血管内皮细胞生长因子基因多态性与糖尿病肾病的相关性

目的研究血管内皮细胞生长因子（VEGF）基因多态性与糖尿病肾病（DN）的关系。方法单纯2型糖尿病（DM）组76例,DN组81例,健康对照（NC）组60例。UNIQ-10柱提取全血基因组DNA。标本基因型的判断用聚合酶链反应-限制性酶切片断长度多态性技术。Hardy-Weinberg平衡法检验各组基因频率的群体代表性。结果（1）DN组VEGF-460和＋405CC基因型频率和C等位基因频率明显高于DM组和NC组。（2）-460位点CC基因型DN患病率明显高于CT和TT基因型。＋405位点CC基因型DN患病率明显高于CG和GG基因型。（3）显示VEGF-460和＋405基因多态性均为DN发生的独立危险因素。结论（1）VEGF-460C/T基因多态性与DN发生有关。C等位基因可能是DN易感基因。（2）VEGF＋405G/C基因多态性与DN发生有关。C等位基因可能是DN的易感基因。     

Circulating vascular endothelial growth factor is unaffected by acute hyperglycemia and hyperinsulinemia in type 1 diabetes mellitus

BACKGROUND: Circulating levels of vascular endothelial growth factor (VEGF) may predict microvascular complications in type 1 diabetes mellitus and are elevated when metabolic control is poor. We tested whether serum VEGF is influenced by prevailing glucose and insulin levels. METHODS: In 15 type 1 diabetic patients, serum VEGF, plasma von Willebrand factor antigen (vWF-Ag), and serum soluble intercellular adhesion molecule-1 (s-ICAM) levels were measured after 210 min of hyperglycemia (blood glucose target 12.0 mmol/l) and hyperinsulinemia (insulin infused at 120 mU/kg/h), alone and in combination. These were then compared with the levels obtained at the end of a 210-min normoglycemic (blood glucose target 5.0 mmol/l) standard insulin clamp (insulin infused at 30 mU/kg/h). RESULTS: VEGF (p>0.60) as well as vWF-AG (p>0.80) and s-ICAM (p>0.20) remained unchanged at the end of the three intervention periods. CONCLUSION: These findings suggest that no special precautions, in terms of concurrent measurement of glucose or timing of insulin administration, are necessary when interpreting circulating VEGF in this patient category.     

Proximal tubular reabsorption of growth hormone and sodium/fluid in normo- and microalbuminuric insulin-dependent diabetes mellitus

Proximal tubular dysfunction may be implicated in the pathogenesis of diabetic nephropathy. An investigation of proximal tubular function was carried out by assessing proximal tubular sodium reabsorption and low molecular weight protein excretion in a group of patients with type 1 diabetes mellitus. Normoalbuminuric [group A, n=6, albumin excretion rate (AER) mean (range) 4 (0–10) µg/min] and microalbuminuric [group B, n=6, AER 88 (35–198) µg/min] patients with type 1 diabetes were compared with matched controls. Simultaneous lithium and growth hormone (GH) clearance and urinary β ₂-microglobulin excretion were assessed. Fasting plasma glucose at the start of the study was [median (range)] 13 (10.2–15.1), 9.3 (5.9–15) and 4.1 (4.0–5.0) mmol/l in groups A, B and controls, respectively, with a mean coefficient of variation during the study of 3.9% (group A) and 5.2% (group B). There was no significant difference in plasma glucose levels between patients in groups A and B. Urinary GH excretion was raised in the patients with microalbuminuria (group B; P<0.05), although there was no difference in serum GH clearance rate between the patient groups and controls. Urinary GH correlated with β ₂-microglobulin in the diabetic subjects (r=0.665, P<0.05) and with the degree of microalbuminuria in group B patients (r=1, P<0.01). Urinary GH was also greater than 10 µU, the median value observed in the controls, in 5 of 6 (83%) patients in group A. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) measured by constant infusion of ⁵¹Cr-ethylene diamine tetra-acetic acid (EDTA) and I¹²⁵-para-amino hippuric acid (PAH), respectively, showed relative hyperfiltration in the normoalbuminuric group compared with controls (P<0.05) and group B (P<0.05). Absolute proximal reabsorption of sodium and of water (APR_Na and APR_H2O) was significantly higher in group A patients (P<0.05). Although GFR was significantly higher in group A patients, no differences were found in fractional proximal reabsorption of sodium and water (FPR_Na+H2O) or end proximal delivery between the patient groups and controls. Therefore, the measurement of protein reabsorptive capacity provides a more sensitive marker of renal tubular impairment in type 1 diabetes than sodium/fluid reabsorptive capacity. In patients with microalbuminuria, both glomerular and tubular damage may co-exist. Our results stress the usefulness of markers of renal tubular function in monitoring the course of diabetic nephropathy. This study also shows that assessment of GH clearance has promise as a marker of renal tubular protein reabsorptive capacity.     

