Adipose tissue function and insulin sensitivity in syndromic obesity of Bardet-Biedl syndrome.

BACKGROUND: Bardet-Biedl syndrome (BBS) is a rare autosomal recessive syndromic obesity of childhood onset among many other features. To date, the excess risk of metabolic complications of severe early-onset obesity in BBS remains controversial. In-depth investigation of adipose tissue structure and function with detailed metabolic phenotype has not been investigated yet. OBJECTIVE: To investigate adipose tissue function in BBS. DESIGN: A prospective cross-sectional study. MAIN OUTCOME MEASURE: To determine if there are differences in insulin resistance, metabolic profile, adipose tissue function and gene expression in patients with BBS compared to BMI-matched polygenic obese controls. METHOD: 9 adults with BBS and 10 controls were recruited from the national centre for BBS, Birmingham, UK. An in-depth study of adipose tissue structure and function along with insulin sensitivity was performed using hyperinsulinemic-euglycemic clamp studies, adipose tissue microdialysis, histology and RNA sequencing, and measurement of circulating adipokines and inflammatory biomarkers. RESULTS: Adipose tissue structure, gene expression and in vivo functional analysis between BBS and polygenic obesity cohorts were similar. Using hyperinsulinemic-euglycemic clamp and surrogate markers of insulin resistance, we found no significant differences in insulin sensitivity between BBS and obese controls. Furthermore, no significant changes were noted in an array of adipokines, cytokines, pro-inflammatory markers and adipose tissue RNA transcriptomic. CONCLUSION: Although childhood-onset extreme obesity is a feature of BBS, detailed studies of insulin sensitivity and adipose tissue structure and function are similar to common polygenic obesity. This study adds to the literature by suggesting that it is the quality and quantity of adiposity not the duration that drives the metabolic phenotype.

Case Report and Review of Paracoccus yeei - A Novel Cause of Peritoneal Dialysis Peritonitis in the United Kingdom.

Peritoneal dialysis (PD) peritonitis poses a significant healthcare problem. Most cases are caused by Gram-positive organisms. Newer molecular diagnostic techniques have now enabled identification of previously unrecognized organisms, fully characterizing disease. We present the first case of Paracoccus yeei PD peritonitis reported in the United Kingdom (UK). A 70-year-old woman with chronic renal failure requiring PD presented with abdominal pain and cloudy dialysate. She was systemically well, with a normal white cell count and elevated C-reactive protein at 176. PD fluid was remarkable for 4495 polymorphonuclear leukocytes, 107 monocytes, and 10 red blood cells/cm3. No organisms were seen on microscopy. She was diagnosed with PD peritonitis and treated empirically with intraperitoneal vancomycin and oral levofloxacin. After two days, small, nonhemolytic gray-white colonies grew on blood agar. Gram stain of culture showed Gram-negative cocco-bacilli with O-shaped morphology. Phenotypic identification using matrix-assisted laser desorption ionization-time of flight mass spectrometry (Biomerieux) identified P. yeei (identification probability 99.9%). The isolate was sent to the reference laboratory for confirmation and antimicrobial susceptibility testing (AST). At present, there are no European Committee on Antimicrobial Susceptibility Testing (EUCAST) clinical breakpoints to guide AST. Proposed minimum inhibitory concentration (MIC) values were determined using broth dilution method interpreted using EUCAST nonspecies-specific PK-PD breakpoints (where available). The isolate was reported as sensitive to quinolones (ciprofloxacin MIC 0.25 mg/L), piperacillin-tazobactam (MIC 2 mg/L), and meropenem (MIC 0.008 mg/L). P. yeei is an aerobic environmental organism found in soil. It has been associated with PD peritonitis in immunosuppressed patients, although this is the first case in the UK. It is possible that true burden of disease is under-represented, and novel molecular techniques have now enabled identification of this previously unknown organism. In this case, her dog could be a potential source, and good hand hygiene may prevent further infections.

Evaluating Patient Safety And Ease Of Use Of A Novel Connection-Assist Device For Peritoneal Dialysis.

