Twelve Thousand Kidney Transplants Over More Than 55 Y: A Single-center Experience.

Background: Kidney transplant outcomes have dramatically improved since the first successful transplant in 1954. In its early years, kidney transplantation was viewed more skeptically. Today it is considered the treatment of choice among patients with end-stage kidney disease. Methods: Our program performed its first kidney transplant in 1966 and recently performed our 12 000th kidney transplant. Here, we review and describe our experience with these 12 000 transplants. Transplant recipients were analyzed by decade of date of transplant: 1966-1975, 1976-1985, 1986-1995, 1996-2005, 2006-2015, and 2016-2022. Death-censored graft failure and mortality were outcomes of interest. Results: Of 12 000 kidneys, 247 were transplanted from 1966 to 1975, 1147 from 1976 to 1985, 2194 from 1986 to 1995, 3147 from 1996 to 2005, 3046 from 2006 to 2015, and 2219 from 2016 to 2022 compared with 1966-1975, there were statistically significant and progressively lower risks of death-censored graft failure at 1 y, 5 y, and at last follow-up in all subsequent eras. Although mortality at 1 y was lower in all subsequent eras after 1986-1995, there was no difference in mortality at 5 y or the last follow-up between eras. Conclusions: In this large cohort of 12 000 kidneys from a single center, we observed significant improvement in outcomes over time. Kidney transplantation remains a robust and ever-growing and improving field.

A Randomized Controlled Trial of Envarsus Versus Immediate Release Tacrolimus in Kidney Transplant Recipients With Delayed Graft Function.

BACKGROUND: The incidence of delayed graft function (DGF) among kidney transplant recipients (KTRs) in the United States continues to increase. The effect of immediate-release tacrolimus (tacrolimus) compared with extended-release tacrolimus (Envarsus) among recipients with DGF is unknown. METHODS: This was a single-center open-label randomized control trial among KTRs with DGF (ClinicalTrials. gov, NCT03864926). KTRs were randomized either to continue on tacrolimus or switch to Envarsus at a 1:1 ratio. Duration of DGF (study period), number of dialysis treatments, and need for adjustment of calcineurin inhibitor (CNI) doses during the study period were outcomes of interest. RESULTS: A total of 100 KTRs were enrolled, 50 in the Envarsus arm and 50 in the tacrolimus arm; of those, 49 in the Envarsus arm and 48 in the tacrolimus arm were included for analysis. There were no differences in the baseline characteristics, all P > .5, except donors in the Envarsus arm had higher body mass index (mean body mass index 32.9 ± 11.3 vs 29.4 ± 7.6 kg/m2 [P = .007]) compared with the tacrolimus arm. The median duration of DGF (5 days vs 4 days, P = .71) and the number of dialysis treatments (2 vs 2, P = .83) were similar between the groups. However, the median number of CNI dose adjustments during the study period in the Envarsus group was significantly lower (3 vs 4, P = .002). CONCLUSIONS: Envarsus patients had less fluctuation in the CNI level, requiring fewer CNI dose adjustments. However, there were no differences in the DGF recovery duration or number of dialysis treatments.

Microwave Ablation as Bridging to Liver Transplant for Patients with Hepatocellular Carcinoma: A Single-Center Retrospective Analysis.

