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Background and objectives Recent epidemiologic studies have provided evidence for an association between nephrolithiasis and cardiovascular disease, although the underlying mechanism is still unclear. Vascular calcification (VC) is a strong predictor of cardiovascular morbidity and the hypothesis explored in this study is that VC is more prevalent in calcium kidney stone formers (KSFs). The aims of this study were to determine (1) whether recurrent calcium KSFs have more VC and osteoporosis compared with controls and (2) whether hypercalciuria is related to VC in KSFs.Design, setting, participants, & measurements This is a retrospective, matched case-control study that included KSFs attending an outpatient nephrology clinic of the Royal Free Hospital (London, UK) from 2011 to 2014. Ageand sex-matched non-stone formers were drawn from a list of potential living kidney donors from the same hospital. A total of 111 patients were investigated, of which 57 were KSFs and 54 were healthy controls. Abdominal aortic calcification (AAC) and vertebral bone mineral density (BMD) were assessed using available computed tomography (CT) imaging. The prevalence, severity, and associations of AAC and CT BMD between KSFs and non-stone formers were compared.Results Mean age was 47614 years in KSFs and 47613 in non-stone formers. Men represented 56% and 57% of KSFs and non-stone formers, respectively. The prevalence of AAC was similar in both groups (38% in KSFs versus 35% in controls, P=0.69). However, the AAC severity score (median [25th percentile, 75th percentile]) was significantly higher in KSFs compared with the control group (0 [0, 43] versus 0 [0, 10], P,0.001). In addition, the average CT BMD was significantly lower in KSFs (159653 versus 194 648 Hounsfield units, P,0.001). A multivariate model adjusted for age, sex, high BP, diabetes, smoking status, and eGFR confirmed that KSFs have higher AAC scores and lower CT BMD compared with non-stone formers (P,0.001 for both). Among stone formers, the association between AAC score and hypercalciuria was not statistically significant (P=0.86).Conclusions This study demonstrates that patients with calcium kidney stones suffer from significantly higher degrees of aortic calcification than age-and sex-matched non-stone formers, suggesting that VC may be an underlying mechanism explaining reported associations between nephrolithiasis and cardiovascular disease. Moreover, bone demineralization is more prominent in KSFs. However, more data are needed to confirm the possibility of potentially common underlying mechanisms leading to extraosseous calcium deposition and osteoporosis in KSFs.

Treatment with OC5 did not significantly reduce Uox or Pox over 8 weeks of treatment. The treatment was well tolerated and successfully delivered to the gastrointestinal tract.

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The aims of the study were to (1) compare peripheral bone mineral density (BMD) in men with diabetes to peripheral BMD in non-diabetic men, and (2) explore factors which may predict BMD in diabetic men. Ninety men with type 2 diabetes and 35 men with type 1 diabetes were randomly selected for participation via a computerised database. Fifty healthy males were also recruited. All patients had peripheral BMD measured by dual energy Xray absorptiometry (DEXA) at the non-dominant distal radius. Information on a number of clinical parameters was obtained by direct questioning, and from patient case notes. The mean age (95% confidence interval (CI)) of the type 1 diabetic group, type 2 diabetic group and control group were, respectively: 49.3 years (44.6-53.9), 62.8 years (60.7-64.8) and 38.5 (34.9-42.1) years. Median (95% CI) Z-scores for the three groups were: -0.18 (-0.68 to +0.32), +0.19 (-0.14 to +0.49) and -0.02 (-0.4 to +0.31), respectively (p=not significant). Only body mass index (BMI) was correlated with BMD in the type 1 diabetic group, and only BMI and age were correlated with BMD in type 2 diabetics. There was no correlation between BMD and glycosylated haemoglobin concentration (HbA(1)c), disease duration or presence of microvascular or macrovascular complications in either of the diabetic groups. We did not find any significant difference in peripheral BMD between patients with type 1 diabetes, type 2 diabetes and controls.

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Cystinuria is the commonest inherited cause of nephrolithiasis (~1% in adults; ~6% in children) and is the result of impaired cystine reabsorption in the renal proximal tubule. Cystine is poorly soluble in urine with a solubility of ~1 mM and can readily form microcrystals that lead to cystine stone formation, especially at low urine pH. Diagnosis of cystinuria is made typically by ion-exchange chromatography (IEC) detection and quantitation, which is slow, laboursome and costly. More rapid and frequent monitoring of urinary cystine concentration would significantly improve the diagnosis and clinical management of cystinuria. We used attenuated total reflection - Fourier transform infrared spectroscopy (ATR-FTIR) to detect and quantitate insoluble cystine in 22 cystinuric and 5 healthy control urine samples. Creatinine concentration was also determined by ATR-FTIR to adjust for urinary concentration/dilution. Urine was centrifuged, the insoluble fraction re-suspended in 5 μL water and dried on the ATR prism. Cystine was quantitated using its 1296 cm−1 absorption band and levels matched with parallel measurements made using IEC. ATR-FTIR afforded a rapid and inexpensive method of detecting and quantitating insoluble urinary cystine. This proof-of-concept study provides a basis for developing a high-throughput, cost-effective diagnostic method for cystinuria, and for point-of-care clinical monitoring

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