Sharma, Amit

Significance Statement Fractalkine receptor 1 (CX3CR1) mediates macrophage infiltration into the vasculature. In this study, we used humanized mice knocked in with the human CX3CR1 gene and inhibited CX3CR1 signaling using a variable domains of camelid heavy-chain-only molecule (BI 655088) to test the hypothesis that blockade of CX3CR1 results in less of the venous neointimal hyperplasia formation that is associated with arteriovenous fistula (AVF) failure. We also used human samples removed from failed AVFs combined with cell culture experiments. Our results demonstrate a novel role for CX3CR1 in reducing venous stenosis formation in AVFs. Background Fractalkine receptor 1 (CX3CR1) mediates macrophage infiltration and accumulation, causing venous neointimal hyperplasia (VNH)/venous stenosis (VS) in arteriovenous fistula (AVF). The effect of blocking CX3CR1 using an anti–human variable VHH molecule (hCX3CR1 VHH, BI 655088) on VNH/VS was determined using a humanized mouse in which the human CX3CR1 ( hCX3CR1 ) gene was knocked in (KI). Methods Whole-transcriptomic RNA sequencing with bioinformatics analysis was used on human stenotic AVF samples, C57BL/6J, hCX3CR1 KI mice with AVF and CKD, and in in vitro experiments to identify the pathways involved in preventing VNH/VS formation after hCX3CR1 VHH administration. Results Accumulation of CX3CR1 and CD68 was significantly increased in stenotic human AVFs. In C57BL/6J mice with AVF, there was increased Cx3cr1, Cx3cl1, Cd68 , and Tnf-α gene expression, and increased immunostaining of CX3CR1 and CD68. In hCX3CR1-KI mice treated with hCX3CR1 VHH molecule (KI-A), compared with vehicle controls (KI-V), there was increased lumen vessel area and patency, and decreased neointima in the AVF outflow veins. RNA-seq analysis identified TNF- α and NF- κ B as potential targets of CX3CR1 inhibition. In KI-A–treated vessels compared with KI-V, there was decreased gene expression of Tnf- α , Mcp-1 , and Il-1 β ; with reduction of Cx3cl1 , NF- κ B, and Cd68 ; decreased M1, Ly6C, smooth muscle cells, fibroblast-activated protein, fibronectin, and proliferation; and increased TUNEL and M2 staining. In cell culture, monocytes stimulated with PMA and treated with hCX3CR1 VHH had decreased TNF- α , CD68 , proliferation, and migration. Conclusions CX3CR1 blockade reduces VNH/VS formation by decreasing proinflammatory cues.

Contrast-induced acute kidney injury (CI-AKI) is a vexing problem, and more than 70 million patients undergo studies using iodinated contrast. The molecular mechanisms responsible for CI-AKI are poorly understood. The goal of the present article was to determine the role of transforming growth factor-β1 (TGF-β1)/mothers against decapentaplegic homolog (SMAD)3 and associated collagen expression in a murine model of intra-arterial CI-AKI. The murine model of CI-AKI after intra-arterial contrast agent administration was created by first performing a partial nephrectomy to induce chronic kidney disease. Twenty-eight days later, 100 μL of contrast agent [iodixanol (320 mg/mL)] or saline were administered via the carotid artery. Two days after contrast administration, compared with saline, average serum creatinine was significantly elevated ( P < 0.05). In the cortex, there was a significant increase in phosphorylated SMAD3 and gene expression of TGF-β1, TGF-β receptor type I, and TGF-β receptor type II at day 2 in the contrast group compared with the saline group. Average gene expressions of connective tissue growth factor, matrix metalloproteinase-2 and −9, and collagen type I-α and type IV-α were significantly increased at 2 days after contrast administration (all P < 0.05). Moreover, there was a decrease in Ki-67 staining in the cortex, with an increase in terminal deoxynucleotidyl transferase dUTP nick-end labeling in the cortex and medulla after contrast administration ( P < 0.05). In the murine intra-arterial CI-AKI model, there was increased hypoxia and TGF-β1/SMAD3 pathway activation and collagen expression, resulting in renal fibrosis. Together, these results suggest that the TGF-β1/SMAD3 pathway could be a potential target in alleviating tissue fibrosis in CI-AKI.

Failure to mature and venous neointimal hyperplasia formation are the two major causes of hemodialysis arteriovenous fistula (AVF) vascular access failure. Percutaneous transluminal angioplasty (PTA) is the firstline treatment for both of these conditions, but, clinically, women have decreased patency rates compared with men. The hypothesis to be tested in the present study was that female mice after PTA of venous areas of higher intimal thickening have increased gene expression of transforming growth factor-β1 (TGF-β1) and TGF-β receptor 1 (TGFβ-R1) accompanied with histological changes of fibrosis compared with male mice. Seventeen male and eighteen female C57BL/6J mice were used in this study. Chronic kidney disease was induced by partial nephrectomy, and, 28 days later, an AVF was created to connect the left carotid artery to the right jugular vein. Two weeks later, the higher intimal thickening area was treated with PTA, and mice were euthanized 3 days later for gene expression analysis or 14 days later for histopathological analysis. Doppler ultrasound was performed weekly after AVF creation. At day 3, female AVF had significantly higher average gene expression of TGF-β1 and TGFβ-R1 compared with male AVF. At day 14, female outflow veins had a smaller venous diameter, lumen vessel area, decreased wall shear stress, lower average peak systolic velocity, and an increased neointima area-to-media area ratio. Moreover, female outflow veins showed a significant increase in α-smooth muscle actin and fibroblast-specific protein-1. There was a decrease in M1/M2 with an increase in CD68.

