[The Hyperoxalurias]. / Le iperossalurie.

Oxalate (Ox) is an end-product of metabolism, important for poor solubility of its calcium salt in biological fluids. Ox can therefore be found in about 70% of urinary calculi. Hyperoxaluria (HOx) defined as Ox exceeding 0.5 mmol)/day, may cause nephrolithiasis/nephrocalcinosis and may be classified as dietary (DH), enteric (EH) or primary (PH). Fractional intestinal absorption of Ox is less than 10%, but increases to over 20% at calcium intakes below 200 mg/day. DH is often related to low-calcium diets. EH is caused by non-absorbed fatty acids which bind to calcium and lower its concentration in the intestinal lumen. Ox forms more soluble complexes with other cations and results in HOx. Similar mechanisms may cause HOx following bariatric surgery. PHs are the most severe causes of HOx. Three types have so far been described, all being autosomic recessive. PH1 is due to mutations of AGXT gene encoding liver alanine-glyoxylate aminotransferase, PH2 is caused by mutations of GR-HPR gene encoding glyoxylate reductase and PH3 by mutations of HOGA1 encoding for hydroxyl-oxoglutarate aldolase. HOx results from deficient detoxification from glyoxylate, which is oxidized to Ox. The three PHs have different severity, though not always clinically distinguishable. They are identified through genetics and, in PH1, good genotype/phenotype correlations have been established. Thanks to early biochemical and genetic diagnosis, which are crucial to either prevent progression to ESRF or choose adequate transplantation strategies, the outlook of PH patients has dramatically improved in the last decades and will furtherly do in view of new therapeutic strategies.

[The effects of Cinacalcet in renal stone formers with primary hyperparathyroidism]. / Effetti del Cinacalcet sulla biochimica urinaria e il rischio litogeno in pazienti con Iperparatiroidismo Primitivo e calcolosi renale.

Primary hyperparathyroidism (PHPT) may favor nephrolithiasis mainly through an increase in calcium and phosphate urinary excretion. Cinacalcet exhibits good efficacy to control hypercalcemia in PHPT, but it is not so far known whether it might be a useful tool to prevent stone recurrences. Of 67 patients with PHPT and recurrent nephrolithiasis, 55 underwent parathyroidectomy (PTX) and 12, not eligible to PTX, were prescribed Cinacalcet. All the patients were evaluated for mineral metabolism, including estimation of state of saturation for calcium oxalate (CaOx) and brushite (bsh), both at baseline and after either PTX or Cinacalcet. PTX compared to baseline reduced PTH (4617 vs 15786 pg/mL, p<0.01), calcemia (9.40.5 vs 11.30.9 mg/dL, p<0.01), calciuria (3.62.3 vs 9.24.5 mmol/24h, p<0.01), phosphaturia (18.47.1 vs 21.99.9 mmol/24h, p<0.05), CaOx (4.73.9 vs 9.86.8, p<0.01) and bsh (1.10.9 vs 3.22.2, p<0.01). Cinacalcet decreased both PTH (13379 vs 17187 pg/mL, p<0.05) and calcemia (9.70.6 vs 11.20.8 mg/dL, p<0.001), whereas no change was seen in calciuria (7.42.2 vs 7.42.4 mmol/24h, p=ns), phosphaturia (21.97.3 vs 23.06.5 mmol/24h, p=ns), CaOx (6.92.7 vs 5.42.5, p=ns) and bsh (1.71.1 vs 1.31.3, p=ns). We conclude that in patients with PHPT, PTX is able to decrease the risk for crystallization of calcium salts, whereas calcimimetic Cinacalcet did not. Therefore, in patients with PHPT complicated with nephrolithiasis only PTX can improve urine biochemistries thereby reducing the risk for recurrent calcium stone disease.

[Genetic approach to nephrolithiasis]. / Approccio genetico alla nefrolitiasi.

