Plasma vascular endothelial growth factor B levels are increased in patients with newly diagnosed type 2 diabetes mellitus and associated with the first phase of glucose-stimulated insulin secretion function of β-cell

Knockdown of VEGF-B improves HFD-induced insulin resistance by enhancing glucose uptake in vascular endothelial cells via the PI3K/Akt pathway

Vascular endothelial growth factor B (VEGF-B) has been suggested to play a crucial role in regulating whole-body glucose homeostasis. However, the involved mechanisms are not fully understood. This study aimed to elucidate the regulatory effects and mechanisms of VEGF-B on glucose uptake in skeletal muscle, focusing on glucose uptake by skeletal muscle cells and vascular endothelial cells. Our results showed that a high-fat diet (HFD) induced significant increase in VEGF-B expression and decrease in glucose uptake by skeletal muscle, accompanied by elevated serum glucose levels. Interestingly, VEGF-B had no direct effect on glucose uptake by skeletal muscle cells (differentiated C2C12). Instead, VEGF-B inhibited glucose uptake of vascular endothelial cells bEnd.3 and subsequent trans-endothelial glucose transport, ultimately resulting in decreased glucose uptake by skeletal muscle cells. Furthermore, VEGF-B suppressed glucose uptake of vascular endothelial cells by downregulating the expression of glucose transporter 1 (GLUT1) through the VEGFR-PI3K/Akt signaling pathway. In vivo, knockdown of VEGF-B in skeletal muscle increased the HFD-impaired glucose uptake of skeletal muscle and improved the HFD-induced glucose intolerance and insulin resistance. This beneficial effect of VEGF-B knockdown was associated with the elevated expression of GLUT1 in the plasma membrane and the activation of the PI3K/Akt pathway in skeletal muscle. In conclusion, our findings demonstrated that knockdown of VEGF-B improved HFD-induced insulin resistance by enhancing glucose uptake in vascular endothelial cells via the PI3K/Akt pathway. These results highlighted the critical role of VEGF-B in regulating glucose uptake by vascular endothelial cells in skeletal muscle, providing a potential new target for improving obesity-induced glucose homeostasis imbalance.

Vascular Endothelial Growth Factor-B Blockade with CSL346 in Diabetic Kidney Disease: A Phase 2A Randomized Controlled Trial

Key Points

The vascular endothelial growth factor B inhibitor CSL346 (8 or 16 mg/kg q4w) did not reduce urinary albumin-creatinine ratio at week 16 versus placebo in patients with type 2 diabetes mellitus and diabetic kidney disease. CSL346 was generally well tolerated at both doses; however, CSL346 (16 mg/kg) significantly increased diastolic BP versus placebo.

Background

Increased vascular endothelial growth factor B (VEGF-B) expression in patients with diabetic kidney disease (DKD) is associated with increased lipid deposition in glomerular podocytes. Reducing VEGF-B activity in animal models of DKD using an anti–VEGF-B antibody improved histological evidence of glomerular injury and reduced albuminuria, effects attributed to prevention of ectopic lipid deposition in the kidney. CSL346 is a novel humanized monoclonal antibody that binds VEGF-B with high affinity. Targeting VEGF-B in patients with type 2 diabetes mellitus may improve DKD progression markers.

Methods

An international, randomized, double-blind, placebo-controlled, phase 2a study (NCT04419467 ) assessed CSL346 (8 or 16 mg/kg subcutaneously every 4 weeks for 12 weeks) in participants with type 2 diabetes mellitus and a urinary albumin-creatinine ratio (UACR) ≥150 mg/g (17.0 mg/mmol), and eGFR >20 ml/min per 1.73 m2. Efficacy, safety/tolerability, pharmacokinetics, and pharmacodynamics of CSL346 were evaluated. The primary analysis compared the change from baseline in log-transformed UACR between the two CSL346 dose groups combined versus placebo at week 16.

Results

In total, 114 participants were randomized. CSL346 did not significantly reduce UACR compared with placebo at week 16 (combined CSL346 group difference from placebo [95% confidence interval], 4.0% [−14.7 to 26.8]). Furthermore, no effect was seen in participant subgroups (degree of kidney impairment or sodium-glucose cotransporter 2 inhibitor use) or on urinary biomarkers reflecting proximal tubular injury. CSL346 was generally well tolerated; however, diastolic BP was significantly higher with CSL346 16 mg/kg versus placebo from week 2 onward, with differences ranging from +3.8 to +5.3 mm Hg (P = 0.002 at week 16).

