Chronic kidney disease leads to hypoxia inducible factor-1alpha to hypoxia inducible factor-2alpha switch in the gastrocnemius muscle.

Hipoxia inducible factor-1 and HIF-2 are responsible for the adaptation of cell metabolism to hypoxia. Previously, a more severe capillary rarefaction was found in locomotor than in postural muscles of uremic animals. The aim of this study was to analyze the expression patterns of HIF and prolyl hydroxylases (PHDs) in functionally different skeletal muscles in uremic rats, an experimental model of chronic kidney disease (CKD). Rats were randomized to sham operation - CON, uninephrectomy - CKD1/2 or subtotal nephrectomy - CKD5/6. After 4 weeks, expression of HIF-1α and -2α and PHD proteins was measured using WB in locomotor, gastrocnemius muscle (MG) and postural, longissimus thoracis muscle (ML). Serum concentrations of creatinine (Cr), hemoglobin (Hb), haptoglobin (Hp), MCP-1, AGEs, homocysteine (Hcy) were measured. HIF-1α increased in MG and ML for CKD1/2 versus CON. HIF-1α decreased in MG and increased in ML for CKD5/6 versus CON and CKD1/2. HIF-2α increased in MG for CKD5/6 and CKD1/2 versus CON. HIF-2α was not detected in ML in any group. PHD1 was not detected in MG in any group. PHD1 in ML was not detected in CON, but increased in CKD5/6 and CKD1/2. PHD2 decreased in MG but increased in ML for CKD5/6 versus CKD1/2 and CON. PHD3 did not differ between groups in MG, but in ML decreased in CKD5/6 versus CON and CKD1/2. There were significant differences for CKD5/6 and CKD1/2 versus CON in: Cr (1.2 ± 0.2; 0.7 ± 0.1 versus 0.8 ± 0.3 mg/dl), Hb (11.4 ± 3.1; 13.7 ± 0.7 versus 14.1 ± 1 g/dl), Hp (1.6 ± 0.6; 1.6 ± 0.6 versus 0.7 ± 0.4 mg/ml), AGEs (5.1 ± 0.6; 4.3 ± 1.2 versus 4.6 ± 0.9 AU), Hcy (7.2 ± 1.2; 5.1 ± 0.5 versus 4.9 ± 0.5 µM), MCP-1 (609 ± 255; 489 ± 265 versus 292 ± 113 pg/ml), respectively. CKD had a different effect on protein expression patterns of HIF-1α, -2α and PHDs depending on muscle type. A HIF-1α to HIF-2α switch in glycolytic MG in CKD5/6 might be a protective mechanism against tissue hypoxia and oxidative stress.

Morphometric analysis of muscle fibre types in rat locomotor and postural skeletal muscles in different stages of chronic kidney disease.

Muscle weakness and progressive loss of skeletal muscle mass are serious complications of chronic kidney disease (CKD). The pathogenesis of this condition is still poorly understood. The study investigated fibre type distribution and diameter in functionally different skeletal muscles: locomotor, gastrocnemius muscle (MG) and postural, longissimus thoracis muscle (ML) together with an evaluation of metabolic disturbances and nutritional parameters of rats with different stages of CKD. Wistar rats were randomized to a sham operation - CON, uninephrectomy - CKD1/2 or subtotal nephrectomy - CKD5/6. After 4 weeks, serum concentration haemoglobin (Hb), haptoglobin (Hp), MCP-1, advanced glycation end products (AGEs), and homocysteine (Hcy) were measured. Muscle specimens were stained for myofibrillary ATPase and NADH-diaphoreses activity according to Ziegan's method. There was a significant increase in the percentage of IID/X with a concomitant decrease of IIB fibres in ML in CKD1/2 vs. CON and CKD5/6. IIB fibre diameters in ML were smaller (53.4±7.3 vs. 58.1±8.1 and 59.8±11.2; p=0.08) for CKD5/6 vs. CKD1/2 and CON, respectively. There were significant differences for CKD5/6 and CKD1/2 vs. CON in: Hb (11.4±3.1; 13.7±0.7 and 14.1±1 g/dl), Hp (1.6±0.6; 1.6±0.6 and 0.7±0.4 mg/ml), AGEs (5.1±0.6; 4.3±1.2 and 4.6±0.9 AU), Hcy (7.2±1.2; 5.1±0.5 and 4.9±0.5 M), MCP-1 (609±255; 489±265 and 292±113 pg/ml), respectively. We concluded that early stages of CKD could induce the process of compensatory fast to slow fibre transformation, while in more advanced CKD this process may be blocked and atrophy of fast-twitch fibres may occur, predominantly in non-locomotor muscles. These disturbances can be secondary to CKD-related metabolic burden and inflammation.

