Optimal strategies for preventing progression of renal disease: should angiotensin converting enzyme inhibitors and angiotensin receptor blockers be used together?

Bone morphogenic protein-7 inhibits progression of chronic renal fibrosis associated with two genetic mouse models

Tubulointerstitial fibrosis is a hallmark feature of chronic renal injury. Specific therapies to control the progression of renal fibrosis toward end-stage renal failure are limited. Previous studies have demonstrated that expression of endogenous bone morphogenic protein-7 (BMP-7) is reduced in the kidneys of several inducible mouse models of acute and chronic renal disease and that administration of exogenous recombinant human BMP-7 (rhBMP-7) has a beneficial effect on kidney function. Here we report that treatment with rhBMP-7 leads to improved renal function, histology, and survival in mice deficient in the alpha3-chain of type IV collagen and MRL/MpJlpr/lpr lupus mice, two genetic models for chronic renal injury and fibrosis. Such therapeutic benefit is also associated with a significant decrease in the expression of profibrotic molecules, such as type I collagen and fibronectin, in renal fibroblasts. Additionally, rhBMP-7 induces expression of active matrix metalloproteinase-2, which is potentially important for removal of fibrotic matrix. Collectively, these studies provide further evidence for rhBMP-7 as an important bone-associated protein with protective function against renal pathology.

Treatment of hypertension in diabetic patients with nephropathy

In type 1 diabetes, hypertension is closely linked to the development of nephropathy. An association of hypertension and the impact of hypertension on the clinical course of type 2 diabetes, including the development of vascular complications, has been well established. However, the association with nephropathy in type 2 diabetes is less clear. Despite that, antihypertensive treatment has a crucial impact on the course of nephropathy in both types of diabetes. In this article, we discuss recent evidence focusing on the nephroprotective potential of various classes of antihypertensive agents and confront it with current recommendations for the treatment of hypertension in diabetic patients with nephropathy. Unlike type 1 diabetes, where the nephroprotection could be a good sole measure for assessing the efficiency of a particular agent or their combination, defining of the optimal antihypertensive agent or agents in type 2 diabetes requires consideration of both cardiovascular, cerebrovascular, and nephroprotective potentials of such a treatment. In both types of diabetes, recent data support the use of inhibitors of the renin-angiotensin system with or without diuretics as the initial therapy. In type 1 diabetes, additional beneficial effect can be expected from calcium channel blockers (CCBs). In type 2 diabetic patients, combining more agents may be necessary early in the course of nephropathy to affect both micro- and macrovascular targets. beta blockers should be applied early to enhance cardioprotectivity, followed by CCBs to achieve goal blood pressure. Although not supported by all recent data, aggressive blood pressure control (< 130/75 mm Hg) is warranted. Furthermore, multifactorial intervention targeting metabolic derangements and lifestyle, is a necessary complimentary measure that must accompany antihypertensive treatment.

Therapeutic potential of ACE inhibitors for the treatment of hypertension in Type 2 diabetes

Type 2 diabetes mellitus is associated with hypertension. If untreated, hypertension has a major impact on the clinical course of Type 2 diabetes and its vascular complications. In this review, we discuss rationale for the use of ACE inhibitors (ACEI) in hypertensive Type 2 diabetic patients and compare those theoretical assumptions with results of recent major clinical trials. Furthermore, possible directions for future clinical and experimental research are outlined. The RAS and its effector angiotensin II are important players in a number of cardiovascular and renal disorders. Recent evidence suggests that RAS and factors functionally linked to RAS are activated in Type 2 diabetes. Therefore, there is a theoretical basis for the use of ACEI in the treatment of hypertension in diabetic patients. Some recent studies reported superior outcome in patients treated with ACEI-based antihypertensive regimens compared with non-ACEI based treatments in reducing the risk of macrovascular disease (CAPPP, FACET, ABCD) or both micro- and macrovascular complications in Type 2 diabetes (HOPE). However, at least two of the large prospective studies discussed in this review (UKPDS 38, HOT), supported by results from previously published SHEP study, have recently suggested that the degree of reduction of blood pressure, rather than the choice of a particular class of antihypertensive agent, is associated with decreased risk of cardiovascular events. Studies focusing on renal end-points suggest that ACEI have a superior antiproteinuric effect than the other agents. However, whether ACEI are more nephroprotective, as assessed by the rate of decline in renal function, still remains to be elucidated. Despite promising results from recent trials, large numbers of patients progress despite ACEI treatment. Incomplete inhibition of the RAS may underlie this phenomenon. Treatment strategies that could enhance the degree of RAS inhibition represent one possible direction for clinical research in the near future. However, it is unlikely that the course of such a complex syndrome as Type 2 diabetes could be dramatically changed by just one class of antihypertensive agents. This goal is more likely to be achieved by multifactorial intervention, reflecting the complexity of metabolic syndrome. ACEI should be viewed as an important, but not the only, part of this complex approach.