Burn Injury-Associated MHCII+ Immune Cell Accumulation Around Lymphatic Vessels of the Mesentery and Increased Lymphatic Endothelial Permeability Are Blocked by Doxycycline Treatment

Burn-induced heterotopic ossification from incidence to therapy: key signaling pathways underlying ectopic bone formation

Burn injury is one of the potential causes of heterotopic ossification (HO), which is a rare but debilitating condition. The incidence ranges from 3.5 to 5.6 depending on body area. Burns that cover a larger percentage of the total body surface area (TBSA), require skin graft surgeries, or necessitate pulmonary intensive care are well-researched risk factors for HO. Since burns initiate such complex pathophysiological processes with a variety of molecular signal changes, it is essential to focus on HO in the specific context of burn injury to define best practices for its treatment. There are numerous key players in the pathways of burn-induced HO, including neutrophils, monocytes, transforming growth factor-β1-expressing macrophages and the adaptive immune system. The increased inflammation associated with burn injuries is also associated with pathway activation. Neurological and calcium-related contributions are also known. Endothelial-to-mesenchymal transition (EMT) and vascularization are known to play key roles in burn-induced HO, with hypoxia-inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) as potential initiators. Currently, non-steroidal anti-inflammatory drugs (NSAIDs) and radiotherapy are effective prophylaxes for HO. Limited joint motion, ankylosis and intolerable pain caused by burn-induced HO can be effectively tackled via surgery. Effective biomarkers for monitoring burn-induced HO occurrence and bio-prophylactic and bio-therapeutic strategies should be actively developed in the future.

Effect of chemically modified tetracycline-8 (CMT-8) on hematology, blood chemistry, cytokines and peripheral blood lymphocyte subsets of healthy dogs

Tetracyclines are antibiotics widely used in human and veterinary medicine. Effects on the immune system and inflammatory response, including effects on blood leukocytes proliferation and function and in cytokines synthesis, have been described. Chemically modified tetracyclines (CMT) have lost their antimicrobial activity, but maintain these other properties. This study analyzes the effect of chemically modified tetracycline-8 (CMT-8) on the evolution of complete blood count, blood chemistry, the mRNA expression of selected cytokines and peripheral blood lymphocyte subpopulations distribution in healthy dogs. CMT-8 at a dose of 10 mg/kg once daily was administered per os to six healthy dogs. A control group of five healthy dogs, living in the same conditions than dogs treated with CMT-8, received placebo with an identical therapeutic regimen. When given at the doses used in this study, no side effects of CMT-8 were detected, suggesting a good tolerance and a limited toxicity of the drug. Dogs treated with CMT-8 showed a gradual increase in mean corpuscular hemoglobin. The administration of CMT-8 in healthy dogs did not affect blood mRNA expression of IFN-γ, TNFα, IL-4, IL-6, IL-10, IL-12 p40 and IL-13. However, the lymphocytes expressing class II MHC on their surface decreased during the first two weeks of CMT-8 treatment and subsequently increased for the next three months. Considering the absence of antimicrobial properties of the drug, the effects of CMT-8 detected in this study seem to be unrelated to the classical antimicrobial activity attributed to tetracyclines.