Long graft cold ischemia time is associated with increased arterial stiffness in renal transplant recipients.

BACKGROUND: Increased pulse wave velocity (PWV), an indicator of arterial stiffness, is associated with greater cardiovascular risk among renal transplant recipients. PWV depends on recipient-related factors and, as shown in recent studies, also on donor age. There is a lack of information whether graft-related factors influence arterial function in recipients. Graft cold ischemia time (CIT) significantly influences renal transplant outcomes. It was shown in an experimental model of aortic grafting that increased CIT promoted arteriosclerosis. The aim of the present study was to evaluate the relationship between renal graft CIT and PWV. METHODS: Carotid-femoral PWV were measured in 103 cadaveric kidney recipients of mean age 45 +/- 12 years. We analyzed clinical data of recipient and donor ages, genders, body mass index, blood pressure, CIT, delayed graft function, and type of immunosuppressive therapy to compare patients with CIT < 24 (n = 24) versus CIT > or = 24 hours (n = 79). RESULTS: PWV was lower among patients with shorter CIT (8.3 +/- 1.6 vs 9.2 +/- 2.0 respectively; P < .05). No significant differences were observed between the groups regarding donor and recipient ages, blood pressure, glomerular filtration rate, or immunosuppressive and cardiovascular therapy. A significant positive correlation was noted between PWV and CIT (r = .23; P = .019). Multiple regression analysis demonstrated that recipient age, therapy with cyclosporine, fasting glucose, systolic blood pressure, and CIT were independently associated with PWV. CONCLUSIONS: Long CIT was associated with increased arterial stiffness. Further studies are necessary to understand the cause effect relationship of this finding.

Bone marrow progenitors from animals with chronic renal failure lack capacity of in vitro proliferation.

BACKGROUND: An interesting way to regenerate a kidney is an autologous bone marrow transplantation. The aim of this study was to examine whether chronic kidney disease influenced bone marrow progenitors. METHODS: Wistar male rats included group I (n = 4, chronic kidney disease 1/2, CKD 1/2) that underwent right nephrectomy. In group II (n = 3, chronic kidney disease 5/6, CKD 5/6) underwent removal of the right kidney and approximately one-third of the cortex of the left kidney. Animals in the control group (n = 4) were intact. Bone marrow cells obtained from femurs were separated using a CD34 Micro-Beads magnetic isolation kit. Isolated cells were counted using a trypan blue exclusion test. Numbers of isolated cells were presented as mean values with standard deviation with P < .05 considered significant. CD34(-) cells were cultivated and observed to the passage 6. RESULTS: The CKD rat model was used for in vitro experiments. There were no differences in cell numbers isolated from control rats versus both CKD rats. No differences were observed in CD34(-) cells after separation when compared to controls. Cell morphology was similar in primary CD34(-) cultures during the first days of primary culture. CD34(-) primary cultures established from chronic renal failure rats collapsed within 2 weeks. No differences were found in CD34(+) cell number after isolation when compared with controls. These cells did not form a monolayer. Cells in cultures established from control animals resembled normal fibroblast-like morphology of mesenchymal stem cells during 3 months. CONCLUSIONS: Bone marrow cells from chronic renal failure rats showed no capacity for in vitro proliferation. We speculated that bone marrow cells obtained from renal chronic failure patients may not be useful for autologous cell transplantation.

Effect of sulodexide on albuminuria, NAG excretion and glomerular filtration response to dopamine in diabetic patients.

