慢性肾衰竭大鼠模型的建立

目的 建立两种慢性肾衰竭大鼠模型,观察瘦素蛋白在大鼠组织、器官中的表达.方法 建立两种慢性肾衰竭CRF动物模型:(1)大鼠肾大部分切除诱发肾衰(Platt法).(2)腺嘌呤诱发大鼠慢性肾衰竭的动物模型(Yokozawa法).分别测定血清中血尿素氮(BUN),血肌酐(Scr)Ca2+、P5+等含量.取肾脏组织,HE染色,行免疫荧光,检测瘦素蛋白在两种慢性肾衰竭大鼠模型中的表达情况.结果 模型组大鼠血清中血尿素氮(BUN),血肌酐(Scr)等含量明显升高,免疫荧光检测显示两种模型大鼠肾脏组织瘦素蛋白的表达.结论 成功建立两种慢性肾衰竭CRF动物模型,显示不同模型组织部位的瘦素蛋白的表达.为进一步探讨瘦素蛋白在动物体内的生物学作用提供实验基础.     

Hyperprolactinemia in chronic renal insufficiency: an interesting model of hypothalamo-hypophyseal dysfunction

It is note that hyperprolactinemia is frequently associated to chronic renal failure (CRF). The etiopathogenesis of this endocrine disorder is not clearly understood, trying to evaluate the possible hypothalamic-pituitary cause we have evaluated the Prl levels under some pharmacological tests: TRH (200 mcg i.v.),Domperidone (DOM)(10 mg i.v.),Nomifensine (NOM)(200 mg p.o.)and Bromocriptine (BRC)(2.5 mg p.o.) in 3 groups of patients: CRF(8 cases), dysfunctional (8 cases) and tumoral (9 cases) hyperPrl. Prl plasma levels have been evaluated by RIA (kits,Biodata,Roma). In patients affected by CRF either direct (BRC) than indirect (NOM) agonist acting dopaminergic drugs failed to induce a reduction in Prl plasma levels, like to tumoral patients for NOM, and in contrast to the significant decrease after BRC (-70%) in tumoral and (-74%) in dysfunctional and NOM (-50%) observed in dysfunctional patients. CRF and dysfunctional patients showed significant response to TRH and DOM, being prolactinoma bearing patients unresponsive to these tests. These results show an hyporesponsivity of pituitary Prl secreting cells to dopaminergic control suggesting the existence of central etiopathological factor in inducing hyperprolactinemia in CRF patients.     

Effects of parathyroid hormone on plasma zinc concentration in rat with chronic renal failure

Although both secondary hyperparathyroidism (HPT) and hypozincemia are commonly observed in humans and animals with chronic renal failure (CRF), the relationship between secondary HPT and hypozincemia is little delineated. The present study was designed to examine whether the elevated plasma parathyroid hormones (PTH) levels do affect the disposition of extrarenal zinc and decrease plasma zinc level in CRF rats. The experiment was performed in normal and CRF rats with intact parathyroid gland and parathyroidectomized (PTX), using an acute zinc load alone or in combination with PTH infusion in five groups of rats: normal control, CRF control, CRF + PTH, CRF + PTX and CRF + PTX + PTH. Five sixths nephrectomy was used to produce CRF. All rats were infused with 0.05 mg/kg/min ZnSO4 alone or in combination with 10 microg/kg/min PTH through intravenous infusion for 90 min with serial monitoring of plasma zinc levels every 30 min. The alteration of plasma interleukin-6 (IL-6) levels and the effect of zinc levels in red blood cells (RBCs), as well as the output of bile juice zinc and urinary zinc excretion during the 90-min infusion were also examined. After 90-min infusion, liver tissue was harvested to determine its contents of zinc and metallothionein (MT). During zinc sulfate infusion, the responses of plasma zinc concentration in PTH-combined infusion groups markedly decreased as compared with those of the non-PTH-combined infusion groups, especially in the CRF rats with PTX. However, when zinc sulfate alone was infused, the response of plasma zinc concentration was found to increase in CRF rats with PTX as compared with that of the CRF control rats. PTH infusion groups significantly increased the levels of plasma IL-6 (P < 0.05), but it did not alter the levels of RBC zinc and the secretion of bile zinc during the 90-min infusion. After 90-min zinc sulfate infusion, higher liver zinc and MT contents were found in CRF control, CRF + PTH and CRF + PTX + PTH rats, but were [corrected] not found in the CRF + PTX rats. Zinc sulfate infused alone was found to increase the excretion of basal zinc in bile juice and urine, in both normal and CRF rats. The percentage of zinc load translocated out from the plasma during 90-min zinc sulfate infusion significantly rises in CRF rats and CRF rats with PTH-combined infusion as compared with normal control rats. However, in CRF rats with PTX, the percentage of zinc load translocated out from plasma during 90-min zinc sulfate infusion was similar to that in the normal control rats. Therefore, we suggested that in CRF rats, the excessive secretion of PTH may play a role in the pathogenesis of hypozincemia because PTH enhanced extrarenal zinc disposal.     

