Renoprotection: focus on TRPV1, TRPV4, TRPC6 and TRPM2.

Members of the transient receptor potential (TRP) cation channel receptor family have unique sites of regulatory function in the kidney which enables them to promote regional vasodilatation and controlled Ca2+ influx into podocytes and tubular cells. Activated TRP vanilloid 1 receptor channels (TRPV1) have been found to elicit renoprotection in rodent models of acute kidney injury following ischaemia/reperfusion. Transient receptor potential cation channel, subfamily C, member 6 (TRPC6) in podocytes is involved in chronic proteinuric kidney disease, particularly in focal segmental glomerulosclerosis (FSGS). TRP vanilloid 4 receptor channels (TRPV4) are highly expressed in the kidney, where they induce Ca2+ influx into endothelial and tubular cells. TRP melastatin (TRPM2) non-selective cation channels are expressed in the cytoplasm and intracellular organelles, where their inhibition ameliorates ischaemic renal pathology. Although some of their basic properties have been recently identified, the renovascular role of TRPV1, TRPV4, TRPC6 and TRPM2 channels in disease states such as obesity, hypertension and diabetes is largely unknown. In this review, we discuss recent evidence for TRPV1, TRPV4, TRPC6 and TRPM2 serving as potential targets for acute and chronic renoprotection in chronic vascular and metabolic disease.

Decreased peroxisome proliferator-activated receptor γ level and signalling in sebaceous glands of patients with acne vulgaris.

Little is known about the altered lipid metabolism-related transcriptional events occuring in sebaceous glands of patients with acne vulgaris. Peroxisome proliferator-activated receptor (PPAR)γ, a lipid-activated transcription factor, is implicated in differentiation and lipid metabolism of sebocytes. We have observed that PPARγ and its target genes, ADRP (adipose differentiation related protein) and PGAR (PPARγ angioprotein related protein) are expressed at lower levels in sebocytes from patients with acne than in those from healthy controls (HCs) Furthermore, endogenous PPARγ activator lipids such as arachidonic acid-derived keto-metabolites (e.g. 5KETE, 12KETE) are increased in acne-involved and nonacne-involved skin of patients with acne, compared with skin from healthy individuals. Our findings highlight the possible anti-inflammatory role of endogenous ligand-activated PPARγ signaling in human sebocyte biology, and suggest that modulating PPARγ- expression and thereby signaling might be a promising strategy for the clinical management of acne vulgaris.

Functional transient receptor potential vanilloid 1 and transient receptor potential vanilloid 4 channels along different segments of the renal vasculature.

AIM: Transient receptor potential vanilloid 1 (TRPV1) and vanilloid 4 (TRPV4) cation channels have been recently identified to promote endothelium-dependent relaxation of mouse mesenteric arteries. However, the role of TRPV1 and TRPV4 in the renal vasculature is largely unknown. We hypothesized that TRPV1/4 plays a role in endothelium-dependent vasodilation of renal blood vessels. METHODS: We studied the distribution of functional TRPV1/4 along different segments of the renal vasculature. Mesenteric arteries were studied as control vessels. RESULTS: The TRPV1 agonist capsaicin relaxed mouse mesenteric arteries with an EC50 of 25 nm, but large mouse renal arteries or rat descending vasa recta only at >100-fold higher concentrations. The vasodilatory effect of capsaicin in the low-nanomolar concentration range was endothelium-dependent and absent in vessels of Trpv1 -/- mice. The TRPV4 agonist GSK1016790A relaxed large conducting renal arteries, mesenteric arteries and vasa recta with EC50 of 18, 63 nm and ~10 nm respectively. These effects were endothelium-dependent and inhibited by a TRPV4 antagonist, AB159908 (10 µm). Capsaicin and GSK1016790A produced vascular dilation in isolated mouse perfused kidneys with EC50 of 23 and 3 nm respectively. The capsaicin effects were largely reduced in Trpv1 -/- kidneys, and the effects of GSK1016790A were inhibited in Trpv4 -/- kidneys. CONCLUSION: Our results demonstrate that two TRPV channels have unique sites of vasoregulatory function in the kidney with functional TRPV1 having a narrow, discrete distribution in the resistance vasculature and TRPV4 having more universal, widespread distribution along different vascular segments. We suggest that TRPV1/4 channels are potent therapeutic targets for site-specific vasodilation in the kidney.

Determination of normal ß values via radio frequency echo-tracking technique in a healthy Central European population.

