Banff 2022 Liver Group Meeting report: Monitoring long-term allograft health.

The Banff Working Group on Liver Allograft Pathology met in September 2022. Participants included hepatologists, surgeons, pathologists, immunologists, and histocompatibility specialists. Presentations and discussions focused on the evaluation of long-term allograft health, including noninvasive and tissue monitoring, immunosuppression optimization, and long-term structural changes. Potential revision of the rejection classification scheme to better accommodate and communicate late T cell-mediated rejection patterns and related structural changes, such as nodular regenerative hyperplasia, were discussed. Improved stratification of long-term maintenance immunosuppression to match the heterogeneity of patient settings will be central to improving long-term patient survival. Such personalized therapeutics are in turn contingent on a better understanding and monitoring of allograft status within a rational decision-making approach, likely to be facilitated in implementation with emerging decision-support tools. Proposed revisions to rejection classification emerging from the meeting include the incorporation of interface hepatitis and fibrosis staging. These will be opened to online testing, modified accordingly, and subject to consensus discussion leading up to the next Banff conference.

Transplantation: platform to study recurrence of disease.

Beyond the direct benefit that a transplanted organ provides to an individual recipient, the study of the transplant process has the potential to create a better understanding of the pathogenesis, etiology, progression and possible therapy for recurrence of disease after transplantation while at the same time providing insight into the original disease. Specific examples of this include: 1) recurrence of focal segmental glomerulosclerosis (FSGS) after kidney transplantation, 2) recurrent autoimmunity after pancreas transplantation, and 3) recurrence of disease after orthotopic liver transplantation (OLT) for cirrhosis related to progressive steatosis secondary to jejuno-ileal bypass (JIB) surgery. Our team has been studying these phenomena and their immunologic underpinnings, and we suggest that expanding the concept to other pathologic processes and/or transplanted organs that harbor the risk for recurrent disease may provide novel insight into the pathogenesis of a host of other disease processes that lead to organ failure.

Benefit of B7-1 staining and abatacept for treatment-resistant post-transplant focal segmental glomerulosclerosis in a predominantly pediatric cohort: time for a reappraisal.

BACKGROUND: Primary FSGS manifests with nephrotic syndrome and may recur following KT. Failure to respond to conventional therapy after recurrence results in poor outcomes. Evaluation of podocyte B7-1 expression and treatment with abatacept (a B7-1 antagonist) has shown promise but remains controversial. METHODS: From 2012 to 2020, twelve patients developed post-KT FSGS with nephrotic range proteinuria, failed conventional therapy, and were treated with abatacept. Nine/twelve (< 21 years old) experienced recurrent FSGS; three adults developed de novo FSGS, occurring from immediately, up to 8 years after KT. KT biopsies were stained for B7-1. RESULTS: Nine KTRs (75%) responded to abatacept. Seven of nine KTRs were B7-1 positive and responded with improvement/resolution of proteinuria. Two patients with rFSGS without biopsies resolved proteinuria after abatacept. Pre-treatment UPCR was 27.0 ± 20.4 (median 13, range 8-56); follow-up UPCR was 0.8 ± 1.3 (median 0.2, range 0.07-3.9, p < 0.004). Two patients who were B7-1 negative on multiple KT biopsies did not respond to abatacept and lost graft function. One patient developed proteinuria while receiving belatacept, stained B7-1 positive, but did not respond to abatacept. CONCLUSIONS: Podocyte B7-1 staining in biopsies of KTRs with post-transplant FSGS identifies a subset of patients who may benefit from abatacept. A higher resolution version of the Graphical abstract is available as Supplementary information.

Percutaneous Ultrasound-Guided Kidney Transplant Biopsy Outcomes: From the Nephrologist to the Radiologist Standpoint.

