Protocadherin 7-Associated Membranous Nephropathy

BACKGROUND

Membranous nephropathy (MN) results from deposition of antigen-antibody complexes along the glomerular basement membrane (GBM). PLA2R, THSD7A, NELL1, and SEMA3B account for 80%-90% of target antigens in MN.

METHODS

We performed laser microdissection and mass spectrometry (MS/MS) in kidney biopsies from 135 individuals with PLA2R-negative MN, and used immunohistochemistry/immunofluorescence and confocal microscopy to confirm the MS/MS finding, detect additional cases, and localize the novel protein. We also performed MS/MS and immunohistochemistry on 116 controls and used immunofluorescence microscopy to screen biopsy samples from two validation cohorts. Western blot and elution studies were performed to detect antibodies in serum and biopsy tissue.

RESULTS

MS/MS studies detected a unique protein, protocadherin 7 (PCDH7), in glomeruli of ten (5.7%) PLA2R-negative MN cases, which also were negative for PLA2R, THSD7A, EXT1/EXT2, NELL1, and SEMA3B. Spectral counts ranged from six to 24 (average 13.2 [SD 6.6]). MS/MS did not detect PCDH7 in controls (which included 28 PLA2R-positive cases). In all ten PCDH7-positive cases, immunohistochemistry showed bright granular staining along the GBM, which was absent in the remaining cases of PLA2R-negative MN and control cases. Four of 69 (5.8%) cases in the validation cohorts (all of which were negative for PLA2R, THSD7A, EXT1, NELL1, and SEMA3B) were PCDH7-positive MN. Kidney biopsy showed minimal complement deposition in 12 of the 14 PCDH7-associated cases. Confocal microscopy showed colocalization of PCDH7 and IgG along the GBM. Western blot analysis using sera from six patients showed antibodies to nonreduced PCDH7. Elution of IgG from frozen tissue of PCDH7-associated MN showed reactivity against PCDH7.

CONCLUSIONS

MN associated with the protocadherin PCDH7 appears to be a distinct, previously unidentified type of MN.

The Effect of Body Mass Index on Presentation of COVID-19 amongst Heart Transplant Recipients: A Multi-Institutional Study

Purpose

Characteristics and outcomes of heart transplant (HT) recipients who contract coronavirus (SARS-CoV-2) have been poorly described. The current study was undertaken to better understand the risk obesity may pose in this patient population

Methods

A prospectively-maintained Trans-CoV-VAD Registry containing HT recipients at 11 participating institutions who presented with SARS-CoV-2 were reviewed. Presenting characteristics, hospitalization rates, ventilator & intensive care unit usage, and mortality were queried. Patients were grouped by body mass index (BMI) into obese (BMI≥30 k/m²) and non-obese cohorts (BMI<30 kg/m²). Comparisons between groups were made utilizing chi-squared, Fisher's exact, and Mann-Whitney U-tests. Multivariable logistic regression models were utilized

Results

Across all centers, 85 HT recipients who tested positive for SARS-CoV-2 were identified, of whom 26 (31%) were obese. Median time from HT to diagnosis was 4.6 (1.8-13.8) years. No differences in age (57 vs 60 p 0.85) or female gender (31% vs 24% p 0.5) were noted between obese and non-obese patients. On presentation, obese patients were more symptomatic with higher rates of cough (76% vs 48% p 0.02), dyspnea (62% vs 41% p 0.09), diarrhea (60% vs 35% p 0.03), and headache (35% vs 14% p 0.03). No differences in rates of admission (62% vs 64% p 0.8), ICU presentation (44% vs 35% p 0.6) or need for mechanical ventilation were noted (38% vs 22% p 0.2). More secondary infections were noted amongst obese patients (32% vs 13% p 0.04). On follow-up, mortality was similar between groups (12% vs 9% p 0.7). On multivariable modeling, BMI was not associated with increased adjusted odds of hospital/ICU admission or mechanical ventilation (p>0.10)

Conclusion

Acute presentations of SARS-CoV-2 amongst HT recipients carry significantly higher mortality over the general population. Obesity appears to impact presenting symptoms and secondary infections, but does not strongly impact ICU requirements or mortality

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Frequency of gonadal tumours in complete androgen insensitivity syndrome (CAIS): A retrospective case-series analysis

BACKGROUND

Complete androgen insensitivity syndrome (CAIS) is an X-linked recessive disorder of sex development (DSD) where affected individuals are phenotypically female, but have an XY karyotype and testes. The risk of gonadal tumour development in CAIS may increase with age; incidence rates have been reported to be 0.8-22% in patients who have retained their gonads into adulthood. Consequently, gonadectomy has been recommended either during childhood or after puberty is complete, although there is no consensus on the optimal timing for this procedure.

