Vitamin D status in apparently healthy medication-free Slovaks: Association to blood pressure, body mass index, self-reported smoking status and physical activity.

BACKGROUND: Vitamin D plays a role in protecting against chronic degenerative diseases. Slovak adults present one of the highest cardiovascular mortality rates among 27 EU countries. OBJECTIVES: We asked whether the 25(OH)D3 status in apparently healthy medication-free Slovaks deteriorates upon ageing, and in the presence of cardiometabolic risk factors. METHODS: We studied the impact of blood pressure, overweight/obesity, smoking, and physical activity on 25(OH)D3 levels determined using RIA method in 578 (5-81 years old) subjects. RESULTS: The average level of 25(OH)D3 was 36±17 ng/ml. A proportion of 15 % of participants were 25(OH)D3­deficient (≤20 ng/ml), 26 % presented insufficient (20-to-30 ng/ml), and 59 % satisfactory (> 30 ng/ml) levels. Neither mean 25(OH)D3 levels, nor the prevalence of hypovitaminosis D showed age dependence. Physically active normotensive non-smokers presented the highest (41±19 ng/ml), and their smoking counterparts with elevated BP the lowest 25(OH)D3 levels (30±12 ng/ml). CONCLUSION: In apparently healthy medication-free Slovaks the prevalence of hypovitaminosis D is high. Vitamin D status does not deteriorate in course of healthy ageing. Physical activity, normotension, and non-smoking status are associated with favorable vitamin D status while low 25(OH)D3 levels are associated with multiple cardiometabolic risk factors. Further studies in subjects at high cardiovascular risk are needed to elucidate the potential association of hypovitaminosis D with high cardiovascular mortality in Slovak adults (Tab. 1, Fig. 4, Ref. 42).

Insulin resistance and vitamin D deficiency in patients with chronic kidney disease stage 2-3.

Vitamin D status and the relationship between serum 25(OH) vitamin D concentrations and the components of insulin resistance were examined in 120 patients with chronic kidney disease stage 2 and 3. Insulin sensitivity/resistance was calculated by the quantitative insulin sensitivity check index (QUICKI). In this analysis, the prevalence of insulin resistance was 42 %. Only 17 % of patients had serum 25(OH) vitamin D concentration in the recommended range (>/=30 ng/ml), 42 % suffered from vitamin D insufficiency and 41 % had moderate vitamin D deficiency. Insulin resistance significantly correlated with serum 25(OH)D and 1,25(OH)(2)D concentrations, renal function and protein excretion rate. Our results support the increasing evidence that vitamin D deficiency may be one of the factors participating in the development of insulin resistance already in the early stages of chronic kidney disease.

A critical gap between recommended and achieved LDL-cholesterol levels. Results of statin therapy in Slovakia.

BACKGROUND: The achievement of low density lipoprotein cholesterol (LDL-C) target levels, as recommended by the evidence-based international guidelines, represents the crucial prerequisite for maximal cardiovascular risk reduction in patients with dyslipidemia. OBJECTIVES: The efficacy of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) monotherapy administered in ambulatory practice was evaluated in cooperation with 387 ambulatory specialists in Slovakia. PATIENTS AND METHODS: Data of 5640 adult patients (21-88 years, 42.8% males) with low (7.4%), high (16.8%), and very high cardiovascular risks (75.7%), treated at least for 12 weeks with a stable statin dose were evaluated regarding the achievement of target LDL-C levels (< 4.2 mmol/L in low risk patients, < 3.4 mmol/L in high risk patients and < 2.6 mmol/L in very high risk patients). RESULTS: The target levels were achieved in 74% of low risk patients (mean level of LDL-C 3.55 mmol/L), in 37.9% of high risk patients (3.7 mmol/L), and in 12.4% of very high risk patients (3.64 mmol/L). The proportion of received statins and their average daily doses were as follows: 64.3% simvastatin (22.5 mg); 21.3% atorvastatin (15.6 mg); 12.2% fluvastatin (69.7 mg); 1.5% pravastatin (19.4 mg), and 0.7% lovastatin (25.4 mg). CONCLUSION: Statin therapy does not correspond with the current guidelines in common clinical practice. In patients with treated hypercholesterolemia the use of low doses of statins without titration seems to be the main reason of poor achieving of LDL-C target levels representing the critical values for reducing the atherosclerosis and its life-threatening complications (Tab. 3, Fig. 1, Ref 19). Full Text (Free, PDF) www.bmj.sk.

Mitochondria and mitochondrial nitric oxide synthase alterations participate in energetical dysbalance, aging and age-related diseases.

