Vascular endothelial growth factor (VEGF) in children, adolescents and young adults with Type 1 diabetes mellitus: relation to glycaemic control and microvascular complications

The Impact of Thyroiditis on the Immune Profile in Young Patients with Uncomplicated Type 1 Diabetes

Autoimmune thyroid disease (AIT) is the most frequently linked autoimmune condition to type 1 diabetes (T1D). The analysis of immune profiles could provide valuable insights into the study of these diseases. This knowledge could play a crucial role in understanding the relationship between immune profiles and microcirculation structures and functions. The present study aimed to test the hypothesis that cytokine levels in T1D patients without and those with comorbid Hashimoto's disease differ significantly. The total study group (total T1D) consisted of 62 diabetic young patients: 43 T1D and 19 T1D + AIT matched for age, age at onset, and duration of diabetes. The control group consisted of 32 healthy young subjects. The levels of cytokines (including TNF-α, IL-35, IL-4, IL-10, IL-18, IL-12, VEGF, and angiogenin) were quantified throughout this investigation. A comparative assessment of the cytokines profiles between the control group and total T1D revealed a statistically significant elevation in the levels of IL-4, TNF-α, IL-18, VEGF, and angiogenin, accompanied by a notable decline in IL-10. However, IL-35 and IL-12 exhibited comparable levels between the two groups. A comparison of cytokine levels between T1D + AIT and T1D groups revealed that only angiogenin levels were statistically significantly higher in T1D + AIT. The results of our study indicated that the alterations in cytokine levels associated with AIT did not correspond to the observed changes in T1D-related outcomes. The sole notable observation was the elevation of angiogenin expression, an angiogenic factor.

The Relationship between TNF-a, IL-35, VEGF and Cutaneous Microvascular Dysfunction in Young Patients with Uncomplicated Type 1 Diabetes

The aim of this study was to analyze the relationship between immunological markers and the dysfunction of cutaneous microcirculation in young patients with type 1 diabetes. The study group consisted of 46 young patients with type 1 diabetes and no associated complications. Microvascular function was assessed with the use of nail fold capillaroscopy before and after implementing post-occlusive reactive hyperemia. This evaluation was then repeated after 12 months. Patients were divided into two subgroups according to their baseline median coverage (defined as the ratio of capillary surface area to surface area of the image area), which was established during the initial exam (coverageBASE). Additionally, the levels of several serum biomarkers, including VEGF, TNF-a and IL-35, were assessed at the time of the initial examination. HbA1c levels obtained at baseline and after a 12-month interval were also obtained. Mean HbA1c levels obtained during the first two years of the course of the disease were also analyzed. Patients with coverageBASE below 16.85% were found to have higher levels of VEGF and TNF-α, as well as higher levels of HbA1c during the first two years following diabetes diagnosis. Our results support the hypothesis that the development of diabetic complications is strongly influenced by metabolic memory and an imbalance of pro- and anti-inflammatory cytokines, regardless of achieving adequate glycemic control.

Hyperglycemia and prematurity: a narrative review

Hyperglycemia is commonly encountered in extremely preterm newborns and physiologically can be attributed to immaturity in several biochemical pathways related to glucose metabolism. Although hyperglycemia is associated with a variety of adverse outcomes frequently described in this population, evidence for causality is lacking. Variations in definitions and treatment approaches have further complicated the understanding and implications of hyperglycemia on the immediate and long-term effects in preterm newborns. In this review, we describe the relationship between hyperglycemia and organ development, outcomes, treatment options, and potential gaps in knowledge that need further research. IMPACT: Hyperglycemia is common and less well described than hypoglycemia in extremely preterm newborns. Hyperglycemia can be attributed to immaturity in several cellular pathways involved in glucose metabolism in this age group. Hyperglycemia has been shown to be associated with a variety of adverse outcomes frequently described in this population; however, evidence for causality is lacking. Variations in definitions and treatment approaches have complicated the understanding and the implications of hyperglycemia on the immediate and long-term effects outcomes. This review describes the relationship between hyperglycemia and organ development, outcomes, treatment options, and potential gaps in knowledge that need further research.

Toceranib phosphate (Palladia) reverses type 1 diabetes by preserving islet function in mice

In recent years, strategies targeting β-cell protection via autoimmune regulation have been suggested as novel and potent immunotherapeutic interventions against type 1 diabetes mellitus (T1D). Here, we investigated the potential of toceranib (TOC), a receptor-type tyrosine kinase (RTK) inhibitor used in veterinary practice, to ameliorate T1D. TOC reversed streptozotocin-induced T1D and improved the abnormalities in muscle and bone metabolism characteristic of T1D. Histopathological examination revealed that TOC significantly suppressed β-cell depletion and improved glycemic control with restoration of serum insulin levels. However, the effect of TOC on blood glucose levels and insulin secretion capacity is attenuated in chronic T1D, a more β-cell depleted state. These findings suggest that TOC improves glycemic control by ameliorating the streptozotocin-induced decrease in insulin secretory capacity. Finally, we examined the role of platelet-derived growth factor receptor (PDGFR) inhibition, a target of TOC, and found that inhibition of PDGFR reverses established T1D in mice. Our results show that TOC reverses T1D by preserving islet function via inhibition of RTK. The previously unrecognized pharmacological properties of TOC have been revealed, and these properties could lead to its application in the treatment of T1D in the veterinary field.

Post hoc analysis of a randomized, double-blind, prospective trial evaluating a CXCR1/2 inhibitor in new-onset type 1 diabetes: endo-metabolic features at baseline identify a subgroup of responders

Aim

In a recent randomized, multicenter trial (NCT02814838) a short-term anti-inflammatory treatment with ladarixin (LDX; an inhibitor of the CXCR1/2 chemokine receptors) did not show benefit on preserving residual beta cell function in new-onset type 1 diabetes. We present a post hoc analysis of trial patients in the predefined subgroup analysis developed according to baseline daily insulin requirement (DIR) tertiles.

Method

A double-blind, randomized (2:1), placebo-controlled study was conducted in 45 men and 31 women (aged 18-46 years) within 100 days of the first insulin administration. Patients received LDX (400 mg twice daily) for three cycles of 14 days on/14 days off, or placebo. The primary endpoint was the area under the curve for C-peptide [AUC (0-120 min)] in response to a 2-h mixed meal tolerance test (MMTT) at week 13 ± 1. Seventy-five patients completed the week 13 MMTT and were divided into three groups according to the DIR tertiles: lower, ≤ 0.23U/kg/die (n = 25); middle, 0.24-0.40 U/kg/die (n = 24); upper, ≥ 0.41 U/kg/die (n = 26).

Results

When considering the patients in the upper tertile (HIGH-DIR), C-peptide AUC (0-120 min) at 13 weeks was higher in the LDX group (n = 16) than in the placebo (n = 10) group [difference: 0.72 nmol/L (95% CI 0.9-1.34), p = 0.027]. This difference reduced over time (0.71 nmol/L at 26 weeks, p = 0.04; 0.42 nmol/L at 52 weeks, p = 0.29), while it has never been significant at any time in patients in the lower and/or middle tertile (LOW-DIR). We characterized at baseline the HIGH-DIR and found that endo-metabolic (HOMA-B, adiponectin, and glucagon-to-C-peptide ratio) and immunologic (chemokine (C-C motif) ligand 2 (CCL2)/monocyte chemoattractant protein 1 (MCP1) and Vascular Endothelial Growth Factor (VEGF)) features distinguished this group from LOW-DIR.

Conclusion

While LDX did not prevent the progressive loss of beta-cell function in the majority of treated subjects, the post hoc analysis suggests that it could work in subjects with HIGH-DIR at baseline. As we found differences in endo-metabolic and immunologic parameters within this subgroup, this generates the hypothesis that the interactions between host factors and drug action can contribute to its efficacy. Further research is needed to evaluate this hypothesis.

