Higher rates of rejection in HIV-infected kidney transplant recipients on ritonavir-boosted protease inhibitors: 3-year follow-up study.

Rejection rates in HIV-infected kidney transplant (KTx) recipients are higher than HIV-negative recipients. Immunosuppression and highly active antiretroviral therapy (HAART) protocols vary with potentially significant drug-drug interactions, likely influencing outcomes. This is an IRB-approved, single-center, retrospective study of adult HIV-infected KTx patients between 5/2009 and 12/2014 with 3-year follow-up, excluding antibody-depleting induction. A total of 42 patients were included; median age was 52 years, 81% male, 50% African American, 29% Hispanic, 17% Caucasian. The most common renal failure etiology was hypertensive nephrosclerosis (50%) with 5.8 median years of pre-transplant dialysis. All patients received IL-2 receptor antagonist, were maintained on tacrolimus (76%) or cyclosporine (17%), and 40% received ritonavir-boosted PI-based HAART (rtv+) regimen. Patient and graft survival at 3 years were 93% and 90%. At 1-, 2-, and 3-year time points, median serum creatinine was 1.49, 1.35, and 1.67; treated biopsy-proven rejection was 38%, 38%, and 40.5%; and 92% of episodes were acute rejection. At these time points, rejection rates were significantly higher with boosted PI HAART regimens compared to other HAART regimens, 59% vs 24% (P = 0.029), 59% vs 24% (P = 0.029), and 68% vs 24% (P = 0.01). Despite higher rejection rates, HIV-infected KTx recipients have reasonable outcomes. Given significantly higher rejection rates using rtv+ regimens, alternative HAART regimens should be considered prior to transplantation.

Pancytopenia caused by allopurinol and azathioprine interaction in a heart transplant patient: a case report.

BACKGROUND: Azathioprine is an immunosuppressive now less commonly prescribed after orthotopic heart transplantation. Patients with solid organ transplantation are at increased risk for numerous comorbidities including gout. Co-administration of allopurinol for gout prophylaxis and azathioprine increases the risk for severe myelosuppression due to drug-drug interactions. CASE SUMMARY: A 57-year-old male with a history of heart transplant 6 years prior presented with a month of severe fatigue and shortness of breath. His admission laboratory values were notable for severe pancytopenia. Medical workup revealed no haematologic malignancy, viral infection, or other consumptive process. After extensive review, it was discovered that the patient was taking excessive allopurinol for gout. His haematologic abnormalities resolved following discontinuation of allopurinol and treatment with filgrastim and romiplostim and was able to be discharged from the hospital. DISCUSSION: Azathioprine and allopurinol can potentially cause profound cytopenias due to the increased production of the active metabolites of azathioprine. Given the association between gout and solid organ transplantation, recognition of the risks of medication interaction as well as communication amongst health care providers and between providers and their patients is paramount.

Challenges in heart transplantation during COVID-19: A single-center experience.

BACKGROUND: Orthotopic heart transplantation (OHT) recipients may be particularly vulnerable to coronavirus disease 2019 (COVID-19). OHT during the pandemic presents unique challenges in terms of feasibility and safety. METHODS: Chart review was performed for consecutive OHT recipients with COVID-19 and waitlisted patients who underwent OHT from March 1, 2020 to May 15, 2020. RESULTS: Of the approximately 400 OHT recipients followed at our institution, 22 acquired COVID-19. Clinical characteristics included median age 59 (range, 49-71) years, 14 (63.6%) were male, and median time from OHT to infection was 4.6 (2.5-20.6) years. Symptoms included fever (68.2%), gastrointestinal complaints (55%), and cough (46%). COVID-19 was severe or critical in 5 (23%). All patients had elevated inflammatory biomarkers. Immunosuppression was modified in 85% of patients. Most (n = 16, 86.4%) were hospitalized, 18% required intubation, and 14% required vasopressor support. Five patients (23%) expired. None of the patients requiring intubation survived. Five patients underwent OHT during the pandemic. They were all males, ranging from 30 to 59 years of age. Two were transplanted at United Network of Organ Sharing Status 1 or 2, 1 at Status 3, and 2 at Status 4. All were successfully discharged and are alive without allograft dysfunction or rejection. One contracted mild COVID-19 after the index hospitalization. CONCLUSION: OHT recipients with COVID-19 appear to have outcomes similar to the general population hospitalized with COVID-19. OHT during the pandemic is feasible when appropriate precautions are taken. Further study is needed to guide immunosuppression management in OHT recipients affected by COVID-19.

A2B adenosine receptors regulate the mucus clearance component of the lung's innate defense system.

