Molecular mechanisms of Wischnewski spot development on gastric mucosa in fatal hypothermia: an experimental study in rats

Wischnewski Spots in a Case of Hyperosmolar Hyperglycemic State

ABSTRACT

Wischnewski spots were first described as a common finding in gastric mucosa of decedents exposed to hypothermic environmental conditions. In recent literature, they were also reported in cases of diabetic ketoacidosis, pancreatitis, and fatal burns. Although Wischnewski spots are not specific to cases of hypothermia, we present a case that further supports this contention. We report a case of a middle-aged woman with type 2 diabetes who died of complications of hyperosmolar hyperglycemic state. Although there were no features of hypothermia, she presented with Wischnewski spots in the gastric mucosa. On histology, the gastric mucosa contained brown-black pigmentations with no neutrophilic infiltration. Biochemical analysis from vitreous humor and femoral blood showed marked elevation of glucose levels, low concentration of ketone bodies, pseudohyponatremia, and prerenal azotemia. The autopsy findings in this case discussion shed light to the possible genesis and pathophysiology of Wischnewski spots and highlight an additional differential diagnosis for these lesions.

Biological Mechanisms behind Wischnewsky Spots Finding on Gastric Mucosa: Autopsy Cases and Literature Review

Hypothermia is an emergency caused by the lowering of the central body temperature with a slowdown of basic vital functions. Reduced mobility, old age, psychiatric or metabolic disorders are relevant risk factors. Diagnosis of death from hypothermia is a challenge, as there are no pathognomonic signs, and supportive findings can be inconstant. Wischnewsky Spots (WS) are blackish lesions of gastric mucosa, typically associated with hypothermic death. The pathophysiology of these lesions is still uncertain. The aim of this paper is to investigate the pathological mechanisms determining the appearance of WS by analyzing the current scientific knowledge in this area. We performed a narrative review of the literature published in the last 20 years, comparing the results with three cases of hypothermia reported from our experience. The review proved that WS show a multifactorial etiology, i.e., not only body temperature decrease, but also various extrinsic and intrinsic factors, such as physical and psychological stress, agony, causa mortis and metabolic comorbidities. The review summarizes the current knowledge in the field of incidence, pathology and morphology of WS by proposing some scientific and technical points for clinical and forensic analysis of this phenomenon.

Helicobacter pylori in Human Stomach: The Inconsistencies in Clinical Outcomes and the Probable Causes

Pathogenic potentials of the gastric pathogen, Helicobacter pylori, have been proposed, evaluated, and confirmed by many laboratories for nearly 4 decades since its serendipitous discovery in 1983 by Barry James Marshall and John Robin Warren. Helicobacter pylori is the first bacterium to be categorized as a definite carcinogen by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO). Half of the world’s population carries H. pylori, which may be responsible for severe gastric diseases like peptic ulcer and gastric cancer. These two gastric diseases take more than a million lives every year. However, the role of H. pylori as sole pathogen in gastric diseases is heavily debated and remained controversial. It is still not convincingly understood, why most (80–90%) H. pylori infected individuals remain asymptomatic, while some (10–20%) develop such severe gastric diseases. Moreover, several reports indicated that colonization of H. pylori has positive and negative associations with several other gastrointestinal (GI) and non-GI diseases. In this review, we have discussed the state of the art knowledge on “H. pylori factors” and several “other factors,” which have been claimed to have links with severe gastric and duodenal diseases. We conclude that H. pylori infection alone does not satisfy the “necessary and sufficient” condition for developing aggressive clinical outcomes. Rather, the cumulative effect of a number of factors like the virulence proteins of H. pylori, local geography and climate, genetic background and immunity of the host, gastric and intestinal microbiota, and dietary habit and history of medicine usage together determine whether the H. pylori infected person will remain asymptomatic or will develop one of the severe gastric diseases.

Body temperature-dependent microRNA expression analysis in rats: rno-miR-374-5p regulates apoptosis in skeletal muscle cells via Mex3B under hypothermia

Forensic diagnosis of fatal hypothermia is considered difficult because there are no specific findings. Accordingly, exploration of novel fatal hypothermia-specific findings is important. To elucidate the molecular mechanism of homeostasis in hypothermia and identify novel molecular markers to inform the diagnosis of fatal hypothermia, we focused on microRNA expression in skeletal muscle, which plays a role in cold-induced thermogenesis in mammals. We generated rat models of mild, moderate, and severe hypothermia, and performed body temperature-dependent microRNA expression analysis of the iliopsoas muscle using microarray and quantitative real-time PCR (qRT-PCR). The results show that rno-miR-374-5p expression was significantly induced only by severe hypothermia. Luciferase reporter assay and qRT-PCR results indicated that Mex3B expression was regulated by rno-miR-374-5p and decreased with decreasing body temperature. Gene ontology analysis indicated the involvement of Mex3B in positive regulation of GTPase activity. siRNA analysis showed that Mex3B directly or indirectly regulated Kras expression in vitro, and significantly changed the expression of apoptosis-related genes and proteins. Collectively, these results indicate that rno-miR-374-5p was activated by a decrease in body temperature, whereby it contributed to cell survival by suppressing Mex3B and activating or inactivating Kras. Thus, rno-miR-374-5p is a potential supporting marker for the diagnosis of fatal hypothermia.