Systemic blood pressure and glomerular leakage with particular reference to diabetes and hypertension

Abstract

Both day and night blood pressure have considerable ranges in normal individuals and also in diabetic patients. In addition, there is considerable variation intra-individually, with considerable excurses in blood pressure, e.g. during exercise, other daily activities as well as on exposure to medical personnel. There is good evidence to suggest that elevated blood pressure is an important factor in the progression of renal disease in diabetes, even from the initial phase of the slight elevation of the albumin excretion rate. From the earliest phase of microalbuminuria, blood pressure may increase by an average of 3-4 mmHg per year in contrast to 1 mmHg per year in healthy controls and in clearly normoalbuminuric individuals. Throughout the course of the complications of diabetes, both insulin-dependent and non-insulin-dependent, there is a correlation between albuminuria and blood pressure in cross-sectional studies; also there is a significant correlation between blood pressure and the progression of albuminuria. The same findings are available in essential hypertension and also to some extent in the background population, although in the latter the correlation between albuminuria and blood pressure is much less precise, although highly significant. Several trials conducted over the years uniformly show that antihypertensive treatment reduces albuminuria and, in many studies, progression in renal disease also, as measured by the glomerular filtration rate (GFR) fall. Therefore, it could be considered as a means to reduce blood pressure generally in diabetic individuals, even from the start of diabetes, with the aim of future further prevention of renal complications and possibly other complications. Such a proposal is less attractive in the background population because renal disease is much more rare. Another similar approach would be the prevention of renal disease, e.g. diabetics. Obviously, abnormalities in the vascular wall of a biochemical/functional nature may make diabetics more pressure-sensitive, and the indication is that several other risk factors are involved, in particular poor metabolic control. Nevertheless, it is proposed that trials should be conducted very early in the course of diabetes, to see if the same positive effect can be obtained early as that documented later in the course of microalbuminaria and overt renal disease, both in insulin-dependent and in non-insulin-dependent diabetes. In essential hypertension, antihypertensive treatment has a profound effect on albuminuria, and this may be associated with long-term renoprotection, but this is less well documented.

C-Reactive Protein Modifies the Relationship Between Blood Pressure and Microalbuminuria

“…20 -22 Albuminuria may therefore occur as a result of direct transmission of raised systemic pressure to the glomerulus 23,24 and/or permselectivity changes of the glomerular filter. 25 Blood pressure is already known to relate to albuminuria in the population, 8 a fact that we confirmed in the present study. A new finding of our study shows that the relation was more pronounced in subjects with an elevated CRP level.…”

“…8,19 Functional abnormalities, indicative of impaired glomerular autoregulation, and structural changes in the glomerulus can be observed in diabetes and hypertension. 20 -22 Albuminuria may therefore occur as a result of direct transmission of raised systemic pressure to the glomerulus 23,24 and/or permselectivity changes of the glomerular filter.…”

“…7 Blood pressure has been shown to be the main determinant of microalbuminuria in diabetes and hypertension. 8 Many other CV risk factors, which cluster within the metabolic syndrome, have been shown to relate to microalbuminuria in the population. 9,10 Because CRP and microalbuminuria reflect closely related components of the same disease processes, one might anticipate a strong relationship between them.…”

Relationship between microalbuminuria and cardiac structural changes in mild hypertensive patients

“…eral other risk factors such as hyperinsulinemia, dislipidemia and obesity, which comprise a cluster of metabolic abnormalities (8,15,25,26). In the present study, UAE was not explained by any of the variables included in a regression model, such as age, duration of hypertension, or BMI.…”

“…The importance of this finding is not completely clear but it seems that there is an association between UAE and the other cardiovascular risk factors such as obesity, insulin resistance, impaired lipid profile and blood pressure (6)(7)(8).…”