Expression of purinergic P2X7 receptors in subpopulations of peripheral blood mononuclear cells in early-stage of chronic kidney disease.

Chronic kidney disease (CKD) is known as a state of chronic low-grade inflammation, enhancing cardiovascular risk and immunodeficiency. Purinergic signaling has been accepted as a crucial component in the pathogenesis of various diseases, mediating a vast array of biological processes. The P2X7 receptor is one of the important cell surface regulators of several key inflammatory molecules. The aim of the study was to examine the expression of surface P2X7 receptors in subpopulations of peripheral blood mononuclear cells (PBMCs), and to evaluate the promising prognostic markers of inflammation (neutrophil/lymphocyte, Ne/Ly ratio) and cardiovascular risk (monocyte/high density lipoprotein cholesterol, Mo/HDL ratio) in early-stage CKD. The study involved 15 healthy volunteers and 15 non-diabetic patients with CKD stage 2 - 3. PBMCs were isolated from heparinized blood by Ficoll gradient centrifugation. To determine the expression of P2X7 receptors in different subpopulations (CD14+ monocytes, CD3+ T-lymphocytes and CD19+ B-lymphocytes), the cells were stained with FITC-conjugated anti-P2X7. The monocyte, lymphocyte and neutrophil counts were measured in whole blood as a part of routine hemogram. The number of T- and B-lymphocytes was determined by flow cytometry using antibodies anti-CD3-PE and anti-CD19-PE, respectively. The expression of surface P2X7 receptors was 1.4 fold increased in PBMCs of CKD patients compared to healthy volunteers. The expression of P2X7 receptors was 2.1 fold higher in monocytes and 1.5 fold higher in the whole lymphocyte population, with significant increase only in B-cells. The monocyte count, as well as the Ne/Ly and Mo/HDL ratios were also significantly increased. In conclusion, the increased P2X7 receptors expression in monocytes, the monocyte count and the Ne/Ly ratio are manifestations of chronic inflammation already in early stages of CKD. The study also supports recent findings that the Mo/HDL ratio could be used as additional parameter for monitoring cardiovascular risk profile in these patients.

[Chronic kidney disease and cellular calcium homeostasis]. / Chronické ochorenie obliciek a vápniková homeostáza bunky.

Free intracellular calcium represents a critical signaling mediator in a number of biological systems. Calcium cations (Ca2+) are an important ubiquitous messenger, controlling a broad range of cellular processes. Free cytosolic calcium concentration ([Ca2+]i) is controlled by mechanisms that regulate Ca2+ entry from the extracellular space and Ca2+ release from intracellular stores, and by the activity of ATP-dependent Ca2+ pumps and antiporters that move Ca2+ back into stores or out of cells. Chronic kidney disease is associated with a significant elevation in [Ca2+]i which is toxic to the cells and may be responsible for a multiple organ dysfunction. Disturbances in cellular calcium homeostasis in patients with chronic kidney disease represent a complex process. Our studies elucidate pathophysiological mechanisms of altered cellular calcium homeostasis in the peripheral blood mononuclear cells which represent the model of nonexcitable cells in patients with chronic kidney disease. The results demonstrate that [Ca2+]i is significantly increased in peripheral blood mononuclear cells already in early stages of chronic kidney disease. The calcium concentration of intracellular stores and the capacitative calcium entry into the cells of these patients are significantly higher in comparison with healthy volunteers. Also the pore-forming P2X7 receptors participate in increased [Ca2+]i in peripheral blood mononuclear cells of patients with chronic kidney disease. An altered P2X7 receptor function and increased P2X7 receptor expression may contribute to the complex disturbances in intracellular calcium homeostasis in chronic kidney disease. On the other hand, the activity of plasmatic membrane Ca2+-ATPases which is responsible for removing excessive calcium out of the cell, was found to be decreased by 25 % when compared to healthy subjects. It means that not only the mechanisms of entry, but also of the removal are impaired by the disease. All these alterations in calcium signaling are contributing very likely to the elevated [Ca2+]i from early stages of chronic kidney disease.

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.

Cardiovascular risk in patients with chronic kidney diseases: a time for new risk markers?