Nitric oxide (NO) is a unique mediator of cellular regulations synthesized by nitric oxide synthases (NOS) present in cytoplasm of various cells. An additional Ca-dependent mitochondrial NOS (mtNOS) detected just recently synthesizes also NO inhibiting oxidative phosphorylation, i.e. mitochondrial energy producing metabolic process and protects mitochondria from oxygen radicals. Mitochondrial membrane possesses electrogenic uniporter transporting Ca into mitochondria (stimulation of mtNOS), while Na+/Ca2+ exchanger removes Ca from mitochondria. Mitochondrial disorders with low mtNOS activity participate in accelerated aging and age-related diseases. The direct NO balance determination is outside of the standard clinical facilities; Indirect alternatives, such as insulin resistance determination are accessible. Pharmacotherapy exploits effective therapeutic and preventive measures (NO donors, ACEI inhibitors, etc.) and pharmaceutical approach (development of mitochondriotropic drugs). We suggest, that mitochondrial disorders participate in aging and age related diseases and propose that the early diagnostics, preventive and therapeutic measures could prevent and even correct at least partially the development of age-related diseases (Tab. 4, Ref. 81).

Calcitriol load test in postmenopausal osteoporosis: a pilot study.

BACKGROUND: Calcium and vitamin D balance is of critical importance in both, prevention and treatment of osteoporosis. The evaluation of this balance is difficult under steady state conditions, therefore the effect of a single oral calcitriol load in postmenopausal women with osteopenia/osteoporosis was used. METHODS: Mineral and hormone concentrations were determined under basal conditions and after the administration of a single 0.5 microg calcitriol dose (Rocaltrol, Roche). RESULTS: Single oral calcitriol dose was administered to 36 postmenopausal women. Increased calciuria (p < 0.001) and calcium fractional excretion (p < 0.001) 24 hours after drug administration indicated kidney participation in calcium homeostasis. Urinary calcium excretion after the calcitriol load correlated with basal urinary calcium excretion (r = 0.772; p < 0.001). On the basis of calciuric response, women could be separated to responders and non-responders; in responders, increase in calciuria was >1.0 mmol/d, while in non-responders < 1.0 mmol/d (p < 0.001). Neither plasma calcium nor plasma 25-hydroxycholecalciferol concentrations increased after the calcitriol load. Both basal (r = -0.361; p < 0.03) and calcitriol stimulated urinary calcium excretion correlated inversely with age (r = -0.425; p < 0.01). No significant changes in measured mineral and hormone parameters were found in women with osteopenia in comparison to women with osteoporosis, with the exception of plasma intact parathormone concentration, which was significantly higher in osteoporotic women (p < 0.05) and significantly decreased (p < 0.001) after the calcitriol load. CONCLUSION: Postmenopausal women suffered from calcium and vitamin D imbalance which could be elucidated by a simple calcitriol test. The reference range, significance and differentiation from other abnormalities are to be defined in an extensive study. (Tab. 4, Ref. 19.).

[Intensive vitamin D supplementation in the treatment of osteoporosis]. / Intenzifikovaná suplementácia vitamínom D v liecbe osteoporózy.

Vitamin D deficiency is not possible to correct with the nutritional vitamin D doses in postmenopausal women with decreased bone mineral density. The aim of study was to evaluated the effectivity and safety of 15,000 IU/week vitamin D administrated in 52 postmenopausal women with osteopenia or osteoporosis. Patients were divided into two groups. Treated group was supplemented by calcium 0.5 g/d and 25-hydroxycholecalciferol 15,000 IU/week and control group was supplemented by calcium and placebo for two months. Plasma calcium concentration did not change in the vitamin D treated group while it decreased (p < 0.001) in the control group. Neither calciuria nor fractional excretion of calcium changed during the treatment period. Plasma inorganic phosphate concentration did not change in any group, but urinary inorganic phosphate excretion increased in the vitamin D treated group (p < 0.001). The starting 25-hydroxycholecalciferol plasma concentrations were almost at the deficiency range in both groups. The 25-hydroxycholecalciferol plasma concentration increased substantially (p < 0.001) in the treated group, but it remained at the starting level in control group during the treatment period. Similar plasma concentration increase (p < 0.001) was apparent also in 1.25-dihydroxycholecalciferol. Plasma intact parathormone concentration did not change in the vitamin D treated patients, while it increased (p < 0.01) in the control group. None of the vitamin D treated women suffered from hypercalcemia and mild hypercalciuria was observed in one patient. In conclusion, the study presents an evidence on the effectiveness and safety of 15,000 IU/week 25-hydroxycholecalciferol dosage schedule.

Insulin resistance in kidney disease patients with mild to moderate kidney disease.