Conclusions

CSL346 did not reduce UACR compared with placebo at 16 weeks in participants with type 2 diabetes mellitus and DKD and was associated with an increase in diastolic BP.

Clinical Trial registry name and registration number:

VEGF-B Blockade with the Monoclonal Antibody CSL346 in Subjects with DKD, NCT04419467 .

Vascular endothelial growth factor B improves impaired glucose tolerance through insulin-mediated inhibition of glucagon secretion

BACKGROUND

Impaired glucose tolerance (IGT) is a homeostatic state between euglycemia and hyperglycemia and is considered an early high-risk state of diabetes. When IGT occurs, insulin sensitivity decreases, causing a reduction in insulin secretion and an increase in glucagon secretion. Recently, vascular endothelial growth factor B (VEGFB) has been demonstrated to play a positive role in improving glucose metabolism and insulin sensitivity. Therefore, we constructed a mouse model of IGT through high-fat diet feeding and speculated that VEGFB can regulate hyperglycemia in IGT by influencing insulin-mediated glucagon secretion, thus contributing to the prevention and cure of prediabetes.

AIM

To explore the potential molecular mechanism and regulatory effects of VEGFB on insulin-mediated glucagon in mice with IGT.

METHODS

We conducted in vivo experiments through systematic VEGFB knockout and pancreatic-specific VEGFB overexpression. Insulin and glucagon secretions were detected via enzyme-linked immunosorbent assay, and the protein expression of phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) was determined using western blot. Further, mRNA expression of forkhead box protein O1, phosphoenolpyruvate carboxykinase, and glucose-6 phosphatase was detected via quantitative polymerase chain reaction, and the correlation between the expression of proteins was analyzed via bioinformatics.

RESULTS

In mice with IGT and VEGFB knockout, glucagon secretion increased, and the protein expression of PI3K/AKT decreased dramatically. Further, in mice with VEGFB overexpression, glucagon levels declined, with the activation of the PI3K/AKT signaling pathway.

CONCLUSION

VEGFB/vascular endothelial growth factor receptor 1 can promote insulin-mediated glucagon secretion by activating the PI3K/AKT signaling pathway to regulate glucose metabolism disorders in mice with IGT.

Reducing VEGFB expression regulates the balance of glucose and lipid metabolism in mice via VEGFR1

In recent years, studies have demonstrated that vascular endothelial growth factor B (VEGFB) can affect the metabolism of fatty acids and glucose, and it is expected to become a target for the diagnosis and treatment of metabolic diseases such as obesity and diabetes. At present, the specific mechanism that VEGFB regulates lipid and glucose metabolism balance is not completely understood. The present study used systemic VEGFB gene-knockout mice to investigate the effects of downregulation of the VEGFB gene on lipid metabolism and insulin secretion, and to explore the mechanism of the VEGFB pathway involved in the regulation of glucose and lipid metabolism. The morphological changes in the liver and pancreas of mice after VEGFB gene deletion were observed under a light microscope and a scanning electron microscope, and the effects of VEGFB gene deletion on lipid metabolism and blood glucose balance were detected by a serological technique. The detection indexes included total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol. Simultaneously, fasting blood glucose, glycosylated hemoglobin A1c (HbA1c), fasting insulin and glucagon were measured. Insulin sensitivity was assessed by using the insulin tolerance tests and glucose tolerance tests, and function of β-cell islets was evaluated by using the insulin resistance index (HOMA-IR) and pancreatic β-cell secretion index (HOMA-β). Τhe protein expression changes of vascular endothelial growth factor receptor 1 (VEGFR1) and vascular endothelial growth factor receptor 2 (VEGFR2) in mouse islets were detected by western blotting and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) after the VEGFB gene was knocked down to analyze the mechanism of VEGFB that may be involved in glucose and lipid metabolism. It was observed that after VEGFB was knocked down, mouse hepatocytes exhibited steatosis and increased secretory vesicles in islet cells. The lipid metabolism indexes such as TG, TC and LDL increased significantly; however, the levels of FBS, postprandial blood glucose and HbA1c decreased, whereas the glucose tolerance increased. Serum insulin secretion increased and HOMA-IR decreased since VEGFB was knocked down. Western blotting and RT-qPCR results revealed that the expression levels of VEGFR1 and neuropilin-1 decreased after the VEGFB gene was knocked down, while the expression levels of VEGFA and VEGFR2 increased. The absence of VEGFB may be involved in the regulation of glucose and lipid metabolism in mice by activating the VEGFA/VEGFR2 signaling pathway. VEGFB is expected to become a new target for the treatment of metabolic diseases such as obesity and diabetes. At present, the mechanism of VEGFB involved in regulating lipid metabolism and glucose metabolism is not completely clear. It was identified that downregulating VEGFB improved lipid metabolism and insulin resistance. The role of VEGFB/VEGFR1 pathway and other family members in regulating glucose and lipid metabolism was detected, which provided a theoretical and experimental basis for VEGFB to affect the regulation of glucose and lipid metabolism balance.

