János P. Kósa

Elevated Fibroblast Growth Factor 23 is a Risk Factor for Kidney Transplant Loss and Mortality

An increased circulating level of fibroblast growth factor 23 (FGF23) is an independent risk factor for mortality, cardiovascular disease, and progression of chronic kidney disease (CKD), but its role in transplant allograft and patient survival is unknown. We tested the hypothesis that increased FGF23 is an independent risk factor for all-cause mortality and allograft loss in a prospective cohort of 984 stable kidney transplant recipients. At enrollment, estimated GFR (eGFR) was 51 ± 21 ml/min per 1.73 m(2) and median C-terminal FGF23 was 28 RU/ml (interquartile range, 20 to 43 RU/ml). Higher FGF23 levels independently associated with increased risk of the composite outcome of all-cause mortality and allograft loss (full model hazard ratio: 1.46 per SD increase in logFGF23, 95% confidence interval: 1.28 to 1.68, P<0.001). The results were similar for each component of the composite outcome and in all sensitivity analyses, including prespecified analyses of patients with baseline eGFR of 30 to 90 ml/min per 1.73 m(2). In contrast, other measures of phosphorus metabolism, including serum phosphate and parathyroid hormone (PTH) levels, did not consistently associate with outcomes. We conclude that a high (or elevated) FGF23 is an independent risk factor for death and allograft loss in kidney transplant recipients.

The Candidate Oncogene CYP24A1: A Potential Biomarker for Colorectal Tumorigenesis

The main autocrine/paracrine role of the active metabolite of vitamin D3, 1α,25-dihydroxyvitamin D3 (1,25-D3), is inhibition of cell growth and induction of cell differentiation and/or apoptosis. Synthesis and degradation of the secosteroid occurs not only in the kidney but also in normal tissue or malignant extrarenal tissues such as the colon. Because 25-hydroxyvitamin D3 24-hydroxylase (CYP24A1) is considered to be the main enzyme determining the biological half-life of 1,25-D3, we have examined expression of the CYP24A1 mRNA (by real-time RT-PCR) and protein (by immunohistochemistry) in normal human colon mucosa, colorectal adenomas, and adenocarcinomas in 111 patients. Although 76% of the normal and benign colonic tissue was either completely devoid of or expressed very low levels of CYP24A1, in the majority of the adenocarcinomas (69%), the enzyme was present at high concentrations. A parallel increased expression of the proliferation marker Ki-67 in the same samples suggests that overexpression of CYP24A1 reduced local 1,25-D3 availability, decreasing its antiproliferative effect.

Evaluation of the Malnutrition-Inflammation Score in Kidney Transplant Recipients

BACKGROUND Chronic protein-energy wasting, termed malnutrition-inflammation complex syndrome, is frequent in patients with chronic kidney disease and is associated with anemia, morbidity, and mortality in patients on maintenance dialysis therapy. The Malnutrition-Inflammation Score (MIS) recently has been developed and validated in dialysis patients. STUDY DESIGN Observational cross-sectional study. SETTING & PARTICIPANTS 993 prevalent kidney transplant recipients. PREDICTOR MIS computed from change in body weight, dietary intake, gastrointestinal symptoms, functional capacity, comorbid conditions, decreased fat store/Systemic Global Assessment, signs of muscle wasting/Systemic Global Assessment, body mass index, serum albumin level, and serum transferrin level. OUTCOMES Markers of inflammation and malnutrition, including serum C-reactive protein, interleukin 6, tumor necrosis factor alpha, serum leptin, prealbumin, body mass index, and abdominal circumference. The relationship was modeled by using structural equation models. RESULTS Mean age was 51 +/- 13 years, 57% were men, and 21% had diabetes. Median time from transplant was 72 months. MIS significantly correlated with abdominal circumference (r = -0.144), serum C-reactive protein level (r = 0.094), serum interleukin 6 level (r = 0.231), and serum tumor necrosis factor alpha level (r = 0.102; P < 0.01 for all). A structural equation model with 2 latent variables (malnutrition and inflammation factor) showed good fit to the observed data. LIMITATIONS Single-center study, lack of information about vascular access, presence of nonfunctioning kidney transplant, relatively high refusal rate. CONCLUSIONS Our results confirm that MIS reflects both energy-protein wasting and inflammation in kidney transplant recipients. This simple instrument appears to be a useful tool to assess the presence of protein-energy wasting in this patient population.