Background: Kidney transplant biopsies are the gold standard for evaluating allograft dysfunction. These biopsies are performed by nephrologists and radiologists under real-time ultrasound guidance. A few studies have examined the outcomes of ultrasound-guided kidney transplant biopsy in transplant recipients; however, none have compared these outcomes between both specialties. Methods: We retrospectively analyzed a cohort of 678 biopsies performed in a single center during a 44-month study period. Biopsies were stratified into two groups based upon the specialist performing the procedure: interventional radiology (IR; N=447) and transplant nephrology (TN; N=231). Results: There were 55 (8%) complications related to biopsies in the entire cohort: 37 (8.2%) in the IR group and 18 (7.7%) in the TN group, without statistical difference between the groups (P=0.94). Blood pressure control and prior use of anticoagulation were significant predictors of complicated biopsies (P=0.004 and 0.02, respectively). Being a woman and prior use of anticoagulation were significant predictors of transfusion of blood products (P=0.01 and 0.01, respectively). Being a woman and blood pressure control were significant predictors of overall perinephric hematoma (P=0.01 and 0.01, respectively), and Black race was a significant predictor of perinephric hematoma without worsening of renal function (P=0.005). The specialist team performing the procedure was not a statistically significant predictor of biopsy complications, transfusion of blood products, or perinephric hematoma with comparable sample yield. Conclusions: Percutaneous ultrasound-guided kidney transplant biopsy performed by transplant nephrologists have similar complication rates when compared with interventional radiologists in an academic center.

Achalasia as an Unusual Cause of Acute Cellular Rejection of a Transplanted Heart.

A 68-year-old female with end-stage heart failure presented to the hospital for heart transplant. She was diagnosed with achalasia 14 months prior and treated with frequent botulinum toxin injections. She underwent orthotopic heart transplant on the day of admission and was extubated a few days later. She developed intractable nausea and vomiting. Her first endomyocardial biopsy revealed moderate, approaching severe rejection. She was treated with high-dose intravenous pulse steroids. Fluoroscopy at the time of follow-up biopsy showed undigested pills in her esophagus with narrowing at the distal end and thus failure to deliver immunosuppressive therapy. This case highlights achalasia as an etiology for acute rejection and its potential management.

Benign course of residual inflammation at end of treatment of liver transplant recipients after sofosbuvir based therapy.

BACKGROUND: Persistent inflammation on histology after successful hepatitis C (HCV) treatment has been reported. However, data regarding the long-term impact in liver transplant recipients is limited, particularly after using direct-acting antiviral (DAA) therapies. AIM: To evaluate the impact of successful treatment with DAAs on histological changes and occult HCV and to describe the clinical course of residual inflammation in liver transplant recipients. METHODS: We conducted a case series of 13 chronic HCV infected liver transplant recipients successfully treated with DAAs between December 2013 and May 2014. All patients were treated for 24 wk and had non-detectable serum HCV RNA by the time of biopsy. Only patients with at least one liver biopsy at or after treatment were included. We examined liver biopsies for evidence of residual inflammation and the presence of intrahepatic HCV RNA. RESULTS: Persistent inflammation was seen in 12/13 patients on end of treatment biopsy. Inflammation was still seen in the available five follow-up biopsies (range 38-48 wk after the end of treatment). Intrahepatic HCV RNA was undetectable in all biopsies. All patients had preserved graft function for a mean follow-up of 2.5 years, except one that developed chronic rejection. CONCLUSION: After successful HCV treatment with DAAs, liver transplant recipients may have persistent inflammation on biopsy without evidence of intracellular RNA. The clinical outcome remained favorable in most patients. Further studies with a larger number and longer follow-up are needed to establish the implication of this finding on long-term graft function.

Pilot study to determine the safety and feasibility of deceased donor liver natural killer cell infusion to liver transplant recipients with hepatocellular carcinoma.

Liver transplantation (LT) is a viable treatment option for cirrhosis patients with hepatocellular carcinoma (HCC). However, recurrence is the rate-limiting factor of long-term survival. To prevent this, we conducted the phase I study of the adoptive transfer of deceased donor liver-derived natural killer (NK) cells. Liver NK cells were extracted from donor liver graft perfusate and were stimulated in vitro with IL-2. The patient received an intravenous infusion of NK cells 3-5 days after LT. Eighteen LT recipients were treated. There were no severe cell infusion-related adverse events or acute rejection episodes. One patient withdrew from the study because the pathological observation revealed sarcoma instead of HCC. All patients who received this immunotherapy completed the follow-up for at least 2 years without evidence of HCC recurrence (median follow-up, 96 months [range, 17-121 months]). Considering that 9 (52.9%) of the 17 patients pathologically exceeded the Milan criteria, liver NK cell infusion is likely to be useful for preventing HCC recurrence after LT. This is the first-in-human immunotherapy study using deceased donor liver-derived NK cells to prevent HCC recurrence after LT. This treatment was well tolerated and resulted in no HCC recurrence after LT.Clinical trial registration www.clinicaltrials.gov ; NCT01147380; registration date: June 17, 2010.