OBJECTIVE AND HYPOTHESES

To establish the frequency of histological abnormalities in CAIS in relation to the age at gonadectomy.

METHOD

Data were collected from the Cambridge DSD database on patients with CAIS (n = 225; age range 3-88 years) who had undergone gonadectomy, and their age of gonadectomy, gonadal histology and immunohistochemistry.

RESULTS

Evaluable data were obtained from 133 patients. Median age at gonadectomy was 14.0 years (range: 18 days-68 years). Pubertal status was: prepuberty, n = 62; postpuberty, n = 68. Thirteen cases were aged >20 years at gonadectomy. The pattern of histology is summarised in the Summary table.

DISCUSSION

In this large case series of CAIS patients who had undergone gonadectomy, while the combined malignant and premalignant gonadal histology prevalence was 6.0%, the findings confirm the low occurrence of gonadal malignancy in CAIS, with a frequency of 1.5%. The two cases of malignancy were postpubertal. Germ cell neoplasia in situ (GCNIS) was observed in six cases, of which one occurred prepuberty and five postpuberty. The study highlighted difficulties in diagnosis of GCNIS and the need for histological analysis in expert centres.

CONCLUSION

The results support the current recommendation that gonads in CAIS can be retained until early adulthood. The small number of individuals with gonadectomy after age 20 years do not allow firm conclusion regarding later adulthood. Therefore, it is recommended that the option of gonadectomy be discussed in adulthood. Some form of regular surveillance of the gonads is then recommended, although none of the available options are ideal.

Safety in out-of-hours operating in trauma and orthopaedics at a district general hospital

INTRODUCTION According to the National Confidential Enquiry into Perioperative Deaths (NCEPOD), out-of-hours operating in trauma and orthopaedics should be reserved for life or limb threatening cases only. The aim of our study was to determine the nature of non-emergency work carried out in our trust at night in 2015. The overall efficacy and clinical safety of the services provided was evaluated. METHODS Surgical activity undertaken after 9pm was reviewed along with patient ASA (American Society of Anesthesiologists) grade, grade of operating surgeon and any complications that occurred following the procedure. Furthermore, the clinical urgency and safety of cases was assessed based on whether there was any record of life or limb threatening indications at the time of admission. RESULTS Overall, 131 procedures were performed after 9pm, with 102 performed between 9pm and midnight, and 29 after midnight. Consultants performed 16 cases and the remaining 115 cases were operated on by middle grades or specialty trainees. A fifth (20%) of the cases were genuinely life or limb threatening. A total of 123 procedures were classed as having good outcomes. The complication rate was 8%. CONCLUSIONS In our study, 80% of the procedures performed after 9pm could not be categorised as life or limb threatening. Appropriate NCEPOD classification would ensure that only life or limb threatening cases were listed for theatre after 9pm. Alternative methods of operating within working hours should be considered.

Sub-segmental pulmonary embolism in three academic teaching hospitals: a review of management and outcomes

BACKGROUND

The availability of computed tomography pulmonary angiography (CTPA) has led to an increase in the diagnosis of sub-segmental pulmonary embolism (SSPE). Current clinical practice guidelines do not make any treatment distinctions for SSPE, though the benefits of anticoagulation for SSPE have not been established.

OBJECTIVES

To review the frequency of pulmonary embolism and sub-segmental pulmonary embolism identified through CTPA as well as their management.

METHODS

Cross-sectional review of the charts of 2213 patients who underwent CTPA in three Hamilton teaching hospitals from 2009 to 2011. In-depth review of the charts of patients with SSPE was undertaken to determine the frequency with which patients received anticoagulation therapy for SSPE, as well as bleeding complications and recurrent thrombosis.

