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A limitation of simulated space radiation studies is that radiation exposure is not the only environmental challenge astronauts face during missions. Therefore, we characterized behavioral and cognitive performance of male WAG/Rij rats 3 months after sham-irradiation or total body irradiation with a simplified 5-ion mixed beam exposure in the absence or presence of simulated weightlessness using hindlimb unloading (HU) alone. Six months following behavioral and cognitive testing or 9 months following sham-irradiation or total body irradiation, plasma and brain tissues (hippocampus and cortex) were processed to determine whether the behavioral and cognitive effects were associated with long-term alterations in metabolic pathways in plasma and brain. Sham HU, but not irradiated HU, rats were impaired in spatial habituation learning. Rats irradiated with 1.5 Gy showed increased depressive-like behaviors. This was seen in the absence but not presence of HU. Thus, HU has differential effects in sham-irradiated and irradiated animals and specific behavioral measures are associated with plasma levels of distinct metabolites 6 months later. The combined effects of HU and radiation on metabolic pathways in plasma and brain illustrate the complex interaction of environmental stressors and highlights the importance of assessing these interactions.

Introduction: Given the negative outcomes associated with uncontrolled diabetes mellitus, non-insulin therapies with glycemic, cardiovascular, and weight-loss benefits in the general population, such as the glucagonlike peptide-1 receptor agonists (GLP1-RA) have become a more alluring therapeutic option in transplant populations. However, limited evidence exists to demonstrate its safety and efficacy in solid organ transplant. Methods: This program evaluation included adult kidney, liver, lung transplant recipients initiated on a GLP1-RA for diabetes mellitus management for a minimum of 3 months, had at least one follow-up visit after starting therapy, and had at least one hemoglobin A1c (HbA1c) level drawn between 3–12 months after GLP1-RA initiation. Outcomes were assessed at time of initiation of GLP1-RA (baseline) and 3–12 months post-initiation. Nadir values between 3–12 months were utilized to assess outcomes. Results: One-hundred eighteen patients met study inclusion criteria. Seventy-percent of patients received a kidney transplant, 19.5% received a liver transplant, and 6.8% received a lung transplant. A statistically significant difference was observed in median fasting blood glucose and HbA1c at baseline to 3–12-month nadir (P < 0.0001). A significant weight loss benefit was also observed. The rate of adverse drug reactions was low. Seven-percent of patients experienced nausea, 4.2% developed pancreatitis, and 7.1% reported having had at least one hypoglycemic event. Discussion: This is the largest study evaluating GLP1-RA in organ transplantation and demonstrates GLP1-RA is both safe and effective. Further assessment on long-term use of these agents on cardiovascular and renal outcomes is still needed.