Intra-islet insulin synthesis defects are associated with endoplasmic reticulum stress and loss of beta cell identity in human diabetes.

AIMS/HYPOTHESIS: Endoplasmic reticulum (ER) stress and beta cell dedifferentiation both play leading roles in impaired insulin secretion in overt type 2 diabetes. Whether and how these factors are related in the natural history of the disease remains, however, unclear. METHODS: In this study, we analysed pancreas biopsies from a cohort of metabolically characterised living donors to identify defects in in situ insulin synthesis and intra-islet expression of ER stress and beta cell phenotype markers. RESULTS: We provide evidence that in situ altered insulin processing is closely connected to in vivo worsening of beta cell function. Further, activation of ER stress genes reflects the alteration of insulin processing in situ. Using a combination of 17 different markers, we characterised individual pancreatic islets from normal glucose tolerant, impaired glucose tolerant and type 2 diabetic participants and reconstructed disease progression. CONCLUSIONS/INTERPRETATION: Our study suggests that increased beta cell workload is accompanied by a progressive increase in ER stress with defects in insulin synthesis and loss of beta cell identity.

Prevalence and clinical impact of high platelet reactivity in patients with chronic kidney disease treated with percutaneous coronary intervention: An updated systematic review and meta-analysis.

BACKGROUND: High platelet reactivity (HPR) on clopidogrel and chronic kidney disease (CKD) are recognized as potent risk factors for adverse outcomes in patients suffering coronary artery disease (CAD) and undergoing percutaneous coronary intervention (PCI). However, conclusive evidence regarding their reciprocal interaction and the consequent impact on clinical events is still lacking. OBJECTIVES: We performed a metaanalysis with the aim to evaluate the prevalence of HPR in patients with and without CKD and the incidence of major adverse cardiovascular events (MACE) according to the renal and platelet function status in current literature (co-primary endpoints). Secondary endpoints were myocardial infarction (MI), all-cause death, and definite/probable stent thrombosis (ST). METHODS: We searched on PubMed, EMBASE, and Cochrane Library studies investigating CKD and HPR on clopidogrel in patients suffering CAD who underwent PCI and their related outcomes. Overall, 13 studies including 22.464 patients were selected. Odds ratios (ORs) and 95% confidence intervals (CI) were calculated using a random-effects model with the Mantel-Haenszel method. RESULTS: Patients with CKD presented significantly higher odds of HPR compared with those without CKD (OR 1.51 [95% CI: 1.29, 1.76]). In patients without CKD, HPR was associated with increased odds of MACE (OR 1.31 [95% CI: 1.01, 1.72]), MI (OR 1.48 [95% CI: 1.17, 1.86]) and definite/probable ST (OR 2.45 [95% CI: 1.08, 5.60]). In patients with CKD, HPR was associated with higher odds of both MACE (OR 1.61 [95% CI: 1.14, 2.27]) and MI (OR 1.69 [95% CI: 1.11, 2.59]), compared to those without HPR. CONCLUSIONS: Our analysis shows that HPR on clopidogrel is more frequent in patients with CKD treated with PCI. Patients with HPR are exposed to a high risk of MACE after PCI, regardless of the renal function status.

Randomized Placebo-Controlled Trial of Reloxaliase in Enteric Hyperoxaluria.

BACKGROUND: Enteric hyperoxaluria is caused by increased intestinal oxalate absorption and can lead to kidney stones, chronic kidney disease, and kidney failure. Reloxaliase is an orally administered recombinant enzyme that degrades oxalate along the gastrointestinal tract, thereby preventing its absorption. METHODS: We randomly assigned participants with enteric hyperoxaluria to reloxaliase or placebo, three to five times per day with food for 4 weeks. The primary end point was percent change from baseline in 24-hour urinary oxalate (UOx) excretion during weeks 1 to 4. Secondary end points included the proportion of participants with more than a 20% reduction in 24-hour UOx and an efficacy assessment in the bariatric surgery subgroup. RESULTS: A total of 115 patients underwent randomization. The 24-hour UOx decreased from a baseline geometric mean of 83.2 to 67.4 mg/24 hr during weeks 1 to 4 in reloxaliase-treated participants. Corresponding data for placebo-treated participants were 84.2 to 78.1 mg/24 hr. Estimates from the mixed-effect model repeated-measures (MMRM) analysis showed a 22.6% reduction in geometric mean UOx during weeks 1 to 4 for reloxaliase and 9.7% for placebo, a difference of 14.3 percentage points (95% confidence interval [CI], 4.9 to 22.8; P=0.004). A 20% or greater reduction in 24-hour UOx was observed in 48.3% of reloxaliase-treated participants and 31.6% of placebo-treated participants (P=0.06). In the bariatric surgery subgroup, MMRM analysis showed a 21.2% reduction in geometric mean UOx for reloxaliase and a 6.0% reduction for placebo, for a difference of 16.2 percentage points (95% CI, 4.2% to 26.7%). Adverse events occurred in 69% of reloxaliase-treated participants versus 53% of individuals taking placebo and were most commonly gastrointestinal. All but one of the adverse events were grade 1 or 2 in severity; no reloxaliase-treated participants discontinued the study. CONCLUSIONS: Reloxaliase treatment for 4 weeks reduced UOx excretion in patients with enteric hyperoxaluria; adverse events were relatively common, but not dose-limiting. These data establish the foundation for a clinical trial to determine the impact of reloxaliase on nephrolithiasis in patients with enteric hyperoxaluria. (Funded by Allena Pharmaceuticals; ClinicalTrials.gov number, NCT03456830.)