Serum vascular endothelial growth factor b and metabolic syndrome incidence in the population based cohort Di@bet.es study

Background/Objectives

Although vascular endothelial growth factor b (VEGFb) might have an impact on the development of obesity, diabetes and related disorders, the possible relationship between VEGFb serum levels and the incidence of these metabolic complications in humans is still unknown. The aim of our study was to evaluate the association between VEGFb serum levels and the new-onset of metabolic syndrome (MS) and its components in the Spanish adult population after 7.5 years of follow-up.

Subjects/Methods

A total of 908 subjects from the Di@bet.es cohort study without MS at cross-sectional stage according to International Diabetes Federation (IDF) or Adult Treatment Panel III (ATP-III) criteria were included. Additionally, five sub-populations were grouped according to the absence of each MS component at baseline. Socio-demographic, anthropometric and clinical data were recorded. The Short Form of International Physical Activity Questionnaire (SF-IPAQ) was used to estimate physical activity. A fasting blood extraction and an oral glucose tolerance test were performed. Serum determinations of glucose, lipids, hsCRP and insulin were made. VEGFb levels were determined and categorized according to the 75th percentile of the variable. New cases of MS and its components were defined according to ATPIII and IDF criteria.

Results

A total of 181 or 146 people developed MS defined by IDF or ATP-III criteria respectively. Serum triglyceride levels, hs-CRP and systolic blood pressure at the baseline study were significantly different according to the VEGFb categories. Adjusted logistic regression analysis showed that the likelihood of developing MS and abdominal obesity was statistically reduced in subjects included in the higher VEGFb category.

Conclusion

Low serum levels of VEGFb may be considered as early indicators of incident MS and abdominal obesity in the Spanish adult population free of MS, independently of other important predictor variables.

Increased Serum VEGF-B Level Is Associated With Renal Function Impairment in Patients With Type 2 Diabetes

Aims/Introduction

Renal function impairment related to type 2 diabetes (T2DM) presents serious threat to public health. Previous studies suggest that vascular endothelial growth factor-B (VEGF-B) might contribute to renal injury. Therefore, this study investigated the association of serum VEGF-B level with the risk of renal function impairment in T2DM patients.

Materials and Methods

Serum VEGF-B levels were measured in 213 patients with type 2 diabetes and 31 healthy participants. Participants with type 2 diabetes were further divided into a group of 112 participants with eGFR<90 mL/min/1.73m2 and 101 participants with eGFR≥ 90 mL/min/1.73m2. Clinical data were collected, and a binary logistic regression model was employed to test the association between potential predictors and eGFR.

Results

Serum VEGF-B levels evaluated in type 2 diabetes patients compared with healthy controls. In patients with type 2 diabetes, serum VEGF-B level was positively correlated with triglyceride, serum creatinine and cystatin C while negatively correlated with HDL-C and eGFR. Binary logistic regression showed that serum VEGF-B level was an independent risk factor of eGFR<90 mL/min/1.73m2.

Conclusions

Serum VEGF-B level is associated with renal function impairment in patients with type 2 diabetes and may be a potential drug target for diabetic kidney disease.

Vascular endothelial growth factor B inhibits insulin secretion in MIN6 cells and reduces Ca2+ and cyclic adenosine monophosphate levels through PI3K/AKT pathway

BACKGROUND

Type 2 diabetes (T2D) is characterized by insufficient insulin secretion caused by defective pancreatic β-cell function or insulin resistance, resulting in an increase in blood glucose. However, the mechanism involved in this lack of insulin secretion is unclear. The level of vascular endothelial growth factor B (VEGF-B) is significantly increased in T2D patients. The inactivation of VEGF-B could restore insulin sensitivity in db/db mice by reducing fatty acid accumulation. It is speculated that VEGF-B is related to pancreatic β-cell dysfunction and is an important factor affecting β-cell secretion of insulin. As an in vitro model of normal pancreatic β-cells, the MIN6 cell line can be used to analyze the mechanism of insulin secretion and related biological effects.

AIM

To study the role of VEGF-B in the insulin secretion signaling pathway in MIN6 cells and explore the effect of VEGF-B on blood glucose regulation.