Nephrolithiasis (NL) has high and increasing prevalence in western countries. Most renal stones contain calcium and/or uric acid and often occur as idiopathic stones, while seldom are caused by genetic disorders. Conversely, cystinuria, xantinuria, 2-8 dihydroxyadeninuria only occur in patients with mutations of corresponding genes. Inherited NL must be suspected in case of early onset, positive family history, severe recurrence rate, associated biochemical disorders, abnormal urinary sediment, renal insufficiency, involvement of other organs or apparatus. Pathophysiology is based on different mechanisms: electrolytic abnormalities, altered tubular transport, acid-base imbalances, cystic renal diseases. Sometimes NL is iatrogenic. Here we review some genetic NL, not only characterized by clinical relevance but also by the scientific interest in view of our better understanding of mechanisms of stone formation. Namely, Dents syndrome, calcium sensing receptor mutations, familial hypopomagnesiemic hypercalciuria (FHHNC), hypophosphatemic rickets (HHRH), renal tubular acidosis (dRTA), primary hyperoxaluria (PH), cystinuria, 2-8 dihydroxyadeninuria (2-8 DHA). We will briefly report on prevalence, genetics, pathophysiology, clinical aspects and treatment. The need for early diagnosis stems from the fact that, for most of these, selective treatment may be highly effective and can prevent progression to ESRD. Lastly, a better knowledge and understanding of genetic NL is a premise to study polymorphisms of candidate genes also in the setting of so-called idiopathic disease.

[Acute pielonephritis and renal abscesses in Piedmont and Aosta Valley]. / Indagine sulla pielonefrite acuta e sugli ascessi renali in Piemonte e Valle d'Aosta.

The Piedmont Group of Clinical Nephrology compared the activity of 18 nephrology centers in Piedmont and Aosta Valley as regards acute pielonephritis (APN). Data from more than 500 cases per year of APN were examined. The microbial spectrum of APN consists mainly of Escherichia coli and Klebsiella pneumoniae. Diagnosis was based on both clinical and radiological criteria in most of the centers (computed tomography-CT o Magnetic Resonance Imaging-MRI). In four centers diagnosis was made with the radiological criteria and in one center only with the clinical features. CT and MRI were performed in about 47% and 44% of cases respectively. Urine culture was positive in 22 up to 100% of cases. The most commonly used antibiotics were fluoroquinolones (ciprofloxacin or levofloxacin) and ceftriaxone (50% of centers) or amoxicillin/clavulanic acid (25% of centers). In 75% of the centers, patients received a combination of two antibiotics (aminoglycoside in 22% of them ). In 72% of the centers, almost 50% of the patients were re-examined, while 38.8% of centers re-examined all the patients. Renal ultrasound was inappropriate to identify abscesses. The mean of patients in whom renal abscesses were detected by CT or MRI was 18.2%. The analysis shows a high variability in the way of diagnosing and treating APN in Piedmont and Aosta Valley regions. This suggests that even if APN is a frequent pathological condition, practical recommendations are required.

[Renal biopsy practice in Piedmont and Valle d'Aosta]. / Indagine sulle modalità di esecuzione delle biopsia renale in Piemonte e Valle d'Aosta.

