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Background: In the United States, rare disease (RD) is defined as a condition that affects fewer than 200,000 individuals. Collectively, RD affects an estimated 30 million Americans. A significant portion of RD has an underlying genetic cause; however, this may go undiagnosed. To better serve these patients, the Mayo Clinic Program for Rare and Undiagnosed Diseases (PRaUD) was created under the auspices of the Center for Individualized Medicine (CIM) aiming to integrate genomics into subspecialty practice including targeted genetic testing, research, and education., Methods: Patients were identified by subspecialty healthcare providers from 11 clinical divisions/departments. Targeted multi-gene panels or custom exome/genome-based panels were utilized. To support the goals of PRaUD, a new clinical service model, the Genetic Testing and Counseling (GTAC) unit, was established to improve access and increase efficiency for genetic test facilitation. The GTAC unit includes genetic counselors, genetic counseling assistants, genetic nurses, and a medical geneticist. Patients receive abbreviated point-of-care genetic counseling and testing through a partnership with subspecialty providers., Results: Implementation of PRaUD began in 2018 and GTAC unit launched in 2020 to support program expansion. Currently, 29 RD clinical indications are included in 11 specialty divisions/departments with over 142 referring providers. To date, 1152 patients have been evaluated with an overall solved or likely solved rate of 17.5% and as high as 66.7% depending on the phenotype. Noteworthy, 42.7% of the solved or likely solved patients underwent changes in medical management and outcome based on genetic test results., Conclusion: Implementation of PRaUD and GTAC have enabled subspecialty practices advance expertise in RD where genetic counselors have not historically been embedded in practice. Democratizing access to genetic testing and counseling can broaden the reach of patients with RD and increase the diagnostic yield of such indications leading to better medical management as well as expanding research opportunities., (© 2023. The Author(s).)