Human SLE variant NCF1-R90H promotes kidney damage and murine lupus through enhanced Tfh2 responses induced by defective efferocytosis of macrophages.

OBJECTIVES: We previously identified a hypomorphic variant, p.Arg90His (p.R90H) of neutrophil cytosolic factor 1 (NCF1, a regulatory subunit of phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 complex), as an putative causal variant for systemic lupus erythematosus (SLE), and established a knock-in (KI) H90 variant in the C57BL/6 background to study how this variant promotes lupus development. METHODS: Wild type (WT) and KI littermates were assessed for immune profiles and lupus-like features. Disease activity and renal damage of patients with SLE were assessed by systemic lupus erythematosus disease activity index (SLEDAI) and renal items of systemic lupus international collaborating clinics (SLICC), respectively. RESULTS: Compared with WT littermates, 5-week-old homozygous KI mice had reduced oxidative burst, splenomegaly, elevated type I interferon (IFN-I) scores, increased ratios of splenic follicular T helper 2 (Tfh2) to either T follicular regulatory (Tfr) or Tfh1 cells, increased ANA+ follicular, germinal centre and plasma cells without spontaneous kidney disease up to 1 year of age. Pristane treatment exacerbated the immune dysregulation and induced IFN-I-dependent kidney disease in 36-week-old H90 KI female mice. Decreased efferocytosis of macrophages derived from KI mice and patients with homozygous H90 SLE promoted elevated ratios of Tfh2/Tfr and Tfh2/Tfh1 as well as dysregulated humoral responses due to reduced voltage-gated proton channel 1 (Hv1)-dependent acidification of phagosome pH to neutralise the decreased electrogenic effect of the H90 variant, resulting in impaired maturation and phagosome proteolysis, and increased autoantibody production and kidney damage in mice and patients with SLE of multiple ancestries. CONCLUSIONS: A lupus causal variant, NCF1-H90, reduces macrophage efferocytosis, enhances Tfh2 responses and promotes autoantibody production and kidney damage in both mice and patients with SLE.

Nonneoplastic Renal Parenchymal Changes in Renal Cell Carcinoma With Tumor Thrombus.

INTRODUCTION: Renal cell carcinoma may extend into the inferior vena cava (IVC) by the tumour thrombus (TT). Renal cell carcinoma with tumour thrombus (RCC/TT) could be associated with multiple collaterals making the surgery in cases of venous involvement very complex and challenging. The pathologic findings of non-neoplastic parenchymal changes in radical nephrectomy specimens of RCC/TT have not been well described. METHODS: We conducted a retrospective study of 200 nephrectomies for RCC/TT during eight years. We only included 22 patients who had a full histopathological examination of the resected nephrectomies, including the non-neoplastic parenchymal tissues. RESULTS: Median tumour thrombus level was III (range: II-IV), and median tumour diameter was 9.3 (range: 4-17) cm. Clear cell RCC was the most common tumour diagnosis in this cohort. Non-neoplastic renal pathologies included: (1) Global Glomerulosclerosis (GGS) in 90.9% (1-9% GGS in 15, 10-30% GGS in 4, >30% GGS in 1); (2) Interstitial fibrosis in 90.9% (mild in nine, moderate in nine, severe in 2); (3) Acute tubular injury in 14 (63.6%) patients; (4) Chronic inflammation in 77.3% (5-25% in 10, 26-50% in 7); (5) Arteriolosclerosis in all patients (mild, moderate and severe in 12, 9 and 1 patients, respectively); (6) Arteriolosclerosis: as none in 12, mild in six, moderate in four patients; (7) Focal Segmental Glomerulosclerosis in one patient. Our findings suggest that non-neoplastic parenchymal changes occur in the presence of RCC/TT. Neither tumour extension (via T-stage) nor tumour thrombus level were associated with the degree of any of these non-neoplastic parenchymal changes. CONCLUSIONS: Knowledge of the existence of these non-neoplastic parenchymal changes in addition to determining the tumour margin(s) will be important in caring for and early determining whether any specific medical intervention(s) to help preserve renal function in the remaining contralateral kidney becomes warranted.