Associations of VEGF-A-Related Variants with Adolescent Cardiometabolic and Dietary Parameters

Previous research has allowed the identification of variants related to the vascular endothelial growth factor-A (VEGF-A) and their association with anthropometric, lipidemic and glycemic indices. The present study examined potential relations between key VEGF-A-related single-nucleotide polymorphisms (SNPs), cardiometabolic parameters and dietary habits in an adolescent cohort. Cross-sectional analyses were conducted using baseline data from 766 participants of the Greek TEENAGE study. Eleven VEGF-A-related SNPs were examined for associations with cardiometabolic indices through multivariate linear regressions after adjusting for confounding factors. A 9-SNP unweighted genetic risk score (uGRS) for increased VEGF-A levels was constructed to examine associations and the effect of its interactions with previously extracted dietary patterns for the cohort. Two variants (rs4416670, rs7043199) displayed significant associations (p-values < 0.005) with the logarithms of systolic and diastolic blood pressure (logSBP and logDBP). The uGRS was significantly associated with higher values of the logarithm of Body Mass Index (logBMI) and logSBP (p-values < 0.05). Interactions between the uGRS and specific dietary patterns were related to higher logDBP and logGlucose (p-values < 0.01). The present analyses constitute the first-ever attempt to investigate the influence of VEGF-A-related variants on teenage cardiometabolic determinants, unveiling several associations and the modifying effect of diet.

Association between Age at Type 2 Diabetes Onset and Diabetic Retinopathy: A Double-Center Retrospective Study

BACKGROUND

With the decreasing age of type 2 diabetes mellitus (T2DM) onset, the incidence of diabetic complications is gradually increasing. We evaluated the independent effect of age at diabetes onset on diabetic retinopathy (DR) development.

METHODS

A total of 7472 patients with T2DM were enrolled in the National Metabolic Management Center from September 2017 to May 2022. Anthropometry data, laboratory reports, and medical history were collected. The independent association of DR with age at diabetes onset was analyzed using multivariable logistic regression models. In addition, a stratified analysis was performed to determine the effect of confounding variables.

RESULTS

Of the 7472 patients recruited, 1642 (21.98%) had DR. Patients with DR had considerably younger ages of diabetes onset than those without DR (45 (38-53) years vs. 50 (43-57) years, P < 0.001). The proportion of patients with T2DM onset at a younger age was higher in the DR group than that in the non-DR group. Participants were divided into four groups according to their age at diabetes onset, namely, ≥60, <40, 40-49, and 50-59 years. Compared with patients with diabetes onset at age ≥ 60 years, those with diabetes onset at <40 years (odds ratio (OR): 5.56, 95% confidence interval (CI): 3.731-8.285, P < 0.001), 40-49 years (OR: 2.751, 95% CI: 2.047-3.695, P < 0.001), and 50-59 years (OR: 1.606, 95% CI: 1.263-2.042, P < 0.001) were at an increased risk of DR after adjusting for potential confounding factors. Furthermore, stratification analyses demonstrated that young age at diabetes onset is an independent risk factor for DR.

CONCLUSIONS

Compared with diabetes onset at an older age, diabetes onset at a younger age is associated with a significantly increased DR risk.

Potential Therapeutic Applications of Natural Compounds in Diabetes-Associated Periodontitis

Diabetes mellitus (DM) is a major worldwide health burden. DM is a metabolic disease characterized by chronic hyperglycemia, and if left untreated, can lead to various complications. Individuals with uncontrolled DM are more susceptible to periodontitis due to both a hyper-inflammatory host response and an impaired immune response. Periodontitis, on the other hand, may exacerbate DM by increasing both local and systemic inflammatory components of DM-related complications. The current standard for periodontal treatment in diabetes-associated periodontitis (DP) focuses mostly on reducing bacterial load and less on controlling the excessive host response, and hence, may not be able to resolve DP completely. Over the past decade, natural compounds have emerged as an adjunct approach for modulating the host immune response with the hope of curing DP. The anti-oxidant, anti-inflammatory, and anti-diabetic characteristics of natural substances are well-known, and they can be found in regularly consumed foods and drinks, as well as plants. The pathophysiology of DP and the treatment benefits of various bioactive extracts for DP will be covered in this review.

Early Onset Age Increased the Risk of Diabetic Retinopathy in Type 2 Diabetes Patients with Duration of 10-20 Years and HbA1C ≥7%: A Hospital-Based Case-Control Study

BACKGROUND

The relationship between onset age of diabetes and diabetic retinopathy (DR) is controversy and not concluded. Therefore, this hospital-based case-control study aimed to investigate the influence of diabetes onset age on the development of DR in patients with type 2 diabetes (T2D), independent of diabetic duration and HbA1c levels.

METHODS

A sample of 780 T2D patients with diabetic duration of 10-20 years and glycated hemoglobin (HbA1c) ≥7% were enrolled in the study. 338 T2D patients with onset age ≤45 years were further selected as cases (early onset) and 79 with onset age ≥ 55 years were chosen as controls (elderly onset). International Clinical Diabetic Retinopathy Disease Severity Scale was applied to estimate the severity of DR.

RESULTS

The prevalence of DR and proliferative diabetic retinopathy (PDR) was notably increased in the early onset group. When stratified by duration of diabetes, the impact of younger age on the risk of DR turned to be greatest in patients with diabetic duration ≥15 years (OR = 5.202, 95% CI 2.625-10.310). In groups stratified by HbA1c, the risk of DR was highest in patients with younger onset age and HbA1c ≥ 9% (OR = 3.889, 95% CI 1.852-8.167). Compared with the elderly onset group, the risk of DR (OR = 1.776, 95% CI = 1.326-2.380, p < 0.001) and PDR (OR = 1.605, 95% CI = 1.106-2.329, p = 0.013) in younger diagnosed patients was increased after multivariable adjustment.

CONCLUSIONS

Age of onset was an independent risk factor for developing DR and PDR. This suggests that it is urgent to closely monitor and treat the metabolic disorders in younger T2D patients to delay the occurrence and progression of DR.

Prevalence of and risk factors for diabetic retinopathy and diabetic macular edema in patients with early and late onset diabetes mellitus

PURPOSE

To compare the prevalence of diabetic retinopathy (DR) and diabetic macular edema (DME), as well as their risk factors in patients with early onset diabetes (EOD, ≤40 years) and late onset diabetes (LOD, >40 years).

METHODS

Patients were recruited from a community-based study, Fushun Diabetic Retinopathy Cohort Study (FS-DIRECT), conducted between July 2012 and May 2013 in China. The presence and severity of the DR and DME were determined by a modified Early Treatment Diabetic Retinopathy Study (ETDRS) retinopathy scale of six-field fundus photographs.

RESULTS

A total of 1932 patients (796 male, 41.2%) with gradable fundus photography were included. The prevalence of any DR and DME was 67.0% (95% confidence interval [CI]: 60.3-73.7%) and 39.3% (95% CI: 32.1-46.5%) in the EOD patients respectively, which were both significantly higher than that in the LOD patients (DR: 41.9%, 39.6-44.2%, p<0.001; DME: 14.4%, 12.7-16.1%, p<0.001). Insulin use was associated with both presence of DR and DME in both EOD and LOD patients. Besides insulin use, high level of income (odds ratio [OR], 95% CI: 0.05, 0.01-0.51) was negatively associated with DR, and higher high density lipoprotein (OR, 95% CI: 4.14, 1.44-11.91) was associated with DME, among EOD patients.

CONCLUSION

In this sample of patients with type 2 diabetes, both the prevalence of DR and DME were apparently higher in patients who developed diabetes ≤40 years of age than those who developed it later.