Background: Recent studies identified underlying genetic causes in a proportion of patients with various forms of kidney disease. In particular, genetic testing reclassified some focal segmental glomerulosclerosis (FSGS) cases into collagen type 4 (COL4)-related nephropathy. This knowledge has major implications for counseling prospective transplant recipients about recurrence risk and screening biologically related donors. We describe our experience incorporating genetic testing in our kidney transplant multidisciplinary practice., Methods: Patients' DNA was analyzed using whole exome sequencing for a comprehensive kidney gene panel encompassing 344 genes associated with kidney diseases and candidate genes highly expressed in the kidney. Results were correlated with phenotype by a multidisciplinary committee of nephrologists, renal pathologists, geneticists, and genetic counselors. Between October 2018 and July 2020, 30 recipient and 5 donor candidates completed testing., Results: Among recipient candidates, 24 (80%) carried the diagnosis of FSGS, 2 (6.7%) tubulointerstitial nephritis, and 1 (3.3%) nephrolithiasis, and 3 (10%) had an unknown cause of kidney disease. The yield for pathogenic/likely pathogenic variants was 43.3%, with majority being COL4 variants (53.8%). Among those with FSGS diagnosis, the yield was 10 of 24 (41.6%), with 29% reclassified into a COL4-related nephropathy. Family history of kidney disease was the only clinical characteristic difference between recipients with positive and negative results (76.9 versus 29.4%; P = 0.025). One of 5 donors tested positive for a pathogenic/likely pathogenic variant and was excluded from donation., Conclusions: We conclude that thoughtful use of genetic testing can be valuable for kidney donor selection and transplant recipient management., Competing Interests: M.E.T. and F.P.V. received support from the Robert W. Faulk Career Development Award, and M.E.T. received support from the Mayo Clinic Transplant Center Scholarly Award. M.C.H. received funding from the Center for Individualized Medicine Research Award. The authors declare no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Mitragyna speciosa, a species of plant that is native to Thailand, Malaysia and Southeast Asia, contains two major psychoactive alkaloids: mitragynine and 7-hydroxymitragynine. Pharmacologically, the alkaloids exhibit biphasic effects-at low doses, stimulant effects are realized, while high doses exhibit sedative effects. For years, the plant has been used recreationally and medicinally for these effects, but its use has been implicated in and associated with intoxications and deaths. In this case report, we describe two cases whereby decedents presented with single-substance fatal intoxications by mitragynine in the absence of other postmortem toxicological findings. The cases entail young male decedents in outdoor settings (e.g., driving a vehicle and bicycle). Postmortem blood concentrations were 2,325 and 3,809 ng/mL. The medical examiner certified the cause of death as acute mitragynine intoxication in both cases. The toxicology results presented become useful when considering mitragynine to be the offending agent in lethal single-drug intoxications; further, the information included is pertinent to medical examiners, forensic pathologists, forensic toxicologists and emergency department personnel in evaluating possible poisoning and lethality by mitragynine., (© The Author(s) 2022. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Rationale & Objective: Data on kidney transplantation outcomes among patients with monoclonal gammopathy of renal significance (MGRS) are lacking., Study Design: Case series of patients with MGRS, some of whom received clone-directed therapies before kidney transplantation., Setting & Participants: 28 patients who underwent kidney transplantation from 1987 through 2016 after diagnosis with MGRS-associated lesions including light-chain deposition disease (LCDD), C3 glomerulopathy with monoclonal gammopathy (C3G-MG), and light-chain proximal tubulopathy (LCPT)., Findings: Of the 19 patients with LCDD, 10 were treated before kidney transplantation and 9 were treatment-naive. Among the treated patients with LCDD, 3 (30%) experienced histologic recurrence, 2 (20%) grafts failed, and 2 (20%) died during a median follow-up of 70 (range, 3-162) months after transplant. In the treatment-naive LCDD group, 8 (89%) had histologic recurrence, 6 (67%) grafts failed, and 4 (44%) patients died during a median follow-up of 60 (range, 35-117) months. Of the 5 patients who had a complete response before transplant, none died, and only 1 experienced graft failure, 162 months after transplant. Of 5 patients with C3G-MG, 3 were treatment-naive before transplant. Both patients who were treated before transplant had histologic recurrence, and 1 experienced graft failure and died. Among the 3 patients with treatment-naive C3G-MG, histologic recurrence occurred in all, and graft loss and death were observed in 2 and 1, respectively. In the LCPT group (n=4), histologic recurrence was observed in all 3 patients who did not receive clone-directed therapies before transplant, and 2 of these patients died, 1 with a functioning kidney. The 1 patient with LCPT who received therapy before transplant did not have histologic recurrence or graft loss and survived., Limitations: Small sample size, nonstandardized clinical management, retrospective design., Conclusions: Recurrence is very common in all MGRS-associated lesions after kidney transplant. Achieving a complete hematologic response may reduce the risks of recurrence, graft loss, and death. More studies are needed to determine the effects of hematologic response on outcomes for each MGRS-associated lesion., (Copyright © 2021 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

Background: Improving both patient and graft survival after kidney transplantation are major unmet needs. The goal of this study was to assess risk factors for specific causes of graft loss to determine to what extent patients who develop either death with a functioning graft (DWFG) or graft failure (GF) have similar baseline risk factors for graft loss., Methods: We retrospectively studied all solitary renal transplants performed between January 1, 2006, and December 31, 2018, at 3 centers and determined the specific causes of DWFG and GF. We examined outcomes in different subgroups using competing risk estimates and cause-specific Cox models., Results: Of the 5752 kidney transplants, graft loss occurred in 21.6% (1244) patients, including 12.0% (691) DWFG and 9.6% (553) GF. DWFG was most commonly due to malignancy (20.0%), infection (19.7%), cardiac disease (12.6%) with risk factors of older age and pretransplant dialysis, and diabetes as the cause of renal failure. For GF, alloimmunity (38.7%), glomerular diseases (18.6%), and tubular injury (13.9%) were the major causes. Competing risk incidence models identified diabetes and older recipients with higher rates of both DWFG and nonalloimmune GF., Conclusions: These data suggest that at baseline, 2 distinct populations can be identified who are at high risk for renal allograft loss: a younger, nondiabetic patient group who develops GF due to alloimmunity and an older, more commonly diabetic population who develops DWFG and GF due to a mixture of causes-many nonalloimmune. Individualized management is needed to improve long-term renal allograft survival in the latter group., Competing Interests: The authors declare no funding or conflicts of interest., (Copyright © 2022 The Author(s). Transplantation Direct. Published by Wolters Kluwer Health, Inc.)