PURPOSE: To evaluate the efficacy and safety of microwave (MW) ablation as first-line locoregional therapy (LRT) for bridging patients with hepatocellular carcinoma (HCC) to liver transplant. MATERIALS AND METHODS: This retrospective study evaluated 88 patients who received percutaneous MW ablation for 141 tumors as first-line LRT for HCC and who were listed for liver transplantation at a single medical center between 2011 and 2019. The overall survival (OS) rate statuses after liver transplant, waitlist retention, and disease progression were evaluated using the Kaplan-Meier techniques. RESULTS: Among the 88 patients (72 men and 16 women; mean age, 60 years; Model for End-Stage Liver Disease score, 11.2) who were listed for transplant, the median waitlist time was 9.4 months (interquartile range, 5.5-18.9). Seventy-one (80.7%) patients received transplant after a median waitlist time of 8.5 months. Seventeen (19.3%) patients were removed from the waitlist; of these, 4 (4.5%) were removed because of tumors outside of the Milan criteria (HCC-specific dropout). No difference in tumor size or alpha-fetoprotein was observed in the transplanted versus nontransplanted patients at the time of ablation (2.1 vs 2.1 cm and 34.4 vs 34.7 ng/mL for transplanted vs nontransplanted, respectively; P > .05). Five (5.1%) of the 88 patients experienced adverse events after ablation; however, they all recovered. There were no cases of tract seeding. The local tumor progression (LTP) rate was 7.2%. The OS status after liver transplant at 5 years was 76.7%, and the disease-specific survival after LTP was 89.6%, with a median follow-up of 61 months for all patients. CONCLUSIONS: MW ablation appears to be safe and effective for bridging patients with HCC to liver transplant without waitlist removal from seeding, adverse events, or LTP.

Complex Ureteral Reconstruction in Kidney Transplantation.

OBJECTIVES: Despite advances in surgical techniques and organ preservation, transplant ureteric strictures remain a common complication in kidney transplantation. A variety of endourological and surgical techniques have been utilized; however, there is a lack of consensus on the optimal modality in dealing with these complex cases. MATERIALS AND METHODS: We present challenging ureteral reconstruction cases after failed attempts at ureteral dilatation, failed conventional open repairs, and/or with bladder dysfunction. RESULTS: All renal allografts were salvaged by successful use of bladder Boari flap and intestinal segment interpositions/diversions. CONCLUSIONS: Operative repair remains the most durable and successful approach, and minimally invasive options should be reserved for nonsurgical candidates, with consideration of a single attempt in patients with early, distal, short (<2 cm), nonischemic strictures.

A comparison of rates and severity of chronic kidney disease in deceased-donor and living-donor liver transplant recipients: times matter

Background/aim: The progression of chronic kidney disease (CKD) in recipients of living-donor liver transplant (LDLT) compared to deceased-donor liver transplant (DDLT) has not been studied in the literature. We hypothesize that CKD stage progression in LDLT recipients is reduced compared to that of their DDLT counterparts. Materials and methods: A retrospective study was undertaken including 999 adult, single-organ, primary liver transplant recipients (218 LDLT and 781 DDLT) at 2 centers between January 2003 and December 2012, in which CKD progression and regression were evaluated within the first 3 years after transplantation. Results: Waiting time from evaluation to transplantation was significantly lower in LDLT patients compared to recipients of DDLT. CKD stage progression from preoperative transplant evaluation to transplantation was significantly greater in DDLT. Deceased-donor liver transplant recipients continued to have higher rates of clinically significant renal disease progression (from stage I­II to stage III­V) across multiple time points over the first 3 years posttransplant. Furthermore, a greater degree of CKD regression was observed in recipients of LDLT. Conclusion: It can be concluded that LDLT provides excellent graft and patient survival, significantly reducing the overall incidence of clinically significant CKD stage progression when compared to DDLT. Moreover, there is a significantly higher incidence of CKD stage regression in LDLT compared to DDLT. These observations were maintained in both high and low model for end-stage liver disease(MELD)populations. This observation likely reflects earlier access to transplantation in LDLT as one of the contributing factors to preventing CKD progression.

The Utility of Donor-specific Antibody Monitoring and the Role of Kidney Biopsy in Simultaneous Liver and Kidney Recipients With De Novo Donor-specific Antibodies.

