA). One-way analysis of variance was used for multigroup comparison.

Western blot revealed that high glucose could increase the expression of p-p38 protein in renal tubular epithelial cells. SB202190 and sitagliptin could significantly reduce the high expression of p-p38 in renal tubular epithelial cells induced by high glucose (0.82±0.12 vs 1.39±0.22, 1.03±0.14 vs 1.39±0.22, t=4.01, 3.71, P<0.05) . Quantitative PCR showed that bax/bcl-2 mRNA in group HG+SB and group HG+ST was significantly lower than that in HG group (1.32±0.54 vs 4.42±0.18, 2.14±0.29 vs 4.42±0.18, t=9.43,11.57, P<0.05). Flow cytometry indicated that compared with NG group, apoptosis rate of HG group increased significantly (17.50±0.35 vs 4.80±0.54, t=34.18, P<0.05) . Compared with the HG group, apoptosis rate in the HG+SB group and the HG+ST group significantly decreased (11.30±1.19 vs 17.50±0.35,14.20±0.81 vs 17.50±0.35, t=8.66, 6.48, P<0.05 respectively). The ELISA results showed that compared with NG group, the expression of TGF-β and FN in HG group increased significantly (536.0±37.9 vs 180.0±17.6, 19.4±2.4 vs 5.3±0.8,t=14.76, 9.64, P<0.05 respectively) . The expression of TGF-β and FN in HG+SB and HG+ST significantly decreased compared with that of HG group (356.0±33.8 vs 536.0±37.9, 390.0+42.3 vs 536.0±37.9,t=6.13, 4.45; 12.5±2.1 vs 19.4±2.4, 14.6±2.7 vs 19.4±2.4, t=3.72, 2.85, P<0.05 respectively) .

Sitagliptin can reduce the apoptosis and fibrosis of renal tubular epithelial cells through inhibiting the activation of p38MAPK signaling pathway induced by high glucose, thereby play a protective role in kidney.

sodium-glucose cotransporter 2 inhibitors (SGLT2i) are a novel drug for the treatment of type 2 diabetes. They reduce blood glucose by specifically inhibiting the reabsorption of glucose by renal tubules, and have a series of potential advantages such as low risk of hypoglycemia and weight loss. However, in terms of weight loss, the specific mechanism has not been fully defined. This paper describes the characteristics of weight loss and its influencing factors related to SGLT2i treatment, and explores the possible potential mechanisms affecting its weight loss in combination with clinical practice, in order to bring more evidence-based medical evidence of benefits to T2DM patients in weight loss.

With the deterioration of pancreatic islet function in patients with type 2 diabetes mellitus (T2DM), the insulin resistance of tissues and organs increases, which aggravates the occurrence and development of diabetes and its comorbidities. Recent studies have found that sodium-glucose cotransporter (SGLT) 2 inhibitor (SGLT2i) not only directly reduces renal glucose reabsorption and blood glucose, but also plays a very important role in improving insulin resistance. Therefore, this paper reviews the latest research progress of SGLT2i in improving insulin resistance in T2DM, and explores its mechanism of improving insulin resistance from various aspects such as improving hyperglycemic toxicity, protecting islet β cells and their functions, increasing insulin sensitivity of skeletal muscle, improving dyslipidemia, anti-inflammatory and antioxidant effects.

Non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease in the world. Its occurrence and development are related to environmental external factors such as poor diet and lifestyle habits, but the specific pathogenesis has not been fully elucidated. Epigenetics can explain the influence of environmental factors on phenotype, and its research mainly focuses on DNA methylation, histone modification and non-coding RNA regulation. More and more studies have shown that epigenetic modification plays an important role in the occurrence and development of NAFLD.

Intestinal flora is closely related to obesity and type 2 diabetes, and diet can regulate the structure of intestinal flora, thus affecting human metabolism. Fiber in the diet can promote the abundance of Prevotella in the intestine, while high-fat and high-protein diet reduces the abundance of Prevotella in the intestine. The study found that various microorganisms in the intestine interact with each other, and Prevotella and other bacteria have both competitive relationship and synergistic effect. At present, different studies have different opinions on the effects of Prevotella on metabolism. Some studies believe that Prevotella can improve glucose metabolism, while others believe that Prevotella can induce insulin resistance, and the elucidated mechanisms are also different. In the future, the intestinal flora can be regulated by food or drugs, and blood glucose and insulin resistance can be improved by microbiological methods.

In recent years, the continuous innovation of blood glucose monitoring technology, especially the advent of flash glucose monitoring (FGM) technology, not only leads continuous glucose monitoring into a new stage, but also promotes important changes in diabetes management. During the 22nd National Academic Conference of the Diabetes Branch of the Chinese Medical Association, Professor Richard M. Bergenstal, Executive Director of the International Diabetes Center of the United States, delivered a wonderful speech, explaining in detail the latest academic understanding of diabetes management, as well as the important role of FGM and its dynamic glucose profile in the individualized blood glucose management of diabetes.

Diabetic kidney disease is an important microvascular complication of diabetes, and the renal effects of hypoglycemic drugs have attracted much attention. Sodium-glucose cotransporter 2 inhibitors improve glomerular filtration rate and significantly reduce the risk of renal events in diabetic patients. Its mechanism is to reduce the reabsorption of sodium ions in the proximal convoluted tubules, and contract into the bulbar arterioles through the feedback of the bulb of the dense plaque, reducing the intraglomerular pressure and improving hyperfiltration. Dipeptidyl peptidase-IV inhibitors decrease urinary albumin excretion. Glucagon-like peptide-1 analogues improve glomerular filtration rate in patients with proteinuria. Whether a drug has a nephroprotective effect depends on the relationship between its site of action and dense plaques.