Objective: To increase the likelihood of finding a causative genetic variant in patients with a focal segmental glomerulosclerosis (FSGS) lesion, clinical and histologic characteristics were analyzed., Patients and Methods: Individuals 18 years and older with an FSGS lesion on kidney biopsy evaluated at Mayo Clinic from November 1, 1999, through October 31, 2019, were divided into 4 groups based on clinical and histologic characteristics: primary FSGS, secondary FSGS with known cause, secondary FSGS without known cause, and undetermined FSGS. A targeted gene panel and a customized gene panel retrieved from exome sequencing were performed., Results: The overall rate of detection of a monogenic cause was 42.9% (21/49). Individuals with undetermined FSGS had the highest rate of positivity (87.5%; 7/8) followed by secondary FSGS without an identifiable cause (61.5%; 8/13) and secondary FSGS with known cause (33.3%; 5/15). Four of 5 (80%) individuals in the latter group who had positive genetic testing results also had a family history of kidney disease. Univariate analysis showed that family history of kidney disease (odds ratio [OR], 13.8; 95% CI, 3.7 to 62.4; P<.001), absence of nephrotic syndrome (OR, 8.2; 95% CI, 1.9 to 58.1; P=.004), and female sex (OR, 5.1; 95% CI, 1.5 to 19.9; P=.01) were strong predictors of finding a causative genetic variant in the entire cohort. The most common variants were in the collagen genes (52.4%; 11/21), followed by the podocyte genes (38.1%; 8/21)., Conclusion: In adults with FSGS lesions, proper selection of patients increases the rate of positive genetic testing significantly. The majority of individuals with undetermined FSGS in whom the clinical presentation and histologic parameters are discordant had a genetic diagnosis., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Experience with sequential hematopoietic stem cell transplant (HSCT) and kidney transplant (KT) is limited., Methods: We conducted a retrospective observational study of adult patients who underwent both HSCT and KT at our center, with a median follow-up of 11 y., Results: In our 54 patients cohort (94% autologous HSCT), 36 (67%) patients received HSCT first followed by KT, while 18 (33%) received KT before HSCT. In both groups, AL amyloidosis represented 50% of hematologic diagnosis. Only 4 patients expired due to hematologic disease relapse (2 patients in each group) and only 3 allografts were lost due to hematologic disease recurrence (HSCT first n = 1 and KT first n = 2). Overall 1, 5, and 10 y death-censored graft survival rates were 94%, 94%, and 94%, respectively, for the HSCT first group and 89%, 89%, and 75%, respectively, for the KT first group. Overall 1, 5, and 10 y patients survival rates were 100%, 97% and 90%, respectively, for the HSCT first group and 100%, 76%, and 63%, respectively, for the KT first group., Conclusions: Our study supports safety of sequential KT and HSCT, with improved overall patient survival compared to recipients of HSCT remaining on dialysis and good long-term kidney allograft outcome., Competing Interests: The authors declare no funding or conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Rationale & Objective: The etiology of kidney disease remains unknown in many individuals with chronic kidney disease (CKD). We created the Mayo Clinic Nephrology Genomics Clinic to improve our ability to integrate genomic and clinical data to identify the etiology of unexplained CKD., Study Design: Retrospective study., Setting & Participants: An essential component of our program is the Nephrology Genomics Board which consists of nephrologists, geneticists, pathologists, translational omics scientists, and trainees who interpret the patient's clinical and genetic data. Since September 2016, the Board has reviewed 163 cases (15 cystic, 100 glomerular, 6 congenital anomalies of kidney and urinary tract (CAKUT), 20 stones, 15 tubulointerstitial, and 13 other)., Analytical Approach: Testing was performed with targeted panels, single gene analysis, or analysis of kidney-related genes from exome sequencing. Variant classification was obtained based on the 2015 American College of Medical Genetics and Genomics and the Association for Molecular Pathology guidelines., Results: A definitive genetic diagnosis was achieved for 50 families (30.7%). The highest diagnostic yield was obtained in individuals with tubulointerstitial diseases (53.3%), followed by congenital anomalies of the kidney and urological tract (33.3%), glomerular (31%), cysts (26.7%), stones (25%), and others (15.4%). A further 20 (12.3%) patients had variants of interest, and variant segregation, and research activities (exome, genome, or transcriptome sequencing) are ongoing for 44 (40%) unresolved families., Limitations: Possible overestimation of diagnostic rate due to inclusion of individuals with variants with evidence of pathogenicity but classified as of uncertain significance by the clinical laboratory., Conclusions: Integration of genomic and research testing and multidisciplinary evaluation in a nephrology cohort with CKD of unknown etiology or suspected monogenic disease provided a diagnosis in a third of families. These diagnoses had prognostic implications, and often changes in management were implemented., (© 2021 The Authors.)