Development of Aptamer-Based TID Assays Using Thermophoresis and Microarrays

Aptamers are single-stranded oligonucleotides which can be used as alternative recognition elements for protein detection, because aptamers bind their targets with a high affinity similar to antibodies. Due to the targetinduced conformational changes of aptamers, these oligonucleotides can be applied in various biosensing platforms. In this work, aptamers directed against the vascular endothelial growth factor (VEGF) were used as a model system. VEGF plays a key role in physiological angiogenesis and vasculogenesis. Furthermore, VEGF is involved in the development and growth of cancer and other diseases like agerelated macular degeneration, rheumatoid arthritis, diabetes mellitus, and neurodegenerative disorders. Detecting the protein biomarker VEGF is therefore of great importance for medical research and diagnostics. In this research, VEGFbinding aptamers were investigated for the systematic development of a targetinduced dissociation (TID) assay utilizing thermophoresis and microarrays. The established aptamer-microarray allowed for the detection of 0.1 nM of VEGF. Furthermore, the systematic development of the TID method using the VEGF model protein could help to develop further TID assays for the detection of various protein biomarkers.

Green tea prevents vascular disturbs and attenuates periodontal breakdown in long-term hyperglycaemia in T1D rats

AIM

The effects of green tea on the modulation of vascularization during the progression of spontaneous periodontitis in long-term hyperglycaemia in streptozotocin-induced type 1 diabetic (T1D) rats were evaluated.

MATERIALS AND METHODS

Wistar rats normoglycaemic (NG) and T1D were divided into two control groups, which received water (NG-W and T1D-W) and two experimental groups that received green tea (NG-GT and T1D-GT). Periodontal structures were evaluated by microtomographic and histological analyses. Number of immunostained cells for VEGF (NcVEGF+/mm² ) and CD31 (NcCD31+/mm² ), as well microvessel density (MVD) in the periodontal ligament (PDL) were evaluated.

RESULTS

Long-term hyperglycaemia in T1D-W rats induced vascular alterations in PDL with a reduction of 36% in MVD, a decrease of 33% in NcCD31+/mm² and an increase of 53% in NcVEGF+/mm² . Concomitantly, a severe degree of periodontitis with higher reduction in bone volume and periodontal bone level was observed. In T1D-GT, green tea maintained the MVD, NcCD31+/mm² and NcVEGF+/mm² in the PDL similar to normoglycaemic groups. Clinically, in T1D-GT rats, green tea reduced dental plaque accumulation and the degree of periodontitis when compared to T1D-W.

CONCLUSION

Daily green tea consumption has a therapeutic effect on the diabetic vascular disorder in PDL and the progression of periodontitis in long-term hyperglycaemia in T1D rats.

VEGF levels in plasma in relation to metabolic control, inflammation, and microvascular complications in type-2 diabetes: A cohort study

The vascular endothelial growth factor (VEGF) level in human circulation may reflect the severity of endothelial dysfunction in patients with diabetes mellitus, which leads to diabetic microvascular complications.We determined plasma VEGF levels as well as metabolic control and inflammatory factors in 26 healthy subjects and 52 type-2 diabetes mellitus (T2DM) patients with or without diabetic microvascular complications. Pearson correlation coefficient was used to evaluate the associations among those indices.The results showed that VEGF levels in plasma were positively correlated with fasting blood glucose level, glycosylated hemoglobin (HbA1c) level, type 1 helper T cell (Th1) percentage, and Th1/Th2 ratio, while they were negatively correlated with regulatory T cell percentage. Multiple linear regression analysis showed that HbA1c and Th1/Th2 ratio were the independent predictors of VEGF levels in T2DM patients.Thus, in T2DM patients with poor glycemic control as well as an elevated Th1/Th2 cell ratio, more VEGF might be released.

Targeted VEGF-triggered release of an anti-cancer drug from aptamer-functionalized metal-organic framework nanoparticles

Amino-triphenyl dicarboxylate-bridged Zr⁴⁺ metal-organic framework nanoparticles (NMOFs), 100-130 nm, are modified with a nucleic acid complementary to the VEGF aptamer. The nucleic acid-functionalized NMOFs were loaded with the anti-cancer drug doxorubicin (or Rhodamine 6G as a drug model), and the loaded NMOFs were capped by hybridization with the VEGF aptamer that yielded VEGF-responsive duplex nucleic acid gates. In the presence of VEGF, a biomarker over-expressed in cancer cells, selective unlocking of the gates proceeds through the formation of VEGF/aptamer complexes, resulting in the release of the loads. In addition, the VEGF aptamer locking units were conjugated to the AS1411 aptamer sequence that binds to nucleolin receptors associated with cancer cells, resulting in the construction of cancer-cell targeted VEGF-responsive doxorubicin-loaded NMOFs. The different drug-loaded stimuli-responsive NMOFs reveal selective permeation into MDA-MB-231 breast cancer cells, compared to their incorporation into normal MCF-10A breast cells, with a two-fold enhanced incorporation into the MDA-MB-231 cells of the AS1411 aptamer-functionalized NMOFs. Cytotoxicity experiments revealed impressive selective apoptosis of the doxorubicin-loaded NMOFs towards the MDA-MB-231 cancer cells compared to the normal MCF-10A breast cells. A 55% and 70% MDA-MB-231 cell apoptosis was observed upon subjecting the cells to the VEGF aptamer and the VEGF aptamer/AS1411 aptamer conjugate-caged NMOFs, respectively, for a time-interval of three days, where only <10% apoptosis of the MCF-10A cells was observed under similar conditions.

VEGF, the underlying factor for metabolic syndrome; fact or fiction?

Metabolic syndrome (MetS) is currently diagnosed by the co-presence of at least three of the five following abnormalities: abdominal obesity, dysglycaemia, elevated serum triglycerides, low high-density cholesterol (HDL) and finally elevated blood pressure. Metabolic syndrome increases the risk of developing cardiovascular disease and diabetes. This review is on the associations between MetS and vascular endothelial growth factor (VEGF). VEGF induces migration and proliferation of endothelial cells (ECs), increases vascular permeability and has a role in tumor growth, adipose tissue expansion, age-related macular degeneration and diabetic retinopathy. Circulating levels of VEGFs are elevated in obese individuals and it has also been suggested that VEGF is secreted from adipose tissues, especially from intra-abdominal adipose tissue. There is abundant evidence to support that poor glycemic control in diabetic patients is associated with increased plasma VEGF, which in turn may cause hypertension and several vascular complications in diabetic patients. Circulating VEGF levels are increased in children and young adults with type 1 diabetes mellitus and middle-aged diabetic patients with proliferative retinopathy. It has been revealed that plasma VEGF increases in patients with hyperlipidemia and may trigger the development of atherosclerosis. It can be concluded that there is a positive association between VEGF and components of MetS. Because of the importance of this relationship, more investigations are needed in this field.

Pro-angiogenic Role of Insulin: From Physiology to Pathology

The underlying molecular mechanisms involve in the regulation of the angiogenic process by insulin are not well understood. In this review article, we aim to describe the role of insulin and insulin receptor activation on the control of angiogenesis and how these mechanisms can be deregulated in human diseases. Functional expression of insulin receptors and their signaling pathways has been described on endothelial cells and pericytes, both of the main cells involved in vessel formation and maturation. Consequently, insulin has been shown to regulate endothelial cell migration, proliferation, and in vitro tubular structure formation through binding to its receptors and activation of intracellular phosphorylation cascades. Furthermore, insulin-mediated pro-angiogenic state is potentiated by generation of vascular growth factors, such as the vascular endothelial growth factor, produced by endothelial cells. Additionally, diseases such as insulin resistance, obesity, diabetes, and cancer may be associated with the deregulation of insulin-mediated angiogenesis. Despite this knowledge, the underlying molecular mechanisms need to be elucidated in order to provide new insights into the role of insulin on angiogenesis.

The Increased Circulating Plasma Levels of Vascular Endothelial Growth Factor in Patients with Type 1 Diabetes Do Not Correlate to Metabolic Control

Aim. To characterize the plasma levels of vascular endothelial growth factor (VEGF) in type 1 diabetes mellitus (T1D) and its relation to both present and historical metabolic control and microvascular complications. Methods. Plasma levels of VEGF and routine clinical parameters were analyzed in 115 patients with long-standing T1D and 45 healthy controls (HC). All patients were under clinical routine diabetes treatment at Uppsala University Hospital. Results. The plasma levels of VEGF were increased by 37% in patients with T1D when compared to HC (18.2 ± 0.8 versus 13.2 ± 1.0 pg/ml, p < 0.001). The levels of VEGF correlated to insulin needs and BMI but not to present or historical metabolic control. The levels of VEGF were similar in patients with T1D and microvascular complications (microalbuminuria and retinopathy) when compared with patients without microvascular complications. Historical HbA1c levels were found to be the best predictor for present metabolic control. Conclusion. Circulating plasma levels of VEGF do not correlate to present or historical metabolic control in long-standing T1D and the levels are not affected by the presence of microvascular complications.