Long-term Persistence of Allosensitization After Islet Allograft Failure.

BACKGROUND: Allosensitization has been reported after discontinuation of immunosuppression following graft failure in islet transplantation (ITx) recipients, though duration of its persistence is unknown. METHODS: We evaluated 35 patients with type 1 diabetes who received ITx, including 17 who developed graft failure (ITx alone, n = 13; ITx plus bone marrow-derived hematopoietic stem cells, n = 4) and 18 with persistent graft function. Panel-reactive antibody (PRA) was measured yearly for the duration of graft function within 1 y after graft failure at enrollment and yearly thereafter. RESULTS: In ITx alone graft failure patients, 61% (8/13) were PRA-positive at 6 y postgraft failure, and 46% (6/13) developed donor-specific anti-HLA antibodies (DSA to 2 ± 1 donors) during follow-up. The degree of sensitization was variable (cPRA ranging between 22% and 100% after graft failure). Allosensitization persisted for 7-15 y. Three subjects (3/13) were not allosensitized. In ITx plus bone marrow-derived hematopoietic stem cell recipients, cPRA-positivity (88%-98%) and DSA positivity persisted for 15 y in 75% (3/4) of subjects. CONCLUSIONS: Allosensitization was minimal while subjects remained on immunosuppression, but after discontinuation of immunosuppressive therapy, the majority of subjects (77%) became allosensitized with persistence of PRA positivity for up to 15 y. Persistence of allosensitization in this patient population is of clinical importance as it may result in longer transplant waiting list times for identification of a suitable donor in the case of requiring a subsequent transplant.

Umbilical cord mesenchymal stem cells for COVID-19 acute respiratory distress syndrome: A double-blind, phase 1/2a, randomized controlled trial.

Acute respiratory distress syndrome (ARDS) in COVID-19 is associated with high mortality. Mesenchymal stem cells are known to exert immunomodulatory and anti-inflammatory effects and could yield beneficial effects in COVID-19 ARDS. The objective of this study was to determine safety and explore efficacy of umbilical cord mesenchymal stem cell (UC-MSC) infusions in subjects with COVID-19 ARDS. A double-blind, phase 1/2a, randomized, controlled trial was performed. Randomization and stratification by ARDS severity was used to foster balance among groups. All subjects were analyzed under intention to treat design. Twenty-four subjects were randomized 1:1 to either UC-MSC treatment (n = 12) or the control group (n = 12). Subjects in the UC-MSC treatment group received two intravenous infusions (at day 0 and 3) of 100 ± 20 × 106 UC-MSCs; controls received two infusions of vehicle solution. Both groups received best standard of care. Primary endpoint was safety (adverse events [AEs]) within 6 hours; cardiac arrest or death within 24 hours postinfusion). Secondary endpoints included patient survival at 31 days after the first infusion and time to recovery. No difference was observed between groups in infusion-associated AEs. No serious adverse events (SAEs) were observed related to UC-MSC infusions. UC-MSC infusions in COVID-19 ARDS were found to be safe. Inflammatory cytokines were significantly decreased in UC-MSC-treated subjects at day 6. Treatment was associated with significantly improved patient survival (91% vs 42%, P = .015), SAE-free survival (P = .008), and time to recovery (P = .03). UC-MSC infusions are safe and could be beneficial in treating subjects with COVID-19 ARDS.

Direct Actions of AT1 (Type 1 Angiotensin) Receptors in Cardiomyocytes Do Not Contribute to Cardiac Hypertrophy.

