The water channel Aquaporin 1 (AQP1) plays a fundamental role in water ultrafiltration during peritoneal dialysis (PD) and its reduced expression or function may be responsible for ultrafiltration failure (UFF). In humans, AQP1 is expressed in the endothelium of the peritoneal capillaries but its expression in mesothelial cells (MC) and its functional role in PD is still being debated. Here, we studied a cohort of 30 patients using PD in order to determine the presence of AQP1 in peritoneal biopsies, AQP1 release in the PD effluent through exosomes and the correlation of AQP1 abundance with the efficiency of peritoneal ultrafiltration. The experiments using immunofluorescence showed a strong expression of AQP1 in MCs. Immunoblotting analysis on vesicles isolated from PD effluents showed a consistent presence of AQP1, mesothelin and Alix and the absence of the CD31. Thus, this suggests that they have an exclusive mesothelial origin. The immunoTEM analysis showed a homogeneous population of nanovesicles and confirmed the immunoblotting results. Interestingly, the quantitative analysis by ELISA showed a positive correlation between AQP1 in the PD effluent and ultrafiltration (UF), free water transport (FWT) and Na-sieving. This evidence opens the discussion on the functional role of mesothelial AQP1 during PD and suggests that it may represent a potential non-invasive biomarker of peritoneal barrier integrity, with predictive potential of UFF in PD patients.

Aims: To describe lung ultrasound (LUS) features of Mycoplasma pneumoniae pneumonia and their distribution in pediatric age, and to correlate imaging findings with clinical and laboratory data. Methods: This is a multicenter, prospective, pilot study that involved three hospitals. In total, 35 patients aged 1 month to 17 years, admitted with a diagnosis of Mycoplasma pneumoniae infection, were enrolled. History, clinical, microbiological, and ultrasound data were collected. The LUS examination was performed at admission, recording the following features: presence of subpleural consolidation, bronchograms, B lines, or pleural effusion, and their characteristics. The scans were performed using a standardized approach, in which a composite score was obtained by summing the scores of the different parameters. Results: Consolidations were seen in 97% of children (mostly located in basal, posterior, and lateral fields), and 65% of patients had multiple ones. Non-perilesional B lines were found in 43% of cases, principally in the posterior and basal fields. Pleural effusion was found in 37% of children. The univariate logistic regression showed a correlation between the age of the patient and large-sized consolidations. Moreover, increased lymphocyte count was associated with a lower risk of large-sized consolidations. Conclusions: LUS is a low-cost, non-invasive tool that can reveal findings suggestive of Mycoplasma pneumoniae infection and help physicians better manage children with lower respiratory tract infections, supporting a more personalized diagnostic and therapeutic approach, including antibiotic selection. These preliminary findings also indicate that a larger, comparative study involving other bacterial and viral etiologic agents is warranted to confirm whether LUS patterns are pathogen-specific and whether they can predict clinical outcomes.

Vitamin D deficiency is very prevalent in dialysis and peritoneal dialysis (PD) patients show lower levels of cholecalciferol (25(OH)D₃) than hemodialysis patients. We conducted a systematic narrative review to assess the effects of vitamin D therapy on control of secondary hyperparathyroidism and clinical outcomes induced by vitamin D pleiotropic effects. Medline database was searched for cohort and intervention studies reporting data on vitamin D (all sterols including synthetic analogs) and peritoneal dialysis without language restriction. Two authors independently extracted data. Twenty-nine observational and eleven interventional studies were identified for inclusion (1,036 subjects). PTH levels decreased in twenty-nine studies, increased in one study and remained stable in ten studies. Thirty-three studies analyzed the oral route for vitamin D administration, ten the intraperitoneal, one the subcutaneous and one the intravenous. A significant decrease of peritonitis risk was observed in two studies. Proteinuria decreased in four studies and remained stable in one study. Peritoneal protein loss decreased in one study and was stable in two studies. Studies on the therapeutic effects of vitamin D in PD are limited and describe small population samples. Moreover, vitamin D compounds do not consistently reduce PTH levels. The administration of active vitamin D in PD may have interesting pleiotropic effects such as decreasing proteinuria and peritoneal protein loss. According to these effects, vitamin D could help to preserve residual renal function and ensure efficient peritoneal membrane dialysance.

CKD in HF patients is very common condition, their dysfunction is closely linked and influence each other, so their management required multidisciplinary and personalized approaches. The diagnosis of HF and CDK relies on signs and symptoms. Several tools, such as blood-based biomarkers and echography help us to clarify and discriminate the main characteristics of these patients. Evidence in improving survival due to new drug-employment in HF, has increasingly challenged physicians to manage patients with multiple diseases, especially in patients with CKD. The difficulty is in the safe administration of these drugs in patients with HF and CKD. Knowing up to which values of creatinine or renal clearance any drug can be administered is fundamental. We wanted to summarize, on this sizable and complex topic, the experiences of various prior study to get clearer ideas and a more precise reference about the assessment and management of HF and CKD.