Adenosine (ADO) signaling is altered in both asthma and chronic obstructive pulmonary disease, and the A(2B) adenosine receptor (A(2B)-R) may drive pulmonary inflammation. Accordingly, it has been proposed that specific inhibition of the A(2B)-R could treat inflammatory lung diseases. However, stimulation of the cystic fibrosis transmembrane conductance regulator (CFTR) by ADO may be crucial in permitting the superficial epithelium to maintain airway surface liquid (ASL) volume, which is required to ensure hydrated and clearable mucus. Our goal was to determine which ADO receptor (ADO-R) underlies ASL volume regulation in bronchial epithelia. We used PCR techniques to determine ADO-R expression in bronchial epithelia and used nasal potential difference measurements, Ussing chambers studies, and XZ-confocal microscopy to look at Cl- secretion and ASL volume regulation. The A(2B)-R was the most highly expressed ADO-R in donor specimens of human bronchial epithelia, and inhibition of ADO-R in vivo prevented activation of CFTR. A(2B)-R was the only ADO-R detected in cultured human bronchial epithelial cells and inhibition of this receptor with specific A(2B)-R antagonists resulted in ASL height collapse and a failure to effect ASL height homeostasis. Removal of ADO with ADO deaminase and replacement with 5'N-ethylcarboxamide adenosine resulted in dose-dependent changes in ASL height, and suggested that the cell surface (ADO) may be in excess of 1 microM, which is sufficient to activate A(2B)-R. A(2B)-R are required for ASL volume homeostasis in human airways, and therapies directed at inhibiting A(2B)-R may lead to a cystic fibrosis-like phenotype with depleted ASL volume and mucus stasis.

Liquid movement across the surface epithelium of large airways.

The cystic fibrosis transmembrane conductance regulator CFTR gene is found on chromosome 7 [Kerem, B., Rommens, J.M., Buchanan, J.A., Markiewicz, D., Cox, T.K., Chakravarti, A., Buchwald, M., Tsui, L.C., 1989. Identification of the cystic fibrosis gene: genetic analysis. Science 245, 1073-1080; Riordan, J.R., Rommens, J.M., Kerem, B., Alon, N., Rozmahel, R., Grzelczak, Z., Zielenski, J., Lok, S., Plavsic, N., Chou, J.L., et al., 1989. Identification of the cystic fibrosis gene: cloning and characterization of complementary DNA. Science 245, 1066-1073] and encodes for a 1480 amino acid protein which is present in the plasma membrane of epithelial cells [Anderson, M.P., Sheppard, D.N., Berger, H.A., Welsh, M.J., 1992. Chloride channels in the apical membrane of normal and cystic fibrosis airway and intestinal epithelia. Am. J. Physiol. 263, L1-L14]. This protein appears to have many functions, but a unifying theme is that it acts as a protein kinase C- and cyclic AMP-regulated Cl(-) channel [Winpenny, J.P., McAlroy, H.L., Gray, M.A., Argent, B.E., 1995. Protein kinase C regulates the magnitude and stability of CFTR currents in pancreatic duct cells. Am. J. Physiol. 268, C823-C828; Jia, Y., Mathews, C.J., Hanrahan, J.W., 1997. Phosphorylation by protein kinase C is required for acute activation of cystic fibrosis transmembrane conductance regulator by protein kinase A. J. Biol. Chem. 272, 4978-4984]. In the superficial epithelium of the conducting airways, CFTR is involved in Cl(-) secretion [Boucher, R.C., 2003. Regulation of airway surface liquid volume by human airway epithelia. Pflugers Arch. 445, 495-498] and also acts as a regulator of the epithelial Na(+) channel (ENaC) and hence Na(+) absorption [Boucher, R.C., Stutts, M.J., Knowles, M.R., Cantley, L., Gatzy, J.T., 1986. Na(+) transport in cystic fibrosis respiratory epithelia. Abnormal basal rate and response to adenylate cyclase activation. J. Clin. Invest. 78, 1245-1252; Stutts, M.J., Canessa, C.M., Olsen, J.C., Hamrick, M., Cohn, J.A., Rossier, B.C., Boucher, R.C., 1995. CFTR as a cAMP-dependent regulator of sodium channels. Science 269, 847-850]. In this chapter, we will discuss the regulation of these two ion channels, and how they can influence liquid movement across the superficial airway epithelium.

Hepatitis C and Human Immunodeficiency Virus Kidney Transplantation: The Mount Sinai Experience.

