Structural and functional analysis of retinal vasculature in HANAC syndrome with a novel intronic COL4A1 mutation.

PURPOSE: Mutations of the COL4A1 gene, a major structural protein of vessels, may cause hereditary angiopathy with nephropathy, aneurysms and muscle cramps (HANAC) syndrome. The vascular structure and function of patients with HANAC is poorly known. Here, we report a family with HANAC syndrome associated to a previously unreported mutation in COL4A1. The structure and function of retinal vessels were detailed by adaptive optics ophthalmoscopy (AOO) and optical coherence tomography (OCT) angiography. METHODS: Clinical data from six affected individuals (43 to 72 years old) from a single family comprising two generations were collected. Imaging charts including conventional fundus imaging, OCT-angiography and AOO in static and dynamic (flicker) mode were reviewed. DNA sequencing was done in the proband. RESULTS: DNA sequencing of the proband revealed a heterozygous deletion of COL4A1 (NM_001845) at position 1120 in the intron 20 resulting in the loss of splicing donor site for exon 20 (c.1120 + 2_1120 + 8del heterozygote). Four patients had arterial hypertension, and three had kidney dysfunction, one of which under dialysis. By fundus examination, five had typical retinal arteriolar tortuosity with arteriolar loops. Wall-to-lumen ratio of arteries was within normal limits, that is, lower than expected for hypertensive patients. Several foci of arteriolar irregularities were noted in the two oldest patients. In three affected subjects, evaluation of the neurovascular coupling showed a higher flicker-induced vasodilation than a control population (6 % to 11 %; n < 5 %). CONCLUSIONS: Structural and dynamic analysis of retinal vessels in a HANAC family bearing a previously unreported intronic COL4 mutation was done. In addition to arteriolar tortuosity, we found reduced wall-to-lumen ratio, arteriolar irregularity and increased vasodilatory response to flicker light. These abnormalities were more marked in the oldest subjects. This abnormal flicker response affected also non-tortuous arteries, suggesting that microvascular dysfunction extends beyond tortuosity. Such explorations may help to better vascular dysfunction related to HANAC and hence better understand the mechanisms of end-organ damage.

[Low flux dialysate daily home hemodialysis: A result for the 62 first French and Belgian patients]. / Hémodialyse quotidienne à bas débit de dialysat à domicile : résultats cliniques et biologiques des 62 premiers patients traités en France et en Belgique.

Since 2011, a new device is available for low flux dialysate quotidian home hemodialysis in France and Belgium. This study aims to evaluate the characteristics and dialysis prescriptions for Nx Stage System One™ users. We retrospectively included patients trained between 2011 and 2013 in France and Belgium. We collected data concerning their clinical features, their dialysis prescriptions, their laboratory parameters until 6 months of dialysis and, reason for dropping in case of cessation. Sixty-two patients from 31 centers, aged 48±18 years old, with a sex ratio 46/16 (M/F) are included with a median Charlson comorbidity index of 1 [0-3]. Of these patients, 71% are anuric and have been on dialysis for a mean time of 136.6±125 months. Previously, most of them had been taken care of in satellite units of dialysis (45%) and 14% are incident patients. In total, A total of 60% have an arterio-veinous fistula (AVF), with 18 patients using the Buttonhole system and 2 patients have a tunneled catheter. Median time for training was 26.5 days (17-45). Among the patients, 69% are dialyzed 6 days a week, during a mean time of 142.5±20 minutes with a volume of 20.9±3 liters of dialysate and without anticoagulant (63%). Predialytic levels of hemoglobin, creatinin, urea, phosphorus and ß2microglobulin remain stable. On the contrary, there is a significant improvement of albumin and bicarbonate levels. Technique survival was 75% at 1 year, and major reason for cessation was kidney transplant. It seems that this device fits for young patients, with few comorbidities and a long past in renal chronic failure. These results suggest that dialysis adequacy is acceptable despite low dialysate volumes but need confirmation with a longer follow up and a larger cohort.

Effect of assistance on peritonitis risk in diabetic patients treated by peritoneal dialysis: report from the French Language Peritoneal Dialysis Registry.

BACKGROUND: Diabetic patients treated by peritoneal dialysis (PD) have been reported to be at an increased risk of peritonitis. This has been attributed to impairment in host defense, visual impairment, disability and muscle wasting, which could compromise ability to safely perform catheter connections. This study aimed to evaluate whether assisted PD is associated with a lower risk of peritonitis in diabetic patients. METHODS: This was a retrospective study based on data from the French Language Peritoneal Dialysis Registry. We included diabetic patients starting PD between 1 January 2002 and 31 December 2012. The end of the observation period was 31 December 2013. Using complementary regression analysis (Fine and Gray, Hurdle models), we assessed the relationship between peritonitis occurrence, peritonitis number over time and the type of assisted PD. RESULTS: Of the 3598 diabetic patients, there were 2040 patients on nurse-assisted PD. These patients were older, more comorbid and more frequently on continuous ambulatory peritoneal dialysis (CAPD). In the multivariate analysis, nurse assistance was associated with a reduced risk of peritonitis in the Fine and Gray [subdistribution hazard ratio: 0.78 (95% confidence interval, CI, 0.68-0.89)] and in the first component of the Hurdle models [rate ratio: 0.82 (95% CI 0.71-0.93)], but not a lower incidence of peritonitis after an initial episode [rate ratio: 0.82 (95% CI 0.95-1.38)]. Transplant failure, glomerulonephritis and CAPD were associated with an increased risk. CONCLUSIONS: In France, nurse-assisted PD is associated with a lower risk of peritonitis in diabetic patients treated by PD but not a lower incidence of peritonitis.