INTRODUCTION: It is estimated that there are currently over 3 million patients receiving dialysis treatment worldwide. With effective pre-dialysis counselling, a majority of patients choose the home-based therapy peritoneal dialysis (PD) but only approximately 11% of prevalent dialysis patients use this modality. Connection-assist devices can overcome the challenges posed by decreased manual dexterity and/or visual acuity, and can allow more patients to be treated with home-based therapies. As part of the CE marking authorization, a connection device has been evaluated for safety and ease of use in a usability study. METHODS: Fifteen patients and nine carers volunteered in this study, ranging from 23 to 86 years in age and from 0.3 to 24 years in experience in the PD therapy. The operating cycle consisted of eight tasks, each having several handling steps. The data analysis focused on the task effectiveness and the subjects' subjective feedback from the NASA task load index (N-TLX) questionnaire and semi-structured interviews. RESULTS: Of 1248 handling steps performed in total, 38 use errors were observed and discussed with the subjects. This equates to 97% of all handling steps being performed safely and easily. In all six dimensions of the N-TLX, more than 50 percent of subjects rated the task load 50 points or less on the scale. Regarding the handling of the device, 13 of 15 of the patients and 8 of 9 of the carers gave positive feedback. DISCUSSION: Safety and ease of use was demonstrated by evaluating task effectiveness (97% SU), interviews and N-TLX. Additionally the study provided valuable individual user feedback, which will inform the final design of the system for PD. The majority of patients and carers gave positive feedback regarding use and handling of this connection device. Innovative connection devices in general promise to reduce the barriers to using this home-based dialysis treatment.

How can we make renal medicine careers more appealing to UK trainees?

BACKGROUND: There is a global decline in interest in careers in renal medicine. This is concerning given the increasing global burden of kidney disease. Previous studies in the USA and Australia have identified factors such as a poor work-life balance, lack of role models and the challenging nature of the speciality as possible reasons behind recruitment struggles. This study aimed to identify factors associated with declining interest among trainees in the UK. METHODS: We conducted a survey of 150 National Health Service Foundation trainees (interns) and Core Medical Trainees in Health Education West Midlands. Participants completed a 14-part paper-based questionnaire capturing data on trainee demographics, medical school and postgraduate exposure to renal medicine and perceptions of a career in renal medicine. RESULTS: There was limited early clinical exposure to renal medicine both in terms of time spent in the speciality and perceived exposure to the range of domains of the speciality. Trainees perceived the speciality as complex with a heavy workload. Very few trainees considered the speciality to be lifestyle oriented. There was also disinterest in taking on the associated general medicine commitments of the training programme. Job experience and identification of role models increased the likelihood of consideration of the speciality. CONCLUSION: This survey has identified key areas to drive interest in the speciality, including early engagement, enthusiastic supervision and increased training flexibility. Urgent attention is required to address these areas and make renal medicine careers more appealing.

Risk Factors for Severe Renal Disease in Bardet-Biedl Syndrome.

Bardet-Biedl syndrome is a rare autosomal recessive, multisystem disease characterized by retinal dystrophy, renal malformation, obesity, intellectual disability, polydactyly, and hypogonadism. Nineteen disease-causing genes (BBS1-19) have been identified, of which mutations in BBS1 are most common in North America and Europe. A hallmark of the disease, renal malformation is heterogeneous and is a cause of morbidity and mortality through the development of CKD. We studied the prevalence and severity of CKD in 350 patients with Bardet-Biedl syndrome-related renal disease attending the United Kingdom national Bardet-Biedl syndrome clinics to further elucidate the phenotype and identify risk indicators of CKD. Overall, 31% of children and 42% of adults had CKD; 6% of children and 8% of adults had stage 4-5 CKD. In children, renal disease was often detected within the first year of life. Analysis of the most commonly mutated disease-associated genes revealed that, compared with two truncating mutations, two missense mutations associated with less severe CKD in adults. Moreover, compared with mutations in BBS10, mutations in BBS1 associated with less severe CKD or lack of CKD in adults. Finally, 51% of patients with available ultrasounds had structural renal abnormalities, and 35% of adults were hypertensive. The presence of structural abnormalities or antihypertensive medication also correlated statistically with stage 3b-5 CKD. This study describes the largest reported cohort of patients with renal disease in Bardet-Biedl syndrome and identifies risk factors to be considered in genetic counseling.

Evaluation of visual function and needs in adult patients with bardet-biedl syndrome.

