Maria P. Martinez Cantarin

The adipose tissue production of adiponectin is increased in end-stage renal disease

Adiponectin has anti-diabetic properties and patients with obesity, diabetes and insulin resistance have low plasma adiponectin levels. However, although kidney disease is associated with insulin resistance, adiponectin is elevated in end stage renal disease. Here we determine if adipose tissue production of adiponectin is increased in renal disease in a case-control study of 36 patients with end stage renal disease and 23 kidney donors. Blood and tissue samples were obtained at kidney transplantation and donation. The mean plasma adiponectin level was significantly increased to 15.6 mg/ml in cases compared to 8.4 mg/ml in controls. Plasma levels of the inflammatory adipokines tumor necrosis factor α, interleukin 6 and high sensitivity C-reactive protein were significantly higher in cases compared to controls. Adiponectin mRNA and protein expression in visceral and subcutaneous fat was significantly higher in cases than controls while adiponectin receptor 1 mRNA expression was significantly increased in peripheral blood cells, muscle and adipose tissue in cases compared to controls. Thus, our study suggests that adipose tissue production of adiponectin contributes to the high plasma levels seen in end stage renal disease.

Acute Humoral Rejection in a Zero Mismatch Deceased Donor Renal Transplant Due to an Antibody to an HLA-DP α

We present a case of a highly sensitized 54-year-old African American male with three prior failed transplants who received a zero mismatch deceased donor kidney and had antibody-mediated rejection directed against a human leukocyte antigen (HLA)-DP donor-specific antigen. The donor was a 21-year-old man with normal renal function. The recipient’s calculated panel reactive antibody was 99%. The standard anti-human globulin-enhanced T-cell and National Institute of Health (NIH) B-cell cytotoxicity crossmatches were negative. Flow cytometric Band T-cell crossmatches were weakly positive by a few channels over the established cutoffs. Intraoperatively, 1 mg/kg antithymocyte globulin, 250 mg methylprednisolone, and 1 g/kg intravenous immunoglobulin (IVIG) were given. Postoperatively, an additional four daily doses of 1 mg/kg antithymocyte globulin, a tapering dose of steroids, and two doses of 500 mg/kg of IVIG were given. The recipient did not have delayed graft function but presented 2 weeks later with increased creatinine and oliguria. Biopsy revealed both borderline acute cellular and acute antibody-mediatedrejection with diffuse C4d positivity in the peritubular capillaries on immunofluorescence. High-resolution HLA typing of the donor was pursued, and a mismatch at the DPA1 locus was identified. Singleantigen bead screening of pretransplant and posttransplant sera revealed a strong complement-fixing antidonor antibody (Luminex C1q antibody fixing assay, reference laboratory: Stanford University Blood Center Histocompatibility Laboratory) against DPA1*0103 with a titer by doubling dilution of 1/1024. The patient received high-dose steroids, multiple rounds of alternate day plasmapheresis, each followed by 100 mg/kg IVIG and 1 g rituximab. His antibody titers decreased to 1/64 and his creatinine nadired at 1.4 mg/ dL. Six months later, he had another 1a cellular and chronic antibody-mediated rejection with a creatinine of 2.1 mg/dL. The United Network for Organ Sharing allocates zero-mismatched kidneys based on six antigens derived from the paired loci A, B, and DR encoded by the major histocompatibility complex located on chromosome 6. The rationale for this policy is improved graft survival in the setting of a more favorable immunologic environment. High-resolution HLA typing is not routinely performed for renal transplantation, and thus, DP status is usually unknown. DPA1 and DPB1 are similarlypolymorphicasA,B,andDR,andasof January 2010, they have 28 and 138 known alleles, respectively (1). DP antigens were discovered in 1980 in restimulation experiments of previously primed T cells. They belong to HLA class II major histocompatibility complex and are composed of polymorphic and chains of similar molecular weight (32 kDa). They are characterized by weak primary allogeneic proliferative response but strong secondary cellmediated cytotoxicity (2). HLA DP mismatches do not influence first kidney transplants but significantly impact outcomes for retransplants (3–5). It has been shown that donor-recipient pairs matched at A, B, and DR have a greater than 80% probability of being mismatched at DP loci (6, 8). We pursued DP typing for the donor, and our pair was matched at A, B, Cw, DR, and DQ alleles as determined by high-resolution (allele level) DNA sequence-specific priming typing (Table 1). The pretransplant sera of recipient contained a strong antidonor antibody against the donor’s DPA1*0103 allele, with a mean fluorescence intensity in the range of 8000 to 14,000. An additional mismatch at DPB1*0601 was revealed and studied, but the antibodies against this allele were found to have mean fluorescence intensity less than 1000. Clinically significant antidonor antibodies to DPB1 have been associated with rejection in both variably matched and zero-mismatched renal allografts (7–9). In addition, antibodies to DPB1 have also been implicated in chronic humoral rejection in retransplants and have been found to share epitope with other HLA molecules (10). Further epitope classification of DPB1 has been pursued, which has helped in the identification of antibodies directed against them (11). It is known that failed renal allografts can elicit an antibody response to DP (12). However, rejection related to antibodies to DPA1 has not been described previously, and our case is unique as it is the first one to report antibody-mediated rejection because of a high-strength antibody to DPA1. It is logical to think that incorporating appropriate donor and recipient HLA-Cw and DP antigens/alleles and antibody information using luminex solid phase assays into UNet would improve concordance between the virtual crossmatching being used for kidney allocation and the actual flow crossmatches. For zero-mismatched grafts, Cw concordance is likely, whereas DP is not. We think that the data forming the basis for virtual crossmatch TABLE 1. Our donor and recipients’ typing by high-resolution DNA sequence-specific priming method