AbstractBackgroundSkin cancer prevalence is well‐characterized for white solid organ transplant recipients. Although the prevalence of skin cancer in non‐white (Black, Asian, Hispanic) kidney transplant recipients (KTRs) has been assessed, no study has reported the prevalence of skin cancer in Native American (NA) KTRs. The aim of this study is to determine if the prevalence of skin cancer in NAKTRs is the same as in white KTRs.MethodsWe conducted a case‐controlled retrospective review from a single transplant center. One hundred thirteen NAKTRs who received a transplant between 2001 and 2011 were age‐ and transplant‐year matched with 113 white controls.ResultsThe 226 KTRs consisted of 141 (62.4%) men and 85 (37.6%) women, with a mean age of 50.2 ± 10.8 years. There was no skin cancer found in NAKTRs prior to or post transplantation, while seven (6.2%) white KTRs had eight skin cancers prior to transplantation, and 28 (24.8%) white KTRs developed 66 skin cancers post transplantation. Twenty‐two (19.5%) NAKTRs did not follow‐up with dermatology at this institution. The median follow‐up in NAKTRs was 3.3 years compared to 3.0 years in white KTRs.ConclusionNAKTRs have a decreased prevalence of skin cancer compared to their white counterparts.

BACKGROUND After histopathological confirmation of a biopsy sample, cutaneous squamous cell carcinoma (cSCC) is often treated surgically; yet, residual tumor within the excision sample is not always found. The prevalence of residual cSCC after shave biopsy in solid organ transplant recipients (SOTRs) is unknown. OBJECTIVE Determine the prevalence of residual cSCC after shave biopsy in SOTRs. METHODS A retrospective case-controlled review was performed from a single center. Data were collected for 117 SOTRs and 117 age-matched nonimmunosuppressed controls diagnosed with shave biopsy–proven cSCC who underwent subsequent wide local excision from January 2004 to December 2016. Multivariable conditional logistic regression was used to determine variables associated with residual tumor in the combined population. Univariate logistic regression was used to investigate if transplant-related variables were associated with residual tumor in the SOTR group. RESULTS Of the 117 SOTRs, 57 (48.7%) had residual tumor within the excisional specimen. Of the 117 controls, 31 (26.5%) had residual tumor within the excisional specimen. Solid organ transplant recipients have 2.59 times greater odds of having residual cSCC after shave biopsy (95% confidence interval: 1.29–5.22, p = .0076). CONCLUSION Solid organ transplant recipients have a higher prevalence of residual cSCC after shave biopsy when compared with nonimmunosuppressed controls and should be prioritized for margin-controlled surgery.

Introduction. The phenomenon of graft-versus-host disease, a solid organ transplant recipient, is a rare development with a very poor prognosis. Case Presentation. A 40-year-old woman with type 1 diabetes developed cutaneous graft-versus-host disease following second pancreas transplantation. Conclusion. The development of a nonspecific rash in the early posttransplant period following a pancreas transplant warrants suspicion for graft-versus-host disease.

AbstractBackgroundThough a rare tumor, sebaceous carcinoma is relatively well‐described in immunocompetent patients, in whom it often occurs in a periorbital distribution where it has an overall poor prognosis with a high metastasis rate. The effect of transplant‐related immunosuppression on the development of sebaceous carcinoma and its outcomes has not been characterized.MethodsWe collected 9 cases from a single institution of patients developing sebaceous carcinoma after solid organ transplantation. We analyzed clinicopathologic features.ResultsWe estimate the prevalence of sebaceous carcinoma post‐solid organ transplantation to be 0.09%. The mean age at diagnosis was 66.1 years (std 7.0 years). The mean time between transplantation and sebaceous carcinoma diagnosis was 7.1 years (std 5.1 years). All tumors occurred in extra‐ocular distribution. Two patients likely had Muir‐Torre syndrome, of whom 1 died from metastatic sebaceous carcinoma. No other patients developed metastatic disease or had disease‐related death. Mohs micrographic surgery and wide local excision were equally effective and there were no recurrences with either procedure.ConclusionsOur study found that sebaceous carcinoma in solid organ transplant recipients occurs in in an extraorbital distribution with only 1 patient developing metastatic disease. Both Mohs micrographic surgery and wide local excision are acceptable treatment modalities for sebaceous carcinoma in transplant recipients.