The number of patients with end-stage renal disease who need expensive dialysis treatment or transplantation is increasing all over the world. Therefore, new possibilities of prevention and treatment of chronic kidney diseases (CKD) are being looked for. However, patients with CKD represent a population not only at risk for progression to renal failure, but also at even greater risk for cardiovascular (CV) diseases. Extreme CV morbidity and mortality in dialysed patients is well-known, but recent studies stress a high CV risk even at early stage of CKD. Impaired renal function and/or albuminuria are now considered major CV risk factors. The reasons for this are not only a high prevalence of traditional CV risk factors in CKD patients or their insufficient treatment, but also the presence of non-traditional CV risk factors that could be specific for CKD. Some of these novel risk factors, particularly markers of inflammation, endothelial function, hemocoagulation and fibrinolysis are discussed, and their significance in the prediction of CV and renal outcome examined (Tab. 1, Ref 57).

Development of a multiplex-PCR for rapid detection of the enteric pathogens Lawsonia intracellularis, Brachyspira hyodysenteriae, and Brachyspira pilosicoli in porcine faeces.

AIMS: To develop an assay to simultaneously detect Lawsonia intracellularis, Brachyspira hyodysenteriae and Brachyspira pilosicoli in pig faeces. METHODS AND RESULTS: A multiplex-polymerase chain reaction (M-PCR) was designed to amplify a 655-base pair (bp) portion of the L. intracellularis 16S rRNA gene, a 354-bp portion of the B. hyodysenteriae NADH oxidase gene, and a 823-bp portion of the B. pilosicoli 16S rRNA gene. Specificity was assessed using 80 strains of Brachyspira spp. and 30 other enteric bacteria. Bacterial DNA was extracted from faeces using the QIAamp DNA Stool Mini Kit. The M-PCR was tested in parallel with culture and/or PCR on 192 faecal samples from eight piggeries. Faeces also were seeded with known cell concentrations of the three pathogenic species, and the limits of detection of the M-PCR tested. The M-PCR was specific, with limits of detection of 10(2)-10(3) cells of the respective species per gram of faeces. CONCLUSIONS: The M-PCR is a rapid, sensitive and specific test for detecting three important enteric bacterial pathogens of pigs. SIGNIFICANCE AND IMPACT OF THE STUDY: The availability of a new diagnostic M-PCR will allow rapid detection and control of three key porcine enteric pathogens.

[Collagenofibrotic glomerulopathy--rare glomerulonephritis]. / Kolagenofibrotická glomerulopatia--raritná glomerulonefritída.

Glomerulopathies with fibrillary deposits form a heterogeneous group of renal diseases that can be identified only by means of electron microscopy. A case of a rare type of such a nephropathy, the collagenofibrotic glomerulopathy with focus on differential diagnostics is presented and current knowledge relating to this renal disease is reviewed.

[Atherosclerotic nephropathy in renal artery stenosis--from randomized studies to individualized therapy]. / Aterosklerotická nefropatia pri stenóze renálnej artérie--od randomizovaných stúdií k individualizácii terapie.

Randomized trials in hypertensive patients with atherosclerotic renal artery stenosis (ARAS) mostly did not reveal any significant difference between antihypertensive treatment and revascularization (by angioplasty or bypass surgery) in their effects on blood pressure or glomerular filtration rate. This unexpected conclusion reflects a fact that in addition to potentially reversible ischemia, some other factors which are not eliminated by technically successful revascularization take part in the decrease of renal function in ARAS, including cholesterol microemboli from atherosclerotic plaques, secondary focal segmental glomerulosclerosis and hypertensive nephroangiosclerosis. Moreover, these changes have been also found in the contralateral kidney without any stenosis. Scintigraphic studies confirmed that the individual kidney function was not related to the presence of ARAS, i.e., the glomerular filtration rate in the stenotic kidney was often equal to, or paradoxically even better than that in the kidney with normal renal artery. This has obviously important consequences for the indication of revascularization which should be based on measurement of the individual kidney function rather than overall renal function. A conservative treatment of ARAS should comprise ACE inhibitors or angiotensin II receptor antagonists, statins and acetylsalicylic acid. The long-term effect of such treatment on the progression of atherosclerotic nephropathy is now being evaluated in randomized trials.

[Treatment of renal hypertension]. / Liecba renálnej hypertenzie.