METHODS

The MIN6 mouse pancreatic islet β-cell line was used as the model system. By administering exogenous VEGF-B protein or knocking down VEGF-B expression in MIN6 cells, we examined the effects of VEGF-B on insulin secretion, Ca²⁺ and cyclic adenosine monophosphate (cAMP) levels, and the insulin secretion signaling pathway.

RESULTS

Exogenous VEGF-B inhibited the secretion of insulin and simultaneously reduced the levels of Ca²⁺ and cAMP in MIN6 cells. Exogenous VEGF-B also reduced the expression of phospholipase C gamma 1 (PLCγ1), phosphatidylinositol 3-kinase (PI3K), serine/threonine kinase (AKT), and other proteins in the insulin secretion pathway. Upon knockdown of VEGF-B, MIN6 cells exhibited increased insulin secretion and Ca²⁺ and cAMP levels and upregulated expression of PLCγ1, PI3K, AKT, and other proteins.

CONCLUSION

VEGF-B can regulate insulin secretion by modulating the levels of Ca²⁺ and cAMP. VEGF-B involvement in insulin secretion is related to the expression of PLCγ1, PI3K, AKT, and other signaling proteins. These results provide theoretical support and an experimental basis for the study of VEGF-B in the pathogenesis of T2D.

Vascular endothelial growth factor B promotes transendothelial fatty acid transport into skeletal muscle via histone modifications during catch-up growth

Caloric restriction (CR) followed by refeeding, a phenomenon known as catch-up growth (CUG), results in excessive lipid deposition and insulin resistance in skeletal muscle, but the underlying mechanisms remain elusive. Recent reports have suggested that vascular endothelial growth factor B (VEGF-B) controls muscle lipid accumulation by regulating endothelial fatty acid transport. Here, we found continuous activation of VEGF-B signaling and increased lipid uptake in skeletal muscle from CR to refeeding, as well as increased lipid deposition and impaired insulin sensitivity after refeeding in the skeletal muscle of CUG rodents. Inhibiting VEGF-B signaling reduced fatty acid uptake in and transport across endothelial cells. Knockdown of Vegfb in the tibialis anterior (TA) muscle of CUG mice significantly attenuated muscle lipid accumulation and ameliorated muscle insulin sensitivity by decreasing lipid uptake. Furthermore, we showed that aberrant histone methylation (H3K9me1) and acetylation (H3K14ac and H3K18ac) at the Vegfb promoter might be the main cause of persistent VEGF-B upregulation in skeletal muscle during CUG. Modifying these aberrant loci using their related enzymes [PHD finger protein 2 (PHF2) or E1A binding protein p300 (p300)] could regulate VEGF-B expression in vitro. Collectively, our findings indicate that VEGF-B can promote transendothelial lipid transport and lead to lipid overaccumulation and insulin resistance in skeletal muscle during CUG, which might be mediated by histone methylation and acetylation.

Plasma vascular endothelial growth factor B is elevated in non-alcoholic fatty liver disease patients and associated with blood pressure and renal dysfunction

Vascular endothelial growth factor B (VEGF-B) is a critical metabolic regulator in insulin resistance, and lipid distribution. We intended to ascertain the relationship between circulating VEGF-B and non-alcoholic fatty liver disease (NAFLD) in the general public. We recruited a total of 194 general participants for a routine physical health examination; of these, 84 participants were identified with NAFLD and 110 without NAFLD based on ultrasonographic findings. Homeostasis model assessment of insulin resistance (HOMA-IR), body mass index (BMI), HbA1c, liver function, kidney function, plasma VEGF-B levels and indexes of metabolic syndrome (blood pressure, fasting plasma glucose, fasting lipids) were evaluated. Plasma VEGF-B values were significantly higher in individuals with NAFLD compared to those without NAFLD (P = 0.022), and analysis of covariance confirmed this result. VEGF-B showed a positive correlation with γ-glutamyl transpeptidase (γ-GT) and HOMA-IR in univariate analysis (q = 0.242; P = 0.001; q =0.174; P = 0.019, respectively). Multiple linear regression analysis showed that γ-GT and ALT were independently correlated with VEGF-B even after adjusted for gender and age (q = 0.286; P = 0.01; q =0.237; P = 0.033, respectively). Moreover, plasma VEGF-B showed a powerful correlation with blood pressure and renal dysfunction. Plasma VEGF-B might be a new clinical variable related to NAFLD and could be a proper biomarker for the early detection of hypertension and renal dysfunction. However, further studies with large cohorts' size are warranted to validate our findings.

