Early Marker Of Renal Damage Research Articles

Microalbuminuria and arterial stiffness in a general population: the Shimanami Health Promoting Program (J-SHIPP) study.

Microalbuminuria is an early marker of renal damage and has been shown to predict future cardiovascular mortality and morbidity in patients with diabetes or hypertension, as well as in subjects in the general population. In this study, we investigated the hypothesis that the presence of microalbuminuria reflects the advancement of arterial stiffness by using a study group of 136 community residents who had no cardiovascular diseases except for hypertension and who were not taking any medications. Urinary albumin concentration was determined by the standard method and corrected by creatinine. Microalbuminuria was defined as a urinary albumin/creatinine ratio of 2.0-30.0 mg/mmol creatinine. Arterial stiffness was evaluated by pulse wave velocity (PWV) determined at three points: from the heart to the carotid artery, to the brachial artery, and to the ankle. Carotid arterial pressure was determined using a tonometric sensor. Carotid ultrasonography was performed to measure carotid intima-media thickness (IMT) and carotid arterial internal dimension. Subjects with microalbuminuria had higher blood pressure and wider pulse pressure not only in the brachial artery but also in the carotid artery. Microalbuminuria was associated with significantly higher PWV compared with that of normoalbuminuric subjects at all sites studied (mean PWV: 821.2+/-137.4 cm/s vs. 933.8+/-137.5 cm/s, p<0.0001). Stepwise regression analysis revealed that the presence of mircroalbuminuria (p=0.047) was a significant independent predictor of PWV in addition to age, sex, and systolic blood pressure. These findings suggest that microalbuminuria is associated with advanced atherosclerosis in the general population. Underlying arterial stiffness may explain the high cardiovascular mortality in subjects with microalbuminuria. Hypertension may be the mechanism linking microalbuminuria and arterial stiffness in the general population.

Organic Solvents and the Kidney

Organic Solvents and the Kidney: Antonio Mum. Laboratory of industrial Toxicology, University of Parma Medical School—The association between solvent exposure and chronic glomerulonephritis is still a controversial scientific issue. Almost all published case‐referent studies consistently show an association between chronic glomerulonephritis and exposure to volatile hydrocarbons. Two nested prospective studies and a recent case‐referent study also suggest a role of solvent exposure in the progression of renal changes towards chronic renal failure. Cross‐sectional studies carried out in groups of workers exposed to relatively low concentrations of single solvents or mixtures demonstrate tubular damage frequently associated with high molecular weight proteinuria and changes in the glomerular basal membrane. In some studies, immunological disturbances (increased titer of antilaminin and/or anti‐glomerular basement membrane antibodies) have been found. Whereas unequivocal evidence of solvent‐induced renal disturbances is apparent on a group basis, the health significance of such changes is difficult to assess at the individual level. Although renal cancer in the male rat chronically exposed to a variety of hydrocarbons including several organic solvents is not a good model for assessing human risk, experimental studies may not be used as a proof to exclude the cancerogenic properties of all organic solvents. Indeed, epidemiological investigations suggest that a small excess mortality from renal‐cell cancer may occur as a consequence of exposure to some organic solvents, including dry‐cleaning products and petroleum‐derived hydrocarbons. Despite consistent results indicating renal effects of solvent exposure, no specific agents appeared to be implied more frequently, neither dose‐ effect nor dose response relationships were found and, finally, possible risk factors accounting for an increased individual susceptibility were not identified. Early markers of renal damage are very useful to identify groups at risk, since these subtle abnormalities may represent an early stage of clinically silent but potentially progressive renal diseases. Follow‐up should confirm the observed changes and assess their course and prognostic meaning. Repeatedly positive markers of renal damage also indicate the need for intervention, including job counseling and removal from exposure.

Detection of Occupational Lead Nephropathy Using Early Renal Markers

Automotive use of leaded gasoline continues to be an important source of occupational exposure to lead in India and other countries. The present study assessed the renal function and markers of early renal damage of 22 mechanics at three automobile garages. Urinary N-acetyl-3-D-glucosaminidase activity and beta-2-microglobulin levels were significantly increased in auto garage mechanics with blood leads of 30-69 micrograms/dL. A significant correlation was observed between blood lead levels and urinary N-acetyl-3-D-glucosaminidase activity but not with urine beta-2-microglobulin levels. A marginal impairment in creatinine clearance was not statistically significant. Urinary N-acetyl-3-D-glucosaminidase activity offers a sensitive monitor of blood lead and renal tubular injury.

Renal isoamylase clearance as a measure of altered renal charge selectivity in patients with diabetes mellitus.

Microalbuminuria is well established as a marker for early renal damage in diabetic patients. Differences in charge selectivity in glomerular protein filtration may also be an early marker of renal damage. We investigated the possible usefulness of the renal clearances of pancreatic and salivary amylases, and the ratio of the two, as markers of early renal damage in 55 diabetic subjects and 21 healthy controls. Diabetic patients with established albuminuria and microalbuminuria had increased clearance of salivary amylase and a trend toward lower pancreatic/salivary amylase clearance ratios compared to healthy controls and diabetic subjects without albuminuria, but the overlap with controls and diabetics without albuminuria was too large for the test to be useful.

Reference values for early markers of renal damage

In addition to the difficulties related to the definition of a reference population and hence of reference limits, special methodological problems have to be dealt with when early markers of renal damage are applied to monitor groups at risk. The urinary excretion of both high and low molecular weight proteins, as measured by sensitive immunoassays, is routinely applied in health surveillance programmes aimed at preventing the occurrence of adverse renal effects resulting from exposure to nephrotoxic chemicals, among which are several metals. Owing to the large intra-individual variability experimentally demonstrated for all indicators of renal impairment, carefully standardized sampling conditions must be adopted. At the individual level, repeated measurements should be performed before a diagnosis of renal disease or dysfunction is established. In fact, several physiological conditions may account for transient changes in renal function, leading to measured levels greatly exceeding reference limits.