In recent years in conjunction with medicamentous treatment of renoparenchymatous hypertension in particular two problems were discussed: target blood pressure values and renoprotective effects of antihypertensive drugs. Prospective studies revealed that a blood pressure reading of < 130/80 mm Hg significantly retards the progression of nephropathy whereby patients with proteinuria > 1 g/d benefit from even lower BP readings. In diabetic nephropathy the drugs of choice are inhibitors of angiotensin converting enzyme (ACEI), already in the incipient stage and also in normotensive patients. The importance of ACEI in the treatment of non-diabetic nephropathies was confirmed recently by controlled prospective studies AIPRI and REIN. A maximal renoprotective effect of ACEI probably calls for larger doses than those needed for normalization of BP. Long-term investigations of the renoprotective effect of antagonists of angiotensin AT1 receptors and comparative studies with ACEI resp. are not available. Dihydropyridine blockers of calcium channels with a short-term action (nifedipine) may have a negative influence on the progression of diabetic nephropathy, the effect of dihydropyridines of the second generation is tested in prospective studies. Non-dihydropyridine calcium channel blockers have a renoprotective action in diabetic nephropathy. In cca two thirds of the patients combined treatment with ACEI and diuretics or with calcium channel blockers is necessary. As to other antihypertensive drugs, vasodilatating beta-blockers and perspectively antagonists of endothelin receptors are useful.

[Renal hypertension: pathogenesis and therapy]. / Renálna hypertenzia: patogenéza a liecba.

The kidney is both the source and target of high blood pressure. The pathogenesis of renal parenchymatous hypertension is significantly affected by sodium retention, inappropriate activity of vasopressoric systems and other factors. Drugs inhibiting the renin-angiotensin system are the treatment of choice in diabetic and non-diabetic nephropathies. The nephroprotective effect of long-acting dihydropyridine calcium channel blockers as well as of other compounds is currently under investigation.

[Hypokalemic renal tubular syndromes: pathogenesis, diagnosis and therapy]. / Hypokáliemické renálne tubulárne syndrómy: patogenéza, diagnostika a terapia.

Hereditary tubular defects include syndromes with the retention of Na+, hypertension, hypokalemic metabolic alkalosis (Conn's and Liddle's syndromes) and syndromes with Na+ restriction, hypotension and hypokalemic metabolic alkalosis (Bartter's and Gitelman's syndromes). The understanding of their molecular mechanisms extended markedly with the improvement of their diagnostics, prevention and therapy. The paper reviews briefly their pathogenesis. (Tab. 4, Fig. 3, Ref. 38.)

[The effect of glycosaminoglycan sulodexide on albuminuria in patients with diabetes mellitus]. / Ucinok glykozaminoglykanu sulodexidu na albuminúriu u pacientov s diabetes mellitus.

BACKGROUND: Experimental and clinical studies showed a decrease in albuminuria, a marker of diabetic nephropathy after administration of heparin or other glycosaminoglycans (GAG). OBJECTIVES: To study the effect of sulodexide on albumin excretion rate (AER) in patients with type 1 or type 2 diabetes mellitus (DM). METHODS: Twenty patients (12 of type 1 DM) aged 33-63 yrs (median 45) with microalbuminuria (AER 20-200 micrograms/min) or macroalbuminuria (AER > 200 micrograms/min) were enrolled in open study and received sulodexide 60 mg/day i.m. for 3 weeks with further 6-week follow-up without treatment. In the 2nd phase, sulodexide 100 mg/day was given p.o. for 8 weeks with further 8-weeks follow-up. Albuminuria in overnight urine samples was analyzed by the RIA method and results (medians with lower and upper quartiles) were compared by the Wilcoxon test. RESULTS: In the 1st phase, AER (microgram/min) decreased from 167 (54-378) at baseline to 118 (78-220) at week 1 (p < 0.05), 105 (68-341) at week 2 (p < 0.05), and to 114 (56-354) at week 3 (NS). After stopping the treatment, AER gradually raised to baseline values. During the oral phase, AER decreased from 253 (37-961) to 137 (35-323) after 1 month (p < 0.05) and to 144 (47-588) after 2 months (NS). This effect was prolonged for further 2 months after treatment withdrawal (AER 110 (65-363) micrograms/min, p < 0.05). In both phases, the decrease in AER was shown only in patients with macroalbuminuria, but not in those with microalbuminuria. Blood pressure, glomerular filtration rate and metabolic compensation of DM were not changed. CONCLUSION: A short-term treatment with sulodexide i.m. or p.o. significantly decreased albuminuria in DM patients. This effect was prolonged for further 2 months after oral administration. Therefore, sulodexide could be useful in the treatment of diabetic nephropathy. (Tab. 3, Ref. 20.)

[Celiprolol improves glucose metabolism in essential hypertension]. / Celiprolol zlepsuje metabolizmus glukózy pri esenciálnej hypertenzii.