BACKGROUND: There is limited information about the utility of donor-specific antibody (DSA) against HLA monitoring and the role of protocol kidney biopsy for de novo DSA (dnDSA) in simultaneous liver and kidney (SLK) transplant recipients. METHODS: We analyzed SLK transplant recipients transplanted between January 2005 and December 2017, who had DSA checked posttransplant. Patients were divided into 2 groups based on whether they developed dnDSA posttransplant (dnDSA+) or not (dnDSA-). Kidney graft rejection ±45 d of dnDSA and a kidney death-censored graft survival were the primary endpoints. RESULTS: A total of 83 SLK transplant recipients fulfilled our selection criteria. Of those, 23 were dnDSA+ and 60 were dnDSA-. Twenty-two of 23 dnDSA+ patients had DSA against class II HLA, predominantly against DQ. Fifteen recipients underwent kidney biopsy ±45 d of dnDSA. Six of these were clinically indicated due to kidney graft dysfunction. The other 9 had a protocol kidney biopsy only due to dnDSA, and 6 of these 9 had a rejection. Also, 3 recipients had sequential biopsies of both the kidney and liver grafts. Among those with sequential biopsies of both grafts, there was a difference between the organs in the rate and types of rejections. At last follow up, dnDSA was not associated with graft failure of either the kidney or liver. CONCLUSIONS: Although our study was limited by a small sample size, it suggests the potential utility of DSA monitoring and protocol kidney biopsy for dnDSA.

A Single-Center Assessment of Delayed Graft Function in Recipients of Simultaneous Liver and Kidney Transplant.

BACKGROUND: The effects of delayed graft function on long-term kidney allograft outcomes are poorly defined among simultaneous liver and kidney transplant recipients. METHODS: We analyzed data of all simultaneous liver and kidney recipients transplanted at the University of Wisconsin between 2010 and 2017. Risk factors for the development of delayed graft function, kidney graft failure, and patient mortality were outcomes of interest. RESULTS: There were a total of 60 simultaneous liver and kidney recipients; 28 (47%) had delayed graft function. After adjustment for multiple variables, we found that pretransplant dialysis >6 weeks (hazard ratio [HR] = 5.6, 95% CI: 1.23-25.59, P = .02), pretransplant albumin <3 g/dL (HR = 5.75, 95% CI: 1.76-16.94, P = .003), and presence of pretransplant diabetes (HR = 2.5, 95% CI: 0.97-4.77, P = .05) were significantly associated with delayed graft function. Multivariate analysis showed that pretransplant albumin <3 (HR = 4.86, 95% CI: 1.07-22.02, P = .02) was associated with a higher risk of all-cause kidney allograft failure, whereas the duration of delayed graft function (HR = 1.07 per day, 95% CI: 1.01-1.14, P = .01) was associated with a higher risk of death-censored kidney allograft failure. The presence of delayed graft function was not associated with all-cause or death-censored kidney or liver allograft failure. Similarly, the presence of delayed graft function was not associated with patient mortality. CONCLUSION: The incidence of delayed graft function was high in simultaneous liver and kidney recipients. However, with appropriate management, delayed graft function may not have a negative impact on patient or kidney allograft survival.

Third-party vessel allografts in kidney and pancreas transplantation: Utilization, de novo DSAs, and outcomes.

Third-party vascular allografts (VAs) are an invaluable resource in kidney and pancreas transplantation when vascular reconstruction is needed and additional vessels from the organ donor are not available. We report the largest single-center experience to date on VA use, at a high-volume U.S. transplant center. Over a 7-year period, VAs were used for vascular reconstruction of 65 kidneys and 5 pancreases, in 69 recipients. The renal vein required reconstruction more often with right kidney transplantation (72.5% vs 27.5%, P < .001), and the renal artery required reconstruction more often with left kidney transplantation (67.6% vs 32.4%, P = .003). Eleven patients (15.9%) developed anti-VA de novo HLA donor-specific antibodies (dnDSAs) at a median time after transplantation of 19.0 months. Higher number of HLA mismatches between the VA donor and the recipient, and development of anti-organ allograft dnDSAs were significant predictors of anti-VA dnDSA development. Those with anti-VA dnDSAs had a higher rate of organ allograft rejection (45.4% vs 13.8%, P = .03) compared to those without, but there was no significant difference in incidence of vascular complications or graft outcomes. VAs can help circumvent challenging surgical situations. Anti-VA dnDSAs do not adversely affect organ allograft outcomes; however, they can contribute to HLA sensitization in the recipients.

Microsteatosis in Livers From Donation After Circulatory Death Donors Is Associated With Inferior Outcomes Following Liver Transplantation.