Hypersomatostatinemia in chronic renal failure

Plasma concentrations of somatostatin-like immunoreactivity (SLI) were determined in uremic patients on maintenance hemodialysis. Plasma SLI levels were significantly (p less than 0.001) elevated in 26 diabetic uremic patients (67.1 +/- 6.8 pg/ml, mean +/- SE) and in 24 non-diabetic uremic patients (43.5 +/- 7.2 pg/ml), when compared with 60 healthy subjects (5.0 +/- 0.7 pg/ml). Paired pooled plasma from uremic patients before and after hemodialysis was subjected to a reverse-phase octadecasilyl-silica (C-18) cartridge and then the extract was gel filtered on a Sephadex G-25 column (1.6 X 90 cm). Both elution profiles showed two peaks of SLI which coeluted with synthetic somatostatin (SS)-28 and SS-14 markers, respectively. The SS-28-like immunoreactivity (LI) peak, which was estimated by using SS-14 as a reference standard, was 3-fold larger than that for SS-14 LI. On the basis of immunoequivalency of the two components in the present assay, SS-28 LI constitutes approximately 75% of circulating somatostatin. In conclusion, plasma SLI is substantially high in uremic patients of both diabetic and non-diabetic etiology and the SS-28 is a predominant form of circulating SLI in these patients, probably, in part, for a lower clearance of this molecule.     

Hyperlipidemia in rats with chronic renal failure]

The character of hyperlipidemia was studied in rats with chronic uremia induced by subtotal nephrectomy--5/6 of the renal tissue was removed. 13 to 30 weeks after this operation the blood serum cholesterol and phospholipid concentration almost doubled. Hyperlipidemia was more pronounced in rats with high azotemia (blood urea nitrogen--BUN). No elevation of serum tryglycerides occurred. Total serum beta- and pre-beta-lipoproteins determined nephelometrically increased significantly only with the BUN level of over 80 mg%. Lipoprotein disc electrophoresis of the serum in rats with uremia demonstrated a distinct rise of alpha-lipoproteins and a slight--of beta-lipoproteins; postheparin lipolytic activity of the plasma was normal. Experimental rats displayed massive proteinuria, but hypoproteinuria was insignificant.     

Increased plasma ghrelin levels in chronic renal failure are not associated with hemodynamic parameters.

BACKGROUND/AIMS: Hardly anything is known about the effect of renal function on plasma ghrelin levels. Ghrelin is an orexigenic hormone with important hemodynamic effects. We examined differences in plasma ghrelin levels between chronic renal failure (CRF) patients and healthy subjects, and ghrelin's relationship with indices of left ventricular (LV) function. METHODS: Fasting total plasma ghrelin levels were measured in 122 CRF patients (57 on, 65 not on hemodialysis) and 57 control subjects. Indices of LV function were evaluated using echocardiography. RESULTS: Total plasma ghrelin levels were higher in patients with CRF compared to controls, but were not different between patients on and those not on hemodialysis. In a multivariate linear regression model, presence of kidney dysfunction explained 41 % of the variability of ghrelin values. The etiology of renal failure (diabetic nephropathy or not) had no influence on ghrelin levels in the renal patients. Ghrelin levels were not associated with indices of LV systolic function or blood pressure in these patients. CONCLUSION: Fasting plasma ghrelin concentrations are higher in CRF patients regardless of their need for hemodialysis compared to controls. The etiology of renal failure does not have any effect on plasma ghrelin levels. In addition, ghrelin levels are not associated with hemodynamic parameters in patients with CRF.     

Vascular function in rats with adenine-induced chronic renal failure

The aim of the present study was to characterize the function of resistance arteries, and the aorta, in rats with adenine-induced chronic renal failure (A-CRF). Sprague-Dawley rats were randomized to chow with or without adenine supplementation. After 6-10 wk, mesenteric arteries and thoracic aortas were analyzed ex vivo by wire myography. Plasma creatinine concentrations were elevated twofold at 2 wk, and eight-fold at the time of death in A-CRF animals. Ambulatory systolic and diastolic blood pressures measured by radiotelemetry were significantly elevated in A-CRF animals from week 3 and onward. At death, A-CRF animals had anemia, hyperphosphatemia, hyperparathyroidism, and elevated plasma levels of asymmetric dimethylarginine and oxidative stress markers. There were no significant differences between groups in the sensitivity, or maximal response, to ACh, sodium nitroprusside (SNP), norepinephrine, or phenylephrine in either mesenteric arteries or aortas. However, in A-CRF animals, the rate of aortic relaxation was significantly reduced following washout of KCl (both in intact and endothelium-denuded aorta) and in response to ACh and SNP. Also the rate of contraction in response to KCl was significantly reduced in A-CRF animals both in mesenteric arteries and aortas. The media of A-CRF aortas was thickened and showed focal areas of fragmented elastic lamellae and disorganized smooth muscle cells. No vascular calcifications could be detected. These results indicate that severe renal failure for a duration of less than 10 wk in this model primarily affects the aorta and mainly slows the rate of relaxation.     