The authors investigated in 18 patients with essential hypertension the action of celiprolol (usually in combination with a diuretic) on the glucose and lipid metabolism in an open three-month trial. They evaluated the glucose, insulin and C-peptide concentration during an oral glucose tolerance test (oGTT) and the serum lipid concentration before and after treatment. It was revealed: 1. There are no significant changes in the glucose, insulin and C-peptide concentrations on fasting, 2. There is a significant reduction of the blood sugar level during the second hour of oGTT after treatment, 3. A significant reduction of glucose and C-peptide during the 1st and 2nd hour of oGTT after treatment in the sub-group with a poor glucose tolerance/insulin sensitivity, 4. There are no differences between the mentioned variables in hypertonic patients with a normal glucose metabolism, 5. There are no significant changes in values of total cholesterol, HDL-, LDL and VLDL-cholesterol and triacylglycerols. Celiprolol can exert in combination with diuretics also a favourable effect on the glucose tolerance/insulin sensitivity in patients with essential hypertension and metabolic syndrome.

Glycosaminoglycan sulodexide decreases albuminuria in diabetic patients.

Albuminuria is a dominant biochemical feature of developing diabetic nephropathy. A disturbed metabolism of heparan sulphate characterized by an increased loss of anionic charges in the basement membrane has been considered as one of the main factors causing an increased albumin output into urine. All therapeutic approaches inducing a reduction of the albumin excretion rate (AER) have a protective effect on renal function. The effect of glycosaminoglycan sulodexide on albuminuria was studied in a group of 53 diabetic patients (26 Type 1 and 27 Type 2) with micro and macroalbuminuria. Sulodexide (Vessel Due F) was administered intramuscularly in one daily dose (600 lipasemic units) for 3 weeks followed by a 6 week wash-out period. A significant decrease of AER was found in a total cohort of patients following just 1 week of sulodexide treatment (mean 162 micrograms/min, range 10-2708 micrograms/min vs mean 248 micrograms/min, range 20-3160 micrograms/min, P < 0.001). This effect lasted 3-6 weeks after drug withdrawal. Similar results were obtained if Type 1 and Type 2 diabetic patients were evaluated separately but a delay of the AER reduction was observed in the latter group. In all patients the mean AER was reduced to 60-65% of the initial values. A greater effect of sulodexide on albuminuria was observed in patients with AER above 200 micrograms/min than in those with microalbuminuria (a reduction to 47 vs 65% of the initial output). Sulodexide did not significantly reduce albuminuria in 28% of diabetic patients ('non-responders'). In conclusion, glycosaminoglycan sulodexide may reduce AER in patients with micro or macroalbuminuria and it could slow down development of diabetic nephropathy.

[The role of platelet-derived growth factor in progression of nephropathy]. / Ucast trombocytárneho rastového faktora (PDGF) na progresii nefropatií.

The platelet growth factor (PDGF) is a potent proliferative factor which stimulates the proliferation of the kidneys in particular of mesangial cells and moreover by stimulating the production of the transforming growth factor beta (TGF-beta) it stimulates also proliferation of the mesangium, glomerulosclerosis and obviously also interstitial fibrosis. By these mechanisms it participates in the progression of experimental and human nephropathies. Production of PDGF can be suppressed by a low protein diet, heparin, acetylsalicylic acid, dipyridamol, and some new antagonists are being developed. These findings were assembled in experimental investigations and must be confirmed in clinical trials.

[A protein-restricted diet combined with ACE inhibitors does not improve insulin sensitivity in renal hypertension]. / Diéta s obmedzeným prívodom bielkovín v kombinácii s ACEI nezlepsuje inzulínovú senzitivitu pri nefrogénnej hypertenzii.

Hypertension is one of the most important accelerating factors for progression of nephropathies. Its prevalence is about 35% in patients with nephropathies, even in minor or medium severe functional impairment. This is evidence that it is essential to select an optimal therapeutic regimen as soon as possible. A group of 38 patients (14 hypertensive patients) with a minor or medium severe functional impairment were included in a controlled trial. The patients were served a low-protein diet--0.6-0.7 g/kg/day and 2-10mg enalapril/day divided into two doses. The amount of enalapril depended on the blood pressure and enalapril was given also to normotensive patients. The investigation lasted 8 months. In the course of 8 months the authors did not reveal progression of the renal disease, as apparent from results of assessment of the creatinine level and clearance, assessment of uric acid and urea. The authors did not find deterioration of metabolic acidosis, nor of nephrogenic anaemia. Hypertensive patients had a tendency to deteriorating of insulin sensitivity while in normotensive patients a decline of triacylglycerols, VLDL and rise of HDL was recorded. The total cholesterol and LDL cholesterol level did not change. The authors conclude that the combination of a low-protein diet with ACEI in hypertensive and normotensive patients with mild to medium severe functional disorders inhibits the progression of nephropathies, but in hypertensive patients it does not prevent deterioration of insulin sensitivity.