Circulating plasma vascular endothelial growth factor and microvascular complications of type 1 diabetes mellitus: the influence of ACE inhibition.

AIMS: To determine whether circulating plasma vascular endothelial growth factor (VEGF) is elevated in the presence of diabetic microvascular complications, and whether the impact of angiotensin-converting enzyme (ACE) inhibitors on these complications can be accounted for by changes in circulating VEGF. METHODS: Samples (299/354 of those with retinal photographs) from the EUCLID placebo-controlled clinical trial of the ACE inhibitor lisinopril in mainly normoalbuminuric non-hypertensive Type 1 diabetic patients were used. Albumin excretion rate (AER) was measured 6 monthly. Geometric mean VEGF levels by baseline retinopathy status, change in retinopathy over 2 years, and by treatment with lisinopril were calculated. RESULTS: No significant correlation was observed between VEGF at baseline and age, diabetes duration, glycaemic control, blood pressure, smoking, fibrinogen and von Willebrand factor. Mean VEGF concentration at baseline was 11.5 (95% confidence interval 6.0--27.9) pg/ml in those without retinopathy, 12.9 (6.0--38.9) pg/ml in those with non-proliferative retinopathy, and 16.1 (8.1--33.5) pg/ml in those with proliferative retinopathy (P = 0.06 for trend). Baseline VEGF was 15.2 pg/ml in those who progressed by at least one level of retinopathy by 2 years compared to 11.8 pg/ml in those who did not (P = 0.3). VEGF levels were not altered by lisinopril treatment. Results were similar for AER. CONCLUSIONS: Circulating plasma VEGF concentration is not strongly correlated with risk factor status or microvascular disease in Type 1 diabetes, nor is it affected by ACE inhibition. Changes in circulating VEGF cannot account for the beneficial effect of ACE inhibition on retinopathy.     

Circulating endothelial progenitor cells are reduced in peripheral vascular complications of type 2 diabetes mellitus

OBJECTIVES: We sought to establish whether a reduction in endothelial progenitor cells (EPCs) has a putative role in peripheral vascular disease (PVD) of type 2 diabetic patients. BACKGROUND: Peripheral vascular disease is a common and severe complication of diabetes mellitus. Impaired collateralization of diabetic vasculopathy has been extensively shown, but causes leading to its pathogenesis are not fully understood. Recently, EPCs have been found to contribute to vascular repair and angiogenesis. Diabetes has been associated with low levels of circulating EPCs, but no data are available in the literature on the relationship between EPCs and PVD in diabetes. METHODS: Flow cytometric analysis was used to quantify circulating progenitor cells (CPCs, CD34+) and EPCs (CD34+KDR+) in 51 patients and 17 control subjects. RESULTS: The CPCs and EPCs from diabetic patients were reduced by 33% and 40%, respectively, compared with healthy subjects (p < 0.001). An inverse correlation was found between the number of EPCs and the values of fasting glucose (r = -0.49, p = 0.006). Peripheral vascular disease was associated with a 47% reduction in EPCs (p < 0.0001) and EPC levels directly correlated with the ankle-brachial index (r = 0.70, p = 0.01). The subgroup of diabetic patients with PVD also had reduced CPCs by 32% (p = 0.037), whereas patients with ischemic foot lesions had the lowest levels of both EPCs and CPCs (p = 0.02). CONCLUSIONS: Our data demonstrate decreased EPC levels in diabetic patients and, for the first time, show that PVD is associated with an extensively low number of EPCs. Depletion of circulating EPCs in diabetic patients may be involved in the pathogenesis of peripheral vascular complications.     