Variants in Genes Involved in Functional Pathways Associated with Hypertension in African Americans

Essential hypertension (HBP) is a complex trait with a substantial heritable component. The purpose of this study was to determine if variants in the G‐protein coupled receptor Kinase‐4 (GRK4), nitric oxide synthase‐3 (NOS3), or angiotensin converting enzyme (ACE) genes are associated singly or through complex interactions, with HBP in African Americans aged 18–49 years. TaqMan Assays were used for genotyping the GRK4 and NOS3 variants. The ACE I/D variant was obtained by polymerase chain reaction and electrophoresis. Allelic association tests were performed for the five markers using PLINK. Logistic regression models were fitted to investigate associations between HBP status and the genetic markers. Multilocus analyses were also conducted. The study included 173 hypertensives and 239 normotensives, with stratification into obese and nonobese groups. The GRK4 A486V variant was negatively associated with HBP in the nonobese group (p= 0.048). The TT/CT genotype of GRK4 A486V was associated with decreased risk for HBP relative to the CC genotype after adjusting for age, sex, and body mass index (p= 0.028). Individuals having at least one NOS3 A allele and GRK4 R65L genotype GG had odds of HBP of 2.97 relative to GG homozygotes for NOS3 and GRK4 R65L. These results show very modest effects and do not fully replicate previous studies. Clin Trans Sci 2010; Volume 3: 279–286

Relationship of blood pressure and obesity with inflammatory cytokines among African Americans

Objectives: Hypertension and obesity are major public health issues. Both conditions are highly prevalent among African Americans and contribute to the increased burden of cardiovascular disease in this group. Inflammation is considered to be an underlying process in both conditions. The authors sought to determine if there is an interaction between high blood pressure (HBP) and obesity that is associated with markedly elevated plasma levels of proinflammatory cytokines in African American adults. Methods: This study examined 484 African Americans, aged 18–45 years, including people with and without obesity, and also with and without HBP. People known to have diabetes were not enrolled. Plasma levels of high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), plasminogen activator inhibitor 1, tumor necrosis factor alpha (TNF-α), and adiponectin were measured. Participants also underwent an oral glucose tolerance test and measurement of blood pressure and body mass index (BMI). Results: There was no statistically significant interaction between obesity and HBP on plasma levels of adiponectin or the inflammatory cytokines. When both conditions were present, HBP and obesity had additive associations with the expected geometric mean ratios for IL-6 (1.44, 95% CI 1.18 to 1.75), TNF-α (1.31, 95% CI 1.11 to 1.53), hsCRP (2.55, 95% CI 1.99 to 3.26) and negative association with adiponectin (0.61, 95% CI 0.52 to 0.71). Compared with HBP, obesity had the predominant association with cytokine levels. An increase in cytokine plasma levels was detectable when BMI exceeded 25 kg/m2. Conclusions: Biomarkers of inflammation in African Americans are strongly associated with BMI. A modest additive effect is found with HBP. Interventions to reduce obesity-related inflammation may impact cardiovascular disease outcomes.