BACKGROUND: Albuminuria is the best and most readily available marker for glomerular damage and progressive renal function loss in patients with diabetic nephropathy. Recently, administration of the oral glycosaminoglycan sulodexide (a mixture of 80% fast-moving heparin and 20% dermatan sulphate) was shown to effectively decrease albumin excretion rate in diabetics with nephropathy. AIMS: To evaluate whether the hypoalbuminuric effect of sulodexide is associated with improvement of the renal vascular or tubule function. METHODS: Forty-five type 1 diabetic patients, affected by diabetic nephropathy with albuminuria for at least 5 years, were randomly allocated to sulodexide or untreated. Those allocated to sulodexide were given 100 mg of sulodexide daily for 120 days. Renal vascular function (DIR) and N-acetyl-beta-D-glucosaminidase (NAG) excretion were estimated before and at the end of the study, the former in thesulodexide group only. DIR was measured as two Cr(cl) lasting 120 min (before and during 2 mug/kg b.w. i.v. dopamine). RESULTS: The analysis of trends during the study demonstrated a marked reduction of albuminuria in the sulodexide group (from 126.1 +/- 15.41 to 93.6 +/- 13.7 mg/day). DIR rose from 13.2 +/- 2.1% to 15.44 +/- 1.9% (relative increase: +16.9%), and NAG excretion showed a decreasing trend decreased in the sulodexide group only (from 5.1 +/- 0.62 to 4.7 +/- 0.40 U/g(creat)). CONCLUSION: The findings presented in this study indicate for the first time that orally available sulodexide may favorably affect the renal vascular function in type 1 diabetic patients with nephropathy and microalbuminuria. The effect of sulodexide on NAG is strongly influenced by the baseline NAG values, with a significant NAG reduction in the patients with the highest baseline NAG values.

Prevalence of sleep apnea syndrome in hemodialyzed patients with end-stage renal disease.

The majority of hemodialyzed patients suffer from sleep disturbances. In the present study the prevalence of sleep apnea syndrome in hemodialyzed patients with end-stage renal disease (ESRD-patients) was investigated by the survey, Epworth Sleepiness Scale (ESS), and polysomnography (PSG). Sixty-one patients: 24 women and 37 men were involved in the study. All subjects participated in the first part of the study consisting of the survey and ESS. The second and third parts consisted of nighttime PSG, performed the night after hemodialysis (17 patients) and between hemodialyses (11 patients). Eleven out of the 61 patients had the symptoms of sleep apnea and heavy daily sleepiness. Eleven subjects were involved in the double PSG study: after and between hemodialyses. Obstructive sleep apnea was found in 7 of those patients during both nights analyzed. Our results confirm the occurrence of sleep disorders in ESRD-patients. Hemodialysis does not change the prevalence of obstructive sleep apnea in chronic renal disease.

Prevalence of arterial hypertension following kidney transplantation--a multifactorial analysis.

Arterial hypertension is one of the most important factors leading to chronic graft nephropathy and causing cardiovascular complications following renal transplantation. Effective control of the blood pressure seems to be vital for satisfactory long-term graft and patient survival. The objective of the study was to evaluate possible factors associated with persistent or de novo hypertension in patients following allogenic cadaveric kidney transplantation. 325 patients with minimum follow-up period of 6 months and only on cyclosporine-based immunosuppression were analyzed. Two groups of patients were compared: group A included normotensive or "well controlled hypertension" patients while group B consisted of patients with uncontrolled hypertension. Results revealed that patients with ill-controlled or uncontrolled hypertension received kidneys from older donors, mean creatinine level within 6 months post-transplant was significantly higher and hypertension was associated with higher rate of urinary tract infections in this group.

Function, structure, and volume of thyroid gland following allogenic kidney transplantation.

