A potent anti-angiogenic factor, vasohibin-1, ameliorates experimental bronchiolitis obliterans

Expression levels of serum vasohibin-1 and other biomarkers in type 2 diabetes mellitus patients with different urinary albumin to creatinine ratios

AIM

To determine the serum levels of vasohibin (VASH)-1 and other biomarkers in type 2 diabetes mellitus (T2DM) patients with different urinary albumin to creatinine ratios (UACR), and correlate VASH-1 expression with the inflammation and fibrosis in diabetic kidney disease (DKD).

METHODS

A total of 697 T2DM patients were stratified into four groups: N-UAlb (UACR <30 mg/g with normal blood pressure, n = 144), M-UAlb (UACR 30-300 mg/g with normal blood pressure, n = 143), L-UAlb (UACR >300 mg/g with normal blood pressure, n = 126), and L-UAlb+HP (UACR >300 mg/g with hypertension, n = 134). In addition, 150 healthy subjects were included as normal controls (NC). In addition to recording the age and duration of diabetes, the serum levels of VASH-1, silent information regulator factor 2-related enzyme 1 (sirtuin-1, SIRT1), hypoxia inducible factor 1α (HIF1α), vascular endothelial growth factor (VEGF), C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1), and the erythrocyte sedimentation rate (ESR) were measured. Clinical parameters related to UACR and VASH-1 were analyzed by one-way ANOVA, Pearson correlation and ridge regression analysis.

RESULTS

The UACR, VASH-1, glycosylated hemoglobin (HbA1c), ESR, CRP, VEGF, HIF1α, TNF-α and TGF-β1 levels in all patient groups were significantly higher, and SIRT1 levels were lower compared to the NC group. Pearson correlation analysis showed that UACR and VASH-1 levels were positively correlated with HbA1c, ESR, CRP, VEGF, HIF1α, TNF-α and TGF-β1, and negatively with SIRT1. Ridge regression analysis showed that every serological marker was an independent factor affecting UACR.

CONCLUSION

Serum VASH-1 may be associated with the expression of renal inflammation and fibrosis-related factors, and have a potential connection with DKD.

Antiangiogenic Therapy for Diabetic Nephropathy

Angiogenesis has been shown to be a potential therapeutic target for early stages of diabetic nephropathy in a number of animal experiments. Vascular endothelial growth factor (VEGF) is the main mediator for abnormal angiogenesis in diabetic glomeruli. Although beneficial effects of anti-VEGF antibodies have previously been demonstrated in diabetic animal experiments, recent basic and clinical evidence has revealed that the blockade of VEGF signaling resulted in proteinuria and renal thrombotic microangiopathy, suggesting the importance of maintaining normal levels of VEGF in the kidneys. Therefore, antiangiogenic therapy for diabetic nephropathy should eliminate excessive glomerular angiogenic response without accelerating endothelial injury. Some endogenous antiangiogenic factors such as endostatin and tumstatin inhibit overactivation of endothelial cells but do not specifically block VEGF signaling. In addition, the novel endothelium-derived antiangiogenic factor vasohibin-1 enhances stress tolerance and survival of the endothelial cells, while inhibiting excess angiogenesis. These factors have been demonstrated to suppress albuminuria and glomerular alterations in a diabetic mouse model. Thus, antiangiogenic therapy with promising candidates will possibly improve renal prognosis in patients with early stages of diabetic nephropathy.

Exacerbation of diabetic renal alterations in mice lacking vasohibin-1

Vasohibin-1 (VASH1) is a unique endogenous inhibitor of angiogenesis that is induced in endothelial cells by pro-angiogenic factors. We previously reported renoprotective effect of adenoviral delivery of VASH1 in diabetic nephropathy model, and herein investigated the potential protective role of endogenous VASH1 by using VASH1-deficient mice. Streptozotocin-induced type 1 diabetic VASH1 heterozygous knockout mice (VASH1^+/−) or wild-type diabetic mice were sacrificed 16 weeks after inducing diabetes. In the diabetic VASH1^+/− mice, albuminuria were significantly exacerbated compared with the diabetic wild-type littermates, in association with the dysregulated distribution of glomerular slit diaphragm related proteins, nephrin and ZO-1, glomerular basement membrane thickning and reduction of slit diaphragm density. Glomerular monocyte/macrophage infiltration and glomerular nuclear translocation of phosphorylated NF-κB p65 were significantly exacerbated in the diabetic VASH1^+/− mice compared with the diabetic wild-type littermates, accompanied by the augmentation of VEGF-A, M1 macrophage-derived MCP-1 and phosphorylation of IκBα, and the decrease of angiopoietin-1/2 ratio and M2 macrophage-derived Arginase-1. The glomerular CD31⁺ endothelial area was also increased in the diabetic VASH1^+/− mice compared with the diabetic-wild type littermates. Furthermore, the renal and glomerular hypertrophy, glomerular accumulation of mesangial matrix and type IV collagen and activation of renal TGF-β₁/Smad3 signaling, a key mediator of renal fibrosis, were exacerbated in the diabetic VASH1^+/− mice compared with the diabetic wild-type littermates. In conditionally immortalized mouse podocytes cultured under high glucose condition, transfection of VASH1 small interfering RNA (siRNA) resulted in the reduction of nephrin, angiopoietin-1 and ZO-1, and the augmentation of VEGF-A compared with control siRNA. These results suggest that endogenous VASH1 may regulate the development of diabetic renal alterations, partly via direct effects on podocytes, and thus, a strategy to recover VASH1 might potentially lead to the development of a novel therapeutic approach for diabetic nephropathy.

Urinary and plasma levels of vasohibin-1 can predict renal functional deterioration in patients with renal disorders

Vasohibin-1 (VASH-1) is a negative feedback regulator of angiogenesis, and a small vasohibin-binding protein (SVBP) serves as its secretory chaperone and contributes to its antiangiogenic effects. In the present study, we aimed to define the clinical significance of VASH-1 and SVBP in patients with chronic kidney disease (CKD). We recruited 67 Japanese hospitalized patients with renal disorders with (n = 45) or without (n = 22) renal biopsy samples and 10 Japanese healthy controls. We evaluated the correlations between the plasma and urinary levels of VASH-1/VASH-1-SVBP complex/SVBP and the clinicopathological parameters. The plasma levels of VASH-1 were inversely correlated with age and systolic and diastolic blood pressure and positively correlated with crescent formation. Increased plasma and urinary levels of VASH-1 and VASH-1-SVBP complex were significantly correlated with worse renal outcomes. These results demonstrate an association between elevated urinary and plasma levels of VASH-1 and progressive decline of the renal function, thus suggesting a potential role for VASH-1 in predicting a worse renal prognosis in patients with renal disease, including CKD.

The vasohibin family: a novel family for angiogenesis regulation

Angiogenesis, a formation of neovessels, is regulated by the local balance between angiogenesis stimulators and inhibitors. A number of such endogenous regulators of angiogenesis have been found in the body. Recently, vasohibin-1 (VASH1) was isolated as a negative feedback regulator of angiogenesis produced by endothelial cells (ECs) and subsequently vasohibin-2 (VASH2) as a homologue of VASH1. It was then explored that VASH1 is expressed in ECs to terminate angiogenesis, whereas VASH2 is expressed in cells other than ECs to promote angiogenesis in the mouse model of angiogenesis. This review will focus on the vasohibin family members, which are novel regulators of angiogenesis.