In 2010 a questionnaire was administered to the renal units of Piedmont and Valle d'Aosta to analyze their procedures for renal biopsy (RB). Seventy-eight percent of units performed RBs, 57% for more than 20 years, but only 43% performed at least 20 BRs per year. 20/21 units performed RB in an inpatient setting and 1/21 in day hospital with the patient remaining under observation the night after. Thirty-two percent did not consider a single kidney as a contraindication to RB, 59% considered it a relative contraindication and 9% considered it an absolute contraindication. In 90.5% of units there was a specific protocol for patient preparation for RB and 86% used a specific informed consent form. Ninety-five percent of units performed ultrasound-guided RB, 60% of them using needle guides attached to the probe. In 81% of units the left side was preferred; 71% put a pillow under the patient's abdomen. All units used disposable, automated or semi-automated needles. Needle size was 16G in 29%, 18G in 58%, and both 16G and 18G in 14% of units; 1 to 3 samples were drawn. One third of units had a microscope available for immediate evaluation of specimen adequacy. After RB, 86% of units kept patients in the prone position for 2-6 hours and all prescribed a period of bed rest (at least 24 hours in 90.5%). 90.5% of units followed a specific postbiopsy observation protocol consisting of blood pressure, heart rate and red blood cell measurements at different times, and urine monitoring and ultrasound control within 12-24 hours (only half of them also employing color Doppler). One third of all units discharged patients after 1 day and two thirds after 2-3 days; all prescribed abstention from effort and from antiplatelet drugs for 7-15 days. In 9 units both RB and tissue processing and examination were done in the same hospital, while 12 units sent the samples elsewhere. 76% obtained results in 2-4 days, 19% in 6-7 days, and 5% in 10-15 days. Less than 20% of the interviewed operators were fully familiar with the clauses of hospital insurance securing their activity. Use of RB is widespread in Piedmont and Valle d'Aosta but its practice shows variation between centers.

Search for genetic association between IgA nephropathy and candidate genes selected by function or by gene mapping at loci IGAN2 and IGAN3.

BACKGROUND: IgA nephropathy (IgAN) is not generally considered a hereditary disease, even though extensive evidence suggests an undefined genetic influence. Linkage analysis identified a number of genome regions that could contain variations linked to IgAN. METHODS: In this case-control association study, genes possibly involved in the development of IgAN were investigated. DNA samples from 460 North Italian patients with IgAN and 444 controls were collected. Candidate genes were selected based on their possible functional involvement (6 genes) or because of their location within linkage-identified genomic regions IGAN2 and IGAN3 (5 and 13 genes within chromosome 4q26-31 and 17q12-22, respectively). One hundred and ninety-two tag and functional single-nucleotide polymorphisms (SNPs) were typed with Veracode GoldenGate technology (Illumina). RESULTS: C1GALT1 showed an association with IgAN (rs1008898: P = 0.0019 and rs7790522: P = 0.0049). Associations were found when the population was stratified by gender (C1GALT1, CD300LG, GRN, ITGA2B, ITGB3 in males and C1GALT1, TRPC3, B4GALNT2 in females) and by age (TLR4, ITGB3 in patients aged <27 years). Furthermore, rs7873784 in TLR4 showed an association with proteinuria (G allele: P = 0.0091; GG genotype: P = 0.0077). CONCLUSIONS: Age and gender are likely to evidence distinct immunological and inflammatory reactions leading to individual susceptibility to IgAN. Overall, a genetic predisposition to sporadic IgAN was found. We might hypothesize that C1GALT1 and TLR4 polymorphisms influence the risk to develop IgAN and proteinuria, respectively.

[Lymphomatous renal involvement]. / Il coinvolgimento renale nei linfomi.

The incidence of lymphomas, especially non-Hodgkin's lymphoma (NHL), has shown a steady increase over the last decades. At the same time, the prognosis has improved. Given the longer survival of lymphoma patients, pathological manifestations related to malignancy might become more frequent. In this setting, the kidney is one of the most important solid organs affected by direct or indirect lymphomatous involvement. Kidney involvement can be related to obstruction or treatment-induced toxicity, but more intriguing are 1) direct infiltration (NHL); 2) renal malignancies in patients affected by Hodgkin's disease or NHL; 3) associated glomerular diseases. Primary infiltration is rarely seen, while secondary infiltration is described most frequently in autopsy series, even in the absence of renal failure. These alterations may mimic glomerular and/or interstitial disease. The association with kidney malignancies, mostly renal cell carcinoma but also urothelial tumors in Hodgkin''s disease, is higher in lymphoma patients than in the general population: the relative risk at 10 years is about 1.5. Glomerulonephritis is described in patients with Hodgkin's disease or NHL; in the former minimal change disease is most frequent, in the latter the glomerular pattern varies widely. Glomerulonephritis can precede, be concurrent with, or follow lymphoma manifestations. Renal biopsy is often needed in this setting.