BACKGROUND: Insulin resistance is a very early sign of atherosclerosis and an increased risk of cardiovascular morbidity and mortality. Insulin resistance detection by the fasting plasma insulin and glucose determination enables early detection, follow-up, treatment and the search for accelerating factors in kidney disease patients threatened by atherosclerosis. PATIENTS AND METHODS: Insulin resistance was evaluated by the Quantitative Insulin Sensitivity Check Index from fasting glucose and insulin plasma concentrations in 66 kidney disease patients with a mild to moderate decrease in kidney function. RESULTS: Forty patients were insulin sensitive and 26 suffered from insulin resistance. These groups of patients did not differ significantly in age, gender, clearance of creatinine and cholesterol concentrations. However, patients with insulin resistance suffered from increased BMI (p < 0.001), fasting plasma glucose (p < 0.01), insulin (p < 0.001) and triglyceride (p < 0.01) concentrations. Insulin resistance correlated with BMI (r = -0.417, p < 0.001) and with plasma triglycerides concentration (r = -0.307, p < 0.01). The absent relationship between insulin resistance and age (r = -0.154, NS) or creatinine clearance (r = -0.061, NS) suggests the need for screening of insulin resistance even in young patients with mild kidney function reduction. CONCLUSION: A considerable number of renal patients in the early stages of kidney function reduction suffers from insulin resistance. They need to improve their life style and take medication (i.e. antihypertensive drugs) improving insulin sensitivity and to omit medications which harm it. (Fig. 2, Tab. 1, Ref. 20.)

Kidney function and age related mineral imbalance in postmenopausal women with osteopenia/osteoporosis.

BACKGROUND: Negative mineral balance in postmenopausal women appears to be an important risk factor for osteoporosis and subsequent bone fractures. Its pathogenesis has not been elucidated. OBJECTIVES: To elucidate the participation of the kidney and ageing on mineral balance in postmenopausal women. METHODS: 36 postmenopausal women with osteopenia or osteoporosis, aged 46-75 years were evaluated by determination of mineral balance, kidney functions, 25(OH)-cholecalciferol [25(OH)D], 1,25(OH)2-cholecalciferol [1,25(OH)2D] and intact parathormone plasma levels. RESULTS: Plasma calcium (Ca) concentrations were low and they did not decrease further with ageing. Urinary Ca excretion decreased (r = -0.425, p < 0.01) with age without changes in the fractional excretion of Ca. A similar decrease of urinary excretion was found in the urinary excretion of phosphorus (Pi) (r = -0.335; p < 0.03) and magnesium (Mg) (r = -0.355; p < 0.03). All patients' kidney functions were in the age-related reference range. Plasma 25(OH)D concentrations were in the range of moderate to severe deficiency, related inversely to age (r = -0.357; p < 0.03) and Ca urinary excretion (r = 0.343; p < 0.04) and to plasma creatinine concentration (r = 0.381; p < 0.02). Plasma 1,25(OH)2D concentrations were also low, they did not change with age and were highly correlated with Ca urinary excretion (r = 0.458; p < 0.005). The intact parathormone (iPTH) plasma concentrations were in the reference range, without any changes during aging. CONCLUSIONS: Pi, Mg and dominantly Ca imbalance in postmenopausal women with osteopenia or osteoporosis accentuates with age and besides their insufficient intake the vitamin D deficiency takes part. These data support the need for increased supplementation of Ca and vitamin D with increasing age. (Tab. 3, Fig. 4, Ref. 18.).

Serum ex vivo lipoprotein oxidizability in patients with ischemic heart disease supplemented with vitamin E.

The decreased oxidizability of plasma lipoproteins is related to the increased vitamin E intake and its association with a relatively lower incidence of coronary heart disease has been proposed. We investigated the effect of the in vivo vitamin E supplementation on the oxidizability of serum lipids in patients with ischemic heart disease and a moderate hypercholesterolemia. Thirty-two patients (16 males and 16 postmenopausal women) participated in this placebo-controlled, randomized trial. They were treated with 400 mg vitamin E/day for 6 weeks. The copper-induced serum lipid oxidizability ex vivo was assessed by measuring conjugated diene formation at 245 nm. We also measured vitamin E, malondialdehyde (MDA) and uric acid concentrations in the plasma. Because of observed significant differences in parameters of serum lipid oxidizability (lag time and maximal rate of oxidation), plasma alpha-tocopherol and MDA levels between male patients and postmenopausal women supplemented with vitamin E, the results were compared between both genders. Six weeks of vitamin E supplementation significantly increased plasma vitamin E levels (by 87 %) in male patients but in postmenopausal women only by 34 %. Concomitantly with increased plasma levels of vitamin E the decrease in plasma MDA levels was observed in male patients (decrease by 20 %; p=0.008), but in postmenopausal women the decrease did not attain statistical significance. Plasma uric acid levels were not apparently changed in placebo or vitamin E supplemented groups of patients. The changes in ex vivo serum lipid oxidizability after vitamin E, supplementation have shown a significantly prolonged lag time (by 11 %; p=0.048) and lowered rate of lipid oxidation (by 21 %; p=0.004) in male patients in comparison with postmenopausal women. Linear regression analysis revealed a significant correlation between plasma vitamin E levels and the lag time (r=0.77; p=0.03) and the maximal rate of serum lipid oxidation (r=-0.70; p=0.05) in male patients. However, in postmenopausal women the correlations were not significant. We conclude that 400 mg vitamin E/day supplementation in patients with ischemic heart disease and a moderate hypercholesterolemia influenced favorably ex vivo serum lipid oxidation of male patients when compared with postmenopausal women. The observed differences between both genders could be useful in the selection of the effective vitamin E doses in the prevention of coronary heart disease.