Activation of AT1 (type 1 Ang) receptors stimulates cardiomyocyte hypertrophy in vitro. Accordingly, it has been suggested that regression of cardiac hypertrophy associated with renin-Ang system blockade is due to inhibition of cellular actions of Ang II in the heart, above and beyond their effects to reduce pressure overload. We generated 2 distinct mouse lines with cell-specific deletion of AT1A receptors, from cardiomyocytes. In the first line (C-SMKO), elimination of AT1A receptors was achieved using a heterologous Cre recombinase transgene under control of the Sm22 promoter, which expresses in cells of smooth muscle lineage including cardiomyocytes and vascular smooth muscle cells of conduit but not resistance vessels. The second line (R-SMKO) utilized a Cre transgene knocked-in to the Sm22 locus, which drives expression in cardiac myocytes and vascular smooth muscle cells in both conduit and resistance arteries. Thus, although both groups lack AT1 receptors in the cardiomyocytes, they are distinguished by presence (C-SMKO) or absence (R-SMKO) of peripheral vascular responses to Ang II. Similar to wild-types, chronic Ang II infusion caused hypertension and cardiac hypertrophy in C-SMKO mice, whereas both hypertension and cardiac hypertrophy were reduced in R-SMKOs. Thus, despite the absence of AT1A receptors in cardiomyocytes, C-SMKOs develop robust cardiac hypertrophy. By contrast, R-SMKOs developed identical levels of hypertrophy in response to pressure overload-induced by transverse aortic banding. Our findings suggest that direct activation of AT1 receptors in cardiac myocytes has minimal influence on cardiac hypertrophy induced by renin-Ang system activation or pressure overload.

Computed Tomography-Guided Kidney Transplant Biopsy Outcomes: A Single-Center Experience.

OBJECTIVES: Percutaneous kidney transplant biopsy is typically performed using ultrasonographic guidance; computed tomography is an alternative modality used to obtain kidney allografttissuewhen ultrasonographyguided percutaneous kidney transplant biopsy is technically challenging. Studies examining postbiopsy outcomes in kidney transplant patients using a computed tomography-guided approach are scarce. Our goal was to reportthe incidence of nonsevere and severe complications in computed tomographyguided percutaneous kidney transplant biopsies and the potential risk factors. MATERIALS AND METHODS: We retrospectively reviewed computed tomography-guided percutaneous kidney transplant biopsies in patients undergoing work-up for kidney allograft rejection between 2013 and 2017. Demographics, comorbidities, laboratory data, history of antiplatelet and/or anticoagulant use, and complications were assessed. RESULTS: : During the study period, 28 patients underwent computed tomography-guided percutaneous kidney transplant biopsies; mean age was 57.5 ± 15.5 years, and 12 (43%)werewomen.Twenty-three patients (82%) were obese, with a body mass index greater than 30 kg/m². Our cohort of kidney transplant recipients included 21 (75%) from deceased donors and 7 (25%) from living-related donors. At the time of biopsy, 6 patients (21%) had elevated blood pressure (defined as > 160/90 mm Hg). One patient had severe complications, which included a significant decrease in hemoglobin requiring transfusion and a perinephric hematoma with worsening renal function. This was a morbidly obese patient whose blood pressure was elevated at the time of biopsy with a platelet count of 93 × 10³/mm³ and international normalized ratio of 1.21. CONCLUSIONS: A computed tomography-guided percutaneous kidney transplant biopsy is a safe and effective alternative to obtain kidney tissue in the obese population and is associated with low rates of complications. In this study, we highlighted the need to achieve adequate blood pressure control and assess bleeding risk factors, such as platelet count and international normalized ratio, prior to biopsy.

GSTM1 Deletion Exaggerates Kidney Injury in Experimental Mouse Models and Confers the Protective Effect of Cruciferous Vegetables in Mice and Humans.

BACKGROUND: GSTM1 encodes glutathione S-transferase µ-1 (GSTM1), which belongs to a superfamily of phase 2 antioxidant enzymes. The highly prevalent GSTM1 deletion variant is associated with kidney disease progression in human cohorts: the African American Study of Kidney Disease and Hypertension and the Atherosclerosis Risk in Communities (ARIC) Study. METHODS: We generated a Gstm1 knockout mouse line to study its role in a CKD model (involving subtotal nephrectomy) and a hypertension model (induced by angiotensin II). We examined the effect of intake of cruciferous vegetables and GSTM1 genotypes on kidney disease in mice as well as in human ARIC study participants. We also examined the importance of superoxide in the mediating pathways and of hematopoietic GSTM1 on renal inflammation. RESULTS: Gstm1 knockout mice displayed increased oxidative stress, kidney injury, and inflammation in both models. The central mechanism for kidney injury is likely mediated by oxidative stress, because treatment with Tempol, an superoxide dismutase mimetic, rescued kidney injury in knockout mice without lowering BP. Bone marrow crosstransplantation revealed that Gstm1 deletion in the parenchyma, and not in bone marrow-derived cells, drives renal inflammation. Furthermore, supplementation with cruciferous broccoli powder rich in the precursor to antioxidant-activating sulforaphane significantly ameliorated kidney injury in Gstm1 knockout, but not wild-type mice. Similarly, among humans (ARIC study participants), high consumption of cruciferous vegetables was associated with fewer kidney failure events compared with low consumption, but this association was observed primarily in participants homozygous for the GSTM1 deletion variant. CONCLUSIONS: Our data support a role for the GSTM1 enzyme in the modulation of oxidative stress, inflammation, and protective metabolites in CKD.