VEGF-B ablation in pancreatic β-cells upregulates insulin expression without affecting glucose homeostasis or islet lipid uptake

Type 2 diabetes mellitus (T2DM) affects millions of people and is linked with obesity and lipid accumulation in peripheral tissues. Increased lipid handling and lipotoxicity in insulin producing β-cells may contribute to β-cell dysfunction in T2DM. The vascular endothelial growth factor (VEGF)-B regulates uptake and transcytosis of long-chain fatty acids over the endothelium to tissues such as heart and skeletal muscle. Systemic inhibition of VEGF-B signaling prevents tissue lipid accumulation, improves insulin sensitivity and glucose tolerance, as well as reduces pancreatic islet triglyceride content, under T2DM conditions. To date, the role of local VEGF-B signaling in pancreatic islet physiology and in the regulation of fatty acid trans-endothelial transport in pancreatic islet is unknown. To address these questions, we have generated a mouse strain where VEGF-B is selectively depleted in β-cells, and assessed glucose homeostasis, β-cell function and islet lipid content under both normal and high-fat diet feeding conditions. We found that Vegfb was ubiquitously expressed throughout the pancreas, and that β-cell Vegfb deletion resulted in increased insulin gene expression. However, glucose homeostasis and islet lipid uptake remained unaffected by β-cell VEGF-B deficiency.

Hyperglycemia induced testicular damage in type 2 diabetes mellitus rats exhibiting microcirculation impairments associated with vascular endothelial growth factor decreased via PI3K/Akt pathway

As an endocrine disease, type 2 diabetes mellitus (T2DM) can cause testicular damage which induces male infertility. However, the underlying mechanism is still not clear. We prove that T2DM induced testicular microcirculation impairment involves the decrease of VEGF and these actions are regulated by PI3K/Akt pathway. In our study, rats were divided into three groups (n=8): control group, diabetes group and diabetes + VEGF group. Intraperitoneal injection of streptozotocin (STZ, 65mg/Kg, at 9^th week) and daily high-fat diet were used to establish T2DM rat model. Serum glucose in diabetes group and diabetes + VEGF group obviously exceeded 13mmol/L after STZ injection. Immunohistochemical studies indicated that VEGF level in diabetes group significantly decreased. In diabetes group, testicular blood velocity and vascular area reduced evaluated by Doppler and FITC. Furthermore, atrophic testicular morphology and increasing apoptosis cells were evaluated by haematoxylin and eosin staining and TUNEL assay. In diabetes + VEGF group, the administration of VEGF (intraperitoneally, 10mg/kg) can significantly alleviated hyperglycemia-induced impairment of testes in above aspects. Finally, we used Western blot to analyze the mechanism of hyperglycemia-induced testicular VEGF decrease. The results indicated that hyperglycemia-induced VEGF decreased is regulated by PI3K/Akt pathway in Rats testicular sertoli cells (RTSCs). Together, we demonstrate that T2DM can reduce testicular VEGF expression, which results in testicular microcirculation impairment, and then induces testicular morphological disarrangement and functional disorder. These actions are triggered by PI3K/Akt pathway. Our findings provide solid evidence for VEGF becoming a therapeutic target in T2DM related male infertility.

Association between the expression of vascular endothelial growth factors and metabolic syndrome or its components: a systematic review and meta-analysis

BACKGROUND

Several studies have linked vascular endothelial growth factors (VEGFs) with metabolic syndrome or its components. However, there has been no systematic appraisal of the findings of these studies to date. The current systematic review and meta-analysis was conducted to explore this association.

METHODS

PubMed, EMBASE, the Cochrane library, and clinical trials registries were used to retrieve peer-reviewed clinical studies that had evaluated the association of VEGFs with metabolic syndrome or its components without applying language and date restrictions. The final search was performed on 29 September 2017.

RESULTS

We included 32 studies in this systematic review and meta-analysis, of which 16 studies (19 study arms) were included in the meta-analysis and remaining studies were qualitatively assessed. Overall, VEGF-A, VEGF-B and VEGF-C were strongly associated with metabolic syndrome or its components. The components of metabolic syndrome varied in their association. Obesity was not correlated with increased VEGF-A expression (p = 0.12), whereas VEGF-B and VEGF-C expression was significantly higher in those with obesity. In contrast, hyperglycemia in type 1 diabetes was strongly associated with increased VEGF-A levels (p < 0.00001), as was type 2 diabetes (p = 0.0006). The studies included in the qualitative analysis similarly showed an increase in VEGF family expression in people with metabolic syndrome, and with its components.

CONCLUSION

The increased concentrations of vascular endothelial growth factors are variably associated with metabolic syndrome or its components. Each VEGF protein has a unique set of associations with the disease state.