Ciprofibrate increases plasma concentration of platelet-derived growth factor AB in patients with advanced atherosclerosis and hyperlipidemia independently of its hypolipidemic effects.

Fibrates, besides their hypolipidemic action, share alternative effects, such as decreased plasma fibrinogen and uric acid levels. Because of their complex action, additional effects have been investigated. A group of 23 patients with clinical signs of atherosclerosis and hyperlipoproteinemia was randomly allocated after a 1-month washout period and treated with either 100 mg/d of ciprofibrate or 100 mg/d of aspirin for 2 months. Patients were then treated with a combination of these two agents for the next 2 months. Ciprofibrate decreased plasma concentrations of triglycerides (-29%) and very-low-density lipoprotein cholesterol (-27%) in monotherapy and a larger reduction was observed if ciprofibrate was added to the aspirin therapy: triglycerides (-39%), very-low-density lipoprotein cholesterol (-33%), total cholesterol (-18%), low-density lipoprotein cholesterol (-17%), and increased high-density lipoprotein cholesterol (+36%). Ciprofibrate increased plasma levels of platelet-derived growth factor (PDGF) AB in both monotherapy patients (+162.9 pg/ml, +297%) and in aspirin-pretreated patients (+129.8 pg/ml, +134%); the increase of PDGF AB platelet store was significant only in aspirin-pretreated patients (+11.1 ng/ml, +51%). Aspirin in monotherapy did not modulate either plasma or platelet store of PDGF AB. Ciprofibrate did not inhibit thromboxane B 2 synthesis in platelets. Aspirin did not influence plasma thromboxane B 2 concentration at all, whereas it decreased thromboxane B 2 platelet production markedly in monotherapy (-85%) and in combination with ciprofibrate (-91%). Ciprofibrate increases PDGF AB content, which is amplified by aspirin pretreatment without correlation with its hypolipidemic action. The increase of PDGF production is suggested to participate in plaque stabilization.

Circulating advanced glycation end product levels in rats rapidly increase with acute renal failure.

BACKGROUND: Advanced glycation end products (AGEs) are formed on proteins and peptides slowly during aging, and they accumulate in circulation and tissues in diabetes and chronic renal failure. Except for nonenzymatic glycation, enhanced oxidative/carbonyl stress is supposed to participate in their formation. The kidney plays a key role in disposal of AGEs, particularly AGE-peptides. We assumed that even a short time combination of enhanced oxidative/carbonyl stress and a lack of renal function should result in elevation of circulating AGE levels. METHOD: To verify this hypothesis, two models of acute renal failure in rats, bilateral nephrectomy and bilateral ureteral ligation, were employed, and the data were compared with those of sham-operated animals. RESULTS: AGE levels determined fluorimetrically or as carboxymethyllysine concentration rose by a factor of three within 48 hours. Enhanced levels of malondialdehyde and lipofuscin pointed to an enhanced oxidative/carbonyl stress. Activity of antioxidant enzymes such as superoxide dismutase and glutathione peroxidase were not compromised, or were even elevated, respectively. Total antioxidant status increased, probably as a consequence of an accumulation of indols and benzoic acid derivatives, uremic toxins with scavenging capacities, as shown for hippurate. CONCLUSIONS: Evidence was given that circulating AGEs in the model of acute renal failure in rats undergo a substantial rise within a short time period. A source of increased AGEs is not clear, since except for the lack of the kidney function, accelerated synthesis of AGEs under enhanced oxidative/carbonyl stress as well as liberation of AGEs from tissues due to protein catabolism might be anticipated. If AGEs accumulate in acute renal failure in humans, their contribution to acute toxicity, or of the development of the complications later, might be of importance.

