Study of body thermal response and its correlation with the pattern of circulatory dynamics in sepsis survivors: experimental study in rats

• Grant number: 22/02423-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2022
• End date: July 31, 2023
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Ivan Hong Jun Koh
• Grantee: Tatiane Lissa Yamada
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil
• Associated research grant: 17/21052-0 - Sepsis: mechanisms, therapeutic targets and epidemiology, AP.TEM

Abstract

The gradual improvement in sepsis survivors has been attributed to the rapid diagnosis combined with antibiotic therapy, volume replacement, and improvement in general care. However, the high post-recovery mortality from sepsis, especially in the first year, has been one of the main research focus today. The target of this study is to determine whether the dysfunction of body thermal regulation and of hemodynamics, observed in the acute phase of sepsis (IC 2021 scolarship), persists or recovers in sepsis survivors. Female Wistar-EPM rats, 3 months old, weighing 250 to 300g, will be induced to severe sepsis by inoculation of 2 mL of E.coli 109 CFU / mL (DL70-80), and the body temperature of the survivors will be evaluated sequentially: 1, 2, 3, 4, 5 and 6 months. (n=5/period). The animals in the control group (CG) will receive an injection of 2 mL of saline and will be monitored (temperature) during the same periods (n=5/period). Body temperature will be captured by the FLIR T540 thermographic camera and the images will be analyzed by the FLIR ResarchIR Max4 computer analysis program. As for circulatory parameters, macrohemodynamics (MAP, CO, HR) and regional (renal artery, superior mesenteric artery and celiac trunk, renal vein, portal, and inferior vein cava) will be measured by means of pressure transducers and perivascular probes (Transonic System Inc. TS420 ) in periods of 3 and 6 months (n=5/period). In addition, tissue perfusion and microcirculation of kidney, liver, and ileum organs will be evaluated by Laser Doppler Flowmeter BLF 21 and by Sidestream Dark Field Imaging videomicroscopy, respectively, at 3 and 6 months (n=5/period). At the end of the monitoring, the animals will be sacrificed under general anesthesia. Thermographic and microcirculatory dysfunction were concomitant events in the acute phase of sepsis and our hypothesis is that these dysfunctions may persist chronically and contribute, at least partially, as additional factors related to high post-sepsis mortality. (AU)