Background: Treatment of proliferative GN with monoclonal Ig deposits (PGNMID) is not established. A monoclonal anti-CD38 antibody (daratumumab) is effective in treating multiple myeloma. Abnormal plasma cell clones may play a role in the pathogenesis of PGNMID., Methods: We evaluated daratumumab's safety and efficacy in an open-label, phase 2 trial in 11 adults with PGNMID and one with C3 glomerulopathy (C3G) with monoclonal gammopathy. Patients had an eGFR >20 ml/min per 1.73 m 2 and proteinuria >1 g/d. They received daratumumab intravenously (16 mg/kg) once weekly for 8 weeks, and then every other week for eight additional doses. Primary outcome was safety, defined as major infections, grade 3 or 4 anemia, leukopenia, or thrombocytopenia. Secondary outcomes were rate of complete remission (proteinuria <500 mg/d with <15% decline in baseline eGFR) or partial remission (>50% reduction in 24-hour proteinuria with <30% decline in eGFR) and proteinuria at 6 and 12 months., Results: One patient with C3G had GN unrelated to the monoclonal gammopathy, and one with PGNMID did not complete the first infusion. Five serious adverse events occurred. During the 12 months of the trial, six of the ten patients with PGNMID who received at least one dose of daratumumab had a partial response, and four had a complete response (an overall response rate of 100%). Three patients experienced relapse, two of whom re-entered partial remission after resuming daratumumab therapy. Proteinuria declined significantly, from a median of 4346 mg/d to 1264 mg/d by 12 months., Conclusions: Daratumumab demonstrated an acceptable safety profile and resulted in significant improvement in proteinuria while stabilizing kidney function in patients with PGNMID, suggesting the drug merits further investigation., Clinical Trial Registry Name and Registration Number: Daratumumab in Treatment of PGNMID and C3 GN, NCT03095118., (Copyright © 2021 by the American Society of Nephrology.)