DNA damage of lymphocytes in experimental chronic renal failure: beneficial effects of losartan.

BACKGROUND: Kidney diseases are associated with the accumulation of various uremic toxins increasing the oxygen free radical (OFR) activity with a number of serious consequences. One of them could be the impairment of DNA stability with the increased formation of DNA breaks. METHODS: The study was performed in 4/6 kidney ablation rat nephropathy lasting for three months. The results of sham-operated (Sham), remnant kidney (Nx), and Nx treated by losartan (NxL) were compared. RESULTS: Nx significantly increased blood pressure, plasma creatinine, urea, hippurate, malondialdehyde (MDA), lipofuscin (LF), and the number of DNA breaks of lymphocytes. Losartan decreased the rise of blood pressure and inhibited the rise of creatinine plasma concentration but not of other variables, while it markedly inhibited the number of DNA breaks (Sham 15.9 +/- 1.1, Nx 54.5 +/- 1.7, P < 0.001; Nx/Sham, NxL 23.3 +/- 2.6 P < 0.001, NxL/Sham and P < 0.001 NxL/Nx). CONCLUSIONS: The 4/6 kidney ablation nephropathy increases the susceptibility of lymphocyte DNA to breaks, and losartan inhibits the number of breaks by a mechanism independent on glomerular filtration, accumulation of MDA or LF (markers of oxidative stress), and hippurate (marker of the accumulation of middle molecular substances). An independent mechanism, probably the interference with proliferation, is suggested.

Hippurate participates in the correction of metabolic acidosis.

Hippurate (Hip), an endogenous conjugate, belongs to the group of uremic toxins. Hip stimulates P-independent glutaminase (PIG) localized at the proximal luminal membrane, desamidating glutamine with the formation of ammonia, a dominant and adaptive elimination product of H+. This appears to be important because metabolic acidosis (MAC) does not stimulate PIG. Moreover, Hip inhibits ammonia production by P-dependent mitochondrial glutaminase (PDG) that is primarily stimulated by MAC. By this mechanism, it shifts the ammonia production from mitochondria to proximal tubular lumen. MAC stimulates Hip synthesis in the liver and kidney and increases Hip plasma concentration and even fractional excretion by the kidney, which creates an effective regulatory loop of ammoniagenesis. Thus, it appears that Hip by its participation in the correction of MAC possesses the modulatory function.

Enalapril inhibits growth and proliferation of various tissues in rat normotensive four-sixths kidney ablation nephropathy.

Most experimental studies on kidney proliferation and its attenuation by angiotensin-converting enzyme inhibitors were performed in the rat hypertensive remnant-kidney model with a five-sixths kidney ablation. The developing hypertension rose the objections on the hypertension and its treatment in control rats. A normotensive four-sixths remnant-kidney model (Nx) was elaborated, compared with sham-operated (S) animals, and a subantihypertensive dosage of enalapril (E) was administered for 4 weeks of intensive kidney tissue proliferation (NxE). The pair-fed groups increased their body weight and blood pressure comparably. Moderately increased plasma creatinine and urea concentrations were found in the Nx group; markedly increased levels in the NxE group. Nx increased proteinuria, and E attenuated its increase. The remnant-kidney weight (Nx 912+/-31 vs. S 1,111+/-36 mg, p<0.001) was still lower, but collagen (Col; Nx 164+/-2 vs. S 148+/-5 mg/100 g, p<0.05) and tubular protein/DNA ratio (Nx 26.2+/-10.8 vs. S 9.8+/-1. 0, p<0.05) increased markedly in the Nx group; E attenuated the kidney growth (NxE 719+/-31 vs. Nx 912+/-31 mg, p<0.01) and decreased the tubular protein/DNA ratio remarkably (NxE 15.3+/-10.5 vs. Nx 26.2 +/-10.8), but E did not inhibit the Col accumulation. Nx decreased the heart (Nx 1,002+/-28 vs. S 1,130+/-41 mg, p<0.05), but not liver weights and did not influence Col concentrations or protein/DNA ratios either in heart or liver. E potentiated the weight decrease of heart (NxE 862+/-20 vs. Nx 1,002+/-28 mg, p<0.01) and liver (NxE 8.3+/-0.44 vs. Nx 10.3+/-0.51 g, p<0.001) and Col accumulation (heart: NxE 113+/-6 vs. Nx 92+/-5 mg/100 g, p<0.01; liver: NxE 134+/-8 vs. Nx 101+/-9 mg/100 g, p<0.01). Nx did not influence either the soleus muscle weight or its Col accumulation, but it increased its protein/DNA ratio (Nx 66.3+/-4.7 vs. S 35.5+/-2. 8 mg/100 g, p<0.01). E increased the Col concentration in muscle (NxE 141+/-3 vs. Nx 110+/-5 mg/100 g, p<0.01), while it attenuated the increase in protein/DNA ratio (NxE 36.6+/-2.1 vs. Nx 66.3+/-4.7, p<0.01). In conclusion, kidney ablation nephropathy stimulating kidney proliferation evokes only minor changes in heart, liver and striated muscle. E inhibits markedly the kidney proliferation and functional recovery, but does not prevent the Col accumulation. E evokes antiproliferative changes also in the heart and surprisingly even in the liver. Alterations in soleus muscle are only borderline.