Association between the malnutrition-inflammation score and post-transplant anaemia

BACKGROUND Post-transplant anaemia (PTA) is common and is associated with adverse consequences. The protein-energy wasting (PEW) syndrome is associated with erythropoietin resistance in patients on maintenance dialysis. We assessed the association between PEW and PTA in a large prevalent cohort of stable kidney-transplanted patients. METHODS Data from 942 prevalent kidney-transplanted patients were analysed. Socio-demographic parameters, laboratory results, transplantation-related data and medication were obtained from the charts. Biomarkers reflecting nutritional status and inflammation [serum leptin, albumin, interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α) and C-reactive protein] were measured. Anthropometric measures and the malnutrition-inflammation score (MIS) were also tabulated. Anaemia was defined according to the guidelines of the American Society of Transplantation. RESULTS Mean age was 51 ± 13 years, 57% were males and 22% had diabetes. The prevalence of PTA was 33%. The haemoglobin (Hb) level significantly and negatively correlated with the MIS (rho = - 0.316), marginally with serum TNF-α (rho = - 0.079) and serum IL-6 (rho = - 0.075) and positively with serum transferrin (r = 0.298), serum albumin (r = 0.274), abdominal circumference (r = 0.254) and serum leptin (rho = - 0.152), P < 0.05 for all. In a multivariable linear regression model, MIS was independently associated with Hb (beta = - 0.118, P = 0.004) in patients with estimated glomerular filtration rate (eGFR) lower than or equal to 60 mL/min/1.73 m(2), but not in patients with higher eGFR. CONCLUSIONS The MIS is independently associated with PTA in the kidney-transplanted population with eGFR lower than or equal to 60 mL/min/1.73 m(2).

Hard ticks infesting dogs in Hungary and their infection with Babesia and Borrelia species

A survey was carried out in Hungary to investigate the occurrence of hard tick species (Acari: Ixodidae) collected from dogs and Borrelia and Babesia spp. detected in them. In total, 1,424 ticks were removed from 477 dogs appearing for clinical consultation in veterinary practices and clinics countrywide. Ixodes ricinus and Dermacentor reticulatus were the most common species occurring in most of the studied areas. Females of these two species were selected for molecular analyses. One to twelve specimens were used in each sample for DNA extraction. Polymerase chain reactions were performed with BSLF/BSL-R primers for detecting Borrelia spp. in I. ricinus and with PIRO-A1/PIRO-B primers to amplify Babesia spp. DNA in D. reticulatus. Randomly selected PCR products were sequenced to identify the pathogens’ species or subspecies. DNA of Borrelia spp. could be detected in six (5.6%) from 108 I. ricinus samples and 43 (29.9%) from 144 D. reticulatus samples were PCR-positive for Babesia spp. Sequencing revealed the highest similarity with Borrelia afzelii, Borrelia garinii and Babesia canis canis, respectively. Babesia and Borrelia spp. were identified in ticks with molecular methods for the first time in Hungary, and a high prevalence of B. canis canis in D. reticulatus females collected from dogs was detected.

Effects of the lactase 13910 C/T and calcium-sensor receptor A986S G/T gene polymorphisms on the incidence and recurrence of colorectal cancer in Hungarian population.

BackgroundEpidemiological studies suggested the chemopreventive role of higher calcium intake in colorectal carcinogenesis. We examined genetic polymorphisms that might influence calcium metabolism: lactase (LCT) gene 13910 C/T polymorphism causing lactose intolerance and calcium-sensing receptor (CaSR) gene A986S polymorphism as a responsible factor for the altered cellular calcium sensation.Methods538 Hungarian subjects were studied: 278 patients with colorectal cancer and 260 healthy controls. Median follow-up was 17 months. After genotyping, the relationship between LCT 13910 C/T and CaSR A986S polymorphisms as well as tumor incidence/progression was investigated.Resultsin patient with colorectal cancer, a significantly higher LCT CC frequency was associated with increased distant disease recurrence (OR = 4.04; 95% CI = 1.71–9.58; p = 0.006). The disease free survival calculated from distant recurrence was reduced for those with LCT CC genotype (log rank test p = 0.008). In case of CaSR A986S polymorphism, the homozygous SS genotype was more frequent in patients than in controls (OR = 4.01; 95% CI = 1.33–12.07; p = 0.014). The number of LCT C and CaSR S risk alleles were correlated with tumor incidence (p = 0.035). The CCSS genotype combination was found only in patients with CRC (p = 0.033).ConclusionLCT 13910 C/T and CaSR A986S polymorphisms may have an impact on the progression and/or incidence of CRC.

Associations between serum leptin level and bone turnover in kidney transplant recipients

BACKGROUND AND OBJECTIVES Obesity is associated with increased parathyroid hormone (PTH) in the general population and in patients with chronic kidney disease (CKD). A direct effect of adipose tissue on bone turnover through leptin production has been suggested, but such an association has not been explored in kidney transplant recipients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This study examined associations of serum leptin with PTH and with biomarkers of bone turnover (serum beta crosslaps [CTX, a marker of bone resorption] and osteocalcin [OC, a marker of bone formation]) in 978 kidney transplant recipients. Associations were examined in multivariable regression models. Path analyses were used to determine if the association of leptin with bone turnover is independent of PTH. RESULTS Higher leptin levels were associated with higher PTH and lower vitamin D levels, and adjustment for vitamin D attenuated the association between leptin and PTH. However, higher leptin was also significantly associated with lower levels of the bone turnover markers: 1 SD higher leptin was associated with 0.13 lower log-OC (-0.17, -0.08, P < 0.001) and 0.030 lower log-CTX (-0.045, -0.016, P < 0.001) after multivariable adjustments. Path analysis indicated that the association of leptin with PTH was mostly mediated through vitamin D, and that the association between leptin and bone turnover was independent of PTH and vitamin D. CONCLUSIONS Elevated leptin level is associated with lower bone turnover independent of its effects on serum PTH in kidney transplant recipients.