Increased ß-Cell Workload Modulates Proinsulin-to-Insulin Ratio in Humans.

Increased proinsulin secretion, which characterizes type 2 diabetes and insulin resistance, may be due to an intrinsic, primitive defect in proinsulin processing or be secondary to increased demand on ß-cells (hyperinsulinemia secondary to insulin resistance). An alternative way to investigate the relation between relative hyperproinsulinemia and increased secretory demand is to study the dynamic changes in the proinsulin-to-insulin ratio after partial pancreatectomy, a model of acute increased ß-cell workload on the remaining pancreas. To pursue this aim, patients without diabetes, scheduled for partial pancreatectomy, underwent 4-h mixed-meal tests and hyperinsulinemic-euglycemic clamps before and after surgery. After acute ß-cell mass reduction, no changes were observed in the fasting proinsulin-to-insulin ratio, whereas the fold change in the proinsulin-to-insulin ratio significantly increased over time after the meal. Further, our data demonstrate that whole-body insulin resistance is associated with underlying defects in proinsulin secretion, which become detectable only in the presence of increased insulin secretion demand.

Changes in urinary risk profile after short-term low sodium and low calcium diet in recurrent Swiss kidney stone formers.

BACKGROUND: Kidney stone disease is common in industrialized countries. Recently, it has attracted growing attention, because of its significant association with adverse renal outcomes, including end stage renal disease. Calcium-containing kidney stones are frequent with high recurrence rates. While hypercalciuria is a well-known risk factor, restricted intake of animal protein and sodium, combined with normal dietary calcium, has been shown to be more effective in stone prevention compared with a low-calcium diet. Notably, the average sodium intake in Switzerland is twice as high as the WHO recommendation, while the intake of milk and dairy products is low. METHODS: We retrospectively analyzed Swiss recurrent kidney stone formers (rKSF) to test the impact of a low-sodium in combination with a low-calcium diet on the urinary risk profile. In patients with recurrent calcium oxalate containing stones, we investigated both, the consequence of a low-sodium diet on urinary volume and calcium excretion, and the influence of a low-sodium low-calcium diet on urinary oxalate excretion. RESULTS: Of the 169 patients with CaOx stones, 49 presented with hypercalciuria at baseline. The diet resulted in a highly significant reduction in 24-h urinary sodium and calcium excretion: from 201 ± 89 at baseline to 128 ± 88 mmol/d for sodium (p < 0.0001), and from 5.67 ± 3.01 to 4.06 ± 2.46 mmol/d (p < 0.0001) for calcium, respectively. Urine volume remained unchanged. Notably, no increase in oxalate excretion occurred on the restricted diet (0.39 ± 0.26 vs 0.39 ± 0.19 mmol/d, p = 0.277). Calculated Psf (probability of stone formation) values were only predictive for the risk of calcium phosphate stones. CONCLUSION: A diet low in sodium and calcium in recurrent calcium oxalate stone formers resulted in a significant reduction of urinary calcium excretion, but no change in urine volume. In this population with apparently low intake of dairy products, calcium restriction does not necessarily result in increased urinary oxalate excretion. However, based on previous studies, we recommend a normal dietary calcium intake to avoid a potential increase in urinary oxalate excretion and unfavorable effects on bone metabolism in hypercalciuric KSFs.

Vitamin D deficiency is prevalent among idiopathic stone formers, but does correction pose any risk?