Relationship of adipokines with insulin sensitivity in African Americans.

Introduction:Cytokines produced by adipose tissue, including adiponectin, have been associated with metabolic abnormalities. The purpose of this study was to examine the relationship of insulin sensitivity measured by euglycemic hyperinsulinemic insulin clamp with plasma adiponectin and other adipokines in young adult African Americans. Methods:Participants were healthy African Americans. Anthropometric measures, blood pressure, an oral glucose tolerance test and an euglycemic hyperinsulinemic insulin clamp were performed. Insulin sensitivity measurements were adjusted for percentage of fat mass. Plasma concentrations of adiponectin, plasminogen activator inhibitor-1 (PAI-1) and interleukin-6 (IL-6) were assayed on plasma from fasting blood samples. Pearson correlation coefficients and multiple regression models were fitted to assess the association between glucose sensitivity and cytokines. Results:In univariate analysis, there were statistically significant correlations of plasma adiponectin level (r = 0.19, P = 0.004), PAI-1 (r = −0.19, P = 0.020) and IL-6 (r = −0.24, P < 0.001) with measures of insulin sensitivity after adjustment for both fat mass and insulin clamp concentration. In multivariate analysis, adiponectin [geometric mean ratios (GMR) 1.15, P = 0.007], PAI-1 (GMR 0.998, P = 0.021) and body mass index (GMR 0.95, P < 0.001) were each independently associated with insulin sensitivity. For IL-6, there was no significant association with insulin sensitivity independent of obesity. Conclusion:These data show a significant and independent positive correlation of adiponectin with insulin sensitivity. The relationship of IL-6 with insulin sensitivity seems to be dependent on adiposity.

Association of Inflammation prior to Kidney Transplantation with Post-Transplant Diabetes Mellitus.

Background/Objective: Post-transplant diabetes mellitus (PTDM) is both common and associated with poor outcomes after kidney transplantation. Our objective was to examine relationships of uremia-associated inflammation and adiponectin with PTDM. Methods: Nondiabetic kidney transplant patients were enrolled with donor controls. Inflammatory cytokines and adiponectin were measured before and after transplantation. Adipose tissue was obtained for gene expression analysis. Glucose transport was quantified in vitro in C2C12 cells following cytokine exposure. The patients were monitored up to 12 months for PTDM. Results: We studied 36 controls and 32 transplant patients, of whom 11 (35%) developed PTDM. Compared to controls, plasma TNFα, IL-6, MCP-1, and CRP levels were higher in transplant patients (p < 0.01). In multivariable analysis, TNFα plasma levels before transplantation were associated with development of PTDM (OR = 2.03, p = 0.04). Visceral adipose tissue TNFα mRNA expression was higher in transplant patients than controls (fold change 1.33; p < 0.05). TNFα mRNA expression was also higher in patients who developed PTDM than in those who did not (fold change 1.42; p = 0.05), and adiponectin mRNA expression was lower (fold change 0.48; p < 0.05). The studies on the C2C12 cells demonstrated an increase in glucose uptake following exposure to adiponectin and no significant change after exposure to TNFα alone. Concomitant TNFα and adiponectin exposure blunted adiponectin-induced glucose uptake (11% reduction; p < 0.001). Conclusion: Our in vitro and clinical observations suggest that TNFα could contribute to PTDM through an effect on adiponectin. Our study proposes that inflammation is involved in glucose regulation after kidney transplantation.