Myocardial infarction is associated with Sp1 binding site polymorphism of collagen type 1A1 gene

Objective — Human atherosclerotic lesions contain collagen type 1, which plays a pivotal role in atherosclerotic plaque stability. In contrast, the normal coronary arteries do not express this type of collagen. Data have shown that the collagen type 1A1 (COL1A1) gene Sp1 binding site (-1245 G/T) polymorphism is associated with disturbed collagen protein production. Methods — In our study, COL1A1 gene Sp1 polymorphism was investigated in 136 patients with myocardial infarction (MI) 5 months after the acute phase, and 212 age-matched control subjects in association with any cardiovascular risk factors (such as serum adiponectin levels, hyperinsulinaemic status, hyperlipaemia). Results — The “SS” genotype of the COL1A1 gene was found to occur significantly more frequently in patients surviving a MI, as compared to the control group and the “Ss” and “ss” genotype frequencies (the presence of the s allele) were lower in our patients, than in control group. However, the occurrence of cardiovascular risk factors was significantly higher among the “s” allelic carriers as compared to patients carrying the “S” allele of the COL1A1 gene. Conclusion — Our results raise the possibility that COL1A1 gene Sp1 polymorphism might have an impact on the development of MI.

The protective role of bone morphogenetic protein-8 in the glucocorticoid-induced apoptosis on bone cells

One of the side effects associated with glucocorticoid therapy is glucocorticoid-induced bone loss. Glucocorticoids partly detain bone formation via the inhibition of osteoblastic function, however, the exact mechanism of this inhibition remains elusive. In this study, we examined the effect of dexamethasone, an active glucocorticoid analogue, on cell viability and expression of bone remodelling-related genes in primary mouse calvarial and cloned MC3T3-E1 osteoblasts. Using sensitive biochemical assays, we demonstrated the apoptotic effect of dexamethasone on osteoblastic cells. Then, utilizing Taqman probe-based quantitative RT-PCR technology, gene expression profiles of 111 bone metabolism-related genes were determined. As a result of dexamethasone treatment we have detected significant apoptotic cell death, and six genes, including Smad3, type-2 collagen α-1, type-9 collagen α-1, matrix metalloproteinase-2, bone morphogenetic protein-4 and bone morphogenetic protein-8 showed (BMP-8) significant changes in their expression on a time- and concentration-dependent manner. BMP-8, (a novel player in bone-metabolism) exhibited a two orders of magnitude elevation in its mRNA level and highly elevated protein concentration by Western blot in response to dexamethasone treatment. The knockdown of BMP-8 by RNA interference significantly increased dexamethasone-induced cell death, confirming a protective role for BMP-8 in the glucocorticoid-induced apoptosis of osteoblasts. Our results suggest that BMP-8 might be an essential player in bone metabolism, especially in response to glucocorticoids.

CYP3A7*1C Polymorphism, Serum Dehydroepiandrosterone Sulfate Level, and Bone Mineral Density in Postmenopausal Women

The CYP3A7 enzyme metabolizes some steroid hormones, including dehydroepiandrosterone sulfate (DHEAS). The age-related decline of serum DHEAS levels is believed to contribute to osteoporosis. Previously, the CYP3A7*1C polymorphism has been shown to cause a persistent high CYP3A7 enzyme activity, resulting in lower levels of DHEAS in men. We hypothesized that the CYP3A7*1C polymorphism might contribute to bone loss through decreased levels of serum DHEAS in postmenopausal women. Postmenopausal women (n = 319) were divided into two subgroups: 217 with osteoporosis and 102 healthy controls. Genotyping, serum DHEAS measurement, and osteodensitometry of the lumbar spine and femoral neck were carried out in all subjects. Homozygous CYP3A7*1C carriers had significantly lower BMD at the lumbar spine compared to wild types (T score −3.27 ± 1.02 in CYP3A7*1C homozygous mutants vs. −1.35 ± 1.53 in wild types, P = 0.041). This association remained significant after adjustment for menopausal age, serum DHEAS level, alcohol consumption, steroid intake, smoking habits, and previous fractures. No association was found between genotypes and serum DHEAS levels in the total study population or in the subgroups. Serum DHEAS levels correlated positively with bone mineral density at the lumbar spine (r = 0.59, P = 0.042) after correction for age. Our data suggest that the CYP3A7 polymorphism might have an influence on bone mass at the lumbar spine independently of serum DHEAS concentrations.