Background: Graft survival after kidney transplant (KTX) is often estimated by the Kaplan-Meier (KM) method censoring for competing endpoints, primarily death. This method overestimates the incidence of graft loss., Methods: In 3157 adult KTX recipients followed for a mean of 79.2 months, we compared kidney and patient survival probabilities by KM versus competing risk analysis (CRA). These methods are extended to comparing different regression methods., Results: Compared with CRA, the probabilities of death and graft loss (censored for the other outcome) were substantially higher by KM. These differences increased with increasing follow-up time. Importantly, differences in graft losses were magnified in subgroups with greater probabilities of death. Among recipients with diabetes, the probabilities of graft loss at 20 years were 57% by KM and 32% by CRA, while for non-diabetes mellitus corresponding values were 44% and 35%. Similar results are noted when comparing older versus younger recipients. Finally, we find that the Fine-Gray method assumptions are violated when using age and gender as covariates and that the alternative method of Aalen-Johansen may be more appropriate., Conclusions: CRA provides more accurate estimates of long-term graft survival and death, particularly in subgroups of recipients with higher rates of the competing event. Overestimation of risk by KM leads to both quantitative and qualitative misinterpretations of long-term KTX outcomes. When using regression analyses, care should be taken to check assumptions to guide the choice of appropriate method., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Longer survival using modern therapies has increased the number of patients with immunoglobulin light-chain amyloidosis receiving kidney transplantation. We evaluated 60 patients with immunoglobulin light chain amyloidosis who underwent kidney transplantation based on their hematologic response for outcomes of death, graft failure, and complications. Patient hematologic responses (light-chain in blood or urine) prior to kidney transplantation were three patients had no response, five had a partial response, six had a very good partial response, 37 had a complete response, and nine were treatment-naive patients (never treated for this disorder). After transplantation, seven of nine treatment-naive patients achieved a complete response. The median follow-up for the entire transplant cohort was 61 months. The estimated median overall survival from the time of kidney transplantation was 123 months for the entire group. Median overall survival was not reached for the very good partial response plus complete response groups, it was 47 months for no response plus partial response groups, and 117 months for the treatment-naive group (all significantly different). Median overall survival of very good partial response was 81 months, while the median was not reached in the complete response group (no significant difference). The time to amyloid recurrence was significantly longer in complete response compared to very good partial response (median 181 vs 81 months). Death-censored graft survival at one- and five-years was 98.3%, and 95.8%, respectively for all groups. Of the 60 patients, three had allograft failure, 19 died with a functioning graft, and 13 had an amyloid recurrence. Thus, outcomes after kidney transplant in patients with immunoglobulin light-chain amyloidosis seem acceptable if a very good partial response or complete response is achieved either before or after transplantation., (Copyright © 2020 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Introduction: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive cyst growth and a loss of functioning renal mass, but a decline in glomerular filtration rate (GFR) and onset of end-stage renal disease (ESRD) occur late in the disease course. There is therefore a great need for early prognostic biomarkers in this disorder., Methods: We measured baseline serum fibroblast growth factor 23 (FGF23) levels in 192 patients with ADPKD from the Consortium for Radiologic Imaging Studies of PKD (CRISP) cohort that were followed for a median of 13 years and tested the association between FGF23 levels and change over time in height-adjusted total kidney volume (htTKV), GFR, and time to the composite endpoints of ESRD, death, and doubling of serum creatinine., Results: Patients in the highest quartile for baseline FGF23 level had a higher rate of increase in htTKV (0.95% per year, P  = 0.0016), and faster rate of decline in GFR (difference of -1.03 ml/min/1.73 m 2 per year, P  = 0.005) compared with the lowest quartile, after adjusting for other covariates, including htTKV and genotype. The highest quartile of FGF23 was also associated with a substantial increase in risk for the composite endpoint of ESRD, death, or doubling of serum creatinine (hazard ratio [HR] of 2.45 in the fully adjusted model, P  = 0.03)., Conclusion: FGF23 is a prognostic biomarker for disease progression and clinically important outcomes in ADPKD, and has additive value to established imaging and genetic biomarkers., (© 2021 International Society of Nephrology. Published by Elsevier Inc.)

Rationale & Objective: Fibrillary glomerulonephritis (FGN) is a rare glomerular disease that often progresses to kidney failure requiring kidney replacement therapy. We have recently identified a novel biomarker of FGN, DnaJ homolog subfamily B member 9 (DNAJB9). In this study, we used sequential protocol allograft biopsies and DNAJB9 staining to help characterize a series of patients with native kidney FGN who underwent kidney transplantation., Study Design: Case series., Setting & Participants: Between 1996 and 2016, kidney transplantation was performed on 19 patients with a reported diagnosis of FGN in their native/transplant kidneys. Using standard diagnostic criteria and DNAJB9 staining, we excluded 5 patients (4 atypical cases diagnosed as possible FGN and 1 donor-derived FGN). Protocol allograft biopsies had been performed at 4, 12, 24, 60, and 120 months posttransplantation. DNAJB9 immunohistochemistry was performed using an anti-DNAJB9 rabbit polyclonal antibody. Pre- and posttransplantation demographic and clinical characteristics were collected. Summary statistical analysis was performed, including nonparametric statistical tests., Observations: The 14 patients with FGN had a median posttransplantation follow-up of 5.7 (IQR, 2.9-13.8) years. 3 (21%) patients had recurrence of FGN, detected on the 5- (n=1) and 10-year (n=2) allograft biopsies. Median time to recurrence was 10.2 (IQR, 5-10.5) years. Median levels of proteinuria and iothalamate clearance at the time of recurrence were 243mg/d and 56mL/min. The remaining 11 patients had no evidence of histologic recurrence on the last posttransplantation biopsy, although the median time of follow-up was significantly less at 4.4 (IQR, 2.9-14.4) years. 3 (21%) patients had a monoclonal protein detectable in serum obtained pretransplantation; none of these patients had recurrent FGN., Limitations: Small study sample and shorter follow-up time in the nonrecurrent versus recurrent group., Conclusions: In this series, FGN had an indolent course in the kidney allograft in that detectable histologic recurrence did not appear for at least 5 years posttransplantation., (Copyright © 2020. Published by Elsevier Inc.)