The aim of the study was to assess the structure, volume, and function of the thyroid gland following kidney transplantation compared with those features of long-term transplant recipients as well as patients with normal native kidney function. Study group A consisted of 30 patients undergoing allogenic kidney transplantation, study group B included 30 long-term kidney transplant recipients who displayed stable renal function at 4 to 11 years following transplantation; control group C comprised 38 patients who were diagnosed or treated for reasons other than thyroid or renal insufficiency. Mean FT-3 concentrations in group A decreased from 2.19 pg/mL preoperatively to 1.52 pg/mL on the first posttransplantation day, returning to the preoperative values (2.06 pg/mL) at 30 days postoperatively. After 6 months the concentrations of thyroid hormones were similar to those among the long-term posttransplantation group (group B), although still lower than those in the control group. Mean thyroid volume in dialyzed patients was 17.10 mL; in the long-term group, 17.60 mL; and in the control group, 15.82 mL between groups that were not statistically significant. Abnormal structure of the thyroid gland was observed in 63% of group A (n = 19), 70% of group B (n = 21), and 29% of the control group. Significantly more abnormal thyroid gland structures were observed among dialyzed or transplanted patients. The thyroid volume was similar in all groups. Significant transient decrease in thyroid stimulating hormone (TSH) and free triidothyronine (FT-3) was not free thyroxine (FT-4) concentrations following kidney transplantation. Occasionally, increase accompanied by a change in FT-4 and TSH concentrations were observed, and antithyroid antibodies were detected only sporadically.

Parathormon, calcium, phosphorus, and left ventricular structure and function in normotensive hemodialysis patients.

Clinical and experimental data suggest that Parathormon (PTH), calcium, and phosphorus participate in left ventricular hypertrophy (LVH) and affect myocardial contractility in end-stage renal disease. Cellular calcium overload and interstitial fibrosis induced by PTH may lead to impairment of left ventricular diastolic function. Hyperphosphatemia is an independent risk of cardiovascular mortality in dialysis patients. The aim of the study was to estimate the influence of PTH and calcium-phosphorus metabolism on left ventricular structure and function in hemodialysis patients, without hypertension and antihypertensive drug therapy (SBP = 126.2 +/- 11.1 DBP = 75.8 +/- 6.5 mmHg). Echocardiographic findings in a group of 22 normotensive HD patients had been compared to 43 hypertensive HD patients. Relationships between PTH, calcium-phosphorus metabolism and echocardiography in normotensive group were then evaluated. Left ventricular mass index (LVMI) was lower in normotensive patients: 128.3 +/- 46.2 versus 165.8 +/- 46.7 (p < 0.01). The prevalence of LVH was 55% in normotensive HD patients compared to 86% in hypertensive group (p < 0.01). In normotensive group we found correlation between PTH and LVMI (r = 0.44; p < 0.05). There were also significant relationships between calcium and posterior wall thickness (r = -0.44; p < 0.05), phosphorus and LVMI (r = 0.47; p < 0.05). A significant correlation was observed between both phosphorus, calcium x phosphorus product and E/A ratio: r = -0.47 and r = -0.43, respectively (p < 0.05 both). Disturbances of calcium-phosphorus metabolism and secondary hyperparathyroidism contributes to left ventricular hypertrophy, and impaired left ventricular diastolic function in normotensive hemodialysis patients.

Selenium and glutathione levels, and glutathione peroxidase activities in blood components of uremic patients on hemodialysis supplemented with selenium and treated with erythropoietin.

Patients with chronic renal failure (CRF) often have reduced concentrations of selenium (Se) and lowered activities of glutathione peroxidase (GSH-Px) in blood components. The kidney is a major source of plasma GSH-Px. We measured Se and glutathione levels in blood components and red cell and plasma GSH-Px activities in 58 uremic patients on regular (3 times a week) hemodialysis (HD). The dialyzed patients were divided in 4 subgroups and were supplemented for 3 months with: 1) placebo (bakers yeast), 2) erythropoietin (EPO; 3 times a week with 2,000 U after each HD session), 3) Se-rich yeast (300 microg 3 times a week after each HD), and 4) Se-rich yeast plus EPO in doses as above. The results were compared with those for 25 healthy subjects. The Se concentrations and GSH-Px activities in the blood components of dialyzed uremic patients were significantly lower compared with the control group. Treatment of the HD patients with placebo and EPO only did not change the parameters studied. The treatment with Se as well as with Se and EPO caused an increase in Se levels and red cell GSH-Px activity. Plasma GSH-Px activity, however, increased only slowly or did not change after treatment with Se and with Se plus EPO. In the group treated with Se plus EPO the element concentration in blood components was higher compared with the group supplemented with Se alone. The weak or absence of response in plasma GSH-Px activity to Se supply indicates that the impaired kidney of uremic HD patients has reduced possibilities to synthesize this enzyme.