Clostridium difficile infection mimics intestinal acute cellular rejection in pediatric multivisceral transplant-A case series.

Clostridium difficile infection (CDI) is the most common health care-associated infection in the United States. Thirty-nine percent of intestinal transplant recipients may develop CDI. Induction of rejection has been reported as a rare event. To our knowledge, this will be the second report of an association between CDI and rejection in the literature. We describe our experience with four pediatric MVT recipients, three of whom on treatment of their CDI alone had resolution of biopsy findings of intestinal ACR. Our patients were males aged 2-5 years old who had their first CDI post-MVT occurring from 2 months to 15 months post-transplant. All first episodes of CDI were treated with a 10-14 day course of metronidazole with one additionally receiving vancomycin. All four recipients had recurrent CDI, and two recipients had septic shock as a manifestation of their CDI. Three recipients had biopsies showing mild rejection during episodes of CDI, and treatment of the CDI resulted in resolution of biopsy findings of rejection. Our case series suggests CDI may mimic ACR on intestinal biopsy. Treatment of rejection during active CDI carries the risk of over-suppression and worsening of CDI. Our experience has taught us that surveillance endoscopy for rejection may be deceiving during an active CDI, and if mild acute rejection is noted during active CDI, treatment of rejection can be safely delayed and potentially avoided.

Steroid-Free Immune Suppression Impairs Glycemic Control in a Healthy Cynomolgus Monkey.

The need for chronic immune suppression (IS) is one of the hurdles precluding widespread use of islet cell transplantation to restore glycemic control in patients with type 1 diabetes. We report the case of a healthy nonhuman primate (NHP) treated on and off for over 2.5 years with steroid-free IS, consisting of daclizumab induction and maintenance therapy with rapamycin and low dose tacrolimus. Treatment for 1 year resulted in a striking destabilization of glycemic control, with concomitant decreases in fasting c-peptide and insulin levels. Although these changes gradually reversed during a wash out period of 7 months, retreatment with the same therapy led to accelerated deterioration in glycemic control. Intravenous glucose tolerance and percentage of glycosylated hemoglobin testing further supported a dramatic effect on metabolic control. IS also led to decreases in weight during treatment. Histological evaluation of the pancreas revealed islet hyperplasia, with varying sizes and endocrine cell ratios that differed from normal islet composition, and parenchymal infiltration with adipose tissue. These deleterious effects of IS on glucose control and endocrine components in the native pancreas of a healthy NHP suggest that IS agents commonly utilized for islet transplantation may contribute to failure in islet allograft function in long-term transplant patients.

Cardioprotective Effects of Paricalcitol Alone and in Combination With FGF23 Receptor Inhibition in Chronic Renal Failure: Experimental and Clinical Studies.