RESULTS

A total of 2216 CTPAs were reviewed. The frequency of PE was 24.8% (n = 550). The most frequent filling defect was SSPE in 82 patients (3.9% of total scans and 15.0% of identified PEs). In 55 of these 82 SSPEs, an alternative diagnosis to PE was identified on CT to explain the patients' symptoms. Approximately 52.4% (n = 43) received anticoagulation for SSPE. Major life-threatening bleeding complications occurred in two of the 43 who received anticoagulation for SSPE. There was no documented recurrent thrombosis in any patients with SSPE, with or without anticoagulation.

SUMMARY/CONCLUSIONS

A substantial proportion of patients received anticoagulation for SSPE (52%) and two developed life-threatening bleeding complications. Randomized controlled trial data are needed to further investigate the risks and benefits of anticoagulation in patients with SSPE.

Culture of primary bovine chondrocytes on a continuously expanding surface inhibits dedifferentiation

Expansion of autologous chondrocytes in vitro is used to generate adequate populations for cell-based therapies. However, standard (SD) culture methods cause loss of chondrocyte phenotype and dedifferentiation to fibroblast-like cells. Here, we use a novel surface expansion culture system in an effort to inhibit chondrocyte dedifferentiation. A highly elastic silicone rubber culture surface was continuously stretched over a 13-day period to 600% of its initial surface area. This maintained cells at a high density while limiting contact inhibition and reducing the need for passaging. Gene expression analysis, biochemical assays, and immunofluorescence microscopy of follow-on pellet cultures were used to characterize the results of continuous expansion (CE) culture versus SD cultures on rigid polystyrene. CE culture yielded cells with a more chondrocyte-like morphology and higher RNA-level expression of the chondrogenic markers collagen type II, aggrecan, and cartilage oligomeric matrix protein. Furthermore, the expression of collagen type I RNA and α-smooth muscle actin protein were significantly reduced, indicating suppression of fibroblastic features. Pellet cultures from CE chondrocytes contained more sulphated glycosaminoglycan and collagen type II than pellets from SD culture. Additional control cultures on static (unexpanded) silicone (SS culture) indicated that benefits of CE culture were partially due to features of the culture surface itself and partially due to the reduced passaging which that surface enabled through CE. Chondrocytes grown in CE culture may, therefore, be a superior source for cell-based therapies.

Effects of caffeinated coffee consumption on intraocular pressure, ocular perfusion pressure, and ocular pulse amplitude: a randomized controlled trial

PURPOSE

To examine the effects of caffeinated coffee consumption on intraocular pressure (IOP), ocular perfusion pressure (OPP), and ocular pulse amplitude (OPA) in those with or at risk for primary open-angle glaucoma (POAG).

METHODS

We conducted a prospective, double-masked, crossover, randomized controlled trial with 106 subjects: 22 with high tension POAG, 18 with normal tension POAG, 20 with ocular hypertension, 21 POAG suspects, and 25 healthy participants. Subjects ingested either 237 ml of caffeinated (182 mg caffeine) or decaffeinated (4 mg caffeine) coffee for the first visit and the alternate beverage for the second visit. Blood pressure (BP) and pascal dynamic contour tonometer measurements of IOP, OPA, and heart rate were measured before and at 60 and 90 min after coffee ingestion per visit. OPP was calculated from BP and IOP measurements. Results were analysed using paired t-tests. Multivariable models assessed determinants of IOP, OPP, and OPA changes.

RESULTS

There were no significant differences in baseline IOP, OPP, and OPA between the caffeinated and decaffeinated visits. After caffeinated as compared with decaffeinated coffee ingestion, mean mm Hg changes (± SD) in IOP, OPP, and OPA were as follows: 0.99 (± 1.52, P<0.0001), 1.57 (± 6.40, P=0.0129), and 0.23 (± 0.52, P<0.0001) at 60 min, respectively; and 1.06 (± 1.67, P<0.0001), 1.26 (± 6.23, P=0.0398), and 0.18 (± 0.52, P=0.0006) at 90 min, respectively. Regression analyses revealed sporadic and inconsistent associations with IOP, OPP, and OPA changes.

CONCLUSION

Consuming one cup of caffeinated coffee (182 mg caffeine) statistically increases, but likely does not clinically impact, IOP and OPP in those with or at risk for POAG.