Circulating homocysteine levels in patients with type 2 diabetes mellitus

Background and aimPrevious studies have shown conflicting results regarding circulating homocysteine levels in patients with type 2 diabetes.Methods and resultsThis observational study included 2121 patients with angiographically proven coronary artery disease (507 patients with type 2 diabetes and 1614 patients without diabetes). Circulating homocysteine levels, methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism, renal function, presence of coronary artery disease (CAD) diagnosed by coronary angiography, and circulating folate and vitamin B₁₂ status were assessed. Plasma homocysteine levels [median (25th; 75th percentile)] were significantly higher in patients with diabetes than in those without [12.4 μmol/L (9.9 μmol/L; 15.9 μmol/L) versus 11.7 μmol/L (9.6 μmol/L; 14.5 μmol/L), P = 0.011]. Diabetes affected homocysteine levels only in patients with a glomerular filtration rate <90 mL/min [13.0 μmol/L (10.5 μmol/L; 16.7 μmol/L) in patients with diabetes versus 12.2 μmol/L (10.1 μmol/L; 15.2 μmol/L) in patients without diabetes, P = 0.006] but not in those with a glomerular filtration rate ≥90 mL/min [10.1 μmol/L (8.1 μmol/L; 12.4 μmol/L) versus 10.2 μmol/L (8.8 μmol/L; 12.3 μmol/L), P = 0.267]. Multivariable analysis did not show an independent association between diabetes and homocysteine level (P = 0.342).ConclusionCirculating homocysteine levels are increased in patients with type 2 diabetes compared with non-diabetic patients due to a more diabetes-associated adverse risk profile rather than to diabetes itself.     

Association between plasma visfatin and vascular endothelial function in patients with type 2 diabetes mellitus

Visfatin is a newly identified adipocytokine that mimics insulin action. However, the pathophysiological role of visfatin in diabetic patients is not fully understood. The main purpose of this study was to investigate the association of plasma visfatin with endothelial function in patients with type 2 diabetes mellitus. In addition, the relationships of visfatin with oxidative stress, low-grade inflammation, atherosclerosis, adiponectin, plasma renin activity, and aldosterone were also explored, and the effect of pioglitazone on visfatin was examined. Visfatin levels were measured in 80 patients with type 2 diabetes mellitus and in 28 age-matched healthy subjects. Endothelial function was evaluated by using flow-mediated vasodilatation (FMD), oxidative stress was assessed by the level of urinary 8-iso-prostaglandin F2alpha, and atherosclerosis and inflammation were measured by using the intimal-medial complex thickness and the levels of high-sensitivity C-reactive protein and fibrinogen. Pioglitazone was administered for 12 weeks at a dose of 30 mg/d in a further 20 patients with type 2 diabetes mellitus. There was a significant negative correlation between the log10-transformed (log) plasma visfatin concentration and FMD or creatinine clearance (R=-0.2672, P=.0167; R=-0.2750, P=.0136). Log visfatin was also positively correlated with log urinary albumin excretion (R=0.2305, P=.0397). In addition, it was also found that visfatin had a significant negative correlation with plasma aldosterone (R=-0.2432, P=.0297). In stepwise regression analysis, creatinine clearance, log aldosterone, FMD, and sex showed a significant association with log visfatin (P=.0040, P=.0069, P=.0444, and P=.0487, respectively), and log 8-iso-prostaglandin F2alpha showed a tendency for an association (P=.0515). Pioglitazone therapy did not affect the visfatin concentration in the 20 pioglitazone-treated patients with diabetes, although a significant elevation of visfatin was obtained in a subgroup of 11 female patients (P=.0381). In conclusion, the current study showed that visfatin is negatively associated with vascular endothelial function evaluated by FMD and creatinine clearance, and positively associated with log urinary albumin excretion. Visfatin was also negatively correlated with circulating aldosterone. Pioglitazone therapy for 12 weeks did not affect the plasma visfatin concentration significantly in all diabetic patients, but a significant elevation in visfatin was obtained in women only.     