No effect of yeast-like fungi on lipid metabolism and vascular endothelial growth factor level in children and adolescents with type 1 diabetes mellitus

BACKGROUND

The objective of the research was to investigate vascular endothelial growth factor (VEGF) levels in the context of lipid metabolism and amount of yeast-like fungi colonizing the digestive tract in children and adolescents with type 1 diabetes mellitus (T1DM).

METHODS

The study included 45 children with T1DM and 27 age- and sex-matched healthy control subjects. In the study sample 33 T1DM patients were administered insulin pump therapy and 12 T1DM patients were administered multiple daily injections with insulin pen devices. All T1DM patients were free of micro- and macrovascular complications. In T1DM patients and healthy controls biochemical tests were performed and measurements of yeast-like fungi colonizing the alimentary tract were conducted. Moreover all study subjects had their serum VEGF levels measured with ELISA test.

RESULTS

The subgroup of children and adolescents with T1DM and yeast-like fungus colony number 10^3 CFU/g was shown statistically significantly lower HbA1c levels, and lower but not statistically significantly total cholesterol, LDL cholesterol and VEGF levels versus T1DM patients with the amount of yeast-like fungi 10^6 CFU/g. Moreover higher HDL levels were observed in this subgroup versus T1DM patients with the amount of yeast-like fungi 10^6 CFU/g although the difference was not statistically significant.

CONCLUSIONS

Our study has shown no influence of yeast-like fungi on lipid metabolism and VEGF level in children and adolescents with T1DM. Comprehensive treatment of T1DM patients and intensive insulin therapy with help of personal insulin pumps can reduce or prevent the development of long-term diabetic complications. Further studies in this field are needed.

Diabetes Onset at 31-45 Years of Age is Associated with an Increased Risk of Diabetic Retinopathy in Type 2 Diabetes

This hospital-based, cross-sectional study investigated the effect of age of diabetes onset on the development of diabetic retinopathy (DR) among Chinese type 2 diabetes mellitus (DM) patients. A total of 5,214 patients with type 2 DM who were referred to the Department of Ophthalmology at the Shanghai First People’s Hospital from 2009 to 2013 was eligible for inclusion. Diabetic retinopathy status was classified using the grading system of the Early Treatment Diabetic Retinopathy Study (ETDRS). Logistic and hierarchical regression analyses were used to identify independent variables affecting the development of DR. Upon multiple logistic regression analysis, patient age at the time of diabetes onset was significantly associated with development of DR. Further, when the risk of retinopathy was stratified by patient age at the onset of diabetes, the risk was highest in patients in whom diabetes developed at an age of 31–45 years (odds ratio [OR] 1.815 [1.139–2.892]; p = 0.012). Furthermore, when patients were divided into four groups based on the duration of diabetes, DR development was maximal at a diabetes onset age of 31–45 years within each group. A diabetes onset age of 31–45 years is an independent risk factor for DR development in Chinese type 2 DM patients.

Review series: The cell biology of renal filtration

The function of the kidney, filtering blood and concentrating metabolic waste into urine, takes place in an intricate and functionally elegant structure called the renal glomerulus. Normal glomerular function retains circulating cells and valuable macromolecular components of plasma in blood, resulting in urine with just trace amounts of proteins. Endothelial cells of glomerular capillaries, the podocytes wrapped around them, and the fused extracellular matrix these cells form altogether comprise the glomerular filtration barrier, a dynamic and highly selective filter that sieves on the basis of molecular size and electrical charge. Current understanding of the structural organization and the cellular and molecular basis of renal filtration draws from studies of human glomerular diseases and animal models of glomerular dysfunction.

Finasteride reduces microvessel density and expression of vascular endothelial growth factor in renal tissue of diabetic rats

BACKGROUND

Vascular endothelial growth factor (VEGF) plays a critical role in the pathogenesis of diabetic microvascular complications. Finasteride has been confirmed to decrease VEGF expression in prostate and prostatic suburethral tissue resulting in limiting hematuria from human benign prostatic hyperplasia. The purpose of this study was to evaluate the effects of finasteride on microvessel density (MVD), VEGF protein and mRNA expressions in the renal tissue of diabetic rats.

METHODS

Diabetic rats induced by streptozotocin were intragastrically given finasteride at 30 mg/kg body weight once a day for 4 weeks. Histomorphologic changes in kidney were observed under light microscope. Immunohistochemistry for CD34 and VEGF on kidney sections was performed to assess MVD and VEGF protein expression in glomeruli of rats, respectively. The VEGF mRNA expression in the renal tissue was examined using reverse transcription polymerase chain reaction analysis.

RESULTS

The glomerular tuft area, glomerular volume, MVD, VEGF protein expression in glomeruli and VEGF mRNA expression in the renal cortex tissue were significantly increased in diabetic rats and finasteride-treated rats when compared with controls (P < 0.01, P < 0.05). When compared with diabetic rats, the glomerular tuft area, glomerular volume, MVD, VEGF protein expression in glomeruli and VEGF mRNA expression in the renal cortex tissue of finasteride-treated rats were significantly decreased (P < 0.05, P < 0.01).

CONCLUSIONS

Finasteride reduces the VEGF expression and decreases the MVD in the renal tissue of diabetic rats, suggesting the therapeutic potential of finasteride on diabetic microvascular complications.

Angiogenesis in diabetes and obesity

The prevalence of diabetes mellitus and obesity continues to increase globally. Diabetic vascular complications are the main chronic diabetic complications and associated with mortality and disability. Angiogenesis is a key pathological characteristic of diabetic microvascular complications. However, there are two tissue-specific paradoxical changes in the angiogenesis in diabetic microvascular complications: an excessive uncontrolled formation of premature blood vessels in some tissues, such as the retina, and a deficiency in the formation of small blood vessels in peripheral tissues, such as the skin. This review will discuss the paradoxical phenomena of angiogenesis and its underlying mechanism in obesity, diabetes and diabetic complications.

Multiphasic changes in systemic VEGF following intravitreal injections of ranibizumab in a child

PURPOSE

To investigate whether intravitreal ranibizumab injections administered to a child alter systemic plasma levels of total and free VEGF 165.

METHODS

A 9-year-old child sustained a choroidal rupture from blunt trauma. He subsequently developed a secondary choroidal neovascular membrane, which was treated with five ranibizumab injections over a period of 8 months. Peripheral venous blood samples were taken at each visit over a period of 12 months and plasma was extracted. Plasma VEGF 165 levels were determined using enzyme-linked immunosorbent assay and were assayed both pre- and post-immunodepletion to remove complexed VEGF.

RESULTS

Plasma VEGF 165 levels proved labile following intravitreal injection of ranibizumab. Levels increased by 30% above baseline following the first intravitreal ranibizumab injection, but then returned to baseline despite two subsequent injections. There was then a rebound increase of 67% in total plasma VEGF levels following a further injection, which remained above baseline for 12 weeks despite two further intravitreal ranibizumab injections. Baseline levels were re-attained 26 weeks after the final injection.

CONCLUSIONS

These results suggest intravitreal ranibizumab injections can cause significant, multiphasic changes in systemic VEGF levels. This may be of particular clinical significance in children as VEGF is known to be vital in the development of major organs, in addition to its role in the maintenance of normal organ function in adults.

Markers of angiogenesis associated with surgical attenuation of congenital portosystemic shunts in dogs

Background

Dogs with congenital portosystemic shunts (CPSS) have hypoplasia of the intrahepatic portal veins. Surgical CPSS attenuation results in the development of the intrahepatic portal vasculature, the precise mechanism for which is unknown, although new vessel formation by angiogenesis is suspected.