While vitamin D (vitD) deficiency is thought to contribute to poor health in a variety of ways and should be corrected, there is still concern about giving vitD supplements to patients with a history of nephrolithiasis. The aim is to study the prevalence of vitD deficiency and the effect on stone risk of cholecalciferol (vitD3) supplementation in a cohort of idiopathic stone formers (ISF). We screened for vitD deficiency and urinary measures of stone risk, comparing vitD deficient (serum 25-OH vitD ≤30 nmol/L; ≤12 ng/mL) with vitD insufficient (31-75 nmol/L; 13-30 ng/mL) or vitD replete (>75 nmol/L; >30 ng/mL); we investigated the effect of giving vitD3 (20,000 IU orally, weekly for 4 months) to 37 of the vitD deficients. Thirty-one percent (142/456) were vitD deficient, 57% (259/456) vitD insufficient, and the rest (12%) vitD replete (55/456). Comparison among the groups showed that baseline 24-h urinary measures related to stone risk expressed as concentration ratios over urine creatinine (Cr), such as U. Calcium/Cr, U. Oxalate/Cr, U. Citrate/Cr, and U. Uric acid/Cr were not significantly different. VitD3 supplementation did significantly increase serum 25-OH vitD levels and U. Phosphate/Cr ratios, as well as reduce serum parathyroid hormone (PTH) concentrations. Following vitD3 supplementation, there was an overall rise in 24-h urine calcium excretion, but it failed to reach statistical significance (p = 0.06). U. Calcium/Cr increased in 22 out of 37 patients (average increase +0.07 mmol/mmol), decreased in 14 (average decrease -0.13 mmol/mmol), and remained unchanged in 1; 6 out of 26 initially normocalciuric ISF developed hypercalciuria; and 6 out of 9 patients who became vitD replete were hypercalciuric after supplementation. It is appropriate to monitor urinary Ca excretion in vitD-supplemented stone formers, because it may reveal underlying hypercalciuria in some treated patients.

Familial clustering of medullary sponge kidney is autosomal dominant with reduced penetrance and variable expressivity.

Medullary sponge kidney (MSK) is a renal malformation typically associated with nephrocalcinosis and recurrent calcium nephrolithiasis. Approximately 12% of recurrent stone formers have MSK, which is generally considered a sporadic disorder. Since its discovery, three pedigrees have been described in which an apparently autosomal dominant inheritance was suggested. Here, family members of 50 patients with MSK were systematically investigated by means of interviews, renal imaging, and biochemical studies in an effort to establish whether MSK is an inheritable disorder. Twenty-seven MSK probands had 59 first- and second-degree relatives of both genders with MSK in all generations. There were progressively lower mean levels of serum calcium, urinary sodium, pH, and volume, combined with higher serum phosphate and potassium from probands to relatives with bilateral, to those with unilateral, and to those unaffected by MSK. This suggests that most affected relatives have a milder form of MSK than the probands, which would explain why they had not been so diagnosed. Thus, our study provides strong evidence that familial clustering of MSK is common, and has an autosomal dominant inheritance, a reduced penetrance, and variable expressivity.

Immunoadsorption apheresis and immunosuppressive drug therapy in the treatment of complicated HCV-related cryoglobulinemia.

The immunosuppressive drug therapy (IDT) is not always effective to avoid the development of complications in hepatitis C virus-related cryoglobulinemia (HCV-Cr). Removal of cryoglobulins by therapeutic plasmapheresis is currently accepted. In this randomized, parallel group study, 17 male and female patients aged 43-79 years, with complicated HCV-Cr, were submitted for 12 weeks (initial immunosuppressive therapy) to IDT (alpha-interferon, pegylated-interferon alpha-2a, cyclophosphamide, methylprednisolone, prednisone, cyclosporine, ribavirin, and melphalan). Then, they were randomly assigned to two parallel groups: A # 9 patients treated by immunoadsorption apheresis (Selesorb((R))) (IA) plus IDT, and B # 8 patients submitted to IDT only, for further 12 weeks. # 187 IA aphereses were performed. No adverse reactions or complications were observed. A Clinical Score (CS) was adapted from a pre-existing scoring model to evaluate signs and symptoms inherent to the underlying immunologic disorder. The CS was calculated at baseline (CS0), after the initial immunosuppressive therapy (CS1 = 12 weeks) when patients were treated only with IDT, and at the end of the study (24 weeks) in the group A (CSA; IA plus IDT) and B (CSB; IDT only). The score did not change significantly from CS0 to CS1. However, statistically significant differences were observed between CS1 and CSA (P < 0.001), and CSA versus CSB (P = 0.03), respectively. The changes observed were favorable to the patients assigned to the IA plus IDT group (A): in most case relief of symptoms and complications have been obtained.