The acceptable threshold remains unknown for the percentage of macrosteatosis (MaS) and microsteatosis (MiS) to yield optimal outcomes after donation after circulatory death (DCD) liver transplantation (LT). The purpose of this analysis was to determine the impact of donor liver MaS and MiS on DCD LT outcomes. Using the Organ Procurement and Transplantation Network database, we analyzed pretransplant biopsy results from adult, solitary, DCD livers transplanted between January 1, 2006, and December 31, 2017. Kaplan-Meier analysis was used to assess graft and patient survival based on MaS and MiS severity. MiS was divided into the groups MiS ≤10% and >10%. MaS was divided into the groups MaS ≤15% and >15%. Of 7757 recovered DCD livers, 11.4% (n = 885) were biopsied and transplanted. Patients who received DCD livers with MaS >15% had significantly worse patient survival (P < 0.04), and those with MiS >10% demonstrated inferior graft and patient survival (P < 0.02). In multivariate analyses including known risk factors, both MaS >15% and MiS >10% were associated with increased risk of graft failure and patient mortality (P < 0.03). Recipient and donor age >60 years were also associated with increased risk of graft failure and patient death. This analysis demonstrates that MaS >15% and MiS >10% are additional risk factors for graft loss and patient mortality in DCD LT.

Risk Factors for Intracardiac Thrombus During Liver Transplantation.

Intracardiac thrombus (ICT) is an intraoperative complication with high mortality that occurs during orthotopic liver transplantation (OLT). Patients with end-stage liver disease have compromised coagulation pathways, and when combined with stressors of surgery, thrombi can form. However, it is unknown which patients are most likely to develop ICT. We performed a retrospective cohort study of all OLT patients at our hospital from 2010 to 2017 to identify risk factors for ICT. An analysis was performed with conventional bivariate tests and logistic regression. The incidence of ICT during OLT was 4.2% (22/528) with a 45.5% (10/22) mortality. Patients who developed ICT had higher physiologic Model for End-Stage Liver Disease scores at the time of transplant (25.1 versus 32.4; P = 0.004), received grafts from donors with a higher body mass index (28.1 versus 32.2 kg/m2 ; P = 0.007), and had longer intraoperative warm ischemia times (53.1 versus 67.5 minutes; P = 0.001). The odds of developing ICT were significantly lower after administration of intravenous (IV) heparin prior to inferior vena cava (IVC) clamping compared with no administration of heparin (odds ratio, 0.25; 95% confidence interval, 0.08-0.75; P = 0.01). In conclusion, the incidence of ICT at our institution is higher than previously reported, which may be explained by our routine use of transesophageal echocardiography. Although many factors associated with ICT in this study are nonmodifiable, administration of IV heparin prior to IVC cross-clamping is modifiable and was found to be protective. Further studies will be needed to confirm findings and ultimately aid in preventing these lethal events.

Family and transplant professionals' views of organ recovery before circulatory death for imminently dying patients: A qualitative study using semistructured interviews and focus groups.

Donation before circulatory death for imminently dying patients has been proposed to address organ scarcity and harms of nondonation. To characterize stakeholder attitudes about organ recovery before circulatory death we conducted semistructured interviews with family members (N = 15) who had experienced a loved one's unsuccessful donation after circulatory death and focus groups with professional stakeholders (surgeons, anesthesiologists, critical care specialists, palliative care specialists, organ procurement personnel, and policymakers, N = 46). We then used qualitative content analysis to characterize these perspectives. Professional stakeholders believed that donation of all organs before circulatory death was unacceptable, morally repulsive, and equivalent to murder; consent for such a procedure would be impermissible. Respondents feared the social costs related to recovery before death were too high. Although beliefs about recovery of all organs were widely shared, some professional stakeholders could accommodate removal of a single kidney before circulatory death. In contrast, family members were typically accepting of donation before circulatory death for a single kidney, and many believed recovery of all organs was permissible because they believed the cause of death was the donor's injury, not organ procurement. These findings suggest that definitions of death and precise rules around organ donation are critical for professional stakeholders, whereas donor families find less relevance in these constructs for determining the acceptability of organ donation. Donation of a single kidney before circulatory death warrants future exploration.