31P NMR investigation of free intracellular magnesium, pH and energy balance in striated muscle of patients with kidney disease: relation to insulin resistance.

BACKGROUND: High prevalence (48%) of insulin resistance (IR) in patients with mild to moderate kidney function reduction, and the potential pathogenetic role of magnesium (Mg) deficiency in IR prompted us to study skeletal muscle free Mg (fMg) concentration in patients with impaired kidney function. METHODS: fMg concentration, intracellular pH (pHi) and parameters of energy balance were determined employing 31P NMR spectroscopy in the calf muscle of the dominant leg of 18 healthy controls (C) and 22 patients (P) with decreased kidney function. 10 patients suffered from insulin resistance (IR). RESULTS: No difference in fMg concentration in skeletal muscle was observed (C: 0.929 +/- 0.075; P: 0.948 +/- 0.062 mmol/l; x +/- SEM). In patients a slight shift of pHi towards acidic values was found (C: 7.036 +/- 0.0.004; P: 7.013 +/- 0.004; p < 0.004), which was even more expressed in IR patients (7.008 +/- 0.005). Serum creatinine levels and creatinine clearance correlated with pHi in the patient's group. Adenosintriphosphate (ATP) to inorganic phosphate (Pi) ratio in skeletal muscle was lower, phosphocreatine (Pcr)/ATP ratio was higher, while that of Pcr/Pi showed only a trend towards an increase in the patient's group. CONCLUSION: In patients with reduction of kidney function IR does not associate with a change in skeletal muscle free magnesium concentration, or deficiency in macroergic phosphate levels. Shift in intracellular pH towards acidic values may participate in IR. Decreased activity of Na+/H+ antiporter is suggested. (Fig. 5, Tab. 2, Ref. 22.)

[The effect of monotherapy with ciprofibrate and in combination with acetylsalicylic acid on the spectrum of lipids, thromboxane and fibrinogen in patients with atherosclerosis and hyperlipoproteinemia]. / Vplyv ciprofibrátu v monoterapii a v kombinácii s acetylosalicylovou kyselinou na spektrum lipidov, tromboxán a fibrinogén u pacientov s manifestnou aterosklerózou a hyperlipoproteinémiou.

Ciprofibrate is one of the basic drugs used to lower risk values of lipid parameters and fibrinogen in atherosclerosis patients. Since antiaggregation treatment with acetylsalicylic acid is a complex part of obligatory therapy of these patients, the authors studied the influence of ciprofibrate on chosen lipid parameters, fibrinogen and thromboxane in monotherapy, and also in combination with acetylsalicylic acid (ASA) in patients with advanced atherosclerosis and hyperlipoproteinemia. In the first group of patients (A-C, n = 12) after one month of low-lipid diet acetylsalicylic acid in a dose of 100 mg was administered daily during a period of 2 months followed by addition of 100 mg of ciprofabrate daily during the next 2 months. In the second group of patients (C-A, n = 11) after one month of low-lipid diet the same drugs were administered but in opposite order. Ciprofibrate was most effective in lowering the levels of triacylglycerids (-41%) and VLDL-cholesterol (-34%), but effectively lowered also the values of total cholesterol and LDL-cholesterol. In both studied groups it led to mild increase of HDL-cholesterol levels. Simultaneous administration of ASA did not significantly influence its hypolipemic activity. Ciprofibrate also significantly lowered the level of fibrinogen (-17%). Increase of the total number of platelets by about 10% was not accompanied by changes of the values and production of thromboxane. Simultaneous administration of ASA caused more than 90% inhibition of thromboxane production in monotherapy and in combination with ciprofibrate. Ciprofibrate is an effective hypolipidemic agent, also lowering the level of fibrinogen. Its combination with ASA is adequate, safe and without negative interaction influencing treatment. (Tab. 6, Fig. 1, Ref. 16.)

The effect of oral protease administration in the rat remnant kidney model.