Quantitave and qualitative changes in vascular endothelial growth factor gene expression in glomeruli of patients with type 2 diabetes

OBJECTIVE: Vascular endothelial growth factor (VEGF) exists in three main splice variants, characterized by 121, 165 and 189 amino acids (VEGF 121, VEGF 165 and VEGF 189) and acts via two specific receptors: VEGF-R1 or Flt-1 and VEGF-R2 or KDR. VEGF plays an important role in the pathogenesis of diabetic retinopathy. This study examined the relationship between VEGF and its isoforms and the severity of diabetic nephropathy in type 2 diabetes. DESIGN: We evaluated the glomerular gene expression of VEGF and its receptors and studied the relationships with renal functional and structural parameters in type 2 diabetic patients. METHODS: Glomeruli from 17 kidney biopsies were microdissected; 14 out of 17 biopsies were also subjected to electron microscopic morphometric analysis to estimate glomerular structural parameters. VEGF mRNA was studied by comparative kinetic RT-PCR and real-time RT-PCR in order to identify the three different isoforms and to quantify VEGF, VEGF-R1 and VEGF-R2 mRNA levels. RESULTS: (i) Glomerular VEGF mRNA levels were inversely related to albumin excretion rate (r=-0.66, P=0.004); (ii) both the degree of mesangial and mesangial matrix expansion were inversely related to VEGF 165 mRNA levels (r=-0.73, P=0.005 and r=-0.64, P=0.017), and directly to VEGF 121 mRNA levels (r=0.74, P=0.003 and r=0.73, P=0.004); and (iii) VEGF and VEGF-R2 mRNA levels were directly related (r=0.62, P=0.033). CONCLUSIONS: These findings suggested that quantitative and qualitative changes in VEGF expression are present in type 2 diabetic patients with nephropathy and might be involved in the pathogenesis and progression of diabetic glomerulopathy.     

Effect of sulodexide on endothelial glycocalyx and vascular permeability in patients with type 2 diabetes mellitus

Aims/hypothesis  

Endothelial glycocalyx perturbation contributes to increased vascular permeability. In the present study we set out to evaluate whether: (1) glycocalyx is perturbed in individuals with type 2 diabetes mellitus, and (2) oral glycocalyx precursor treatment improves glycocalyx properties.     

Hemorheology and vascular reactivity in patients with diabetes mellitus type 2

The study aimed to investigate the hemorheological parameters in patients with diabetes mellitus type 2 and to estimate their relationship with the cerebral and cutaneous blood flow and their responses to postural changes. The basic hemorheological constituents: hematocrit (Ht), fibrinogen (Fib), whole blood (WBV) and plasma viscosity (PV) were examined in 20 patients with diabetes mellitus type 2 and in 10 healthy age and sex matched controls. Blood flow velocity in the middle cerebral artery (MCA) was measured by transcranial Doppler monitoring at rest and during 5-min head-up tilt. Also laser Doppler-recorded tiptoe skin blood flow was investigated and venoarteriolar reflex perfusion responses to postural impact was monitored. Significant increase of Fib and WBV at shear rates of 0.0237 s(-1) to 128.5 s(-1) in the patients in comparison to controls was found. The postural challenge caused decrease of the cerebral blood flow velocity and increase of the resistance index (RI) in the diabetic patients. The initial mean skin perfusion values of the tiptoes and the venoarteriolar constriction response indices were significantly higher in the diabetes group. In the patients with diabetes mellitus type 2 the increased blood viscosity values were associated with impaired cerebrovascular and peripheral vascular responces.     

Circulating endothelial cells are elevated in patients with type 2 diabetes mellitus independently of HbA1c

Aims/hypothesis Patients with diabetes mellitus are well known to be at high risk for vascular disease. Circulating endothelial cells (CECs) have been reported to be an ex vivo indicator of vascular injury. We investigated the presence of CECs in the peripheral blood of 25 patients with diabetes mellitus and in nine non-diabetic control donors.Methods Endothelial cells were isolated from peripheral blood with anti-CD-146–coated immunomagnetic Dynabeads, and were stained with acridine orange dye and counted by fluorescence microscopy. The cells were also stained for von Willebrand factor and Ulex europaeus lectin 1.Results Patients with diabetes mellitus had an elevated number of CECs (mean 69±30 cells/ml, range 35–126) compared with healthy controls (mean 10±5 cells/ml, range 3–18) (p<0.001). The increase in CECs did not correlate with the levels of HbA₁c. Circulating endothelial cell numbers were elevated regardless of glucose levels, suggesting that, even with control of glucose levels, there is increased endothelial cell sloughing.Conclusions Our study suggests that the higher number of CECs in patients with type 2 diabetes may reflect ongoing vascular injury that is not directly dependent on glucose control.     