Real-world PM extracts differentially enhance Th17 differentiation and activate the aryl hydrocarbon receptor (AHR).

Atmospheric particulate matter (PM) is a complex component of air pollution and the leading environmental risk factor for death worldwide. PM is formed from a combination of primary sources that emit PM directly into the atmosphere and secondary sources that emit gaseous precursors which oxidize in the atmosphere to form PM and composed of both inorganic and organic components. Currently, all PM is regulated by total mass. This regulatory strategy does not consider individual chemical constituents and assumes all PM is equally toxic. The chemically-extracted organic fraction (OF) of PM retains most organic constituents such as polycyclic aromatic hydrocarbons (PAHs) and excludes inorganics. PAHs are ubiquitous environmental toxicants and known aryl hydrocarbon receptor (AHR) ligands. This study addressed the role of individual components, specifically PAHs, of PM and how differences in chemical composition of real-world samples drive differential responses. This study tested the hypothesis that real-world extracts containing different combinations and concentrations of PAHs activate the AHR and enhance T helper (Th)17 differentiation to different degrees based on specific PAHs present in each sample, and not simply the mass of PM. The ability of the real-world OF, with different PAH compositions, to enhance Th17 differentiation and activate the AHR was tested in vitro. Cumulatively, the results identified PAHs as possible candidate components of PM contributing to increased inflammation and demonstrated that the sum concentration of PAHs does not determine the extent to which each PM activates the AHR and enhances Th17 differentiation suggesting individual components of each PM, and interactions of those components with others in the mixture, contribute to the inflammatory response. This demonstrates that not all PM are the same and suggests that when regulating PM based on its ability to cause human pathology, a strategy based on PM mass may not reduce pathologic potential of exposures.

Ambient urban dust particulate matter reduces pathologic T cells in the CNS and severity of EAE.

BACKGROUND: Autoimmune diseases have increased in incidence and prevalence worldwide. While genetic predispositions play a role, environmental factors are a major contributor. Atmospheric particulate matter (PM) is a complex mixture composed of metals, nitrates, sulfates and diverse adsorbed organic compounds like polycyclic aromatic hydrocarbons (PAHs) and dioxins. Exposure to atmospheric PM aggravates autoimmune diseases such as type 1 diabetes, rheumatoid arthritis, multiple sclerosis, and systemic lupus erythematosus, among others. PAHs and dioxins are known aryl hydrocarbon receptor (AHR) ligands. The AHR modulates T cell differentiation and directs the balance between effector and regulatory T cells in vitro and in experimental autoimmune encephalomyelitis (EAE), a murine model of autoimmune disease. This study aims to identify pathways that contribute to autoimmune disease and their potential use as therapeutic targets to alleviate symptoms and the need for global immunosuppression. This study tests the hypothesis that atmospheric PM enhances effector T cell differentiation and aggravates autoimmune disease. RESULTS: An atmospheric ambient urban dust PM sample, standard reference material (SRM)1649b, was tested for its effects on autoimmunity. SRM1649b PM enhanced Th17 differentiation in an AHR-dependent manner in vitro, however intranasal treatment of SRM1649b PM delayed onset of EAE and reduced cumulative and peak clinical scores. Chronic and acute intranasal exposure of SRM1649b PM delayed onset of EAE. Chronic intranasal exposure did not reduce severity of EAE while acute intranasal exposure significantly reduced severity of disease. Acute intranasal treatment of low dose SRM1649b PM had no effect on clinical score or day of onset in EAE. Delayed onset of EAE by intranasal SRM1649b PM was AHR-dependent in vivo. Oral gavage of SRM1649b PM, in the absence of AHR ligands in the diet, had no effect on day of disease onset or severity of EAE. Day 10 analysis of T cells in the CNS after intranasal treatment of SRM1649b PM showed a reduction of pathologic T cell subsets in vivo. Moreover, MOG-specific splenocytes require AHR to generate or maintain IL-10 producing cells and reduce IFNγ producing cells in vitro. CONCLUSIONS: These results identify the AHR pathway as a potential target for driving targeted immunosuppression in the CNS in the context of atmospheric PM-mediated autoimmune disease. The effects of SRM1649b PM on EAE are dependent on route of exposure, with intranasal treatment reducing severity of EAE and delaying disease onset while oral gavage has no effect. Intranasal SRM1649b PM reduces pathologic T cells in the CNS, specifically Th1 cells and Th1Th17 double positive cells, leading to reduced severity of EAE and AHR-dependent delayed disease onset. Additionally, SRM1649b PM treatment of antigen-specific T cells leads to AHR-dependent increase in percent IL-10 positive cells in vitro. These findings may shed light on the known increase of infection after exposure to atmospheric PM and serve as the first step in identifying components of the AHR pathway responsible for Th1-mediated immunosuppression in response to atmospheric PM exposure.

