Renal Damage During Continuous Versus Intermittent Treatment with Lithium.

The aim of this study was to evaluate renal damage in animals treated with lithium continuously versus intermittently. Rats were randomized into three groups: control group fed ad libitum powered standard diet for 3 months and two experimental groups, one of them fed ad libitum the same diet or the same diet supplemented with 60 mmol of lithium/kg diet every alternate week, for 3 months and the other fed ad libitum powered standard diet for one and a half month and the same diet supplemented with 60 mmol of lithium/kg diet for the last month and a half. Lithemias in experimental groups were within therapeutic range used in humans. At the end of the protocol, diuresis was higher in experimental groups compared to control group. There was no difference in serum creatinine and creatinine clearance. Both experimental groups showed hypertrophy, hyperplasia, and dilatation of cortical collecting tubules although dilatation was greater in continuous group. Longer studies are necessary to clarify the evolution of renal damage. Our preliminary study shows that histopathological damage associated with the use of lithium occurs during both continuous and intermittent treatment, but it seems to be somewhat greater in the continuous group.

Relationship between serum lithium concentration and kidney damage in a preclinical model.

OBJECTIVES: The aim of the present study was to assess whether there is a relationship between serum lithium concentrations and the magnitude of kidney damage in a preclinical model. METHODS: Thirty Wistar male rats were randomized into three groups: control group fed ad libitum powered standard diet for 3 months; and experimental groups fed ad libitum the same diet supplemented with 30 or 60 mmol/kg diet for 3 months (LowLi and HighLi groups respectively). Laboratory parameters were assessed at months 1 and 3 and histopathological changes were evaluated after 3 months. RESULTS: Serum lithium levels in experimental rats were within therapeutic range used in humans throughout the entire experiment. After 3 months of treatment, lithium levels were statistically higher in HighLi group. Rats of the LowLi group showed dilation of cortical tubules although with similar clearance of creatinine. Rats from the HighLi group had greater histopathological damage in addition to lower creatinine clearance than the other two groups. CONCLUSIONS: Our study suggests that during long-term treatments, even with serum lithium levels within the therapeutic range used in humans, the risk of kidney damage could increase proportionally to the serum lithium concentration.

Role of Oxidative Stress in Lithium-Induced Nephropathy.

Long-term lithium treatment was associated with chronic kidney disease and renal failure although the underlying pathogenic mechanisms are not certainty known. The aim of this study was to evaluate changes in oxidative stress measures as well as renal functional and structural alterations associated with chronic use of lithium in rats. Forty Wistar male rats were randomized into four groups: control groups fed ad libitum powered standard diet for 1 and 3 months and experimental groups fed ad libitum the same diet supplemented with 60 mmol/kg diet for 1 and 3 months. Histopathological changes, laboratory parameters, and oxidative stress measurements were assessed at months 1 and 3. The experimental animals showed alteration of the cortical tubules from the first month of lithium-treatment and a decrease in the glomerular filtration rate and in the glomerular area at the third month. There was an increase in thiobarbituric acid reactive substances and carbonyls, as well as an increase in reduced glutathione, in the kidney of rats exposed to lithium. These changes were evident from the first month of treatment and remained throughout the experiment. Our results suggest that, oxidative stress could be one of the pathogenic mechanisms involved in the structural and functional alterations of the kidney associated with prolonged use of lithium. The study of the pathogenic mechanisms involved in lithium-induced nephropathy is a critical issue for the development of new strategies for prevention and/or early detection.

Menhaden Oil Rich Diet and Experimental Renal Damage Due to Ischemia Reperfusion.

Renal necrosis can be induced in weanling rats due to choline deficient diet. Menhaden oil has a protective effect against the development of renal necrosis in choline deficient weanling rats. The aim of this work was to determine the effects of menhaden oil in a model of acute kidney injury due to ischemia reperfusion. Wistar rats were divided into two groups and fed vegetable oils or menhaden oil as lipids. Unilateral renal ischemia was performed for 30 minutes and animals were sacrificed 48 hours later. Histopathological examination showed no significant differences between groups. Menhaden oil did not prevent histopathological lesions.

Short-term menhaden oil rich diet changes renal lipid profile in acute kidney injury.