The aim of our article is to report normal values of ß stiffness parameter and pulse wave velocity (PWV) determined via radio frequency echo-tracking technique first in different age groups of a healthy Central European population in both gender. Values of PWV and ß stiffness parameters increase normally during aging and in certain vascular diseases including atherosclerosis. Detection of significant deviation from the normal values provides opportunity to diagnose the early stage atherosclerosis before morphological changes become visible and while therapy is more efficient. Atherosclerosis is responsible great percentage of morbidity and mortality in western world population therefore the detection of these parameters could be important and useful in primary and secondary prevention.

Neutrophil gelatinase-associated lipocalin: pathophysiology and clinical applications.

Neutrophil gelatinase-associated lipocalin (NGAL), a 25 kDa protein produced by injured nephron epithelia, is one of the most promising new markers of renal epithelial injury. In contrast to serum creatinine and urinary output, which are the measures of kidney function, NGAL is specifically induced in the damaged nephron and then released into blood and urine, where it can be readily measured. Careful proof-of-concept studies using defined animal models have uncovered the sources and trafficking of NGAL in acute kidney injury (AKI) and have addressed the contributions of renal and non-renal sources. Clinical studies indicate that NGAL, unlike creatinine, is a marker responsive to tissue stress and nephron injury, but less so to adaptive hemodynamic responses. In certain clinical settings, NGAL is an earlier marker compared with serum creatinine. In addition, clinical studies have shown that NGAL is a powerful predictor of poor clinical outcomes, which can be used to risk stratify patients when combined with serum creatinine. NGAL has important limitations, including its responsiveness in systemic inflammation, which is partially uncoupled from its response to kidney injury and which needs to be considered when interpreting NGAL results clinically. This review covers the biology and pathophysiology of NGAL and summarizes the results of the growing body of clinical studies that have addressed the utility of NGAL in the early diagnosis of AKI, in the distinction of intrinsic AKI and in the prognostic assessment of broad patient populations.

Novel signalling mechanisms and targets in renal ischaemia and reperfusion injury.

Acute kidney injury (AKI) induced by ischaemia and reperfusion (I/R) injury is a common and severe clinical problem. Vascular dysfunction, immune system activation and tubular epithelial cell injury contribute to functional and structural deterioration. The search for novel therapeutic interventions for I/R-induced AKI is a dynamic area of experimental research. Pharmacological targeting of injury mediators and corresponding intracellular signalling in endothelial cells, inflammatory cells and the injured tubular epithelium could provide new opportunities yet may also pose great translational challenge. Here, we focus on signalling mediators, their receptors and intracellular signalling pathways which bear potential to abrogate cellular processes involved in the pathogenesis of I/R-induced AKI. Sphingosine 1 phosphate (S1P) and its respective receptors, cytochrome P450 (CYP450)-dependent vasoactive eicosanoids, NF-κB- and protein kinase-C (PKC)-related pathways are representatives of such 'druggable' pleiotropic targets. For example, pharmacological agents targeting S1P and PKC isoforms are already in clinical use for treatment for autoimmune diseases and were previously subject of clinical trials in kidney transplantation where I/R-induced AKI occurs as a common complication. We summarize recent in vitro and in vivo experimental studies using pharmacological and genomic targeting and highlight some of the challenges to clinical application of these advances.

Selective association of endogenous ouabain with subclinical organ damage in treated hypertensive patients.

According to previous studies endogenous ouabain (EO) closely correlates with high blood pressure, congestive heart failure and kidney disease in humans. Our aims were to analyse associations between plasma, urinary EO level and various markers of cardiovascular damage in treated hypertensive patients. Forty-one adult patients with hypertension and/or diabetes mellitus (DM) and/or chronic kidney disease (CKD) were studied. We assessed plasma and urinary EO, pro-brain natriuretic peptide and catecholamines, profile of ambulatory blood pressure monitor and cardiovascular status by echocardiography and echo-tracking. The highest level of plasma EO (19.7±9.5 pmol l⁻¹) was measured in hypertensive patients with DM and CKD. The nighttime mean arterial blood pressure independently correlated with the level of plasma EO (P=0.004), while independent predictor of the ß-stiffness of carotid artery was the urinary EO (P=0.011). Elevated level of EO was associated with nighttime blood pressure and subclinical organ damage in treated hypertensive patients, suggesting possible role of EO in the pathogenesis of impaired diurnal blood pressure rhythm and arterial stiffness.

Haplotype analysis of the apolipoprotein A5 gene in patients with the metabolic syndrome.