BACKGROUND: In uremic animals, vitamin D receptor (VDR) agonists like paricalcitol (Pc) attenuate cardiac hypertrophy, but this effect has not been replicated consistently in humans with chronic kidney disease. Elevated fibroblast growth factor 23 (FGF23) levels cause cardiac hypertrophy with activation of the myocardial calcineurin/nuclear factor of activated T cell (NFAT) axis and may antagonize the cardioprotective effects of VDR agonist therapy. We hypothesized that the effectiveness of Pc may depend on the prevailing circulating levels of FGF23 and could be potentiated by the combined administration of a pan-FGF23 receptor (FGFR) blocker agent (PD173074). METHODS: In rats with 5/6 nephrectomy treated with Pc or PD173074 or both agents concurrently, myocardial mRNA expression of renin-angiotensin system, VDR, FGFR4, and calcineurin/NFAT target genes was determined. In adolescents on hemodialysis, we analyzed sequential echocardiograms, blood pressures and serial FGF23 measurements, and their relations to the cumulative administered dose of parenteral Pc. RESULTS: The ratio of Pc dose/plasma levels of FGF23 correlated inversely (P < 0.005) with the cardiac mass in uremic rats and in hemodialysis patients, independently of hypertension. Despite persistently elevated FGF23 levels and myocardial FGFR4 activation, Pc suppressed upregulated myocardial calcineurin/NFAT target genes, and the effects were amplified by coadministration of PD173074. CONCLUSIONS: The beneficial effects of Pc on uremic cardiac hypertrophy are counterbalanced by the increased FGF23 levels. Blockade of FGF23-mediated signaling increased the Pc-induced suppression of the myocardial calcineurin/NFAT system. Higher doses of Pc should be considered in the treatment of patients with uremic cardiomyopathy.

Stable perfluorocarbon emulsions for the delivery of halogenated ether anesthetics.

BACKGROUND: Research into injectable volatile anesthetics has been ongoing for approximately 40 years, with limited success, in an attempt to address the deficiencies of inhalational anesthesia. The purpose of this work was to formulate and optimize volatile anesthetic carrier emulsions based on our prior work in perfluorocarbon emulsions. METHODS: Perfluorocarbons were screened for their volatilty and emulsion stability. Optimal anesthetic emulsions were manufactured by high pressure homogenization of a select, clinically relevant perfluorocarbon, isoflurane and a surfactant-containing aqueous phase. Longitudinal particle size, polydispersity and isoflurane content analysis was performed. Observational studies of in vivo efficacy and safety were performed in 225-300 g Lewis Rats (n = 34) with blood chemistry and post study tissue pathology analysis. RESULTS: Emulsion particle size and isolflurane content in select emulsions were stable at room temperature greater than 300 days. This stability was depedent on perfluorocarbon molecular weight and boiling point. in vivo, emulsions demonstrated a rapid onset and offset. Variability in onset metrics (loss of righting reflex, pain reflexes and time to recovery) was less than 40% amongst individual emulsion preparations (n = 9) utilized in induction trials. No adverse effects due to the intravenous administration of emulsions were observed in blood chemistry results or post-study pathological examination. CONCLUSIONS: These formulations showed stability, safety and efficacy. In addition to induction and general anesthesia, these emulsions could have utility in global health or in military applications where equipment and resources are limited.

Kidney-derived c-kit+ progenitor/stem cells contribute to podocyte recovery in a model of acute proteinuria.

Kidney-derived c-kit+ cells exhibit progenitor/stem cell properties and can regenerate epithelial tubular cells following ischemia-reperfusion injury in rats. We therefore investigated whether c-kit+ progenitor/stem cells contribute to podocyte repair in a rat model of acute proteinuria induced by puromycin aminonucleoside (PAN), the experimental prototype of human minimal change disease and early stages of focal and segmental glomerulosclerosis. We found that c-kit+ progenitor/stem cells accelerated kidney recovery by improving foot process effacement (foot process width was lower in c-kit group vs saline treated animals, P = 0.03). In particular, these cells engrafted in small quantity into tubules, vessels, and glomeruli, where they occasionally differentiated into podocyte-like cells. This effect was related to an up regulation of α-Actinin-4 and mTORC2-Rictor pathway. Activation of autophagy by c-kit+ progenitor/stem cells also contributed to kidney regeneration and intracellular homeostasis (autophagosomes and autophagolysosomes number and LC3A/B-I and LC3A/B-II expression were higher in the c-kit group vs saline treated animals, P = 0.0031 and P = 0.0009, respectively). Taken together, our findings suggest that kidney-derived c-kit+ progenitor/stem cells exert reparative effects on glomerular disease processes through paracrine effects, to a lesser extent differentiation into podocyte-like cells and contribution to maintenance of podocyte cytoskeleton after injury. These findings have clinical implications for cell therapy of glomerular pathobiology.