Selenium, glutathione peroxidases, and some other antioxidant parameters in blood of patients with chronic renal failure.

In the present study several parameters associated with oxidative stress were examined in the blood of 25 chronic renal failure (CRF) patients and the results were compared with 18 healthy subjects. Mean creatinine concentration in patients was 1,216 +/- 292 micromol/l. Selenium (Se) concentration in red cells, whole blood and in plasma of CRF patients (106 +/- 32.5, 59.0 +/- 16.7 and 42.4 +/- 13.8 ng/ml, respectively) was significantly (0.0001 < P 0.01) lower (by 20-42%) compared with the controls. Red cell and plasma glutathione peroxidase (GSH-Px) activities (16.6 +/- 3.4 U/g Hb and 93.7 +/- 32.9 U/l plasma) were lower by 12 and 53% (P < 0.05 and < 0.0001, respectively) in patients than in healthy subjects. GSH concentration in red cells of patients (2.81 +/- 0.45 mmol/l) was significantly (P < 0.001) higher (by 20%) than in control group. Malonyldialdehyde (MDA) concentration (expressed as thiobarbituric acid-reactive substances) in red cells of patients (725 +/- 155 nmol/g Hb) was significantly (P < 0.001) higher (by 28%) than in control group. No significant difference was observed in the activity of superoxide dismutase in pLasma between the two groups. In conclusion, our results confirm that the aLterations in Se levels in blood components and in GSH-Px activity in plasma show that the kidney plays an important role in Se homeostasis and in plasma GSH-Px synthesis.

[Does any relationship exist between metabolic disturbances and some markers of renal damage in patients with untreated essential hypertension?]. / Czy istnieja zaleznosci pomiedzy niektórymi zaburzeniami metabolicznymi a wybranymi wskaznikami uszkodzenia nerek u chorych z nieleczonym pierwotnym nadcisnieniem tetniczym?

The essential arterial hypertension is the second (after diabetes mellitus) cause of chronic renal failure which means a great social and economic burden to the society. It is well known that hypertension is a metabolic syndrome resulting in tissue injury. We tried to investigate the possible influence of some metabolic disturbances on renal function in nontreated essential hypertension. We have compared 25 patients with nontreated essential hypertension (11 women, 14 men) with 14 healthy volunteers (7 women, 7 men) matched for age. The patients' group was characterized by significantly higher urine excretion of NAG (N-acetyl-beta-D-glucosaminidase) (2.75 +/- 1.69 vs 1.82 +/- 1.46 p < 0.05) and a tendency to significantly higher urine fractional sodium excretion without significant difference in albumin excretion. These findings suggest that the tubular damage is present. We noticed the negative linear correlation between mean arterial pressure and (MAP) and NAG urine excretion in the group of hypertensive patients which may reflect the renal ischemia in tubulo-interstitial pathology. Our data suggests that in nontreated arterial hypertension the renal blood flow disturbances are the important cause of the deterioration of tubular function (which are earlier to glomerular damage).

[Cyclophosphamide pulse therapy in patients with primary glomerulonephritis]. / Leczenie pulsami cyklofosfamidu pacjentów z pierwotnymi glomerulopatiami.