Parathyroid Hormone-Related Peptide–Linked Hypercalcemia in a Melanoma Patient Treated With Ipilimumab: Hormone Source and Clinical and Metabolic Correlates

A patient diagnosed with metastatic melanoma developed the paraneoplastic syndrome of humoral hypercalcemia of malignancy and cachexia after receiving ipilumumab. The cause of the hypercalcemia was thought to be secondary to parathyroid hormone-related peptide (PTHrP) as plasma levels were found to be elevated. The patient underwent two tumor biopsies: at diagnosis (when calcium levels were normal) and upon development of hypercalcemia and cachexia. PTHrP expression was higher in melanoma cells when hypercalcemia had occurred than prior to its onset. Metabolic characterization of melanoma cells revealed that, with development of hypercalcemia, there was high expression of monocarboxylate transporter 1 (MCT1), which is the main importer of lactate and ketone bodies into cells. MCT1 is associated with high mitochondrial metabolism. Beta-galactosidase (β-GAL), a marker of senescence, had reduced expression in melanoma cells upon development of hypercalcemia compared to pre-hypercalcemia. In conclusion, PTHrP expression in melanoma is associated with cachexia, increased cancer cell lactate and ketone body import, high mitochondrial metabolism, and reduced senescence. Further studies are required to determine if PTHrP regulates cachexia, lactate and ketone body import, mitochondrial metabolism, and senescence in cancer cells.

Patient Selection and Pretransplantation Care for Kidney Transplant Recipients

Abstract The goal of the pretransplantation evaluation is to identify risks to successful transplantation and to long-term patient and graft survival. The transplant evaluation centers on measures to reduce perioperative risk and to improve long-term survival of the patient and allograft. Patients will undergo exhaustive cardiac evaluation, infectious and malignancy workup, and detailed evaluation of comorbidities. Many renal diseases will recur after transplant but rarely preclude transplantation. An appropriate waiting period should be observed in patients with prior malignancy before listing. Evaluation of potential renal transplant recipients is increasingly challenging, but careful attention to elimination of potential barriers has resulted in continued improvements in patient and allograft survival.

Correlation of acute tubular injury in reperfusion biopsy with renal transplant outcomes

Acute tubular injury (ATI) is common at reperfusion, but its relationship to graft outcomes is unclear. Prior studies lack standardization of morphological assessments and included elements of acute and chronic tubular injury. This study aimed to evaluate the impact of ATI on graft outcomes. Reperfusion biopsies from 2004 to 2009 were retrospectively reviewed. ATI was assessed by a new standardized scoring system. We also assessed chronic injury (CI) by the Banff criteria. Outcomes evaluated included glomerular filtration rate (GFR) at 1 and 5 years and delayed graft function (DGF), acute rejection (AR), graft and patient survival. ATI did not correlate with DGF, AR, graft or overall survival. Mild–moderate ATI was not predictive of GFR post‐transplant. Moderate–severe CI was associated with lower GFR at 5 years with a mean difference of −7.14 mL/min/1.73 m2 (P=.04) and overall survival (HR 2.44, P=.01). Other predictors of graft function included donor age, DGF, and AR. Histologic criteria of ATI at implantation in the absence of donor demographics or clinical information do not provide sufficient predictability in outcomes after transplantation. On the other hand, histologic assessment of CI correlates with GFR and overall survival.

Contents Vol. 6, 2016

Michael Bursztyn – Hadassah University Hospital, Jerusalem, Israel Kunal Chaudhary – Harry S. Truman Veterans’ Hospital, Columbia, USA Kevin C. Dellsperger – Georgia Regents Health System, Augusta, USA Vincent DeMarco – University of Missouri, Columbia, USA Jamie P. Dwyer – Vanderbilt University Medical Center, Nashville, USA Keith C. Ferdinand – Tulane University School of Medicine, New Orleans, USA John M. Flack – Southern Illinois University, Springfi eld, USA Elise P. Gomez-Sanchez – University of Mississippi, Jackson, USA Erik J. Henriksen – University of Arizona, Tucson, USA Gianluca Iacobellis – University of Miami, Miami, USA Kamyar Kalantar-Zadeh – University of California, Orange, USA Guido Lastra – University of Missouri, Columbia, USA James M. Luther – Vanderbilt University Medical Center, Nashville, USA Ferid Murad – George Washington University, Washington, USA Naft ali Stern – Sourasky Medical Center, Tel Aviv, Israel Craig S. Stump – University of Arizona, Tucson, USA Adam T. Whaley-Connell – University of Missouri, Columbia, USA