Hypothesis

That the degree of portal vascular development and the increase in portal vascularization after CPSS attenuation is significantly associated with hepatic vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) gene expression and serum VEGF concentration.

Animals

Client‐owned dogs with CPSS undergoing surgical treatment. Forty‐nine dogs were included in the gene expression data and 35 in the serum VEGF data.

Materials and Methods

Dogs surgically treated by partial or complete CPSS attenuation were prospectively recruited. Relative gene expression of VEGF and VEGFR2 was measured in liver biopsy samples taken at initial and follow‐up surgery using quantitative polymerase chain reaction. Serum VEGF concentration was measured before and after CPSS attenuation using a canine specific ELISA. Statistical significance was set at the 5% level (P ≤ .05).

Results

There was a significant increase in the mRNA expression of VEGFR2 after partial attenuation (P = .006). Dogs that could tolerate complete attenuation had significantly greater VEGFR2 mRNA expression than those that only tolerated partial attenuation (P = .037). Serum VEGF concentration was significantly increased at 24 (P < .001) and 48 (P = .003) hours after attenuation.

Conclusions and Clinical Importance

These findings suggest that intrahepatic angiogenesis is likely to occur after the surgical attenuation of CPSS in dogs, and contributes to the development of the intrahepatic vasculature postoperatively.

Molecular and pathological studies in the posterior interosseous nerve of diabetic and non-diabetic patients with carpal tunnel syndrome

AIMS/HYPOTHESIS

We sought to establish the molecular and pathological changes predisposing diabetic and non-diabetic patients to the development of carpal tunnel syndrome (CTS).

METHODS

The posterior interosseous nerve (PIN) was biopsied in 25 diabetic and 19 non-diabetic patients undergoing carpal tunnel decompression for CTS. Detailed morphometric and immunohistological analyses were performed in the nerve biopsy.

RESULTS

In diabetic patients median nerve distal motor latency was prolonged (p < 0.05 vs non-diabetic patients), PIN myelinated fibre density (p < 0.05), fibre area (p < 0.0001) and axon area (p < 0.0001) were reduced, the percentage of unassociated Schwann cell profiles (p < 0.0001) and unmyelinated axon density (p < 0.0001) were increased and the axon diameter was reduced (p < 0.0001). Endoneurial capillary basement membrane area was increased (p < 0.0001) in diabetic patients, but endothelial cell number was increased (p < 0.01) and luminal area was reduced (p < 0.05) in non-diabetic patients with CTS. There was no difference in the expression of hypoxia-inducible factor 1α between diabetic and non-diabetic patients with CTS. However, the expression of vascular endothelial growth factor A (VEGF) (p < 0.05) and its receptors VEGFR-1 (p < 0.01) and VEGFR-2 (p < 0.05) was significantly increased in diabetic patients, particularly those with type 1 diabetes, and related to the severity of nerve fibre pathology.

CONCLUSIONS/INTERPRETATION

This study demonstrates increased nerve fibre and microvascular pathology in relation to enhanced expression of VEGF and its receptors in a non-compressed nerve in diabetic compared with non-diabetic patients with CTS. It therefore provides a potential molecular and pathological basis for the predisposition of diabetic patients to the development of CTS.

Role of metformin in suppressing 1,2-dimethylhydrazine-induced colon cancer in diabetic and non-diabetic mice: effect on tumor angiogenesis and cell proliferation

Several studies indicated that type 2 diabetes mellitus and insulin resistance are associated with increased colon cancer risk. Recently, studies suggest that metformin can reduce cancer risk in diabetic or non-diabetic patients with unclear mechanisms. This work aimed to determine the effect of metformin on chemically-induced colon cancer in mice. Colon cancer was induced using 1,2-dimethylhydrazine (DMH, 20 mg/kg/week, s.c.) for fifteen weeks. Experiment I: healthy mice were fed with basal diet for four weeks and then allocated into seven groups, (i) saline, (ii) DMH, (iii) oxaliplatin, (iv-v): metformin (100 or 200 mg/kg) and (vi-vii): oxaliplatin+metformin (100 or 200 mg/kg), respectively. Experiment II: type 2 diabetes mellitus was induced by injection of STZ (30 mg/kg) after four weeks of high-fat feeding and then mice were allocated into seven groups similar to those reported in experiment I. Examination of the colonic tissue at the end of the experiment highlighted an increase in angiogenic markers and cell proliferation and showed a greater immunostaining for insulin growth factor I receptors and CD34 in the colon of diabetic mice compared to non-diabetics. In general, metformin downregulated tumor angiogenesis and augmented the antitumor effect of oxaliplatin. Overall, the current results showed that metformin protected against DMH-induced colon cancer in non-diabetic and diabetic mice. This therapeutic effect was, at least in part, attributed to its anti-angiogenic and anti-proliferative mechanisms.

Vascular endothelial growth factor in Coats' disease

PURPOSE

To examine whether vascular endothelial growth factor (VEGF) as one of the most important intraocular cytokines for angiogenesis and increased vascular permeability is associated with Coats' disease.

METHODS

The clinical interventional study included 28 patients with Coats' disease and seven control patients with congenital cataract. During intraocular surgery, we obtained aqueous humour samples in which the VEGF concentration was measured by double-antibody sandwich enzyme-linked immunosorbent assay (ELISA). Coats' disease was graded into four stages.

RESULTS

The mean aqueous VEGF level was significantly higher in the Coats' study group than in the control group (158±88 versus 97±21 pg/ml; p=0.002). The VEGF concentrations increased significantly (p<0.001) from 91±32 pg/ml in Coats' disease stage 2 to 100±37 pg/ml in stage 3A1, 185±56 pg/ml in stage 3A2 to 256±93 pg/ml in patients with stage 3B. Vascular endothelial growth factor concentrations in Coats' stage 2 and 3A1 did not differ significantly from the values in the control group. Parallel to the association with the stage of the diseases, the VEGF concentrations were significantly (p<0.001) correlated with extent of exudative retinal detachment.

CONCLUSIONS

Increasing severity of Coats' disease is significantly associated with intraocular VEGF concentrations. These results favour the intravitreal application of anti-VEGF drugs as medical therapy of Coats' diseases.

Kolaviron improved resistance to oxidative stress and inflammation in the blood (erythrocyte, serum, and plasma) of streptozotocin-induced diabetic rats

AIMS

Bitter kola seed (Garcinia kola, family: Guttiferae) has been used as a social masticatory agent in Africa for several years and is believed to possess many useful medicinal properties. The present study evaluates the antioxidative, anti-inflammatory, and antilipidemic effects of kolaviron (an extract from the Garcinia kola seeds) in the blood of streptozotocin- (STZ) induced diabetic rats. METHODS. Diabetic rats were treated with kolaviron (100 mg/kg b·wt) orally, five times a week for a period of six weeks. Serum glucose and HBA(1C) concentrations were estimated in experimental groups. The activities of antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX) (in erythrocytes) as well as plasma concentration of malondialdehyde (MDA), a product of lipid peroxidation, oxygen radical absorbing capacity (ORAC) and ferric-reducing antioxidant power (FRAP) were investigated. Serum levels of proinflammatory cytokines and growth factor: interleukin- (IL-) 1, monocyte chemotactic protein-1 (MCP-1), and vascular endothelial growth factor (VEGF), respectively, were also analyzed.

RESULTS

Kolaviron treatment markedly improved antioxidant status and abated inflammatory response evidenced by reduction in the levels of proinflammatory cytokines and growth factor, lipid peroxidation product, and the restoration of activities of erythrocyte antioxidant enzymes in the blood of diabetic rats.

CONCLUSION

Kolaviron improved antioxidant status, reduced inflammation, and protected against hyperglycemic-induced oxidative damage in the blood of diabetic rats.

