Molecular Pathways Underlying Adaptive Repair of the Injured Kidney: Novel Donation After Cardiac Death and Acute Kidney Injury Platforms

International audienceObjective: To test the hypothesis that gene expression profiling in peripheral blood from patients who have undergone kidney transplantation (KT) will provide mechanistic insights regarding graft repair and regeneration.Background: Renal grafts obtained from living donors (LD) typically function immediately, whereas organs from donation after cardiac death (DCD) or acute kidney injury (AKI) donors may experience delayed function with eventual recovery. Thus, recipients of LD, DCD, and AKI kidneys were studied to provide a more complete understanding of the molecular basis for renal recovery.Methods: Peripheral blood was collected from LD and DCD/AKI recipients before transplant and throughout the first 30 days thereafter. Total RNA was isolated and assayed on whole genome microarrays.Results: Comparison of longitudinal gene expression between LD and AKI/DCD revealed 2 clusters, representing 141 differentially expressed transcripts. A subset of 11 transcripts was found to be differentially expressed in AKI/DCD versus LD. In all recipients, the most robust gene expression changes were observed in the first day after transplantation. After day 1, gene expression profiles differed depending upon the source of the graft. In patients receiving LD grafts, the expression of most genes did not remain markedly elevated beyond the first day post-KT. In the AKI/DCD groups, elevations in gene expression were maintained for at least 5 days post-KT. In all recipients, the pattern of coordinate gene overexpression subsided by 28 to 30 days.Conclusions: Gene expression in peripheral blood of AKI/DCD recipients offers a novel platform to understand the potential mechanisms and timing of kidney repair and regeneration after transplantation

The Human Pancreas as a Source of Protolerogenic Extracellular Matrix Scaffold for a New-generation Bioartificial Endocrine Pancreas

OBJECTIVES: Our study aims at producing acellular extracellular matrix scaffolds from the human pancreas (hpaECMs) as a first critical step toward the production of a new-generation, fully human-derived bioartificial endocrine pancreas. In this bioartificial endocrine pancreas, the hardware will be represented by hpaECMs, whereas the software will consist in the cellular compartment generated from patient's own cells. BACKGROUND: Extracellular matrix (ECM)-based scaffolds obtained through the decellularization of native organs have become the favored platform in the field of complex organ bioengineering. However, the paradigm is now switching from the porcine to the human model. METHODS: To achieve our goal, human pancreata were decellularized with Triton-based solution and thoroughly characterized. Primary endpoints were complete cell and DNA clearance, preservation of ECM components, growth factors and stiffness, ability to induce angiogenesis, conservation of the framework of the innate vasculature, and immunogenicity. Secondary endpoint was hpaECMs’ ability to sustain growth and function of human islet and human primary pancreatic endothelial cells. RESULTS: Results show that hpaECMs can be successfully and consistently produced from human pancreata and maintain their innate molecular and spatial framework and stiffness, and vital growth factors. Importantly, hpaECMs inhibit human naïve CD4+ T-cell expansion in response to polyclonal stimuli by inducing their apoptosis and promoting their conversion into regulatory T cells. hpaECMs are cytocompatible and supportive of representative pancreatic cell types. DISCUSSION: We, therefore, conclude that hpaECMs has the potential to become an ideal platform for investigations aiming at the manufacturing of a regenerative medicine-inspired bioartificial endocrine pancreas

Health Outcomes of Gastric Bypass Patients Compared to Nonsurgical, Nonintervened Severely Obese

Favorable health outcomes at 2 years postbariatric surgery have been reported. With exception of the Swedish Obesity Subjects (SOS) study, these studies have been surgical case series, comparison of surgery types, or surgery patients compared to subjects enrolled in planned nonsurgical intervention. This study measured gastric bypass effectiveness when compared to two separate severely obese groups not participating in designed weight-loss intervention. Three groups of severely obese subjects (N = 1,156, BMI ≥ 35 kg/m2) were studied: gastric bypass subjects (n = 420), subjects seeking gastric bypass but did not have surgery (n = 415), and population-based subjects not seeking surgery (n = 321). Participants were studied at baseline and 2 years. Quantitative outcome measures as well as prevalence, incidence, and resolution rates of categorical health outcome variables were determined. All quantitative variables (BMI, blood pressure, lipids, diabetes-related variables, resting metabolic rate (RMR), sleep apnea, and health-related quality of life) improved significantly in the gastric bypass group compared with each comparative group (all P < 0.0001, except for diastolic blood pressure and the short form (SF-36) health survey mental component score at P < 0.01). Diabetes, dyslipidemia, and hypertension resolved much more frequently in the gastric bypass group than in the comparative groups (all P < 0.001). In the surgical group, beneficial changes of almost all quantitative variables correlated significantly with the decrease in BMI. We conclude that Roux-en-Y gastric bypass surgery when compared to severely obese groups not enrolled in planned weight-loss intervention was highly effective for weight loss, improved health-related quality of life, and resolution of major obesity-associated complications measured at 2 years

