Elena Dogliotti

Polymorphisms at the regulatory regions of the CASR gene influence stone risk in primary hyperparathyroidism

BACKGROUND AND OBJECTIVE Single nucleotide polymorphisms (SNPs) of the calcium-sensing receptor (CASR) gene at the regulatory region were associated with idiopathic calcium nephrolithiasis. To confirm their association with nephrolithiasis, we tested patients with primary hyperparathyroidism (PHPT). DESIGN A genotype-phenotype association study. METHODS In all, 332 PHPT patients and 453 healthy controls were genotyped for the rs7652589 (G>A) and rs1501899 (G>A) SNPs sited in the noncoding regulatory region of the CASR gene. Allele, haplotype, and diplotype distribution were compared between PHPT patients and controls, and in stone forming and stone-free PHPT patients. RESULTS The allele frequency at rs7652589 and rs1501899 SNPs was similar in PHPT patients and controls. The A minor alleles at these two SNPs were more frequent in stone forming (n=157) than in stone-free (n=175) PHPT patients (rs7652589: 36.9 vs 27.1%, P=0.007; rs1501899: 37.1 vs 26.4%, P=0.003). Accordingly, homozygous or heterozygous PHPT patients for the AA haplotype (n=174, AA/AA or AA/GG diplotype) had an increased stone risk (odds ratio 1.83, 95% confidence interval 1.2-2.9, P=0.008). Furthermore, these PHPT patients had higher serum concentrations of ionized calcium and parathyroid hormone (1.50 ± 0.015 mmol/l and 183 ± 12.2 pg/ml) than patients with the GG/GG diplotype (n=145, 1.47 ± 0.011 mmol/l (P=0.04) and 150 ± 11.4 pg/ml (P=0.049)). Using a logistic regression model, the increase in stone risk in PHPT patients was predicted by AA/AA or AA/GG diplotype, the highest tertile of serum ionized calcium values and the lowest tertile of age. CONCLUSIONS Polymorphisms located in the regulatory region of the CASR gene may increase susceptibility of the PHPT patients to kidney stone production.

Calcimimetic R-568 effects on activity of R990G polymorphism of calcium-sensing receptor

Previous studies have demonstrated a gain-of-function of the calcium-sensing receptor (CASR) gene R990G polymorphism. In this study, activation of the R990G CASR stably transfected in HEK-293 (HEK-990G) cells compared with that of the common variant (HEK-wild-type (WT)) by increasing concentrations of CaCl(2) or calcimimetic R-568 caused significantly higher intracellular free calcium concentration ([Ca(2+)](i)) and lower Ca-EC(50). Moreover, the [Ca(2+)](i) oscillation percentage was higher with a larger sinusoidal pattern in HEK-990G. R-568 induced a shift of the oscillatory events from 4 to 2  mmol/l extracellular calcium concentration in HEK-990G cells and increased the sinusoidal oscillation percentage in comparison with HEK-WT. Preincubation with thapsigargin or phospholipase C inhibitors completely prevented oscillations in both cell lines, consistent with the involvement of the inositol trisphosphate pathway, while protein kinase C inhibitor prevented oscillations in HEK-WT cells only. Finally, CaCl(2) and R-568 caused a significant increase in p44/42 extracellular signaling-regulated kinase phosphorylation, with the mean Ca-EC(50) values being significantly lower in HEK-990G. Our findings demonstrated that the 990G allele is associated with high sensitivity to R-568, which provided new evidence for differences in CASR signaling.

Calcium-sensing receptor and calcium kidney stones

Calcium nephrolithiasis may be considered as a complex disease having multiple pathogenetic mechanisms and characterized by various clinical manifestations. Both genetic and environmental factors may increase susceptibility to calcium stones; therefore, it is crucial to characterize the patient phenotype to distinguish homogeneous groups of stone formers. Family and twin studies have shown that the stone transmission pattern is not mendelian, but complex and polygenic. In these studies, heritability of calcium stones was calculated around 50%Calcium-sensing receptor (CaSR) is mostly expressed in the parathyroid glands and in renal tubules. It regulates the PTH secretion according to the serum calcium concentration. In the kidney, it modulates electrolyte and water excretion regulating the function of different tubular segments. In particular, CaSR reduces passive and active calcium reabsorption in distal tubules, increases phosphate reabsorption in proximal tubules and stimulates proton and water excretion in collecting ducts. Therefore, it is a candidate gene for calcium nephrolithiasis.In a case-control study we found an association between the normocitraturic stone formers and two SNPs of CaSR, located near the promoters region (rs7652589 and rs1501899). This result was replicated in patients with primary hyperparathyroidism, comparing patients with or without kidney stones. Bioinformatic analysis suggested that the minor alleles at these polymorphisms were able to modify the binding sites of specific transcription factors and, consequently, CaSR expression.Our studies suggest that CaSR is one of the candidate genes explaining individual predisposition to calcium nephrolithiasis. Stone formation may be favored by an altered CaSR expression in kidney medulla involving the normal balance among calcium, phosphate, protons and water excretion.

Resveratrol inhibits cell growth in a human cholangiocarcinoma cell line

Background/Aims: Cholangiocarcinoma is a devastating tumour with a poor prognosis. An efficient therapy is unavailable in unoperable patients and new drugs are widely sought for and required. Resveratrol (RES) is a natural molecule with a reported anticancer effect, evaluated on different tumour cell lines. We tested the efficacy of RES on a cholangiocarcinoma cell line for the first time.

