Angiotensin-(1-7) improves cognitive function and reduces inflammation in mice following mild traumatic brain injury

Introduction: Traumatic brain injury (TBI) is a leading cause of disability in the US. Angiotensin 1-7 (Ang-1-7), an endogenous peptide, acts at the G protein coupled MAS1 receptors (MASR) to inhibit inflammatory mediators and decrease reactive oxygen species within the CNS. Few studies have identified whether Ang-(1-7) decreases cognitive impairment following closed TBI. This study examined the therapeutic effect of Ang-(1-7) on secondary injury observed in a murine model of mild TBI (mTBI) in a closed skull, single injury model. Materials and methods: Male mice (n = 108) underwent a closed skull, controlled cortical impact injury. Two hours after injury, mice were administered either Ang-(1-7) (n = 12) or vehicle (n = 12), continuing through day 5 post-TBI, and tested for cognitive impairment on days 1–5 and 18. pTau, Tau, GFAP, and serum cytokines were measured at multiple time points. Animals were observed daily for cognition and motor coordination via novel object recognition. Brain sections were stained and evaluated for neuronal injury. Results: Administration of Ang-(1-7) daily for 5 days post-mTBI significantly increased cognitive function as compared to saline control-treated animals. Cortical and hippocampal structures showed less damage in the presence of Ang-(1-7), while Ang-(1-7) administration significantly changed the expression of pTau and GFAP in cortical and hippocampal regions as compared to control. Discussion: These are among the first studies to demonstrate that sustained administration of Ang-(1-7) following a closed-skull, single impact mTBI significantly improves neurologic outcomes, potentially offering a novel therapeutic modality for the prevention of long-term CNS impairment following such injuries. Copyright © 2022 Bruhns, Sulaiman, Gaub, Bae, Davidson Knapp, Larson, Smith, Coleman, Staatz, Sandweiss, Joseph, Hay, Largent-Milnes and Vanderah.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Effect of mild diarrhea on tacrolimus exposure

Item does not contain fulltextBACKGROUND: Diarrhea is a frequent adverse event in patients treated with the combination of tacrolimus and mycophenolate mofetil (MMF). In case of severe diarrhea, the total exposure to tacrolimus can substantially increase, which is reflected in a rise of the predose trough level (C0). In mild diarrhea (two to three stools per day), an increased exposure might occur without trough levels exceeding the target range, resulting in "silent" chronic tacrolimus overexposure. The aim was to assess the degree of unnoticed tacrolimus overexposure in renal transplant patients with mild diarrhea while on treatment with tacrolimus and MMF. METHODS: A prospective pharmacokinetic study was performed in 12 recipients of a renal allograft using a combination of tacrolimus and MMF with mild diarrhea and in 12 controls. Tacrolimus levels were assessed by a validated dried blood spot method for sampling and measurement. RESULTS: The C0 did not differ between patients with mild diarrhea and controls (mean [95% confidence interval], 9.6 microg/L [8.6-10.9 microg/L] and 8.3 microg/L [6.9-9.9 microg/L]). In addition, there was no significant difference in the 12-hr area under the curve between patients with mild diarrhea and controls (185.6 microg. h/L [153.6-224.2 microg.h/L] vs. 170.5 microg.h/L [137.2-221.8 microg.h/L]). As a result, the ratio between the 12-hr area under the curve and C0 was similar in both groups (19.2 [17.5-21.1] vs. 20.6 [19.0-22.4]). The intraindividual variability in tacrolimus exposure was limited and not affected by the presence of mild diarrhea. CONCLUSIONS: We found no evidence for the presence of hidden tacrolimus overexposure in patients with mild diarrhea while on treatment with tacrolimus and MMF

Immunosuppressive drugs and the gastrointestinal tract in renal transplant patients

Item does not contain fulltextGastrointestinal (GI) discomfort is common after renal transplantation and can be caused by the use of various immunosuppressive drugs. GI symptoms affect the quality of life, lead to an impaired graft survival and an increased mortality. Moreover, diseases and disturbances of the GI tract also affect the pharmacokinetics of immunosuppressive drugs. This review addresses the interaction between immunosuppressive agents and GI disorders. The GI tract is involved in the metabolism of several immunosuppressive drugs. Calcineurin inhibitors, mTor inhibitors, and corticosteroids are subjected to metabolism by the intestinal cytochrome P450 (CYP3A) and by the drug efflux pump ABCB1. Mycophenolate is partly metabolized in the stomach and intestine and undergoes enterohepatic recirculation. Gastrointestinal disturbances can lead to a modified exposure to immunosuppressive drugs. In the first and second part of this review, we focus on the role of the GI tract in the pharmacokinetics of the immunosuppressive drugs and how to adjust immunosuppressive therapy in patients with vomiting, need for tube feeding, delayed gastric emptying, intestinal resection, and diarrhea. In the third part, we review the GI adverse effects of the various immunosuppressive drugs, with special attention for diarrhea and dyspepsia. Finally, we discuss the effects of drugs used for relief of GI complaints on the exposure to immunosuppressive agents