PURPOSE: To assess the visual needs of the adult population with Bardet-Biedl syndrome (BBS) and to ensure that this is addressed by a national Bardet-Biedl Service. METHODS: A cross-sectional analysis of all adults under a national BBS Clinic (Birmingham, United Kingdom) was performed using the BBS Ophthalmic Assessment Tool, a novel tool designed to capture the key elements of visual function, impact on lifestyle, and clinical findings relevant to BBS. RESULTS: Sixty-two adult patients were confirmed to have BBS. Bardet-Biedl syndrome mutations were identified in 51, most commonly BBS1 (n = 35), BBS2 (n = 6), and BBS10 (n = 5). In 11 patients (18%), BBS had not been diagnosed until adulthood. Median visual acuity was hand motion (range, 0.0 logMAR-no perception of light). More advanced retinopathy was associated with increasing age, worsening visual acuity, and the presence of nystagmus. Forty patients (65%) had undertaken mainstream education with 29 (47%) achieving higher education; 7 patients (11%) had moderate or severe learning difficulties. Most (90%) were registered sight-impaired or severely sight-impaired patients. CONCLUSION: The BBS Ophthalmic Assessment Tool provides a wide-ranging assessment of ophthalmic status and vision-related needs of the BBS population. This evaluation demonstrates the spectrum of visual disability in this population and its correlation with worsening retinopathy over time.

Developing a higher specialist training programme in renal medicine in the era of competence-based training.

Renal specialty medical training in the UK was reformed in August 2007, with an emphasis placed on competency-based training and the publication of a new curriculum and assessment blueprint. This model of training places additional time demands on both trainees and trainers, with implications for job planning and service delivery. We evaluated the resource requirements and impact on service delivery of implementing a high-quality training programme in renal medicine. Each trainee maintained a portfolio containing details of workplace-based assessments. The change in educational environment led to improved trainee satisfaction. The mean total consultant time involved in implementing the training programme was 0.7 programmed activities (PAs) per trainee per week in the first year, which decreased to 0.5 PAs per trainee per week in the second year. This pilot study indicates that it is possible to integrate successful and high-quality specialty training in a busy clinical environment. The model outlined could form a template for postgraduate specialist training delivery in a variety of medical specialties.

Complete renal recovery from severe acute renal failure after thrombolysis of bilateral renal vein thrombosis.

A previously healthy young man presented with acute renal failure due to extensive spontaneous deep vein thrombosis, including the inferior vena cava (IVC) and both renal veins. The patient was treated with selectively delivered thrombolytic therapy over a 7-day-period, which resulted in renal vein patency and complete recovery of renal function. A stent was placed over a segment stenosis of the IVC. No thrombophilic factors were identified. Bilateral renal vein thrombosis in young fit individuals is an unusual cause of acute renal failure. Thrombolytic therapy, even with delay, can completely restore renal function.

Treatment of acute renal failure secondary to multiple myeloma with chemotherapy and extended high cut-off hemodialysis.

BACKGROUND AND OBJECTIVES: Extended hemodialysis using a high cut-off dialyzer (HCO-HD) removes large quantities of free light chains in patients with multiple myeloma. However, the clinical utility of this method is uncertain. This study assessed the combination of chemotherapy and HCO-HD on serum free light chain concentrations and renal recovery in patients with myeloma kidney (cast nephropathy) and dialysis-dependent acute renal failure. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: An open-label study of the relationship between free light chain levels and clinical outcomes in 19 patients treated with standard chemotherapy regimens and HCO-HD. RESULTS: There were sustained early reductions in serum free light chain concentrations (median 85% [range 50 to 97]) in 13 patients. These 13 patients became dialysis independent at a median of 27 d (range 13 to 120). Six patients had chemotherapy interrupted because of early infections and did not achieve sustained early free light chain reductions; one of these patients recovered renal function (at 105 d) the remaining 5 patients did not recover renal function. Patients who recovered renal function had a significantly improved survival (P < 0.012). CONCLUSION: In dialysis-dependent acute renal failure secondary to myeloma kidney, patients who received uninterrupted chemotherapy and extended HCO-HD had sustained reductions in serum free light chain concentrations and recovered independent renal function.

Efficacy and safety of sevelamer hydrochloride and calcium acetate in patients on peritoneal dialysis.

