Clinical Factors Associated With the Culture of Primary Human Peritoneal Mesothelial Cell From Peritoneal Dialysate Effluent

Background: The culture of primary human peritoneal mesothelial cell (HPMC) provides us an in vitro tool to investigate peritoneal fibrosis and ultrafiltration failure. The aim of the present study was to establish the method of culturing HPMC and to explore clinical factors associated with the success rate of culture.Methods: HPMCs were aseptically harvested by centrifuge from peritoneal dialysate effluent (PDE) of patients with end-stage renal disease (ESRD) who underwent peritoneal dialysis (PD) catheterization for less than 2 weeks and were cultured in vitro. Cells were identified by simple morphological observation and immunofluorescent staining. Clinical data of PD patients was collected. Comparison between groups and binary logistic regression analysis were employed to explore the clinical factors associated with the success rate of culture.Results: The study included 36 patients (26 male (72.2%); mean age 53.9±15.6 years). HPMC from PDE successfully grew and survived in 22 patients. A typical cobblestone-like appearance was observed by inverted phase contrast microscope. Immunofluorescence staining showed positive expression of cytokeratin-18 (CK-18) and Vimentin. Comparison between groups demonstrated significant differences in diabetes (P=0.041), days from catheterization (P=0.002) and the use of erythrocyte lysate (P=0.019) between the two groups. Multivariate logistic regression analysis revealed that the success rate was correlated with days from catheterization (OR=0.318, 95%CI=0.107-0.946, P=0.039) and the level of C-reactive protein (CRP, OR=0.893, 95%CI=0.805-0.991, P=0.032). Conclusions: The method of culturing primary HPMC from PDE has been successfully established. The success rate of culture is correlated with CRP level and days from catheterization.

Cefoperazone and sulbactam-related eosinophilic peritonitis: a case report and literature review

Eosinophilic peritonitis (EP) is a well-described complication of peritoneal dialysis that occurs because of an overreaction to constituents that are related to the catheter or tubing, peritoneal dialysate, pathogenic infection, or intraperitoneal drug use. EP caused by antibiotic use is rare. We present the case of a patient with cefoperazone and sulbactam-related EP. A 59-year-old woman who was undergoing peritoneal dialysis presented with peritonitis with abdominal pain and turbid peritoneal dialysis. Empiric intraperitoneal cefazolin in combination with cefoperazone and sulbactam was started after peritoneal dialysis effluent cultures were performed. Her peritonitis achieved remission in 2 days with the help of cephalosporin, but she developed EP 1 week later, when her dialysate eosinophil count peaked at 49% of the total dialysate white blood cells (absolute count, 110/mm3). We excluded other possible causes and speculated that cefoperazone and sulbactam was the probable cause of EP. The patient continued treatment with cefoperazone and sulbactam for 14 days. EP resolved within 48 hours after stopping cefoperazone and sulbactam. Thus, EP can be caused by cefoperazone and sulbactam use. Physicians should be able to distinguish antibiotic-related EP from refractory peritonitis to avoid technique failure.

