Investigation by infrared microspectroscopy of hydroxyapatite microcrystal deposits in peritoneal membrane biopsies

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Etude histologique et analyse des calcifications vasculaires au sein de biopsies peritonéales: nouvelles pistes physiopathologiques de la sclérose péritonéale

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Infrared Microspectroscopy using Synchrotron Radiation (Sr Μftir) and Infrared Microspectroscopy as New Tools for Rapid Detection of Ectopic Calcifications Associated with Peritoneal Dialysis

International audienceThe cardiovascular calcifications (CVC) represent a central complication of chronic kidney disease (CKD) responsible of high cardiovascular mortality particularly in patients on peritoneal dialysis. Unfortunately, electron beam and multislice computed tomography, planar X-ray, ultrasonography or cardiac echocardiography methods are not accurate to detect calcium phosphate microcrystals since of its small size. We investigated the ectopic calcifications by Von Kossa staining and infrared microspectroscopy using synchrotron radiation (SR μFTIR) and infrared microspectroscopy in formalin-fixed peritoneal tissues from 3 cases. Von Kossa staining allowed us to detect vascular calcifications only in one of 3 studied peritoneal biopsies. Vascular calcifications contained mainly carbapatite accordingly to the presence of the IR absorption bands positioned at 1030 cm-1 (ν3), 960 cm-1 (ν1). In all studied biopsy, we found several tissue microcrystals also composed by carbapatite. To our knowledge, we report for the first time the usefulness of infrared microscopy and SR μFTIR for the assessment of calcium phosphate microcrystals and identification of biochemical composition of VC associated with CKD in peritoneal membrane from patients on peritoneal dialysis. SR μFTIR technique and infrared microspectroscopy are new, remarkable, and rapid tools for detection of early stage of ectopic calcifications associated with peritoneal dialysis. Investigation of calcium phosphate microcrystals by both methods might improve our understanding of early stage of CVC pathophysiology. Citation: Pozdzik AA, Demetter P, Tooulou M, Hamade A, Nortier J, et al. (2015) Infrared Microspectroscopy using Synchrotron Radiation (Sr Μftir) and Infrared Microspectroscopy as New Tools for Rapid Detection of Ectopic Calcifications Associated with Peritoneal Dialysis

Analysis of peritoneal biopsies in patients with encapsulating peritoneal sclerosis.

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Morphological Retrospective Study of Peritoneal Biopsies from Patients with Encapsulating Peritoneal Sclerosis: Underestimated Role of Adipocytes as New Fibroblasts Lineage?

Background. Encapsulating peritoneal sclerosis (EPS) is a rare but serious complication of peritoneal dialysis (PD). Besides the endothelial-to-mesenchymal transition (EMT), recently peritoneal adipocytes emerged as a potential source of fibrosis. We performed immunohistochemistry to approach EMT and to localize peritoneal adipocytes in peritoneal biopsies from PD-related EPS patients. Material and Methods. We investigated tissue expression of podoplanin, cytokeratin AE1/AE3 (mesothelium), calretinin (adipocytes), alpha-smooth muscle actin [α-SMA] (mesenchymal cells), interstitial mononuclear cell inflammation, and neoangiogenesis (CD3, CD4, CD8, CD20, CD68, and CD31 immunostainings, resp.). Results. Three patients (1 man/2 women; 17, 64, and 39 years old, resp.) developed EPS after 21, 90, and 164 months of PD therapy. In patients with EPS, we observed (1) loss of AE1/AE3 cytokeratin+ mesothelial cells without any evidence of migration into the interstitium, (2) disappearance of adipose tissue, (3) diffuse infiltration of calretinin+ cells in the areas of submesothelial fibrosis with a huge number of α-SMA and calretinin+ fusiform cells, and (4) increased vascular density. Conclusion. We report that the involvement of EMT in peritoneal fibrosis is difficult to demonstrate and that the calretinin+ adipocytes might be an underestimated component and a new source of myofibroblasts in peritoneal remodeling during PD-related EPS

Histological study and analysis of vascular calcifications in peritoneal biopsies: Adipocytes as new players in encapsulating peritoneal sclerosis?

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Mycobacterium fortuitum and Polymicrobial Peritoneal Dialysis-Related Peritonitis: A Case Report and Review of the Literature

Mycobacterium fortuitum is a ubiquitous, rapidly growing nontuberculous mycobacterium (NTM). It is the most commonly reported NTM in peritoneal dialysis (PD) associated peritonitis. We report a case of a 52-year-old man on PD, who developed refractory polymicrobial peritonitis necessitating PD catheter removal and shift to hemodialysis. Thereafter, M. fortuitum was identified in the PD catheter culture and in successive cultures of initial peritoneal effluent and patient was treated with amikacin and ciprofloxacin for six months with a good and sustained clinical response. Months after completion of the course of antibiotics, the patient successfully returned to PD. To our knowledge, this is the first reported case of M. fortuitum peritonitis in the field of polymicrobial PD peritonitis. It demonstrates the diagnostic yield of pursuing further investigations in cases of refractory PD peritonitis. In a systematic review of the literature, only 20 reports of M. fortuitum PD peritonitis were identified. Similar to our case, a delay in microbiological diagnosis was frequently noted and the Tenckhoff catheter was commonly removed. However, the type and duration of antibiotic therapy varied widely making the optimal treatment unclear

Encapsulating peritoneal sclerosis in Akidney graft recipient unmasked by everolimus switch

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