Measurement of free and bound alcohol metabolites and methanol in human biological samples--free and bound alcohol metabolites and methanol in acute alcohol administration.

There are almost no studies on the in vivo distribution kinetics of free and bound ethanol, alcohol metabolites (acetaldehyde and acetate) or the related substance, methanol, during alcohol oxidation. Thus, an acute alcohol administration experiment (alcohol consumption experiment) was carried out using volunteers (five healthy adult males; 2 flushers, 3 non-flushers), and distribution kinetics were investigated in biological samples (blood and urine). The levels of alcohol metabolites and methanol were measured as free compounds in blood samples and bound and free compounds in urine samples. The results showed an increase over time of free alcohol metabolites in both the flusher and non-flusher groups, followed by a subsequent decrease. In addition, free methanol increased over time. Both bound alcohol metabolites and bound methanol were found to increase over time. Based on these findings, levels of free and bound alcohol metabolites and methanol in the biological samples were found to increase relative to levels before consumption in both the flusher and non-flusher groups. This is thought to be due to the binding of alcohol metabolites and methanol to biological components and increases during ethanol oxidation. It was concluded that this is the mechanism by which ethanol, alcohol metabolites and methanol accumulate in the body as a result of chronic alcohol consumption, suggesting that it may be possible to use these compounds as markers of consumption by measuring these compounds in biological samples taken from alcohol abusers or alcoholics.

Suppression of renal alpha-dicarbonyl compounds generated following ureteral obstruction by kidney-specific alpha-dicarbonyl/L-xylulose reductase.

Renal unilateral ureteral obstruction (UUO) causes acute generation of alpha-dicarbonyl stress substances, such as glyoxal, 3-deoxyglucosone, and methylglyoxal, in the kidneys. These alpha-dicarbonyl compounds are prone to form advanced glycation end products (AGEs) via the nonenzymatic Maillard reaction. Using transgenic (Tg) mice overexpressing a kidney-specific short-chain oxidoreductase, alpha-dicarbonyl/L-xylulose reductase (DCXR), we measured generation of alpha-dicarbonyls following UUO by means of electrospray ionization/liquid chromatography/mass spectrometry in their kidney extracts. The accumulation of 3-deoxyglucosone was significantly reduced in the kidneys of the mice Tg for DCXR compared to their wild-type littermates, demonstrating 4.91 +/- 2.04 vs. 6.45 +/- 1.85 ng/mg protein (P = 0.044) for the obstructed kidneys, and 3.68 +/- 1.95 vs. 5.20 +/- 1.39 ng/mg protein (P = 0.026) for the contralateral kidneys. Despite the reduction in accumulated alpha-dicarbonyls, collagen III content in kidneys of the Tg mice and their wild-type littermates showed no difference as monitored by in situ hybridization. Collectively, DCXR may function in the removal of renal alpha-dicarbonyl compounds under oxidative circumstances, but it is not sufficient to suppress acute renal fibrosis during 7 days UUO.

Suppression of AGE precursor formation following unilateral ureteral obstruction in mouse kidneys by transgenic expression of alpha-dicarbonyl/L-xylulose reductase.

Unilateral ureteral obstruction (UUO) of kidneys causes acute generation of carbonyl stress. By electrospray ionization/liquid chromatography/mass spectrometry (ESI/LC/MS) we measured the content of methyl glyoxal, glyoxal, and 3-deoxyglucosone in mouse kidney extracts following UUO. UUO resulted in elevation of these dicarbonyls in the obstructed kidneys. Furthermore, the accumulation of 3-deoxyglucosone was significantly reduced in the kidneys of mice transgenic for alpha-dicarbonyl/L-xylulose reductase (DCXR) as compared to their wild-type littermates, demonstrating 4.91+/-2.04 vs. 6.45+/-1.85 ng/mg protein (P=0.044) for the obstructed kidneys, and 3.68+/-1.95 vs. 5.20+/-1.39 ng/mg protein (P=0.026) for the contralateral kidneys. On the other hand, collagen III content in kidneys showed no difference as monitored by in situ hybridization. Collectively, DCXR may function in the removal of renal alpha-dicarbonyl compounds under oxidative circumstances, but it was not sufficient to suppress acute renal fibrosis during 7 d of UUO by itself.

Transgenic mice over-expressing dicarbonyl/L-xylulose reductase gene crossed with KK-Ay diabetic model mice: an animal model for the metabolism of renal carbonyl compounds.

Carbonyl compounds in the blood stream tend to accumulate in the kidney of diabetic or end stage renal failure subjects. Previously we isolated cDNA encoding dicarbonyl/L-xylulose reductase (DCXR) from a mouse kidney cDNA library. In the present study, transgenic (Tg) mice were generated to study the functional role of DCXR in the kidney. With a six-fold increase in the DCXR protein expression levels in the kidney, the homozygous Tg mice did not show any notable histological abnormalities. While the elevated DCXR expression was observed throughout the body, its renal distribution was similar to that of the endogenous DCXR protein, namely, the major expression site was the collecting tubules, along with moderate expression in other tubules and Bowman's capsule, but it was absent from the interstitial area and glomeruli. The Tg mice were crossed with KK-A(y) diabetic model mice to examine the role of DCXR in the progression of diabetic nephropathy. The resulting progeny, Tg/A(y), showed lighter body weight, lower levels of blood glucose, water uptake and creatinine clearance compared to their +/A(y) littermates. Although remarkable pathological differences were not observed at the microscopic level and in the renal accumulation of carboxymethyl lysine, the data imply that DCXR might function in the metabolism of glucose or carbonyl compounds, and play a protective role in a kidney which is under hyperglycemic pressure. The DCXR Tg mice and the Tg x KK-A(y) hybrid mice, therefore, serve as specific models for carbonyl metabolism in the kidney with diabetic background.