MO685PRESENCE OF SARS-COV-2 ANTIBODIES IN SPENT PERITONEAL DIALYSATE

Background and Aims Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) elicits cellular and humoral immune responses. In patients with coronavirus disease 2019 (COVID-19), IgM, IgA, and IgG antibodies against SARS-CoV-2 emerge within a few days and can be detected in several body fluids, such as serum and oral fluids. End Stage Kidney Disease patients are especially vulnerable in this pandemic as they are immunocompromised, putting them at higher risks of infection and impaired response to vaccines. While repeated blood draws in hemodialysis patients pose no substantial medical or logistic problems, the situation is different in those treated by peritoneal dialysis. To overcome that limitation, we explored the presence or absence of SARS-CoV-2 antibodies in spent peritoneal dialysate in patients treated with acute and chronic peritoneal dialysis, respectively. Method We analyzed spent PD dialysate samples from four distinct patient groups, namely Pre-Covid-19 controls (Group 1; 15 samples collected between May 2019 and Feb 2020), Covid-19 negative controls during ongoing pandemic (Group 2; 33 samples collected between March and September 2020); chronic PD patients with confirmed Covid-19 (Group 3; 30 samples collected between March and September 2020,); and patients with confirmed Covid-19 and acute kidney injury treated with acute PD (Group 4; 18 samples collected in April 2020). SARS-CoV-2 IgG titer in spent PD dialysate was measured by enzyme-linked immunosorbent assay (ELISA) targeting Nucleocapsid (N) protein of SARS-CoV-2 virus (MPBIO cat#: 08440100). Total SARS-CoV-2 antibodies (IgG, IgM, and IgA) were measured using ELISA targeting recombinant N Protein and Spike protein (S Protein) (AFFYPRO Cat#: EA821). Absolute IgG concentration was calculated using IgG standard provided by the MPBIO ELISA kit. The total antibody titer was calculated as a relative value to the mean of antibody levels of COVID-19 negative patients. To account for different dialysate and ultrafiltration volumes, antibody titers were also normalized to total protein concentrations in the spent dialysate samples. The ratio of IgG or total antibody to total protein reflects the normalized titer. Results Normalized anti-SARS-CoV-2 IgG titer in the four groups is illustrated in Figure 1A. The mean IgG/protein levels in Group 3 and Group 4 are 86-fold (p=0.023) and 220-fold (p=0.0003), respectively, above the mean IgG/protein levels in COVID negative patients (Group 1 and 2 combined). The discrimination between patients with and without COVID-19 is excellent (AUC 0.938). At a threshold of 0.0024%, the sensitivity and specificity are 89.6% and 97.9%, respectively (Figure 1B). Using same threshold as Figure 1B, in Group 3, 9 out of 11 patients had a positive IgG response in all samples. In 5 patients, IgG levels decreased over time. The mean normalized total antibody/protein levels in Group 3 and Group 4 are 7.3-fold and 24-fold above those in COVID negative patients (combined Group 1 and 2; both p<0.001). Distribution pattern, ROC analysis, and dynamic change over time of total SARS-CoV-2 antibodies are like those of IgG (Figure 1D-F). Conclusion Covid-19 serology tests can provide much information including diagnosis, immune response, local seroprevalence, et al. Currently, most of serology tests are done using blood-related specimens. To our knowledge, this is the first study reporting SARS-CoV-2 antibodies in spent PD dialysate. Presence of SARS-CoV-2 antibodies in spent PD dialysate of peritoneal dialysis patients potentially provides a new way to perform frequent serology tests for this high-risk group. As USA is moving fast on national vaccination at this moment, using test strip developed for PD effluent to quickly and frequently check SARS-CoV-2 antibody in PD effluent could be used to monitor the vaccination efficiency while avoiding clinic visit.

Soluble CD59 in peritoneal dialysis: a potential biomarker for peritoneal membrane function

Introduction Various studies have reported the importance of complement regulators in preventing mesothelial damage during peritoneal dialysis (PD). Its assessment, however, is limited in clinical practice due to the lack of easy access to the peritoneal membrane. Recently, a soluble form of the complement regulatory protein CD59 (sCD59) has been described. We therefore aimed to investigate the role of sCD59 in PD. Methods Plasma sCD59 was measured in 48 PD patients, 41 hemodialysis patients, 15 non-dialysis patients with chronic kidney disease and 14 healthy controls by ELISA (Hycult; HK374-02). Additionally, sCD59 and sC5b-9 were assessed in the peritoneal dialysate. Results sCD59 and sC5b-9 were detectable in the peritoneal dialysate of all patients, and marginally correlated (r = 0.27, P = 0.06). Plasma sCD59 levels were significantly higher in PD patients than in patients with chronic kidney disease and healthy controls, but did not differ from hemodialysis patients. During follow-up, 19% of PD patients developed peritoneal membrane failure and 27% of PD patients developed loss of residual renal function. In adjusted models, increased sCD59 levels in the dialysate (HR 3.44, 95% CI 1.04–11.40, P = 0.04) and in plasma (HR 1.08, 95% CI 1.01–1.17, P = 0.04) were independently associated with the occurrence of peritoneal membrane failure. Higher plasma levels of sCD59 were also associated with loss of residual renal function (HR 1.10, 95% CI 1.04–1.17, P < 0.001). Conclusions Our study suggests that sCD59 has potential as a biomarker to predict peritoneal membrane function and loss of residual renal function in PD, thereby offering a tool to improve patient management. Graphic abstract