Introduction: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive cyst enlargement, leading to kidney failure. Sirtuin-1 is upregulated in ADPKD and accelerates disease progression by deacetylating p53. Niacinamide is a dietary supplement that inhibits sirtuins at high doses., Methods: We conducted an open-label, single-arm intervention trial (study 1, N  = 10), and a randomized, double blinded, placebo-controlled trial (study 2, N  = 36) to assess the biological activity and safety of niacinamide. Patients with ADPKD were given 30 mg/kg oral niacinamide or placebo, for 12 months. The primary endpoint was the ratio of acetylated p53 to total p53 protein in peripheral blood mononuclear cells (PBMCs)., Results: There was no sustained effect of niacinamide on acetylated/total p53 in either study and no difference between placebo and niacinamide arms. There was no difference in the change in height-adjusted total kidney volume over 12 months between niacinamide and placebo. Niacinamide was generally well tolerated. The most common adverse effects were nausea, diarrhea, gastroesophageal reflux, headache, and acneiform rash but there was no difference in their incidence between niacinamide and placebo., Conclusions: In conclusion, niacinamide is safe and well-tolerated in patients with ADPKD. However, we were unable to detect a sustained inhibition of sirtuin activity over 12 months of treatment, and there was no signal to suggest a beneficial effect on any efficacy measure., (© 2020 International Society of Nephrology. Published by Elsevier Inc.)

Background: Proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) is a distinct form of glomerulonephritis that often recurs after kidney transplantation causing severe graft injury and often failure., Methods: We describe post transplant outcomes and response to therapy in 20 recipients with PGNMID. Evidence of PGNMID recurrence or lack thereof was determined by protocol and clinical biopsies., Results: Histologic recurrence (deposition of monoclonal immunoglobulin) occurred in 18 of 20 recipients (90%), a median of 7 (1 to 65) months post transplant. At diagnosis, recurrence was generally associated with mild or no clinical manifestations and often with mild glomerular morphologic changes by light microcopy. Four of the 18 patients with recurrence did not progress and were not treated. Another 4 patients with recurrences were treated with cyclophosphamide with or without plasmapheresis, and 2 of these grafts were lost from glomerulonephritis. Nine patients with recurrences were treated with anti-CD20 antibodies (rituximab) alone, resulting in improvements in estimated glomerular filtration rate (31.5 ± 16 versus 38.8 ± 13.3 mL/min/1.73 m, P = 0.011) and proteinuria (1280 [117 to 3752] versus 168 [83 to 1613] mg/24 h, P = 0.012) although complete clinical remission was rare. One graft in this later group was lost from recurrence 141 months post transplant. Posttreatment biopsies demonstrated stable or improved glomerular histology in most cases. However, PGNMID did not resolve in any case. Four patients received rituximab 4 months pretransplant to prevent recurrence. However, 3 had mild recurrences., Conclusions: Rituximab treatment of early PGNMID recurrence is effective, resulting in reasonable, long-term graft survival. Whether pretransplant rituximab modifies the course of recurrence requires additional studies.

Background: Caffeine has been proposed, based on in vitro cultured cell studies, to accelerate progression of autosomal dominant polycystic kidney disease (ADPKD) by increasing kidney size. Since ADPKD patients are advised to minimize caffeine intake, we investigated the effect of caffeine on disease progression in the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease (CRISP), a prospective, observational cohort study., Methods: Our study included 239 patients (mean age = 32.3 ± 8.9 ys; 188 caffeine consumers) with a median follow-up time of 12.5 years. Caffeine intake reported at baseline was dichotomized (any vs. none). Linear mixed models, unadjusted and adjusted for age, race, sex, BMI, smoking, hypertension, genetics and time, were used to model height-adjusted total kidney volume (htTKV) and iothalamate clearance (mGFR). Cox proportional hazards models and Kaplan-Meier plots examined the effect of caffeine on time to ESRD or death., Results: Caffeine-by-time was statistically significant when modeling ln(htTKV) in unadjusted and adjusted models (p <  0.01) indicating that caffeine consumers had slightly faster kidney growth (by 0.6% per year), but htTKV remained smaller from baseline throughout the study. Caffeine consumption was not associated with a difference in mGFR, or in the time to ESRD or death (p > 0.05). Moreover the results were similar when outcomes were modeled as a function of caffeine dose., Conclusion: We conclude that caffeine does not have a significant detrimental effect on disease progression in ADPKD.

