Ghrelin therapy mitigates bone marrow injury and splenocytopenia by sustaining circulating G-CSF and KC increases after irradiation combined with wound

Abstract

BackgroundRadiation injury combined wound (CI) enhances acute radiation syndrome and subsequently mortality as compared to radiation injury alone (RI). We previously reported that ghrelin (a 28-amino-acid-peptide secreted from the stomach) treatment significantly increased a 30-day survival, mitigated hematopoietic death, circulating white blood cell (WBC) depletion and splenocytopenia and accelerated skin-wound healing on day 30 after CI. Herein, we aimed to study the ghrelin efficacy at early time points after CI.MethodsB6D2F1/J female mice were exposed to 60Co-γ-photon radiation at 9.5 Gy (LD50/30) followed by a 15% total-body-surface-area skin wound. Several endpoints were measured at 4–5 h, days 1, 3, 7 and 15.ResultsHistological analysis of sternums on day 15 showed that CI induced more adipocytes and less megakaryocytes than RI. Bone marrow cell counts from femurs also indicated CI resulted in lower bone marrow cell counts on days 1, 7 and 15 than RI. Ghrelin treatment mitigated these CI-induced adverse effects. RI and CI decreased WBCs within 4–5 h and continued to decrease to day 15. Ghrelin treatment mitigated decreases in CI mice, mainly from all types of WBCs, but not RBCs, hemoglobin levels and hematocrit values. Ghrelin mitigated the CI-induced thrombocytopenia and splenocytopenia. CI increased granulocyte-colony stimulating factor (G-CSF) and keratinocyte chemoattractant (KC) in blood and bone marrow. Ghrelin therapy was able to enhance and sustain the increases in serum on day 15, probably contributed by spleen and ileum, suggesting the correlation between G-CSF and KC increases and the neutropenia mitigation. Activated caspase-3 levels in bone marrow cells were significantly mitigated by ghrelin therapy on days 3 and 15.ConclusionsOur novel results are the first to suggest that ghrelin therapy effectively decreases hematopoietic death and splenocytopenia by sustaining circulating G-CSF and KC increases after CI. These results demonstrate efficacy of ghrelin as a radio-mitigator/therapy agent for CI.

Co-Therapy of Pegylated G-CSF and Ghrelin for Enhancing Survival After Exposure to Lethal Radiation

“…Ghrelin, obtained from Phoenix Pharmaceutical (Burlingame, CA), was subcutaneously (s.c.) administered at three doses of 113 μg/kg in a volume of 0.2 ml 24 h, 48 h, and 72 h after sham or RI. The dose was calculated based on a publication ( Shah et al, 2009 ) and utilized previously ( Kiang et al, 2018 ; Kiang et al, 2020 ). The vehicle given to control mice was sterile 0.9% sodium chloride solution for injection, USP ( Kiang et al, 2020 ).…”

“…The resulted pellets were re-suspended in 10 ml 1x PBS buffer. The cell suspensions were then placed in Countess™ cell-counting-chamber slides (Invitrogen) and counted using a Countess™ automated cell counter (Invitrogen) ( Kiang et al, 2014b ; Kiang et al, 2018 ). Bone marrow cells were finally centrifuged again at 800x g for 10 min.…”

“…The exogenous Ghrelin treatment reduced IL-18, decreased JNK activation and increased enterocytes and tight junction of ileum ( Kiang et al, 2020 ). Moreover, the exogenous Ghrelin treatment significantly recovered lymphocytes, monocytes, and basophils, and enhanced increases in G-CSF in spleen samples after RI ( Kiang et al, 2018 ). Therefore, it was of interest to investigate a hypothesis/concept, whether co-therapy of Peg-G-CSF and Ghrelin could enhance Peg-G-CSF’s efficacy to save lives and mitigate ARS after RI.…”

Radiation: a poly-traumatic hit leading to multi-organ injury

“…Shah et al [ 41 ] reported that human ghrelin attenuated organ injury and improves survival in a rat model of radiation combined with sepsis. Our laboratory has reported that ghrelin [ 10 , 121 , 122 ], Alxn4100TPO [ 123 ], Ciprofloxacin [ 72 , 124 , 125 ] and mesenchymal stem cells [ 10 , 12 ] are effective to mitigate radiation combined injury. In fact, due to the radiation-induced polytraumatic detriment on multi-organs, polypharmacy approaches have been investigated [ 29 ].…”

Interleukin-12 as a biomarker of the beneficial effects of food restriction in mice receiving high fat diet or high carbohydrate diet

“…However, the terms pro-inflammatory and anti-inflammatory cytokines in general oversimplify the highly complex physiopathological process. For example, increased IFN-γ and KC mediated the protective effects of FR in hippocampus ( 11 ) and neutrophils ( 12 ), respectively. Furthermore, the increased production of GM-CSF by NK cells of C57BL/6 mice submitted to FR is critical to prevent viral infections ( 13 ).…”