BACKGROUND: Inadequate phosphorus control is associated with increased morbidity and mortality in patients with CKD stage 5. Although phosphate binders are often used in patients on peritoneal dialysis (PD), no large randomized controlled studies evaluating their use solely in this population have previously been reported. METHODS: In this multicentre, open-label study, adult patients on PD with serum phosphorus >5.5 mg/dl were randomized (2:1) to 12 weeks of treatment with sevelamer hydrochloride or calcium acetate. Doses were titrated to achieve serum phosphorus of 3.0-5.5 mg/dl. Changes in serum phosphorus, calcium, intact parathyroid hormone (iPTH), lipids and plasma biomarkers were assessed. RESULTS: A total of 253 patients were screened, 143 of whom were randomized (sevelamer hydrochloride, n = 97; calcium acetate, n = 46). Treatment groups were well balanced with regard to baseline demographics. Serum phosphorus levels were significantly reduced after 12 weeks with both sevelamer hydrochloride and calcium acetate (P < 0.001). Serum PTH was also reduced in both groups while serum calcium increased in the calcium acetate group (P = 0.001) but not in the sevelamer hydrochloride group. Sevelamer hydrochloride was also associated with decreases in total cholesterol, low-density lipoprotein cholesterol and uric acid and an increase in bone-specific alkaline phosphatase (all P < 0.001 versus baseline). Both treatments were well tolerated and safety profiles were consistent with previous reports in haemodialysis patients. Hypercalcaemia was experienced by more calcium acetate-treated patients (18 versus 2%; P = 0.001). CONCLUSIONS: In summary, sevelamer hydrochloride provides a reduction in serum phosphorus compared to that obtained with calcium-based binders in PD patients. The effects of sevelamer hydrochloride appear similar in both PD and haemodialysis populations.

Timely initiation of dialysis--single-exchange experience in 39 patients starting peritoneal dialysis.

OBJECTIVE: To establish the effectiveness and patient acceptability of initiating peritoneal dialysis (PD) according to published guidelines. SETTING: A university teaching hospital and a neighboring district general hospital. DESIGN: Nonrandomized prospective pilot study. PATIENTS: 39 patients with a Kt/V > 2.0 attending predialysis clinics at both hospitals agreed to participate in this study. METHODS: Patients were started on a single exchange of dialysate overnight. Dialysis adequacy was monitored at least every 2 months and incremental increases in dialysis were used to maintain combined urinary and dialysis Kt/V above 2.0. Routine laboratory parameters and complications of dialysis were monitored during the follow-up period. RESULTS: The mean weekly Kt/V at initiation of dialysis was 2.09. Median actuarial survival on a single exchange before requiring incremental dialysis was 297 days. At the end of the study period, all patients were still alive: 8 remained on 1 exchange, 18 were on more than 1 exchange, 8 had switched to hemodialysis, and 5 had received renal transplants. During the 12,665 patient-days on single-exchange dialysis, there were 14 hospital admissions of 12 patients. This resulted in a mean of 1.64 hospital days per patient-year for the whole group. During the follow-up period there were 2 episodes of bacterial peritonitis, 3 pleural leaks, 1 patent processus vaginalis, and 1 inguinal hernia that required surgical intervention. The use single daily icodextrin exchanges was associated with a 46% incidence of culture-negative peritonitis. CONCLUSIONS: This pilot study has shown that a timely start of dialysis with a single overnight PD exchange is acceptable to patients. Incremental dialysis as residual renal function falls is easily managed and patients also find this acceptable. Complication and hospitalization rates were low. The presence of residual renal function often allows complications to be managed without the need for hemodialysis. The use of icodextrin as a single-exchange dialysate is associated with sterile peritonitis in a significant proportion of cases.

Cellular and subcellular distribution of polycystin-2, the protein product of the PKD2 gene.

Mutations in the PKD1 and PKD2 genes account for 85 and 15% of cases of autosomal dominant polycystic kidney disease, respectively. Polycystin-2, the product of the PKD2 gene, is predicted to be an integral membrane protein with homology to a family of voltage-activated Ca(2+) channels. In vitro studies suggest that it may interact with polycystin-1, the PKD1 gene product, via coiled-coil domains present in their C-terminal domains. In this study, the cellular and subcellular distribution of polycystin-2 is defined and compared with polycystin-1. A panel of rabbit polyclonal antisera was raised against polycystin-2 and shown to recognize a single band consistent with polycystin-2 in multiple tissues and cell lines by immunoprecipitation and Western blotting. Immunostaining of human and murine renal tissues demonstrated widespread and developmentally regulated expression of polycytin-2, with highest levels in the kidney in the thick ascending limbs of the loop of Henle and the distal convoluted tubule. In contrast, polycystin-1 expression, while localizing to the same tubular segments, was highest in the collecting ducts. Immunohistochemical staining and immunofluorescence microscopy localized polycystin-2 to the basolateral plasma membrane of kidney tubular epithelial cells compared with the junctional localization of polycystin-1. Differences in the developmental, cellular, and subcellular expression of polycystin-1 and polycystin-2 suggest that they may be able to function independently of each other in addition to a potential in vivo interaction via their C-termini.