Peculiarities of erythropoiesis in patients with chronic renal failure

In 600 patients suffering from chronic renal insufficiency the cellularity of bone marrow, erythroid cells proliferative activity, erythroid cells destruction and iron incorporation rate, data of ferrokinetics, intracellular iron distribution, porphyrin synthesis rate were examined. On the basis of the obtained data the suggestion is put forward that metabolic disturbances are important in anemia development in uremic patients. One of the aspects of this problem is the role of disorders in the protein turnover causing changes in the synthesis of globin and porphyrin which are the primary components for heme synthesis. Special importance is attached to the changes in iron turnover, i.e. to its redistribution between stromal and heme pools.     

Erythropoietin therapy in patients with chronic renal failure.

Symptomatic anemia is a common complication of chronic renal failure. Treatment is now possible with the availability of recombinant human erythropoietin (epoetin alfa). Previous experimental studies have suggested that correcting the anemia of chronic renal failure may be harmful in that renal failure may be accelerated. Although experience with this drug has been primarily restricted to its use in patients with end-stage renal disease, several recent trials have been reported in patients with varying degrees of chronic renal failure. We review these studies with particular reference to the progression of renal failure and the drug''s reported side effects. We conclude that the use of epoetin is beneficial and well tolerated and that there is no compelling evidence for the acceleration of renal failure associated with its use in patients.     

Tumor markers in patients with chronic renal failure.

In order to evaluate the specificity of tumor markers in chronic renal failure, we have determined serum levels of carcinoembryonic antigen (CEA), carbohydrate antigen 19.9 (CA 19.9), carbohydrate antigen 50 (CA 50), alphafetoprotein (AFP), neuron-specific enolase (NSE), prostatic acid phosphatase (PAP), prostatic specific antigen (PSA), squamous cell carcinoma antigen (SCC), carbohydrate antigen 15.3 (CA 15.3) and carbohydrate antigen 125 (CA 125) in 30 patients with chronic renal failure and in 36 hemodialyzed patients without clinical evidence of neoplasia. CEA, CA 50, NSE and SCC frequently show increased serum levels, suggesting a renal metabolism, while others remain, generally, within the normal levels.     

Oxidative stress in chronic renal failure

Cardiovascular disease is the major cause of morbidity and mortality in chronic renal failure. The aim of this review is to summarise current evidence suggesting that there is increased free radical production, antioxidant depletion and changes in lipoprotein composition in renal failure which will lead to oxidation of LDL and hence to accelerated development of atherosclerosis.     

Acetylcholinesterase activity in chronic renal failure

Twenty healthy subjects and 39 Chronic Renal Failure patients (CRF-patients) maintained on chronic hemodialysis were used in this investigation to study the changes in acetylcholinesterase (AChE) activity of red blood cells (RBCs). The CRF-patients were all undergoing hemodialysis treatment. AChE activity from the CRF-patients was determined before and after dialysis. An additional objective was to study the effect of chronic renal failure on human red blood cell aging. Blood samples were drawn from controls and CRF-patients in tubes containing EDTA or sodium heparin as an anticoagulant. Red blood cells were purified to avoid interference with monocytes, reticulocytes and leukocytes. The purified RBCs were subfractionated into young (y) (1.08-1.09), mid (m) (1.09-1.11) and old (o) (1.11-1.12) percoll density (g/mL) fractions using a discontinous percoll gradient. The mean +/- SD AChE per gram hemoglobin (U/g Hgb) activities in whole blood (WB), purified human red blood cells (PRBCs), young human red blood cells (y-RBCs), mid age human red blood cells (m-RBCs) and old human red blood cells (o-RBCs) in CRF-patients were 31.2+/-3.43, 29.3+/-3.26, 30.4+/-3.91, 25.1+/-5.25, 17.1+/-6.02 in females and 29.8+/-5.39, 28.8+/-5.29, 28.7+/-5.29, 23.7+/-5.39 and 16.0+/-5.60 in males. AChE activity from CRF-patients were higher than that found in the control subjects. The aging of human RBCs in both the controls and CRF-patients showed a progressive reduction in AChE activity. AChE activity of RBCs from female CRF-patients were significantly higher (p < 0.05) than that of the female control subjects. The RBCs isolated from male CRF-patients showed a higher AChE activity than control males, but a significant difference was only observed with the mid-age-cells. These studies further indicate that AChE activity remained insignificantly different in the various density based age subfractions of RBCs of both CRF-patients and controls.