Gut Symbionts Lactobacillus reuteri R2lc and 2010 Encode a Polyketide Synthase Cluster That Activates the Mammalian Aryl Hydrocarbon Receptor.

A mechanistic understanding of microbe-host interactions is critical to developing therapeutic strategies for targeted modulation of the host immune system. Different members of the gut symbiont species Lactobacillus reuteri modulate host health by, for example, reduction of intestinal inflammation. Previously, it was shown that L. reuteri activates the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that plays an important role in the mucosal immune system, by the production of tryptophan catabolites. Here, we identified a novel pathway by which L. reuteri activates AhR, which is independent of tryptophan metabolism. We screened a library of 36 L. reuteri strains and determined that R2lc and 2010, strains with a pigmented phenotype, are potent AhR activators. By whole-genome sequencing and comparative genomics, we identified genes unique to R2lc and 2010. Our analyses demonstrated that R2lc harbors two genetically distinct polyketide synthase (PKS) clusters, functionally unknown (fun) and pks, each carried by a multicopy plasmid. Inactivation of pks, but not fun, abolished the ability of R2lc to activate AhR. L. reuteri 2010 has a gene cluster homologous to the pks cluster in R2lc with an identical gene organization, which is also responsible for AhR activation. In conclusion, we identified a novel PKS pathway in L. reuteri R2lc and 2010 that is responsible for AhR activation.IMPORTANCE Temporary changes in the composition of the microbiota, for example, by oral administration of probiotics, can modulate the host immune system. However, the underlying mechanisms by which probiotics interact with the host are often unknown. Here, we show that Lactobacillus reuteri R2lc and 2010 harbor an orthologous PKS gene cluster that activates the aryl hydrocarbon receptor (AhR). AhR is a ligand-activated transcription factor that plays a key role in a variety of diseases, including amelioration of intestinal inflammation. Understanding the mechanism by which a bacterium modulates the immune system is critical for applying rational selection strategies for probiotic supplementation. Finally, heterologous and/or optimized expression of PKS is a logical next step toward the development of next-generation probiotics to prevent and treat disease.

The Aryl Hydrocarbon Receptor as an Immune-Modulator of Atmospheric Particulate Matter-Mediated Autoimmunity.

This review examines the current literature on the effects of atmospheric particulate matter (PM) on autoimmune disease and proposes a new role for the aryl hydrocarbon receptor (AHR) as a modulator of T cells in PM-mediated autoimmune disease. There is a significant body of literature regarding the strong epidemiologic correlations between PM exposures and worsened autoimmune diseases. Genetic predispositions account for 30% of all autoimmune disease leaving environmental factors as major contributors. Increases in incidence and prevalence of autoimmune disease have occurred concurrently with an increase in air pollution. Currently, atmospheric PM is considered to be the greatest environmental health risk worldwide. Atmospheric PM is a complex heterogeneous mixture composed of diverse adsorbed organic compounds such as polycyclic aromatic hydrocarbons (PAHs) and dioxins, among others. Exposure to atmospheric PM has been shown to aggravate several autoimmune diseases. Despite strong correlations between exposure to atmospheric PM and worsened autoimmune disease, the mechanisms underlying aggravated disease are largely unknown. The AHR is a ligand activated transcription factor that responds to endogenous and exogenous ligands including toxicants present in PM, such as PAHs and dioxins. A few studies have investigated the effects of atmospheric PM on AHR activation and immune function and demonstrated that atmospheric PM can activate the AHR, change cytokine expression, and alter T cell differentiation. Several studies have found that the AHR modulates the balance between regulatory and effector T cell functions and drives T cell differentiation in vitro and in vivo using murine models of autoimmune disease. However, there are very few studies on the role of AHR in PM-mediated autoimmune disease. The AHR plays a critical role in the balance of effector and regulatory T cells and in autoimmune disease. With increased incidence and prevalence of autoimmune disease occurring concurrently with increases in air pollution, potential mechanisms that drive inflammatory and exacerbated disease need to be elucidated. This review focuses on the AHR as a potential mechanistic target for modulating T cell responses associated with PM-mediated autoimmune disease providing the most up-to-date literature on the role of AHR in autoreactive T cell function and autoimmune disease.