UNLABELLED: Cyclophosphamide is a cytostatic drug, widely used in therapy of secondary glomerulonephritis. Because pulse therapy bears less side effects than oral one we aimed to follow the cyclophosphamide effect on the course of patients with primary glomerulonephritis. We observed 20 pts (7 women and 13 men), mean age 33 +/- 10.0 yrs, age range 18-50 yrs with primary glomerulonephritis and proteinuria more than 3.5 g. 12 patients also had erythro-cyturia. In all pts kidney biopsy was performed, but in one woman the biopsy was not diagnostic. Renal biopsy revealed: FSG in 2 pts, membranous glomerulonephritis in 2 pts, in 9 pts mesangial proliferative changes and in 6--mesangiocapillary lesions. In 5 pts renal failure was observed. Cyclophosphamide was administered i.v. in the dose 0.75 g/m2 b.s., no more than 1.0 g per dose, in renal failure 0.5 g/m2. During the first six months patients received cyclophosphamide every month and then every three months. Before cyclophosphamide pulse therapy all patients were pretreated with steroids, 3 pulses of 1.0 g Methylprednisolone and then oral prednisone in the dose 20 mg/m2 body surface. RESULTS: In 3 patients we obtained remission of proteinuria, in 11 patients decrease of proteinuria but 6 patients didn't answer to the introduced treatment. In whole group of examined patients we obtained the statistically significant decrease of proteinuria from 12.2 +/- 10.5 to 5.3 +/- 5.2 g (p < 0.05) after the treatment. The creatinine clearance did not change in the time of the treatment and any special complications during the treatment were observed. We suggest that cyclophosphamide pulse therapy could be an effective treatment in pts with primary glomerulonephritis. Our results showed that the answer of proposed treatment was independent of the type to the changes found in kidney biopsy.

The effect of nitrendipine on renal haemodynamics and tubular reabsorption and its neural control in anaesthetised rats with chronic renal failure.

This study examined the influence of a calcium channel antagonist, nitrendipine, on blood pressure and kidney function in a rat model of chronic renal failure. Additionally, the effects of low frequency renal nerve stimulation were studied in the presence and absence of nitrendipine. Male Wistar rats were fed a diet high in adenine for 4 weeks and then acutely anaesthetised and prepared for renal functional measurements. Blood pressure was elevated but renal blood flow and glomerular filtration rate were reduced, between 30 to 50%, urine flow and absolute sodium excretion were lower and fractional sodium excretion was two to three times higher than in normal rats. Nitrendipine (0.25 microg/kg/min i.v.) decreased blood pressure at 114+/-7 mm Hg, by 11% (P<0.05), increased left renal blood flow, at 1.3+/-0.2 ml/min(-1) g(-1), by 16% (P<0.01), and urine flow, absolute and fractional sodium excretions, by between 50-83% (all P<0.05). Renal nerves stimulation (0.7-1.3 Hz, 15V, 0.2 ms) decreased (P<0.02) left renal blood flow by 10% but had no effect on excretory variables, irrespective of nitrendipine administration. These results show that in renal failure rats the vascular and tubular responses to nitrendipine are preserved. However, the neural regulation of tubular reabsorption is abolished in this experimental model, irrespective of nitrendipine administration.

Hypertensive nephropathy - an increasing clinical problem.

Arterial hypertension-related renal damage is an increasingly common problem recently, because approximately 25% of patients currently treated with dialysis were hypertensive before renal replacement therapy was started. Hypertension is also known as a metabolic disease, while carbohydrate, purine and lipid disturbances are the features of this syndrome. On the other hand, the progression of renal disease depends on the extent of tubulointerstitial injury. For this reason, we undertook a study to evaluate the relationship between excretion of the markers of tubular damage (NAG) and some parameters of carbohydrate, purine and lipid metabolism in untreated essential hypertension. Both healthy volunteers (n = 15) aged 32. 6+/-7.8 and essential hypertensives (n = 25) aged 37.24+/-11.39 underwent the same tests. These tests were performed at 2-day intervals: intravenous glucose tolerance test with 0.5 g/kg b.w. as 40% glucose solution and oral fructose load test with 1.0 g/kg b.w. Area under glucose curve (GA) and serum uric acid post-fructose (PUAA) were calculated. Fasting: insulin, total cholesterol and LDL, triglycerides, free fatty acids (FFA) and urine excretion of NAG, albumin were determined. Glomerular filtration rate was estimated as creatinine clearance. Hypertensives showed statistically higher BMI (p<0.007), NAG (p<0.02), total cholesterol (p<0.01), LDL (p<0.007), FFA (p<0.007), insulin (p<0.01), PGA (p<0.01) and PUAA (p<0.03). NAG excretion correlated positively with WHR (r = 0.40), MAP (r = 0.47) and PUAA (r = 0.47) in hypertensives only. We presume that tubular injury at an early stage of renal damage in patients with essential hypertension could be a part of metabolic syndrome X.