BACKGROUND AND AIMS: In recent studies, the T-1131C variant of apolipoprotein A5 (APOA5) gene was found to confer a risk for metabolic syndrome (MS). Here we determined four haplotype-tagging polymorphisms (T-1131C, IVS3+G476A, T1259C, and C56G), and studied the distribution of the naturally occurring major haplotype profiles in MS. METHODS AND RESULTS: A total of 343 MS patients and 284 controls were genotyped using PCR-RFLP methods. Both in MS and control groups, we confirmed the already known association of -1131C, IVS3+473A and 1259C minor alleles with elevated triglyceride levels. The prevalence of the APOA5*2 haplotype (the combination of T-1131C, IVS3+G476A and T1259C SNPs) was 13.1% in MS patients, and 4.9% in controls (p<0.001); multiple logistic regression analysis revealed that this haplotype confers risk for the development of MS (OR=2.880; 95% CI: 1.567-5.292; p=0.001). We also observed a gender effect: in males a more prominent degree of susceptibility was found. Contrary to the APOA5*2 haplotype, the prevalence rate of APOA5*4 (determined by the T-1131C SNP alone) did not differ between MS patients and controls. We identified a novel haplotype, designated here as APOA5*5 (1259C allele alone); which appears to be protective against MS. CONCLUSION: Our results refined the role of SNP T-1131C in the development of MS. The susceptibility nature of this SNP is limited to the APOA5*2 haplotype, while in APOA5*4 haplotype it did not confer a risk for the disease. In addition, as our current data suggest, the novel APOA5*5 haplotype can confer protection against MS.

Microalbuminuria in inflammatory bowel diseases using immunoturbidimetry and high-performance liquid chromatography.

BACKGROUND AND STUDY AIMS: To measure urinary albumin excretion using immunoturbidimetry (IT) and high-performance liquid chromatography (HPLC) in inflammatory bowel diseases. PATIENTS AND METHODS: A cross-sectional study was carried out on 60 selected patients with Crohn's disease (CD), 57 with ulcerative colitis (UC) and 22 healthy volunteers, as controls. Urinary albumin excretion was measured by IT and HPLC, and albumin-creatinine ratio was calculated. This ratio was compared in patients with active and inactive CD and UC and in healthy volunteers. RESULTS: Patients with CD and UC had higher albumin-creatinine ratio compared to controls using both IT and HPLC (p < 0.05). We measured higher albumin-creatinine ratio in patients with active compared to inactive CD (p < 0.05). Albuminuria did not correlate with disease duration of CD or UC, but patients with more extended CD according to the Montreal classification had higher HPLC-albumin-creatinine ratio. In CD, we found a significant correlation between HPLC-albumin-creatinine ratio and some inflammatory markers i.e. white blood cells (p < 0.05) and erythrocyte sedimentation rate (p < 0.05). In UC, there was no significant correlation between HPLC-albumin-creatinine ratio and the above markers of systemic inflammation or activity of UC. Albumin-creatinine ratio measured by HPLC was higher in both active and inactive CD and UC groups than albumin-creatinine ratio measured by IT. Using a receiver operating characteristics curve analysis, in case of HPLC-albumin-creatinine ratio cut-off values of the activity of CD were 2.46 mg/mmol for men, 5.30 mg/mmol for women. CONCLUSIONS: HPLC-urinary albumin-creatinine ratio is associated with the clinical and laboratory disease activity indices in CD, but not in UC. Using HPLC we found a more sensitive method compared to IT to measure albuminuria that would be a sensitive activity marker in CD.

Morphology of glomerular hematuria is reproduced in vitro by carbonyl stress.

BACKGROUND: In glomerulonephritides, dysmorphic red blood cells (RBCs) with membrane blebs can be found in the urine; this is referred to as glomerular hematuria. Glomerulonephritides are characterized by increased carbonyl stress and elevated methylglyoxal (MGO) levels. MGO causes oxidative stress and intracellular calcium accumulation. In the present study, we investigated whether the effect of MGO-induced calcium accumulation in RBCs develops through increased oxidative stress. Furthermore, we studied whether MGO can lead to RBC membrane blebbing. METHODS: RBC suspensions from healthy volunteers were incubated with different concentrations of MGO at 37 degrees C. We measured oxidative stress and intracellular calcium level using fluorescent indicators. We determined the frequency of dysmorphic RBCs, and also performed scanning electron microscopy. RESULTS: MGO increased oxidative stress and caused accumulation of calcium in isolated RBCs. These effects could be prevented using antioxidants. In the presence of MGO, RBC membrane blebbing developed. CONCLUSION: According to our findings, MGO causes calcium accumulation through oxidative stress. Carbonyl and oxidative stress may play an important role in the formation of dysmorphic RBCs in glomerular hematuria.