Mount Sinai Hospital in New York has a long history in the field of organ transplantation. The first kidney transplant at Mount Sinai was performed in 1967 by the late Dr. Lewis Burrows and the first laparoscopic donor nephrectomy in New York was performed at Mount Sinai in 1996. Over 3000 kidney transplantations have been performed at Mount Sinai. In the early 1990s, the first hepatitis C virus (HCV) positive patient at Mount Sinai underwent a kidney transplant and the first kidney transplant in a patient with human immunodeficiency virus (HIV) in New York was performed at Mount Sinai in 2001. In general, these patients have done well after renal transplantation, with outcomes similar to those seen in non-infected patients. This chapter will describe the evolution of immunosuppressive regimens in HCV positive and HIV positive patients, and will describe the outcomes of kidney transplantation in these patients. Given the favorable outcomes, it is reasonable to continue to offer renal transplantation as a treatment for end stage renal disease patients with HCV and/or HIV.

Evaluation of oral anticoagulants for the extended treatment of venous thromboembolism using a mixed-treatment comparison, meta-analytic approach.

PURPOSE: Target-specific oral anticoagulants (apixaban, rivaroxaban, and dabigatran) are widely available for the treatment of venous thromboembolism (VTE). Although analyses comparing these agents to placebo or warfarin exist, direct comparisons of these agents for extended VTE treatment have not been conducted. Therefore, this network meta-analysis aimed to evaluate the efficacy and tolerability of VKA and target-specific oral anticoagulants for extended VTE treatment using a mixed-treatment comparison, meta-analytic approach. METHODS: A comprehensive literature search of EMBASE and MEDLINE was conducted to identify relevant randomized, controlled trials published in English between 1960 and November 2013. Eligible studies investigated the extended use (≥6 months) of oral anticoagulants (apixaban, dabigatran, rivaroxaban, and/or warfarin [conventional or low dose]) and placebo in patients with confirmed VTE. Search terms included extension or extended treatment or therapy, venous thromboembolism (or VTE), deep vein thrombosis (or DVT), pulmonary embolism (or PE), and anticoagulant or anticoagulant agent. Key articles were cross-referenced for additional studies. The efficacy end points evaluated were recurrent VTE or death from any cause, DVT, and nonfatal pulmonary embolism PE. Tolerability end points included major bleeding and nonmajor or clinically relevant bleeding. The data were screened, evaluated, and entered into statistical software to generate direct and indirect comparisons of the various anticoagulants across each study. The data are reported as rate ratios and 95% credible intervals. FINDINGS: Ten trials were analyzed and aggregated, representing data from >14,000 patients. With respect to efficacy end points, no statistically significant between-treatment differences in the composite end point of VTE or death, nonfatal PE, or DVT were found. Major bleeding was significantly greater with warfarin versus apixaban (rate ratio, 4.24; credible interval, 1.28-25.0), and the risk for major bleeding varied somewhat with warfarin and greatly with rivaroxaban. The assessment of nonmajor or clinically relevant bleeding did not identify any meaningful differences between these agents. IMPLICATIONS: The majority of the data represented in this study were derived from noninferiority trials. In the present meta-analysis, efficacy end points in the extended treatment of VTE with apixaban, dabigatran, rivaroxaban, warfarin (conventional and low dose), and placebo were not significantly different. Elevated bleeding risks were identified with rivaroxaban and warfarin; however, the wide credible intervals with rivaroxaban prevent the interpretation of these increased risks.

SPLUNC1 expression reduces surface levels of the epithelial sodium channel (ENaC) in Xenopus laevis oocytes.

Throughout the body, the epithelial Na(+) channel (ENaC) plays a critical role in salt and liquid homeostasis. In cystic fibrosis airways, for instance, improper regulation of ENaC results in hyperabsorption of sodium that causes dehydration of airway surface liquid. This dysregulation then contributes to mucus stasis and chronic lung infections. ENaC is known to undergo proteolytic cleavage, which is required for its ability to conduct Na(+) ions. We have previously shown that the short, palate lung and nasal epithelial clone (SPLUNC1) binds to and inhibits ENaC in both airway epithelia and in Xenopus laevis oocytes. In this study, we found that SPLUNC1 was more potent at inhibiting ENaC than either SPLUNC2 or long PLUNC1 (LPLUNC1), two other PLUNC family proteins that are also expressed in airway epithelia. Furthermore, we were able to shed light on the potential mechanism of SPLUNC1's inhibition of ENaC. While SPLUNC1 did not inhibit proteolytic activity of trypsin, it significantly reduced ENaC currents by reducing the number of ENaCs in the plasma membrane. A better understanding of ENaC's regulation by endogenous inhibitors may aid in the development of novel therapies designed to inhibit hyperactive ENaC in cystic fibrosis epithelia.