Along came a spider: an unusual organism identified in a peritoneal dialysis patient, a case report and literature review

Background Peritoneal dialysis-associated peritonitis can uncommonly be caused by fungal infections. When they do present, they are associated with significant mortality and morbidity. We describe a case where a sample of peritoneal dialysate fluid grew Rhodotorula muciliginosa, a yeast organism present in the normal environment which has previously been reported as rarely causing peritonitis. We believe this is the first case where the Rhodotorula spp. and its origin has been identified. Case presentation A 20 year old male grew Rhodotorula muciliginosa from his peritoneal dialysis fluid on three separate occasions when a fluid sample was sent following a disconnection and subsequent set change. He was not systemically unwell and his peritoneal dialysate was clear. As Rhodotorula spp. is exceedingly difficult to treat our patient had his Tenchkoff catheter removed. Subsequent samples of soil and sand from his bearded dragon and Chilean tarantula cases, kept in his bedroom where dialysis occurred, were tested. The tarantula sand was identified as the source of the Rhodotorula spp. Of note, Candida was isolated from sand from the bearded dragon case. Once his Tenchkoff was removed he was treated with an intravenous course of antifungal therapy. He has since had a new Tenchkoff catheter inserted and recommenced PD following education around pets and hygiene. Conclusions In this era where people are keeping increasingly rare and unusual wildlife in their homes, this case highlights the need for clinician and nursing staff awareness of a patient’s home environment and hobbies when they are undergoing peritoneal dialysis. Sand from our patient’s tarantula case grew the colonising organism but interestingly soil from his bearded dragon case also isolated candida. This can also cause difficult to treat peritonitis.

Influence of dialysate temperature on creatinine peritoneal clearance in peritoneal dialysis patients: a randomized trial

Background Patients on continuous ambulatory peritoneal dialysis (PD) are encouraged to warm dialysate to 37 °C before peritoneal infusion; main international PD guidelines do not provide specific recommendation, and patients generally warm dialysate batches partially or do not warm them at all. Warming of dialysate is a time-consuming procedure, not free from potential risks (i.e. degradation of glucose), and should be justified by a clear clinical benefit. Methods We designed a single blind randomized controlled trial where 18 stable PD patients were randomized to receive a peritoneal equilibration test either with dialysate at a controlled temperature of 37 °C (intervention group) or with dialysate warmed with conventional methods (control group). Primary end-point was a higher peritoneal creatinine clearance in patients in the intervention group. Results Patients in the intervention group did not show a significantly higher peritoneal creatinine clearance when compared to the control group (6.38 ± 0.52 ml/min vs 5.65 ± 0.37 ml/min, p = 0.2682). Similar results were obtained for urea peritoneal clearance, mass transfer area coefficient of creatinine and urea. There were no significant differences in total abdominal discomfort questionnaire score, blood pressure and body temperature between the two groups. Conclusions Using peritoneal dialysate at different temperatures without causing significant side effects to patients appears feasible. We report a lack of benefit of warming peritoneal dialysate to 37 °C on peritoneal clearances; future PD guidelines should not reinforce this recommendation. Trial registration NCT04302649, ClinicalTrials.gov; date of registration 10/3/2020 (retrospectively registered).