[Pharmacodynamics of angiotensin-converting enzyme inhibitors]. / Farmakodynamika inhibítorov angiotenzín konvertujúceho enzýmu (ACEI).

ACEI form a group of antihypertensives which inhibit the angiotensin II (A II) production and thus not only reduce the blood pressure but exert also a positive metabolic and antiproliferative effect (A II is a proliferative hormone). They are therefore indicated nowadays in the treatment of essential and secondary hypertension, left-ventricular hypertrophy, chronic heart failure, acute myocardial infarction, insulin resistance and other disorders. Despite intensive studies we still do not know many, in particular mediated effects, of ACEI but these drugs have become one of the key groups in therapy.

[Prevention of progression in nephropathies]. / Prevencia progresie nefropatií.

Intermittent dialysis is excessively expensive and pretentious psychologically and socially. As a result the research is concentrated on the prevention of kidney disease progression. Preventive measures: a) Protein restriction forms the basis of nonpharmacologic measures. b) Consequent antihypertensive therapy, with the aim to decrease blood pressure < 17.5/11.25 kPa (140/90 Torr), is the most effective prevention. The basic drugs are ACEI eventually in combination with Ca antagonists. They even reverse kidney disease progression in early phases. c) Antiaggregation therapy prevents the formation of fibrin deposits in glomeruli and the thrombogenesis. d) Insulin resistance correction prevents the development of glomerulosclerosis and atherosclerosis. e) Antihyperlipemic therapy is required only in a small number of patients. f) Correction of mineral balance prevents or corrects osteodystrophy. These measures could decrease kidney disease progression and the entrance of patients into intermittent dialysis by 10-20% and a further decrease to 50% is expected to be reached until the year 2000. (Fig. 3, Tab. 3, Ref. 43.).

Effects of angiotensin-converting enzyme inhibitors on glucose and lipid metabolism in essential hypertension.

Data of 52 patients, 29 women and 23 men aged 32-68 years (mean age 47 years) with essential hypertension, participating in three open therapeutic trials with either enalapril, lisinopril, or perindopril were evaluated to assess the effects of angiotensin-converting enzyme (ACE) inhibition on glucose and lipid metabolism. The 75-g oral glucose tolerance test (oGTT) was performed, and plasma glucose and insulin levels, as well as total cholesterol, high-density lipoprotein (HDL)-cholesterol, and triglycerides levels were determined before and after the 8- to 12-week treatment. Minor differences in the blood pressure (BP)-lowering effect and metabolic response were obtained with the ACE inhibitors studied; only lisinopril improved glucose tolerance significantly; blood lipids were not changed by any drug. The entire patient population showed only a slight reduction in 1-h postload glucose after treatment. More obvious improvement in glucose tolerance was evident in hypertensive patients who were glucose intolerant and/or insulin resistant (GI/IR, 53.8% of all), however. This subgroup also showed a slight but not significant increase in HDL-cholesterol and a decrease in triglycerides levels. Only a slight change or no change in plasma glucose, insulin, and lipid values was noted in hypertensive patients with normal glucose tolerance (NGT) and insulin sensitivity. These favorable effects were expressed only after ACE inhibitor monotherapy, but not when hydrochlorothiazide was added. The results indicate that a lack of stratification of hypertensive patients with regard to glucose tolerance or insulin sensitivity could be a confounding factor in evaluation of metabolic effects of ACE inhibitors.

Metabolic effects of enalapril in the treatment of essential hypertension.

In an open two-month study with an initial placebo period, the effect of enalapril on glucose tolerance, insulin (IRI) sensitivity and lipid profile was evaluated in 20 patients with mild to moderate essential hypertension. The following results were obtained: 1. Enalapril produced a favourable effect of blood pressure both in monotherapy and if combined with a diuretic. 2. Therapy did not lead to significant differences in blood glucose, IRI or IRI/glucose increase at 1 or 2 hours of oral glucose tolerance test either in patients with monotherapy or combination therapy, and with normal or disturbed glucose tolerance, respectively. 3. Serum lipids (total and HDL-cholesterol and triglycerides) did not change significantly in any group of patients.