Polycyclic aromatic hydrocarbons (PAHs) present in ambient urban dust drive proinflammatory T cell and dendritic cell responses via the aryl hydrocarbon receptor (AHR) in vitro.

Atmospheric particulate matter (PM) is a complex component of air pollution that is a composed of inorganic and organic constituents. The chemically-extracted organic fraction (OF) of PM excludes inorganics but retains most organic constituents like polycyclic aromatic hydrocarbons (PAHs). PAHs are ubiquitous environmental toxicants and known aryl hydrocarbon receptor (AHR) ligands. The AHR is a ligand activated transcription factor that responds to endogenous ligands and exogenous ligands including PAHs. Activation of the AHR leads to upregulation of cytochrome P450 (CYP) metabolizing enzymes which are important for the biotransformation of toxicants to less toxic, or in the case of PAHs, more toxic intermediates. Additionally, the AHR plays an important role in balancing regulatory and effector T cell responses. This study aimed to determine whether PAHs present in PM aggravate inflammation by driving inflammatory T cell and dendritic cell (DC) responses and their mechanism of action. This study tests the hypothesis that PAHs present in PM activate the AHR and alter the immune balance shifting from regulation to inflammation. To test this, the effects of SRM1649b OF on T cell differentiation and DC function were measured in vitro. SRM1649b OF enhanced Th17 differentiation in an AHR and CYP-dependent manner and increased the percent of IFNγ positive DCs in an AHR-dependent manner. SRM1649b PAH mixtures enhanced Th17 differentiation in an AHR-dependent but CYP-independent manner and increased the percent of IFNγ positive DCs. Cumulatively, these results suggest that PAHs present in PM are active components that contribute to immune responses in both T cells and BMDCs through the AHR and CYP metabolism. Understanding the role of AHR and CYP metabolism of PAHs in immune cells after PM exposure will shed light on new targets that will shift the immune balance from inflammation to regulation.

Differential effects of diesel exhaust particles on T cell differentiation and autoimmune disease.

BACKGROUND: Exposure to particulate matter (PM) has been associated with increased incidence and severity of autoimmune disease. Diesel PM is primarily composed of an elemental carbon core and adsorbed organic compounds such as polycyclic aromatic hydrocarbons (PAHs) and contributes up to 40% of atmospheric PM. The organic fraction (OF) of PM excludes all metals and inorganics and retains most organic compounds, such as PAHs. Both PM and OF increase inflammation in vitro and aggravate autoimmune disease in humans. PAHs are known aryl hydrocarbon receptor (AHR) ligands. The AHR modulates T cell differentiation and effector function in vitro and in experimental autoimmune encephalomyelitis (EAE), a murine model of autoimmune disease. This study aims to identify whether the total mass or active components of PM are responsible for activating pathways associated with exposure to PM and autoimmune disease. This study tests the hypothesis that active components present in diesel PM and their OF enhance effector T cell differentiation and aggravate autoimmune disease. RESULTS: Two different diesel samples, each characterized for their components, were tested for their effects on autoimmunity. Both diesel PM enhanced effector T cell differentiation in an AHR-dose-dependent manner and suppressed regulatory T cell differentiation in vitro. Both diesel PM aggravated EAE in vivo. Fractionated diesel OFs exhibited the same effects as PM in vitro, but unlike PM, only one diesel OF aggravated EAE. Additionally, both synthetic PAH mixtures that represent specific PAHs found in the two diesel PM samples enhanced Th17 differentiation, however one lost this effect after metabolism and only one required the AHR. CONCLUSIONS: These findings suggest that active components of PM and not total mass are driving T cell responses in vitro, but in vivo the PM matrix and complex mixtures adsorbed to the particles, not just the OF, are contributing to the observed EAE effects. This implies that examining OF alone may not be sufficient in vivo. These data further suggest that bioavailability and metabolism of organics, especially PAHs, may have an important role in vivo.