Biomarkers in diabetic retinopathy and the therapeutic implications

The main problem both in type 1 (T1DM) and type 2 (T2DM) diabetes is the development of chronic vascular complications encompassing micro- as well as macrocirculation. Chronic complications lower the quality of life, lead to disability, and are the cause of premature death in DM patients. One of the chronic vascular complications is a diabetic retinopathy (DR) which leads to a complete loss of sight in DM patients. Recent trials show that the primary cause of diabetic retinopathy is retinal neovascularization caused by disequilibrium between pro- and antiangiogenic factors. Gaining knowledge of the mechanisms of action of factors influencing retinal neovascularization as well as the search for new, effective treatment methods, especially in advanced stages of DR, puts special importance on research concentrating on the implementation of biological drugs in DR therapy. At present, it is antivascular endothelial growth factor and antitumor necrosis factor that gain particular significance.

Vascular endothelial growth factor gene polymorphism prevalence in patients with diabetic macular oedema and its correlation with anti-vascular endothelial growth factor treatment outcomes

BACKGROUND

To study the possible association between vascular endothelial growth factor gene polymorphism and diabetic macular oedema, and its correlation to the outcomes of anti-vascular endothelial growth factor treatment.

DESIGN

Prospective study.

PARTICIPANTS

392 diabetic patients were included; 180 patients of them had no retinopathy, 212 patients had diabetic retinopathy. Diabetic retinopathy patients were classified into four groups as defined by the absence or presence of macular oedema or proliferative retinopathy.

METHODS

In all subjects, polymerase chain reaction-restriction fragment length polymorphism was conducted to detect the vascular endothelial growth factor gene C-634G polymorphism. Serum levels of vascular endothelial growth factor were estimated. Changes of visual acuity and central macular thickness after bevacizumab treatment in diabetic macular oedema patients of different genotypes were monitored for 9-12 months.

MAIN OUTCOME MEASURES

Vascular endothelial growth factor C-634G genotypes distribution in different groups; correlation between genotypes, and changes in visual acuity and central macular thickness after intravitreal bevacizumab treatment.

RESULTS

CC genotype was significantly prevalent among diabetic macular oedema patients (P = 0.019). Significant higher serum levels of vascular endothelial growth factor were detected in diabetic retinopathy and diabetic macular oedema patients with CC genotype (P = 0.02, 0.016). After bevacizumab treatment, individuals with genotypes CG and GG have a decreased chance of positive treatment outcomes compared t with CC genotype (P < 0.001).

CONCLUSIONS

Vascular endothelial growth factor C-634G polymorphism (CC genotype) is a genetic risk factor for diabetic macular oedema, and its presence provides significantly better visual outcome following bevacizumab treatment.

Inhibition of VEGFR-2 reverses type 1 diabetes in NOD mice by abrogating insulitis and restoring islet function

The dysregulation of receptor tyrosine kinases (RTKs) in multiple cell types during chronic inflammation is indicative of their pathogenic role in autoimmune diseases. Among the many RTKs, vascular endothelial growth factor receptor (VEGFR) stands out for its multiple effects on immunity, vascularization, and cell migration. Herein, we examined whether VEGFR participated in the pathogenesis of type 1 diabetes (T1D) in nonobese diabetic (NOD) mice. We found that RTK inhibitors (RTKIs) and VEGF or VEGFR-2 antibodies reversed diabetes when administered at the onset of hyperglycemia. Increased VEGF expression promoted islet vascular remodeling in NOD mice, and inhibition of VEGFR activity with RTKIs abrogated the increase in islet vascularity, impairing T-cell migration into the islet and improving glucose control. Metabolic studies confirmed that RTKIs worked by preserving islet function, as treated mice had improved glucose tolerance without affecting insulin sensitivity. Finally, examination of human pancreata from patients with T1D revealed that VEGFR-2 was confined to the islet vascularity, which was increased in inflamed islets. Collectively, this work reveals a previously unappreciated role for VEGFR-2 signaling in the pathogenesis of T1D by controlling T-cell accessibility to the pancreatic islets and highlights a novel application of VEGFR-2 antagonists for the therapeutic treatment of T1D.

Comparison of osteoprotegerin and vascular endothelial growth factor in normoalbuminuric Type 1 diabetic and control subjects

BACKGROUND

The aim of the current study was to evaluate the association of osteoprotegerin and vascular endothelial growth factor (VEGF) with glycemic indices and diabetes status.

METHODS

A total of 44 normoalbuminuric Type 1 diabetic patients and 44 healthy control subjects, matched for age, body mass index, sex ratio, and lipid measures were enrolled. Univariate and multivariate logistic regression analyses were used to determine the association of osteoprotegerin and VEGF with diabetes status. Further, linear regression analysis was performed to investigate the roles of osteoprotegerin and VEGF as determinants of glycated hemoglobin (HbA1c).

RESULTS

Osteoprotegerin and VEGF were significantly elevated in diabetic subjects (2.76±0.85 vs 2.26±0.75 pmol/l and 187.1±92.7 vs 125.9±52.3 pg/ml, respectively, p<0.01) and were positively correlated with glycemic indices (i.e. fasting plasma glucose and HbA1c, p<0.001). After controlling for possible confounding factors, odds ratios (confidence interval) of osteoprotegerin and VEGF for diabetes were 2.532 (1.003-6.392) and 1.021 (1.002-1.041), respectively (p<0.05). Further, linear regression analysis revealed that the association of osteoprotegerin with HbA1c is independent of VEGF and vice versa (p<0.001).

CONCLUSION

Osteoprotegerin and VEGF are elevated in normoalbuminuric Type 1 diabetic subjects and are independently associated with glycemic indices and diabetes status.

VEGF and podocytes in diabetic nephropathy

Vascular endothelial growth factor-A (VEGF-A) is a protein secreted by podocytes that is necessary for survival of endothelial cells, podocytes, and mesangial cells. VEGF-A regulates slit-diaphragm signaling and podocyte shape via VEGF-receptor 2-nephrin-nck-actin interactions. Chronic hyperglycemia-induced excess podocyte VEGF-A and low endothelial nitric oxide drive the development and the progression of diabetic nephropathy. The abnormal cross-talk between VEGF-A and nitric oxide pathways is fueled by the diabetic milieu, resulting in increased oxidative stress. Recent findings on these pathogenic molecular mechanisms provide new potential targets for therapy for diabetic renal disease.

Endothelial cell-selective adhesion molecule in diabetic nephropathy

BACKGROUND

Endothelial cell-selective adhesion molecule (ESAM) contributes to the integrity of tight junctions and modulates endothelial function. ESAM has been linked to experimental diabetic nephropathy; its soluble fraction is related to atherosclerosis in humans. In this cross-sectional observational study, we describe for the first time serum ESAM in type 2 diabetic patients with different stages of chronic kidney disease (CKD) and its relationship to vascular endothelial growth factor-A (VEGF-A). Materials and methods  We included diabetic patients with different stages of CKD and controls. History, laboratory evaluation, serum ESAM and VEGF-A and urinary albumin/creatinine ratio were obtained.

RESULTS

Endothelial cell-selective adhesion molecule was higher in non-CKD diabetic patients 13.80 (6.15-18.70) ng/mL (n=45) than controls 7.30 (4.60-9.40) ng/mL (n=48), P=0.001. VEGF-A had a similar pattern: 71.3 (54.75-120.70) vs. 43.20 (30.1-65.90) pg/mL, P<0.0001. ESAM was 10.4 (5.6-17.4) ng/mL in predialysis CKD patients (n=59) and 22.35 (8.55-29.95) ng/mL in dialysis patients (n=36), P<0.001. Patients with glomerular filtration rate (GFR)<15 mL/min had the highest ESAM (P=0.003). ESAM was similar in normoalbuminuric, microalbuminuric and proteinuric patients. ESAM was directly correlated with the duration of diabetes (r(2)=0.048, P=0.009), C-reactive protein (r(2)=0.028, P=0.05), VEGF-A (r(2)=0.040, P=0.01) and inversely with HbA1C (r(2)=0.036, P=0.03), haemoglobin (r(2)=0.062, P=0.005) and albumin (r(2)=0.0·40, P=0.026). In multiple regression diabetes duration, HbA1C and VEGF-A were significant predictors of ESAM. In controls, ESAM was inversely related to VEGF (r(2)=037, P=0.01).