Cigarette smoke-induced alterations in endothelial nitric oxide synthase phosphorylation: role of protein kinase C.

Endothelial nitric oxide synthase (eNOS) is regulated by phosphorylation of Ser(1177) and Thr(495), which affects NO bioavailability. Cigarette smoke disturbs the eNOS-cGMP-NO pathway and causes decreased NO production. Here the authors investigated the acute effects of cigarette smoke on eNOS phosphorylation, focusing on protein kinases (PKs). Endothelial cell culture was concentration- and time-dependently treated first with cigarette smoke buffer (CSB), then with reduced glutathione (GSH) or various PK inhibitors (H-89, LY-294002, Ro-318425, and ruboxistaurin). eNOS, phospho-Ser(1177)-eNOS, phospho-Thr(495)-eNOS, Akt(PKB), and phospho-Akt protein levels were determined by Western blot. CSB increased the phosphorylation of eNOS at Ser(1177) and more at Thr(495) in a concentration- and time-dependent manner (p < .01, p < .05 versus control, respectively) and resulted in the dissociation of the active dimeric form of eNOS (p < .05). GSH decreased the phosphorylation of eNOS at both sites (p < .05 versus CSB without GSH) and prevented the decrease of dimer eNOS level. CSB treatment also decreased the level of phospho-Ser(473)-Akt (p < .05 versus control). Inhibition of PKA by H-89 did not affect CSB-induced phosphorylation, whereas the PKB inhibitor LY-294002 enhanced it at Ser(1117). The PKC blockers Ro-318425 and ruboxistaurin augmented the CSB-induced phosphorylation at Ser(1177) but decreased phosphorylation at Thr(495) (p < .05 versus CSB). Cigarette smoke causes a disruption of the enzymatically active eNOS dimers and shifts the eNOS phosphorylation to an inhibitory state. Both effects might lead to reduced NO bioavailability. The shift of the eNOS phosphorylation pattern to an inhibitory state seems to be independent of the PKA and phosphoinositol 3-kinase (PI3-K)/Akt pathways, whereas PKC appears to play a key role.

Single dose of acetylsalicylic acid in patients with Type 2 diabetes mellitus and/or chronic renal failure ameliorates anaemia by decreasing the rate of neocytolysis.

BACKGROUND: Anaemia in diabetes mellitus (DM) and/or chronic renal failure (CRF) may be caused by a decreased production of erythropoietin (EPO), EPO resistance, and by the lysis of the young circulating red blood cells (neocytolysis) induced by subclinical inflammation and low EPO level. Aims of this study were to detect EPO resistance in patients with DM and/or CRF and to prove, that acetylsalicylic acid (ASA) is able to improve the haemopoietic status by decreasing neocytolysis. METHODS: In a cross-sectional study, three groups of selected patients (patients with DM; patients with DM+CRF; patients with CRF without DM, n=15 each) and a group of controls (non-diabetic, nonazotemic subjects, n = 10) were compared. In the intervention part of the study, the effect of a single dose of 1 gram ASA on neocytolysis was investigated in a subgroup of these patients. RESULTS: Despite the similar EPO level (p = 1.000), all three patient groups had lower haemoglobin and haematocrit than control persons (p < 0.05 in all cases). Patients with DM+CRF had lower haemoglobin than patients with DM or CRF alone (p < 0.05). Single dose of ASA induced a fast increase in serum EPO level, a concomitant rise of the Rtc number and rate, red blood cell count, haematocrit and haemoglobin p < 0.01 for each). These changes were accompanied by a marked decrease in serum lactate dehydrogenase activity (p < 0.01). CONCLUSIONS: DM and CRF may induce erythropoietin resistance. In these patients, ASA treatment increases serum EPO level. The higher EPO level and the anti-inflammatory effect of ASA may decrease neocytolysis.

Self-concordance, goal attainment, and the pursuit of happiness: can there be an upward spiral?