It has been demonstrated that intraperitoneal administration of proteolytic enzymes ameliorates the progression of renal diseases in various animal models. In the present study, we employed the rat remnant kidney model to study the effectiveness of oral administration of proteases. Twenty male Wistar rats underwent sham operation (CTRL), while 25 were subjected to 5/6 nephrectomy (5/6 NX). Rats were randomised into placebo (PL) (2 ml tap water/day by gavage), or Phlogenzym (E; fixed mixture of trypsin 2.42 mg, bromelain 4.54 mg, and rutozid 5.04 mg added as antioxidant, in 2 ml tap water daily by gavage) treated group. Duration of the study was 45 days. Rats were pair-fed. Enzyme treatment exerted salutary effects on various functional and morphological parameters. Proteinuria was higher in both 5/6 NX group rats throughout the study. Administration of proteases ameliorated its rise effectively (data at sacrifice: CTRL-PL 6.27 +/- 1.25, CTRL-E 9.27 +/- 0.99, 5/6 NX-PL 74.04 +/- 21.33, 5/6 NX-E 39.09 +/- 7.93 mg/24 h; P < 0.01). Increased urinary excretion of the fibrogenic cytokine transforming growth factor (TGF-beta 1) was improved, too (CTRL-PL 0.349 +/- 0.051, CTRL-E 0.693 +/- 0.230, 5/6 NX-PL 3.044 +/- 0.540, 5/6 NX-E 1.390 +/- 0.238 ng/mumol creatinine; P < 0.05). At sacrifice, tubulointerstitial fibrosis was less pronounced in E-treated rats. Correspondingly, the volume fraction of tubulointerstitial tissue in the renal cortex was improved in 5/6 NX-E rats (CTRL-PL 9.9 +/- 0.2, CTRL-E 10.0 +/- 0.2, 5/6 NX-PL 17.9 +/- 1.8, 5/6 NX-E 13.8 +/- 0.9%; P < 0.05). The protein/DNA ratio in isolated glomeruli and tubules, as an estimate of glomerular matrix accumulation and hypertrophy of tubules, was enhanced in 5/6 NX groups and a tendency towards lower values was observed after E treatment. Renal function as evaluated by serum creatinine and urea levels was not influenced by the enzyme therapy. No between-group differences in blood pressure were observed. In summary, oral administration of proteolytic enzymes improved proteinuria and urinary TGF-beta 1 excretion, as well as the severity of tubulointerstitial fibrosis without signs of toxicity.

Enalapril in subantihypertensive dosage attenuates kidney proliferation and functional recovery in normotensive ablation nephropathy of the rat.

Most studies on the antiproliferative action of angiotensin converting enzyme inhibitors (ACEI) were performed in a rat hypertensive remnant kidney model with 5/6 kidney ablation which raised objections about the antihypertensive effect of ACEI and the influence of other antihypertensive drugs administered to remnant kidney control rats. To prevent these objections, a normotensive 4/6 remnant kidney model was elaborated and a subantihypertensive dosage of enalapril was used to evaluate its antiproliferative action. Subtotally nephrectomized rats (Nx) markedly increased the remnant kidney weight during a 4-week period and this rise was prevented by the treatment with enalapril (NxE) (Nx +297+/-35 mg vs. sham-operated +145+/-32 mg, p<0.001; NxE +154+/-35 mg vs. Nx p<0.001). While collagen concentration in the kidney cortex was not increased in sham-operated rats (Sham) in comparison with the control group (Ctrl) at the beginning of the study, the subsequent increase was significant in the Nx group and enalapril did not attenuate this increase (Sham 148+/-5 mg/100 g w.w. vs. Nx 164+/-2 mg/100 g w.w., p<0.01; NxE 161+/-4 mg/100 g w.w. vs. Sham p<0.05). The tubular protein/DNA ratio increase, which was significant in the Nx group, was inhibited by enalapril (Nx 26.2+/-10.5 vs. NxE 15.3+/-2.6, p<0.05). The protein/DNA ratio was much lower in glomeruli, with no significant changes in either the Nx or NxE groups. Serum urea concentrations were slightly higher in the Nx group than in the sham-operated group, but markedly elevated in the NxE group (Nx 10.71+/-0.76 mmol/l vs. Sham 6.10+/-0.33 mmol/l, p<0.001; NxE 28.9+/-2.6 mmol/l vs. Sham p<0.001). Creatinine concentrations in the Nx group were increased in comparison with the sham-operated group and markedly increased in the NxE group (Nx 63.7+/-3.56 micromol/l vs. Sham 37.2+/-2.84 micromol/l, p<0.001; NxE 107.0+/-5.2 micromol/l vs. Sham p<0.001). The clearance of creatinine was lower in the Nx group than in the sham-operated group and was markedly reduced in the NxE group (Nx 0.89+/-0.06 ml/min.g kidney wt. vs. Sham 1.05+/-0.16 ml/min x g kidney wt., p<0.01; NxE 0.58+/-0.029 ml/min x g kidney wt. vs. Sham, p<0.001). Enalapril improved proteinuria in comparison with the Nx group (NxE 5.6+/-0.6 mg/24 h vs. Nx 16.1+/-3.4 mg/24 h, p<0.05). Thus remnant kidney proliferation is substantial even in normotensive rats. It includes both proliferation and collagen accumulation with partial recovery of kidney weight and function, but is accompanied by enhanced proteinuria. Enalapril attenuates the proliferation and decreases proteinuria but prolongs kidney function recovery.