Introduction: Peripherally inserted central venous catheters (PICCs) may adversely impact future successful arteriovenous fistulae (AVF). As part of a quality improvement project, the performance of tunneled small bore tunneled central venous catheters (TSB-CVCs), as alternatives to PICCs, was evaluated., Methods: A retrospective observational study, involving individuals ≥18 years of age who underwent TSB-CVC placement by Interventional Radiology at Mayo Clinic, Rochester, MN between 1/1/2010 and 8/30/2013., Findings: The study cohort included 92 patients with a median age of 55 (46-67) years, who underwent 108 TSB-CVC placements. Baseline renal disease was present in 71% (77/108). Most TSB-CVCs were placed in hospitalized patients (94%; 102/108); five French in diameter (61%; 66/108) and located in an internal jugular vein (84%; 91/108). Median catheter indwelling time was 20 (11-43) days (n = 84). TSB-CVC-related bloodstream infection, deep venous thrombosis (DVT), and superficial venous thrombosis (SpVT) rates per line were 0.009 (1/108), 0.018 (2/108), and 0.009 (1/108), respectively. Venous outcomes in a subgroup of 54 patients, who had documented PICC placements (n = 161) in addition to TSB-CVC (n = 58) were compared. TSB-CVC-DVT rate was lower than the PICC-DVT rate (0.017 [1/58] vs. 0.106 per line [17/161]; P = 0.04). The TSB-CVC-SpVT rate was not different from the PICC-SpVT rate (0 [0/58] vs. 0.037 [6/161] per line; P = 0.14)., Discussion: TSB-CVCs demonstrated an excellent safety profile in our study. These catheters should be preferentially utilized for arm vein preservation in advanced kidney disease. Their impact on future AVF success needs further evaluation., (© 2016 International Society for Hemodialysis.)

Crystalline nephropathy refers to renal parenchymal deposition of crystals leading to kidney damage. The most common forms of crystalline nephropathy encountered in renal pathology are nephrocalcinosis and oxalate nephropathy. Less frequent types include urate nephropathy, cystinosis, dihydroxyadeninuria, and drug-induced crystalline nephropathy (e.g., caused by indinavir or triamterene). Monoclonal proteins can also deposit in the kidney as crystals and cause tissue damage. This occurs in conditions such as light chain proximal tubulopathy, crystal-storing histiocytosis, and crystalglobulinemia. The latter is a rare complication of multiple myeloma that results from crystallization of monoclonal proteins in the systemic vasculature, leading to vascular injury, thrombosis, and occlusion. In this report, we describe a case of crystalglobulin-induced nephropathy and discuss its pathophysiology and the differential diagnosis of paraprotein-induced crystalline nephropathy., (Copyright © 2015 by the American Society of Nephrology.)

The survival of patients with diabetes mellitus in the general population has improved in recent years. Here we assessed whether similar trends have occurred in 1688 kidney recipients, including 413 with diabetes prior to transplant between 1996 and 2007. Compared to patients without diabetes, the 5-year mortality was significantly increased (hazard ratio (HR) 2.68 (1.95-3.69)) due to higher cardiovascular-, infection-, and malignancy-related deaths in those with diabetes. However, 5-year mortality in patients with diabetes significantly declined over time (HR 0.883 (0.817-0.954)), narrowing the mortality difference between patients with and those without diabetes and in more recent years largely eliminating it. Post transplant, patients with diabetes experienced a significant decline in major fatal/nonfatal cardiac events (HR 0.853 (0.782-0.930)) and infectious deaths over time. In contrast, neither cardiac events nor overall mortality declined in recipients without diabetes. The decline in mortality due to diabetes did not relate to a reduced pretransplant risk profile and was independent of posttransplant variables. The use of cardioprotective medications and glycemic control improved over time post transplant. Furthermore, graft function and serum albumin significantly improved over time and these parameters related to better survival (albumin, HR 0.365 (0.223-0.599); eGFR, HR 0.803 (0.756-0.852)). Thus, survival of kidney recipients with diabetes mellitus has improved markedly since 1996 likely reflecting, at least in part, enhanced posttransplant management and outcomes.