Two studies used the self-concordance model of healthy goal striving (K. M. Sheldon & A. J. Elliot, 1999) to examine the motivational processes by which people can increase their level of well-being during a period of time and then maintain the gain or perhaps increase it even further during the next period of time. In Study 1, entering freshmen with self-concordant motivation better attained their 1st-semester goals, which in turn predicted increased adjustment and greater self-concordance for the next semester's goals. Increased self-concordance in turn predicted even better goal attainment during the 2nd semester, which led to further increases in adjustment and to higher levels of ego development by the end of the year. Study 2 replicated the basic model in a 2-week study of short-term goals set in the laboratory. Limits of the model and implications for the question of how (and whether) happiness may be increased are discussed.

[Malignant melanoma of soft parts (clear cell sarcoma)--a rare case of multiorgan localization]. / Malígny melanóm mäkkých castí (svetlobunkový sarkóm)--raritný prípad viacorgánovej lokalizácie.

Malignant melanoma of soft parts (MMSP) is a rare tumor originally described by Enzinger in 1965 as clear cell sarcoma of tendons and aponeuroses because of its affinity to tenosynovial structures. Tumors are found predominantly at the extremities. First visceral case was described in 1993 in the duodenum. We describe the case of 64-years old man with malignant melanoma of soft parts in the stomach, in the pancreas, in the mesocolon, in the left thigh and in the left axilla. This patient was successfully treated surgically by the resection of the stomach, resection of the pancreatic head, extirpation of the tumor from mesocolon, from the left thigh and from the left axilla. In all these localisations the tumor was histologically and imunohistochemically proved to be MMSP (positivity: s-100 protein, vimentin, HMB-45 and negativity CK, EMA, desmin, actin). This multivisceral occurrence is extremely rare and according to the review of literature this is probably the first published case of MMSP in the stomach and in the pancreas.

[Initial experience with laparoscopic adrenalectomy]. / Prvé skúsenosti s laparoskopickou adrenalektómiou.

We present the first experience with laparoscopic adrenalectomy, which was in Slovakia introduced to the surgical practice on March 3, 1996. We analyse first seven patients who underwent completed laparoscopic adrenalectomy (five leftsided, two right-sided). Four patients had cortex adenoma (clinically 2 incidentalomas and 2 Cishing syndroma), three patients had cortex hyperplasia (clinically Conn syndroma). Average duration of operation was 120 minutes, there were no postoperative complications. Average postoperative hospital stay was 5 days. Our initial experiences are comparable with that of surgical departments which has more than two-years experiences. Laparoscopic adrenalectomy is a perfect method for the small adrenal tumors and it is better than traditional transabdominal approach.

[Pancreatic abscesses]. / Abscesy pankreasu.

The paper deals with pancreatic abscess as one of three entities of pancreatic infection. In spite of the common origin with infected pancreatic necrosis and infected pancreatic pseudocyst, the treatment of each kind of pancreatic necrosis has its own requirements. By comparing 30 pancreatic abscesses (mortality 18%), 29 infected pancreatic pseudocysts (mortality 6%) and 35 infected pancreatic necroses (mortality 43.5%) we concluded that the best treatment for pancreatic abscess is surgical evacuation with external drainage, for that of infected pancreatic pseudocyst internal drainage operation, and for infected pancreatic necrosis surgical debridement with external drainage, lavage and open-abdomen procedure. Differences in CT scan, treatment and prognosis require different surgical approach to each type of pancreatic necrosis. (Fig. 3, Ref. 24.)

[Changes in mouse erythropoiesis during continuous irradiation with a daily dose of 957 mGy]. / Veränderungen der Blutbildung bei Mäusen während einer kontinuierlichen Bestrahlung mit einer Dosisleistung von 957 mGy pro Tag.

Quantitative and qualitative changes in the blood producing organs and in the peripheral blood of mice are evaluated in this paper. The animals were irradiated for 42 days continually with a daily dosage of 957 mGy. Until the 7th day of irradiation a significant diminution of the cellularity of the bone-marrow and of the cellularity as well as the mass of the spleen could be observed. After the 14th day or irradiation a temporary stabilization of the cell number in the bone-marrow could be found until the 28th day, after that time there was a moderately strong decrease. The cellularity and the mass of the spleen increased temporarily until the 28th day of irradiation because of erythropoiesis and myelopoiesis increasing from 20% to 50%. The most significant changes in the peripheral blood could be observed in not granulated cells as a kind of sudden and permanent decrease. The diminution of the granulocyte and reticulocyte number proceeded somewhat more slowly, temporarily revealing an increasing tendency on the 28th day of irradiation. The erythrocyte numbers as well as the haematocrit and haemoglobin values decreased continually beginning from the 7th day of irradiation until the death of the test animals.