CONCLUSION

Endothelial cell-selective adhesion molecule and VEGF-A are higher in patients with diabetes than in controls. The highest ESAM is found in dialysis patients. ESAM correlates with diabetes duration and control, inflammation and VEGF-A in patients with diabetes, but not in controls.

Threshold serum concentrations of tumour necrosis factor alpha (TNFα) as a potential marker of the presence of microangiopathy in children and adolescents with type 1 diabetes mellitus (T1DM)

The aim of this study was to estimate the threshold serum concentrations of advanced glycation end products (AGEs) and their soluble receptors (sRAGE) as well as tumour necrosis factor alpha (TNFα), vascular endothelial growth factor(165) (VEGF(165)) and interleukin-12 (IL-12) in predicting the occurrence of microangiopathy in children and adolescents with type 1 diabetes mellitus (T1DM). We studied 88 children and adolescents (age range: 6-20 yrs) with T1DM and 32 control subjects (age range: 7-20 yrs). All study participants had their daily urinary albumin excretion, HbA1c and serum creatinine levels measured, and underwent an eye examination and 24-h blood pressure monitoring. Moreover, serum concentrations of AGEs, sRAGE, TNFα, VEGF(165) and IL-12 were measured. In order to calculate the threshold values of the studied parameters, the Receiver Operating Characteristic (ROC) curve analysis was used. The results of our study have shown that among all the studied parameters a discriminative ability was found for TNFα, VEGF(165), duration of the disease, serum AGEs concentrations and daily urinary albumin excretion. However, the highest value of the area under the ROC curve (AUC(ROC)) in predicting the occurrence of diabetic microangiopathy was found for serum TNFα concentrations with its threshold value of 1.7 pg/ml [AUC(ROC) = 0.88 (95% CI: 0.79-0.97)]. The sensitivity and specificity for this variable was at the level of 85.7% and 94.3%, respectively. In conclusion, according to our results serum TNFα concentrations over 1.7 pg/ml may point to the presence of diabetic microangiopathy in children and adolescents T1DM.

Soluble serum Klotho in diabetic nephropathy: relationship to VEGF-A

OBJECTIVES

Both kidney expression and soluble serum Klotho are influenced by chronic kidney disease (CKD) and diabetes. Serum Klotho is a yet poorly explored biomarker. We describe, for the first time to our knowledge, serum Klotho in diabetic patients with CKD and its relationship to vascular endothelial growth factor A (VEGF-A).

DESIGN AND METHODS

We included 43 controls and 146 diabetic patients with different stages of CKD. Laboratory evaluation, urinary albumin/creatinine ratio (UACR), Klotho (ELISA), VEGF-A (ELISA) were performed.

RESULTS

Klotho was 0.40(0.10-1.30)ng/mL in diabetic patients without CKD and 0.80(0.30-1.30)ng/mL in controls, p=0.20; VEGF-A was higher in diabetic patients 73.85(57.32-119.00)pg/mL than in controls 43.20(30.1-65.9)pg/mL, p<0.0001. Klotho increased with CKD stage: 0.2(0.10-0.40)ng/mL in CKD 1/2, 0.60(0.20-1.1)ng/mL in CKD 3/4 and 1.45(0.425-2.90)ng/mL in dialysis patients, p<0.0001; it also increased with decreasing glomerular filtration rate (GFR). Klotho was lower in albuminuric (UACR>30 mg/g) patients 0.20(0.10-0.70)ng/mL than in normoalbuminuric (UACR<30 mg/g) ones 0.50(0.20-1.30)ng/mL, p=0.03; lowest Klotho was found in microalbuminuric (UACR 30-300 mg/g) patients, p=0.07. VEGF was lower in microalbuminuric patients but was not influenced by GFR. In diabetic patients but not in controls, Klotho correlated to VEGF-A (r=0.29, p=0.0003); in multiple regression VEGF-A was the only significant predictor of Klotho: b=0.27, 95%CI (0.01-0.04), p=0.001.

CONCLUSIONS

In diabetic patients, Klotho is decreased in early CKD and increases thereafter, paralleling reduced GFR. VEGF-A is higher in diabetic patients than in controls. Both Klotho and VEGF-A are decreased in the presence of microalbuminuria. In diabetes, Klotho strongly correlates to VEGF-A.

Prevention of microalbuminuria in patients with type 2 diabetes: what do we know?

Cardiovascular and chronic kidney disease are epidemic throughout industrialized societies. Diabetes leads to premature cardiovascular disease and is regarded by many as the most common etiological factor for chronic kidney disease. Because most studies of blood-pressure lowering agents in people with diabetes and hypertension have been conducted in individuals who already have some target organ damage, it is unclear whether earlier intervention could prevent or delay the onset of renal or systemic vascular disease. In early disease there is only a low possibility of observing cardiovascular or renal events; thus intervention trials in this population must rely on disease markers such as microalbuminuria. Accordingly, the authors review the evidence to support the use of microalbuminuria as a disease marker in diabetic patients based on its strong association with renal and cardiovascular events, and discuss recent trials that examine the impact of preventing or delaying the onset of microalbuminuria.

The role of vascular endothelial growth factor +405 G/C polymorphism and albuminuria in patients with type 2 diabetes mellitus

Observations on the association between the vascular endothelial growth factor (VEGF) gene polymorphism and nephropathy have been inconsistent, which might be due to ethnic and geographical variations. Furthermore, the relationship between +405 G/C polymorphism and albuminuria in the diabetic population has not been sufficiently studied. The aim of this study was to evaluate for the first time the possible association between +405 G/C polymorphism and albuminuria in an population from Tehran of Iran. A total of 255 consecutive patients with type 2 diabetes and microalbuminuria (Group A) and 235 patients with type 2 diabetes and normoalbuminuria (Group B) were included. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were used to detect the VEGF alleles. In univariate analysis, the groups were statistically similar in all variables except for HbA1c (8.53 ± 1.7 in Group A vs. 8.2 ± 1.73 in Group B; P = 0.034), 24-h urinary albumin (201.33 ± 84.8 in Group A vs. 22.88 ± 3.5 in Group B; P < 0.001), and the frequency of GG genotype (31% in Group A vs. 18.7% in Group B; P = 0.006). The GG genotype was the independent predictor of albuminuria [P = 0.014, OR = 1.771, 95% confidence interval (CI) = 1.124-2.790]. Our study showed that the G allele was not associated with albuminuria, but the GG genotype in the VEGF gene is independently associated with development of nephropathy in the our diabetic population.

Erythropoietin and vascular endothelial growth factor as risk markers for severe hypoglycaemia in type 1 diabetes

OBJECTIVE

Circulating erythropoietin (EPO) and vascular endothelial growth factor (VEGF) increase during hypoglycaemia and may represent protective hormonal counter-regulatory responses. We tested the hypothesis that low levels of EPO and VEGF are associated with a higher frequency of severe hypoglycaemia in a cohort of patients with type 1 diabetes.

DESIGN

Prospective observational follow-up study.

METHODS

Totally 219 patients with type 1 diabetes (41% females, age 46+/-13 years (mean+/-s.d.), duration of diabetes 21+/-12 years, and HbAlc 8.5+/-1.1%) were followed in a 1-year observational study. Plasma EPO and serum VEGF levels were measured at baseline with ELISA. Events of severe hypoglycaemia defined by third party assistance were recorded and validated in telephone interviews within 24 h.

RESULTS

Totally 235 episodes of severe hypoglycaemia (1.1 episodes per patient-year) were reported by 82 patients (37%). At baseline, plasma EPO was 8.6 (3.1-34.3) U/l (median (range)), and serum VEGF was 52.2 (6.6-337) pg/ml. The levels of EPO and VEGF were not associated with frequency of severe and mild hypoglycaemia. The levels of EPO were not associated with age, sex, duration of diabetes, body mass index, HbAlc, C-peptide level or hypoglycaemia awareness status. The levels of VEGF were positively associated with age and female sex.

