Effect of melatonin on electrical impedance and biomarkers of damage in a gastric ischemia/reperfusion model

Abstract

The damage to the gastrointestinal mucosa induced by ischemia/reperfusion (I/R) is closely related to high mortality in critically ill patients, which is attributable, in part, to the lack of an early method of diagnosis to show the degree of ischemia-induced injury in this type of patients. Electrical Impedance Spectroscopy (EIS) has been shown to be a tool to early diagnose gastric mucosal damage induced by ischemia. A therapeutic alternative to reduce this type of injury is melatonin (MT), which has gastroprotective effects in I/R models. In this work, the effect of treatment with MT on the electrical properties of gastric tissue, biomarkers of inflammatory (iNOS and COX-2), proliferation, and apoptotic process under I/R conditions in male Wistar rats was evaluated through EIS, histological and immunohistochemical analysis. Treatment with MT prevents gastric mucosa damage, causing a decrease in gastric impedance parameters related to the inflammatory process and cellular damage. This suggests that EIS could be used as a tool to diagnose and monitor the evolution of gastric mucosal injury, as well as in the recovery process in critically ill patients.

Comparison of gastric reactance with commonly used perfusion markers in a swine hypovolemic shock model

“…Maximum lactate measurements (Lac_Max) were chosen, as it is generally accepted that soaring lactatemia is a marker of shock. Similarly, soaring XL measurements have been documented to indicate hypoxia and metabolic stress [ 5 – 12 ]; however, minimum values (XL_Min) were chosen for building the curves to consider the worst-case scenario for the XL marker. In other words values were chosen to favor the predictive performance of lactate while undermining the performance of XL.…”

“…Throughout the past three decades, technological innovations have targeted "canary organs", which can be easily and safely accessed and whose perfusion is believed to deteriorate before other organ beds, therefore, providing an early warning of systemic hypoperfusion. Pioneering technologies include gastric tonometry [ 2 ], sublingual capnometry [ 3 ], and microcirculation imaging [ 4 ], whereas recent developments include gastric impedance spectroscopy (GIS) [ 5 – 12 ], urethral photoplethysmography [ 13 ], and bladder tissue oxygen monitoring [ 14 ]. However, gastric tonometry fell out of favor, [ 15 ] and sublingual capnometry devices are no longer commercially available [ 16 ], while microcirculation imaging has acquired increasing relevance in intensive care [ 4 ].…”

Efecto del modelo de isquemia-reperfusión en mucosa gástrica sobre la organización tisular de los túbulos seminíferos en ratas macho de la cepa Wistar

“…Como sugieren nuestros resultados y otros estudios mencionados en este apartado, los niveles de TNF-α nivel local, sistémico y en órganos periféricos, son totalmente dependientes del tiempo de reperfusión y están relacionados al SIRS, con una tendencia a presentar sus mayores picos a las pocas horas de reperfusión (1-3 h), y comenzando a disminuir a partir de las 6, hasta alcanzar niveles basales a las 24 h (Figura 16). Esto indica que conforme el tiempo de reperfusión sea más largo, los ejemplares comienzan a recuperarse del daño inicial; sin embargo, pareciera que dependiendo la gravedad del daño los niveles de TNF-α regresan a su estado basal, pues en estudios anteriores de nuestro grupo de trabajo se encontró que el daño que se presenta en la mucosa gástrica a los 60 min de isquemia, por 24 h es reversible, en comparación con el daño que se presenta a los 90 y 120 min de isquemia por 24 h de reperfusión (Peña-Mercado et al, 2022). Los resultados de este estudio, sugieren que el daño que se presenta en la mucosa, a nivel sistémico y en órganos reproductivos a los 60 min de isquemia es reversible, pues los parámetros morfométricos del testículo y los niveles de TNF-α en suero y testículo, se observan iguales a las condiciones control, en comparación con los que se observan a los 120 min de isquemia (Figs 10,12 B y 14), esto podría indicar que el daño no se está presentando o, en caso de que se presente, que este es menor y por lo tanto tarda menos tiempo en ser reparado.…”