Serum and intraocular concentrations of erythropoietin and vascular endothelial growth factor in patients with type 2 diabetes and proliferative retinopathy

AimThis study compared systemic and intraocular concentrations of erythropoietin (EPO) and vascular endothelial growth factor (VEGF) in patients with type 2 diabetes (T2D) and proliferative diabetic retinopathy (PDR) with levels in patients without diabetes, and looked for possible correlations between the concentrations found and other variables analyzed.MethodsConcentrations of EPO and VEGF were measured in the aqueous and vitreous humours and serum of patients undergoing vitrectomy for PDR (33 patients) or for macular holes or puckers (20 control patients). EPO was assayed by radioimmunoassay, with a lower limit of detection (LOD) of 1.0 mIU/mL. VEGF was assayed using enzyme-linked immunosorbent assay (ELISA), with a lower LOD of 10.0 pg/mL.ResultsEPO concentrations in serum did not differ significantly between the two groups, whereas EPO in vitreous and aqueous were higher in diabetic than in non-diabetic patients. VEGF in serum was lower in diabetic patients than in non-diabetics; conversely, VEGF concentrations in vitreous were significantly higher in diabetic patients. A direct correlation was found between vitreous and aqueous EPO concentrations, and between vitreous EPO and blood glucose concentrations. A significant, negative correlation between vitreous EPO concentration and age was also recorded.ConclusionHigh EPO concentrations in the vitreous of patients with PDR and its correlation with blood glucose suggest that EPO could play a role in the pathogenesis of PDR. All possible factors affecting serum and ocular concentrations of EPO and VEGF should be determined to identify compounds able to prevent and control this serious microvascular complication of diabetes.     

Plasma and urinary vascular endothelial growth factor and diabetic nephropathy in Type 2 diabetes mellitus.

AIMS: Vascular endothelial growth factor (VEGF) has been implicated in the pathogenesis of diabetes mellitus. We determined whether alterations of plasma and urinary VEGF levels are related to diabetic nephropathy in Type 2 diabetic patients. METHODS: One hundred and seven patients and 47 healthy controls were studied. Study subjects were divided into four groups using urinary albumin-to-creatinine ratio (ACR): a non-diabetic healthy control group (n = 47), a normoalbuminuric diabetic group (n = 37), a microalbuminuric diabetic group (n = 37) and an overt proteinuric diabetic group (n = 33). VEGF levels were measured by enzyme-linked immunosorbent assay. RESULTS: (i) Urinary VEGF concentrations were significantly higher in the diabetic groups, even at the normoalbuminuric stage (log VEGF/Cr, normoalbuminuria; 4.33 +/- 1.06 vs. control; 3.53 +/- 0.79, P = 0.009). Urinary VEGF excretions increased as diabetic nephropathy advanced. (ii) Plasma and urinary VEGF levels were higher in hypertensive diabetic patients than in the normotensive individuals with diabetes. (iii) In those with diabetes, plasma VEGF levels were found to be positively correlated with plasma urea (r = 0.398, P = 0.039) and urinary ACR (r = 0.251, P = 0.044), and urinary VEGF to be positively correlated with urinary ACR (r = 0.645, P < 0.001), and creatinine (r = 0.336, P = 0.009), and to be negatively correlated with serum albumin (r = -0.557, P < 0.001). Urinary VEGF and serum creatinine were independently correlated with urinary ACR. CONCLUSIONS: Urinary excretion of VEGF increased during the earlier stage of diabetic nephropathy and was significantly correlated with urinary albumin excretion. This suggests that urinary VEGF might be used as a sensitive marker of diabetic nephropathy and for predicting disease progression.     