CONCLUSIONS

Although several studies suggest that VEGF and EPO may affect brain function during hypoglycaemia, this study does not support random VEGF or EPO levels to determine future risk of severe hypoglycaemia in people with type 1 diabetes.

Effect of intensive insulin therapy on macular biometrics, plasma VEGF and its soluble receptor in newly diagnosed diabetic patients

BACKGROUND

To evaluate whether intensive insulin therapy leads to changes in macular biometrics (volume and thickness) in newly diagnosed diabetic patients with acute hyperglycaemia and its relationship with serum levels of vascular endothelial growth factor (VEGF) and its soluble receptor (sFlt-1).

METHODS

Twenty-six newly diagnosed diabetic patients admitted to our hospital to initiate intensive insulin treatment were prospectively recruited. Examinations were performed on admission (day 1) and during follow-up (days 3, 10 and 21) and included a questionnaire regarding the presence of blurred vision, standardized refraction measurements and optical coherence tomography. Plasma VEGF and sFlt-1 were assessed by ELISA at baseline and during follow-up.

RESULTS

At study entry seven patients (26.9%) complained of blurred vision and five (19.2%) developed burred vision during follow-up. Macular volume and thickness increased significantly (p = 0.008 and p = 0.04, respectively) in the group with blurred vision at day 3 and returned to the baseline value at 10 days. This pattern was present in 18 out of the 24 eyes from patients with blurred vision. By contrast, macular biometrics remained unchanged in the group without blurred vision. We did not detect any significant changes in VEGF levels during follow-up. By contrast, a significant reduction of sFlt-1 was observed in those patients with blurred vision at day 3 (p = 0.03) with normalization by day 10.

CONCLUSION

Diabetic patients with blurred vision after starting insulin therapy present a significant transient increase in macular biometrics which is associated with a decrease in circulating sFlt-1.

Circulating vascular endothelial growth factor in the normo- and/or microalbuminuric patients with type 2 diabetes mellitus

Relationship between serum vascular endothelial growth factor (VEGF) level and parameters of endothelial injury and/or dysfunction in patients with diabetes mellitus type 2 with or without microalbuminuria was investigated. Eighty-four diabetic patients were divided in two subgroups (42 each): normoalbuminuric (NAU) and microalbuminuric (MAU). Forty-two blood donors were in control group. Serum VEGF and plasma von Willebrand factor, soluble thrombomodulin, plasminogen activator inhibitor 1, thrombin-activatable fibrinolysis inhibitor (TAFI) and tissue plasminogen activator (t-PA) were measured using enzyme-linked immunosorbent assay in all subjects. VEGF was significantly higher in NAU compared to controls. The difference between MAU and controls was not statistically significant, but there was a trend toward significance. Only TAFI correlated with VEGF in MAU. An observed significant increase of serum VEGF level already in NAU suggests that serum VEGF could be a sensitive predictor of endothelial dysfunction in type 2 diabetes.

Antiangiogenic effects and transcriptional regulation of pigment epithelium-derived factor in diabetic retinopathy

The effects of the antiangiogenic cytokine PEDF on key steps in retinal angiogenesis, specifically endothelial cell proliferation and vascular tubule formation, and the regulation of PEDF expression in retinal capillary endothelial cells were evaluated. HUVECs were co-cultured with fibroblasts to construct a model of angiogenesis using the Angiokit assay, and image analysis software was used to measure the effects of PEDF and VEGF on vascular tubule formation. Quantitative real-time PCR analysis was used to determine the expression of PEDF in microvascular endothelial cells exposed to glucose 20 mM, insulin 100 nM and VEGF 10 ng/ml. PEDF inhibited endothelial cell proliferation and significantly decreased the number of tubules (629+93 AU vs 311+31, p=0.001), number of branching points (145+19 AU vs 46+5, p=0.03) and total tubule length (4848+748 AU vs 11,172+2353, p=0.001). In bovine retinal capillary endothelial cells (BRCECs), PEDF mRNA and protein expression was suppressed by insulin (22%) in a rapamycin-sensitive manner; wortmannin had no effect. PEDF mRNA expression was also significantly reduced in the presence of high glucose (23%) and VEGF (25%). In conclusion, PEDF inhibits key steps in the angiogenic response of BRCECs, including endothelial cell proliferation and vascular tubule formation. Gene expression of PEDF is negatively regulated by glucose, insulin (via an mTOR-dependent pathway) and VEGF.

Role of the VEGF 936 C/T polymorphism in diabetic microvascular complications in type 2 diabetic patients

AIM

Vascular endothelial growth factor (VEGF) is important in the pathogenesis of diabetic microvascular complications and the genetic polymorphism of this gene may contribute to the development and progression of diabetic microvascular complications. In this study, we investigated whether a genetic polymorphism of VEGF is associated with diabetic complications.

METHODS

A total of 398 type 2 diabetic patients and 526 healthy controls were enrolled. The study subjects were divided based on the state of nephropathy, retinopathy and neuropathy. The VEGF 936 C/T polymorphism was evaluated using standard PCR techniques, and plasma and urinary levels of VEGF were determined by enzyme-linked immunosorbent assay.

RESULTS

There was no difference in VEGF genotype distribution between the control and diabetic patients based on the state of diabetic nephropathy and neuropathy. However, a higher frequency of the TT genotype was observed in patients with proliferative diabetic retinopathy. Additionally, plasma levels of VEGF were significantly higher in the TT genotype. However, urinary levels of VEGF did not show a significant relationship with the VEGF genotype. Urinary VEGF levels showed a significant relationship with urinary albumin excretion, proteinuria, serum creatinine level and creatinine clearance, as well as fasting blood glucose levels, postprandial 2 h glucose levels and C-reactive protein.

CONCLUSION

Our study suggests that the 936 C/T polymorphism of the VEGF gene may be an important factor determining plasma VEGF levels and that its polymorphism is related with diabetic retinopathy. Urinary levels of VEGF are not associated with plasma VEGF levels and associated with the stage of diabetic nephropathy.

Vascular endothelial growth factor inhibition by dRK6 causes endothelial apoptosis, fibrosis, and inflammation in the heart via the Akt/eNOS axis in db/db mice

OBJECTIVE

Vascular endothelial growth factor (VEGF), which is associated with the stimulation of angiogenesis and collateral vessel synthase, is one of the crucial factors involved in cardiac remodeling in type 2 diabetes.

RESEARCH DESIGN AND METHODS

We investigated VEGF inhibition by dRK6 on the heart in an animal model of type 2 diabetes. Male db/db and db/m mice either were treated with dRK6 starting at 7 weeks of age for 12 weeks (db/db-dRK6 and db/m-dRK6) or were untreated.

RESULTS

Cardiac dysfunction and hypertrophy were noted by echocardiogram and molecular markers in the db/db-dRK6 mice. The presence of diabetes significantly suppressed the expression of VEGF receptor (VEGFR)-1 and VEGFR-2, phospho-Akt, and phospho-endothelial nitric oxide synthase (eNOS) in the heart. In db/db-dRK6 mice, dRK6 completely inhibited VEGFR-2, phospho-Akt, and phospho-eNOS expression, whereas no effect on VEGFR-1 was observed. Cardiac fibrosis, microvascular scarcity associated with an increase in apoptotic endothelial cells, and inflammation were prominent, as well as increase in antiangiogenic growth factors. Cardiac 8-hydroxy-deoxyguanine and hypoxia-inducible factor-1alpha expression were significantly increased. No such changes were found in the other groups, including the db/m-dRK6 mice. The number of apoptotic human umbilical vein endothelial cells was increased by dRK6 in a dose-dependent manner only at high glucose concentrations, and this was associated with a decrease in phospho-Akt and phospho-eNOS related to oxidative stress.

CONCLUSIONS

Our results demonstrated that systemic blockade of VEGF by dRK6 had deleterious effects on the heart in an animal model of type 2 diabetes; dRK6 induced downregulation of the VEGFR-2 and Akt-eNOS axis and enhancement of oxidative stress.