Weanling male Wistar rats fed a choline-deficient diet develop acute kidney injury. Menhaden oil, which is a very important source of omega-3 fatty acids, has a notorious protective effect. The mechanism of this protection is unknown; one possibility could be that menhaden oil changes renal lipid profile, with an impact on the functions of biological membranes. The aim of this work was to study the renal lipid profile in rats fed a choline-deficient diet with menhaden oil or vegetable oil as lipids. Rats were divided into 4 groups and fed four different diets for 7 days: choline-deficient or choline-supplemented diets with corn and hydrogenated oils or menhaden oil. Serum homocysteine, vitamin B12, and folic acid were analyzed. Renal lipid profile, as well as the fatty acid composition of the three oils, was measured. Choline-deficient rats fed vegetable oils showed renal cortical necrosis. Renal omega-6 fatty acids were higher in rats fed a cholinedeficient diet and a choline-supplemented diet with vegetable oils, while renal omega-3 fatty acids were higher in rats fed a choline-deficient diet and a choline-supplemented diet with menhaden oil. Rats fed menhaden oil diets had higher levels of renal eicosapentaenoic and docosahexaenoic acids. Renal myristic acid was increased in rats fed menhaden oil. The lipid renal profile varied quickly according to the type of oil present in the diet.

Variable number tandem repeats in the promoter region of prostacyclin synthase gene in choline deficient rats.

Weanling Sprague-Dawley rats were fed on a choline-deficient diet with hydrogenated vegetable oil and corn oil as lipids develop acute renal failure. Pathogenesis of the latter is controversial and an ischemic mechanism has been proposed. Arachidonic acid derivatives are involved in the regulation of vascular tonus. Vasospasm could be due to an increase in tromboxane A2-mediated vasoconstriction or to a decrease in prostacyclin-induced vasodilatation. Enzymes involved in the synthesis of both compounds are tromboxane A2- and prostacyclin-synthase respectively. The aim of this study was to identify the variable number tandem repeats (VNTR) in the promoter region of prostacyclin synthase gene and verify if there exists a relationship between the occurrence of VNTR in those choline-deficient rats which die because of acute renal failure and those which do not. We verified the presence of the VNTR in the prostacyclin synthase rat gene, but we did not find any difference in the molecular weight of the alleles between experimental and control rats. Renal reparation of the acute kidney injury due to choline deficiency in some rats is not related with differences in VNTR in the promoter region of the prostacyclin synthase gene.

Variable number tandem repeats in the promoter region of prostacyclin synthase gene in choline deficient rats

Weanling Sprague-Dawley rats were fed on a choline-deficient diet with hydrogenated vegetable oil and corn oil as lipids develop acute renal failure. Pathogenesis of the latter is controversial and an ischemic mechanism has been proposed. Arachidonic acid derivatives are involved in the regulation of vascular tonus. Vasospasm could be due to an increase in tromboxane A2-mediated vasoconstriction or to a decrease in prostacyclin-induced vasodilatation. Enzymes involved in the synthesis of both compounds are tromboxane A2- and prostacyclin-synthase respectively. The aim of this study was to identify the variable number tandem repeats (VNTR) in the promoter region of prostacyclin synthase gene and verify if there exists a relationship between the occurrence of VNTR in those choline-deficient rats which die because of acute renal failure and those which do not. We verified the presence of the VNTR in the prostacyclin synthase rat gene, but we did not find any difference in the molecular weight of the alleles between experimental and control rats. Renal reparation of the acute kidney injury due to choline deficiency in some rats is not related with differences in VNTR in the promoter region of the prostacyclin synthase gene.

Variable number tandem repeats in the promoter region of prostacyclin synthase gene in choline deficient rats

Weanling Sprague-Dawley rats were fed on a choline-deficient diet with hydrogenated vegetable oil and corn oil as lipids develop acute renal failure. Pathogenesis of the latter is controversial and an ischemic mechanism has been proposed. Arachidonic acid derivatives are involved in the regulation of vascular tonus. Vasospasm could be due to an increase in tromboxane A2-mediated vasoconstriction or to a decrease in prostacyclin-induced vasodilatation. Enzymes involved in the synthesis of both compounds are tromboxane A2- and prostacyclin-synthase respectively. The aim of this study was to identify the variable number tandem repeats (VNTR) in the promoter region of prostacyclin synthase gene and verify if there exists a relationship between the occurrence of VNTR in those choline-deficient rats which die because of acute renal failure and those which do not. We verified the presence of the VNTR in the prostacyclin synthase rat gene, but we did not find any difference in the molecular weight of the alleles between experimental and control rats. Renal reparation of the acute kidney injury due to choline deficiency in some rats is not related with differences in VNTR in the promoter region of the prostacyclin synthase gene.(AU)