Serum Vascular Adhesion Protein-1 correlates with vascular endothelial growth factor in patients with type II diabetes

AimsTo study serum levels of soluble vascular adhesion protein (sVAP)-1 in type II diabetic patients with retinopathy.MethodsSerum samples were obtained from 53 consecutive patients, including 14 cases with non-angiogenic ocular diseases, i.e., epiretinal membrane (ERM) and idiopathic macular hole (MH), 19 cases with age-related macular degeneration (AMD), and 20 cases with diabetic retinopathy (DR). Protein levels of sVAP-1, intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1, and vascular endothelial growth factor (VEGF) were determined by enzyme-linked immunosorbent assay. Enzymatic activity of semicarbazide-sensitive amine oxidase (SSAO) was also measured.ResultsSerum level of sVAP-1 showed a moderate correlation with SSAO activity in all cases. Patients with DR had higher levels of serum sVAP-1 than subjects with ERM and MH, or those with AMD; however, severity of DR is not related to the serum levels of sVAP-1. Serum sVAP-1 correlated positively with VEGF in patients with DR, but not in those with ERM and MH, or those with AMD. Neither soluble ICAM-1 nor VCAM-1 correlated with VEGF, even in subjects with DR.ConclusionThe current data demonstrate the elevated serum levels of sVAP-1 and correlation between sVAP-1 and VEGF in patients with type II diabetes.     

Circulating plasma levels of vascular endothelial growth factor in patients with sleep disordered breathing

INTRODUCTION: Cellular vascular endothelial growth factor (VEGF) expression is increased in response to regional hypoxia, however, contradictory results were reported on the effects of systemic hypoxemia on circulating VEGF levels. This study investigated plasma concentrations of VEGF in patients with a variable degree of overnight hypoxemia due to sleep disordered breathing (SDB). METHODS: VEGF levels were assessed by ELISA in non-activated (VEGFbl) and thrombin stimulated platelet rich plasma (VEGFprp) of 45 patients with SDB: Group 1 patients with obstructive sleep apnea and an apnea-hypopnea index (AHI) > 15/h; Group 2 subjects with an AHI < 5/h; Group 3 patients on CPAP treatment for sleep apnea. RESULTS: 39 patients were included in the final analysis. Patients in Group 1 had a higher %time of sleep with SaO2 <90% and a significantly lower mean and minimum overnight oxygen saturation than subjects in Group 2 and patients in Group 3 (P<0.05). Despite significant differences in overnight oxygenation, VEGFbl and VEGFprp concentrations were not significantly different between the three study groups. However, plasma levels of VEGFbl were significantly higher (P = 0.02) in SDB patients with arterial hypertension (n = 19; VEGFbl: 14.0+/-3.3 pg/ml) than in those without arterial hypertension (n = 20; VEGFbl: 10.9+/-5.2 pg/ml). There were no relationships between VEGF levels and polysomnographic oxygenation parameters. In univariate analysis we observed significant relationships for VEGFbl with BMI (C: 0.393; P<0.05) and serum fibrinogen (C: 0.399; P<0.05). CONCLUSIONS: Circulating plasma VEGF levels in patients with sleep disordered breathing may be unrelated to night time hypoxemia (257 Words).     

通心络对改善2型糖尿病患者血管内皮功能的临床观察

目的 探讨通心络胶囊对2型糖尿病患者血管内皮依赖性舒张功能的影响及相关机理.方法 80例2型糖尿病患者,随机分为对照组和通心络组,利用高分辨率超声观察治疗前后肱动脉舒张功能,以及血清一氧化氮(NO)、内皮素(ET)、6-酮-前列腺素F1α(6-keto-PGF1α)和血栓素B2(TXB2)浓度的变化.结果 经4周的治疗,通心络组血流介导的血管舒张(FMD)由治疗前的(8.19±0.71)%,上升为(12.47±0.98)%(P＜0.05).血清NO浓度也较治疗前显著升高[(47.65±4.38)pg/ml对(52.91±4.83)pg/ml,P＜0.001].ET浓度较治疗前显著降低[(31.23±2.46)pg/ml对(24.34±2.46)pg/ml;P＜0.001],而非内皮依赖性的血管舒张反应治疗前后无明显改变(P＞0.05).对照组上述参数治疗前后均无明显变化.结论 在4周的疗程中通心络可以调控NO/ET的平衡,改善2型糖尿病患者血管内皮依赖性的舒张功能,未发现明显的不良反应.