Advanced glycation end-product levels in subtotally nephrectomized rats: beneficial effects of angiotensin II receptor 1 antagonist losartan.

The angiotensin II receptor 1 antagonist losartan (L) inhibited the advanced glycated end-products (AGEs) induced expression of transforming growth factor beta(1) in in vitro experiments performed on renal tubuloepithelial cells. To test the pathophysiological importance of these findings, the possible link between serum AGEs levels and angiotensin system was investigated in the model of normotensive subtotally nephrectomized rats(4/6-NX). Concentration of AGEs in serum of placebo administered 4/6-NX rats (n = 7, 1.09+/-0.09 U/l) increased slightly in comparison with sham-operated healthy controls (CTRL, n = 8, 0.94+/-0.10 U/l, p<0.02) as measured by competitive ELISA. Treatment of 4/6-NX rats with L over 12 weeks ameliorated the rise in serum AGEs concentration (1.00+/-0.12 U/l, n = 15 <0.005) almost to the level observed for CTRL. This effect was further corroborated by the observation, that the impaired renal excretion of AGEs in 4/6-NX-placebo rats (0.07+/-0.02 U/micromol creatinine) was significantly restored by L (0.09+/-0.02 U/micromol creatinine, <0.009) and resembled that of the CTRL (0.10+/-0.03 U/micromol creatinine). Administration of L to 4/6-NX rats significantly improved renal function as evaluated by a smaller rise in serum creatinine and urea concentration. In spite of the improvement in renal function, there were no differences in concentrations of transforming growth factor beta(1) in serum and in urine among the two groups. These effects were independent of blood pressure. Our data give first evidence, that long-term treatment with angiotensin II receptor 1 antagonist may exert salutary effects on AGEs levels in the rat remnant kidney model, probably due to improved renal function.

Effect of chronic therapy with proteolytic enzymes on hypertension-induced renal injury in the rat model of Goldblatt hypertension.

This study investigated the possible beneficial effect of intraperitoneal proteolytic enzyme administration on the development of hypertension-induced renal injury in the rat model of 2-kidney 1-clip (2K1C) Goldblatt hypertension. Male Wistar rats (120-150 g) underwent either sham surgery (control, n = 5) or clipping of the left renal artery. From day one 2K1C rats were randomized into 2 groups, placebo treatment (n = 7), and proteolytic enzyme treatment (n = 9). To the verum group a fixed mixture of trypsin (2.42 mg), bromelain (4.54 mg), and rutin (5.04 mg) dissolved in 2 ml of sterile 0.9% NaCl was administered intraperitoneally daily, while the placebo group received only vehicle. Rats were pair-fed. The duration of the study was 7 weeks. All 2K1C rats developed hypertension and the mean values of systolic blood pressure (SBP) did not differ significantly between the groups at any time recorded (SBP at sacrifice: controls 122.0 +/- 8.5 mm Hg; placebo 191.4 +/- 7. 6 mm Hg; enzyme 180.5 +/- 6.5 mm Hg). Enzyme treatment prevented the rise in proteinuria (controls 12.4 +/- 2.6 mg/24 h; placebo 19.7 +/- 3.9 mg/24 h; enzyme 12.2 +/- 1.3 mg/24 h; p < 0.05) and ameliorated the increase in serum urea concentrations. Histomorphologically, signs of malignant nephrosclerosis were not found in control rats, while they were present in 4/7 (57%) of placebo-treated rats, but only in 1/9 (11%) of the enzyme-treated group. The volume fraction of renocortical interstitium was increased in both 2K1C groups in comparison with controls; however, enzyme treatment decreased the accumulation of interstitial tissue significantly (-22%) compared to placebo treatment. Cellular infiltration with mononuclear cells was also lower in the protease-treated group. To summarize, in the rat model of 2K1C hypertension, systemic treatment with proteases ameliorates the severity of nephrosclerosis and tubulointerstitial fibrosis in the non-clipped kidney, as well as proteinuria, without affecting high blood pressure.