Plasma glycerol during the acute post-exercise recovery period: Influence of exercise intensity

Intensity of exercise can influence substrate utilization, with increasing intensity resulting in lower rates of fat oxidation and the reliance on carbohydrate as the preferred fuel. Fat oxidation (or more specifically, mobilization) can be assessed via the measurement of circulating glycerol, with most prior research focusing on aerobic exercise and measurements obtained during the actual exercise bout. The present study determined the degree of fat oxidation/mobilization by measuring plasma glycerol concentrations during the one hour post-exercise recovery period following three difference exercise bouts. On four different days, exercise trained men (n=12; 23.7±1.1 years) either rested quietly or performed aerobic cycle exercise (60 min at 70% heart rate reserve), 60 s cycle sprints at 100% max wattage obtained during graded exercise testing (GXT) - a total of five, or 15 s cycle sprints at 200% max wattage obtained during GXT - a total of 10. Blood was collected before and at 1, 30 and 60 min post-exercise. Haematocrit and haemoglobin were measured to correct for changes in plasma volume. Glycerol was analysed in plasma and the area under the curve was calculated. Glycerol increased across time (P \u3c 0.0001) from pre-exercise (8.4±0.3 μg/dl) to 1 min (13.1±0.7 μg/dl), 30 min (11.3±0.6 μg/dl) and 60 min (9.1±0.5 μg/dl) post-exercise, with 1 min and 30 min post-exercise greater than pre-exercise and 60 min post-exercise (P \u3c 0.05). Area under the curve was greater (P=0.0004) for aerobic exercise (24.7±2.0 μg/dl/h), 60 second sprints (23.4±1.9 μg/dl/h) and 15 sec sprints (24.4±1.5 μg/dl/h), as compared to rest (15.3±0.8 μg/dl/h), with no differences noted between exercise bouts (P \u3e 0.05). All exercise bouts increase circulating glycerol, with no differences noted between bouts. Although previous data indicate that low intensity aerobic exercise results in greater fat oxidation than high intensity exercise (when assessed during the actual exercise session), our findings suggest that high intensity exercise may result in similar fat oxidation/mobilization as compared to aerobic exercise during the acute post-exercise period

Safety profile of caffeine and 1,3-dimethylamylamine supplementation in healthy men

Caffeine and 1,3-dimethylamylamine (DMAA) are widely used alone and in combination with dietary supplements. No investigation has determined the safety profile of chronic intake of caffeine or DMAA, alone or in combination, within the same study design. A total of 50 young and healthy men completed 12 weeks of daily supplementation with either a placebo (n = 11), caffeine at 250 mg day-1 (n = 14), DMAA at 50 mg day-1 (n = 13), or caffeine at 250 mg day-1 + DMAA at 50 mg day-1 (n = 12). Before and after 6 and 12 weeks of supplementation, the following variables were measured: body mass/composition, resting respiratory rate, blood pressure, 12-lead electrocardiogram, urinalysis, complete blood count, metabolic panel, lipid panel, and oxidative stress, inflammatory, and cardiac biomarkers. No interaction effects were noted for any variable (p \u3e 0.05), with little change occurring across time for subjects in any of the four conditions. With the exception of urinary pH (p = 0.05; Pre (6.5 ± 0.1) higher than week 6 (6.1 ± 0.1)) and blood CO2 (p = 0.02; week 12 (25.9 ± 0.3 mmol L-1) higher than week 6 (24.8 ± 0.3 mmol L -1)), no time effect was noted for any other variable (p \u3e 0.05). These data indicate that 12 weeks of daily supplementation with caffeine and DMAA, alone or in combination, does not result in a statistically significant change in any of the measured outcome variables. © 2013 The Author(s)

Prospect for kidney bioengineering: Shortcomings of the status quo

Dialysis and renal transplantation are the only two therapeutic options offered to patients affected by end-stage kidney disease; however, neither treatment can be considered definitive. In fact, dialysis is able to replace only the filtration function of the kidney without substituting its endocrine and metabolic roles, and dramatically impacts on patient's quality of life. On the other hand, kidney transplantation is severely limited by the shortage of transplantable organs, the need for immunosuppressive therapies and a narrow half-life. Regenerative medicine approaches are promising tools aiming to improve this condition