Dietary style and acid load in an Italian population of calcium kidney stone formers

BACKGROUND AND AIMS Animal protein intake may cause an acid load that predisposes individuals to stones by influencing calcium and citrate excretion. These associations were not confirmed in recent studies. Therefore the present study was aimed to compare acid load of diet in stone formers and controls. METHODS AND RESULTS Participants to the study were 157 consecutive calcium stone formers and 144 controls. Diet was analyzed in these subjects using a software that evaluated nutrient intake from a three-day food intake diary. This software also estimated the potential renal acid load (PRAL, mEq/day). Twenty-four-hour urine excretion of ions and citrate was measured in stone formers. Stone former diet had lower intake of glucose, fructose, potassium and fiber and higher PRAL in comparison with controls. The multinomial logistic regression analysis showed that stone risk decreased in association with the middle and the highest tertiles of fiber intake and increased in association with the highest tertile of PRAL. The linear multiple regression analysis showed that calcium excretion was associated with the sodium excretion and that citrate excretion was associated with the PRAL and animal protein intake in stone formers. CONCLUSION Our findings suggest that stone formers may undergo a greater dietary acid load sustained by a low vegetable intake and base provision. Dietary acid load does not appear as the main determinant of calcium excretion, but may promote stone risk by decreasing citrate excretion. Sodium intake may predispose to stones by stimulating calcium excretion.

Cytogenetic characterization and cell cycle analysis of three human colon adenocarcinoma cell lines: comparison between two- and three-dimensional cell culture systems.

ABSTRACT The aim of the study was to investigate whether changes in the pattern of gene copy number and cell cycle were present passing from the two- to the three-dimensional cell culture system. We used three human colon adenocarcinoma cell lines grown two- and three-dimensionally. We analyzed morphology, karyotype, chromosomal gain and losses, and cell cycle. In three-dimensional cell cultures the growth is delayed and arrested in G1 phase without specific rearrangements in the three-dimensional cultures compared to the two-dimensional cultures. These data suggest that the differences between the two- and three-dimensional cell culture systems do not involve chromosomal rearrangements.

Nephrolithiasis: nutrition as cause or therapeutic tool

Nephrolithiasis is a very common disease with an increasing prevalence among industrialized populations. Kidney stone formation is a complex phenomenon, involving genetic and metabolic patterns, and nutrition can play an important role in this match both as a promoter or as a protective factor. To promote a deeper knowledge of such a challenging disease, clinicians and researchers have met in Rome, Italy, last March 2013, at the International Congress “Nephrolithiasis: a systemic disorder” to discuss patho-physiology and possible treatment of kidney stones. During the meeting, a whole session was dedicated to nutrition, seen both as a cause or a therapeutic tool for nephrolithiasis. Due to its etiopathogenesis, nephrolithiasis is also an ideal model for a nutrigenetics and nutrigenomics approach. Nutrigenomics and nutrigenetic respectively study the effects of a dietary treatment on gene expression and, on the other hand, the impact of an inherited trait on the response to a specific dietary treatment.

Introducing the nutrition & metabolism section of journal of translational medicine

Nutrition experts, as well as specialists of different pathologies, are disclosing an ever increasing interest for protocols devoted to the welfare of patients and to prevention of nutrition related diseases. In fact, it is extensively acknowledged that nutrition plays a primary role in those complex diseases most widespread in the western countries like cardiovascular disease [1], cancer [2], Alzheimers disease [3], diabetes [4], nephrolithiasis [5] etc. that account for over 60% of deaths world-wide. Even in our country, Italy, and in other South Europes countries, until now protected by the Mediterranean diet, which in 2010 was awarded by UNESCO the human heritage status, the next generation will be the first with a life expectancy lower than of their parents, principally due to unhealthy eating habits and the obesity epidemic. To counteract this trend, in the last decade attention has been focused on the human nutrition field, with significant research topics being new molecules contrasting cholesterol accumulation in the arterial walls or capable of diminishing visceral fat [6], the role of bacterial microflora [7], the production of functional foods, studies on antioxidant properties of vitamins and polyphenols, etc. Moreover, beside knowledge acquired with traditional investigation techniques, the field of human nutrition can now avail itself of the new omics techniques that could give a significant contribute to mapping the interactions between genetics, nutrition and health [8]. In the area of Translational Medicine, we believe that the field of nutrition ought to be taken into greater account, as an interaction and mutual validation agency between basic and applied research, in order to generate advanced applications for diagnosis and therapy and to develop at the same time new instruments of investigation. We here propose a new section devoted to the rapid publication of research papers on all aspects of nutrition with applications in medicine and biotechnology. This section welcomes contributions that employ traditional clinical, metabolic and epidemiologic methods, but is also open to molecular and cell biology research applied to animal and human nutrition. Topics include: diet interactions in chronic diseases, gene-environment interactions, genes and cell metabolism, protein and aminoacid metabolism, lipid metabolism and diseases, carbohydrate metabolism and diseases, micronutrients and functional foods. Other topics relevant to nutrition will be appreciated as well.

Nephrolithiasis and nutrition in obesity

Background Obesity is a risk factor for nephrolithiasis (NL). According to an American study of a large cohort with a BMI >30, males increased the risk of NL of 30% and females of 200%. Moreover, diet plays an important role as NL risk factor, mainly in those western countries characterized by a large meet consume. This epidemiology study investigated the NL frequency in an obese Italian population, also considering the relation with metabolic syndrome and interaction with diet.

Nutritional case-control study of Calcium Nephrolithiasis

Background It is well established that nutritional habits are relevant in the prevention of Idiopathic Calcium Nephrolithiasis (ICN) and the Mediterranean diet is believed to be protective against nephrolithiasis and not only against cardiovascular events. A case-control study was performed to establish the nutritional habits of Italian ICN patients and the nutritional determinants of lithogenic risk in the considered population.