Objective: To report 3 cases of reversible hypothyroidism-induced kidney dysfunction and review the interaction between these commonly encountered, yet seemingly disparate, conditions., Methods: We describe the clinical course and laboratory and physical findings of 3 patients who presented with kidney dysfunction that improved after initiating thyroid hormone replacement therapy. We also review similar cases in the literature and discuss the pathophysiologic mechanisms., Results: A 68-year-old male presented with classical signs and symptoms of hypothyroidism, including fatigue, confusion, and gait imbalance. Physical exam showed bradycardia, thyromegaly, slow mentation, and cracked, thin skin; he was found to have decreased kidney function. Second, a 42-year-old previously healthy female presented with bilateral hand swelling and elevated serum creatinine with an otherwise unremarkable physical exam. The third patient was a 72-year-old male with advanced heart failure on amiodarone and stage 3 chronic kidney disease who presented with fatigue, acute kidney injury, and lower extremity edema. In all cases, serum creatinine and thyroid-stimulating hormone (TSH) were elevated at presentation (1.4-3.0 mg/dL and 94.1-184 mIU/L respectively), and free thyroxine (T4) was low (undetectable-0.4 ng/dL). The initiation or increased dose of levothyroxine normalized serum creatinine to baseline within 2 to 10 months., Conclusion: Hypothyroidism and kidney dysfunction are both commonly encountered clinical entities, but the interplay between the thyroid gland and kidneys may be infrequently recalled, causing the reversible relationship between these 2 disorders to be missed.

Background: Although an arteriovenous fistula (AVF) is the hemodialysis access of choice, its prevalence continues to be lower than recommended in the United States. We assessed the association between past peripherally inserted central catheters (PICCs) and lack of functioning AVFs., Study Design: Case-control study., Participants & Setting: Prevalent hemodialysis population in 7 Mayo Clinic outpatient hemodialysis units. Cases were without functioning AVFs and controls were with functioning AVFs on January 31, 2011., Predictors: History of PICCs., Outcomes: Lack of functioning AVFs., Results: On January 31, 2011, a total of 425 patients were receiving maintenance hemodialysis, of whom 282 were included in this study. Of these, 120 (42.5%; cases) were dialyzing through a tunneled dialysis catheter or synthetic arteriovenous graft and 162 (57.5%; controls) had a functioning AVF. PICC use was evaluated in both groups and identified in 30% of hemodialysis patients, with 54% of these placed after dialysis therapy initiation. Cases were more likely to be women (52.5% vs 33.3% in the control group; P = 0.001), with smaller mean vein (4.9 vs 5.8 mm; P < 0.001) and artery diameters (4.6 vs 4.9 mm; P = 0.01) than controls. A PICC was identified in 53 (44.2%) cases, but only 32 (19.7%) controls (P < 0.001). We found a strong and independent association between PICC use and lack of a functioning AVF (OR, 3.2; 95% CI, 1.9-5.5; P < 0.001). This association persisted after adjustment for confounders, including upper-extremity vein and artery diameters, sex, and history of central venous catheter (OR, 2.8; 95% CI, 1.5-5.5; P = 0.002)., Limitations: Retrospective study, participants mostly white., Conclusion: PICCs are commonly placed in patients with end-stage renal disease and are a strong independent risk factor for lack of functioning AVFs., (Copyright © 2012 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

Recurrent AA amyloidosis in a kidney transplant is rare, especially when the underlying inflammatory condition is controlled. We present a 59-year-old man who underwent a living donor kidney transplant 17 years ago for kidney failure due to AA amyloid nephropathy in the setting of long-standing Crohn disease. His Crohn disease was quiescent before and after the kidney transplant. Transplant function had been stable until a month before presentation, when he developed worsening proteinuria and decreased kidney function. A transplant biopsy showed recurrent AA amyloidosis despite excellent clinical and histologic control of Crohn disease., (Copyright © 2011 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)