Specific Donor HLA-DR Types Correlate With Altered Susceptibility to Development of Chronic Lung Allograft Dysfunction.

BACKGROUND: The greatest challenge to long-term graft survival is the development of chronic lung allograft dysfunction. Th17 responses to collagen type V (colV) predispose lung transplant patients to the severe obstructive form of chronic lung allograft dysfunction, known as bronchiolitis obliterans syndrome (BOS). In a previous study cohort (n = 54), pretransplant colV responses were increased in recipients expressing HLA-DR15, consistent with the high binding avidity of colV (α1) peptides for HLA-DR15, whereas BOS incidence, which was known to be strongly associated with posttransplant autoimmunity to colV, was higher in patients who themselves lacked HLA-DR15, but whose lung donor expressed it. METHODS: To determine if this DR-restricted effect on BOS incidence could be validated in a larger cohort, we performed a retrospective analysis of outcomes for 351 lung transplant recipients transplanted between 1988 and 2008 at the University of Wisconsin. All subjects were followed until graft loss, death, loss to follow-up, or through 2014, with an average follow-up of 7 years. Comparisons were made between recipients who did or did not develop BOS. Grading of BOS followed the recommendations of the international society for heart and lung transplantation. RESULTS: Donor HLA-DR15 was indeed associated with increased susceptibility to severe BOS in this population. We also discovered that HLA-DR7 expression by the donor or HLA-DR17 expression by the recipient decreased susceptibility. CONCLUSIONS: We show in this retrospective study that specific donor HLA class II types are important in lung transplantation, because they are associated with either protection from or susceptibility to development of severe BOS.

Renal Transplantation as a Platform for Teaching Residents Open Vascular Surgical Techniques: Effects on Early Graft Function.

BACKGROUND: Over the past decade, increases in vascular fellowships and the use of endovascular technology have decreased the general surgery residents' exposure to open vascular surgery. We sought to elucidate whether renal transplant is a safe way to teach general surgery residents the essential tenants of vascular surgery without adversely affecting early patient outcomes. METHODS: All solitary, adult deceased donor kidney transplants performed at the University of Wisconsin from 2011 through 2016 were identified and divided into a resident-assist (RA) and fellow-assist cohorts (FA). DGF, defined by the requirement of dialysis within 1 week of transplant, was the primary outcome. Early graft survival and postoperative complications were considered the secondary endpoints. RESULTS: Of the 774 total cases, there were 228 (29.5%) in the RA cohort and 546 (70.5%) in the FA cohort. The RA and FA cohorts had comparable characteristics, except for a nonclinically significant difference in mean donor creatinine (0.96 vs 0.88mg/dL, p = 0.03). RA cases had a similar DGF rate compared to FA cases (25% vs 26%, p = 0.93). Additionally, there was no difference in 2-year graft survival (93.7% vs 95.5%, p = 0.38), nor the rates of graft thromboses (0.4% vs 0.7%, p = 0.65), incisional hernias (0.9% vs 1.8%, p = 0.35), and ureteral strictures (2.2% vs 1.6%, p = 0.55) between the 2 cohorts. CONCLUSIONS: Resident involvement in renal transplantation has no effect on DGF and early allograft function. Though the procedural involvement of each resident in a case is variable, it seems to be a safe way to teach retroperitoneal vascular exposure and anastomotic techniques.