Enhanced peritubular capillary flow and renal function can be accomplished in normoalbuminuric type 2 diabetic nephropathy

Under common practice, treatment of diabetic nephropathy (DN) is usually initiated at late stage of CKD due to the insensitiveness of the available diagnostic markers. Such treatment fails to restore renal perfusion and function. This is due to the defective mechanism of vascular homeostasis and impaired nitric oxide production observed in late stage of DN. In contrast, the mechanism of vascular repair is adequately functional in early stage of DN (normoalbuminuria). In this study, we treated 50 normoalbuminuric diabetic patients with multidrug vasodilators, namely ACE inhibitor, angiotensin receptor blocker, ± calcium channel blocker in conjunction with correction of metabolic disorders for 24-36 months. Following the treatment, increment in peritubular capillary flow in response to vasodilators was observed, and thus supports the adequate role of vascular repair. In addition, increase in renal function documented in this study also implies that an effective preventive strategy to minimize end-stage renal disease can be accomplished in normoalbuminuric DN.

Genetic Markers of Fibrinolytic Responses of Older Persons to Exercise Training

We assessed the interactive effect of genetic polymorphisms and exercise training on fibrinolysis in 50 - 75 yr old men (n = 17) and women (n = 28). Subjects had tissue plasminogen activator (t-PA) antigen levels and activity and plasminogen activator inhibitor-1 (PAI-1) activity measured before and after 6 mo of endurance-exercise training. Subject's DNA was typed for the PAI-1 4 G/5 G and t-PA I/D variants. Baseline PAI-1 activity, t-PA activity, and t-PA antigen levels were not different among PAI-1 or t-PA genotype groups. Overall, exercise training did not change PAI-1 activity (- 0.43 +/- 0.81 IU/mL, p = NS), increased t-PA activity (0.37 +/- 0.16 IU/mL, p = 0.02), and decreased t-PA antigen levels (- 0.88 +/- 0.20 ng/mL, p < 0.001). Although the differences in changes with training were not significant among genotype groups, significant t-PA antigen level improvements were evident only in PAI-1 4 G allele carriers and significant t-PA activity increases only in PAI-1 4 G homozygotes. t-PA genotype affected the training-induced t-PA antigen level improvements (p = 0.033) after covarying for gender and baseline t-PA antigen levels, with the smallest and largest reductions in the D homozygotes and I/D heterozygotes, respectively. These findings could have important treatment implications for the use of exercise training to reduce CV disease and thrombotic risk in older men and women.

A hemodynamically mediated mechanism of renal disease progression in severe glomerulonephritides or nephrosis

Glomerular endothelial cell (GEC) dysfunction due to oxidative stress and enhanced proinflammatory cytokines plays an important role in inducing proteinuria and procoagulant activity, namely blood hypercoagulability, hyperviscosity and local intravascular coagulation and altered hemorheology in NS. A dysfunctioning GEC releases fewer endothelium-dependent vasodilators but produces more vasoconstrictors. Severe intrarenal hemodynamic alteration associated with hemodynamic maladjustment with preferential constriction at the efferent arteriole has been uniquely implicated in severe GN and NS-FSGS. Such a constriction exerts three significant hemodynamic impacts. Proximal to the efferent arteriolar constriction, it induces (i) an overestimated GFR due to hyperfiltration and (ii) an elevated intraglomerular hydrostatic pressure. Distal to the efferent arteriolar constriction, it (iii) exaggeratedly reduces PTCF which correlates with the TIF.