Gastroprotective action of glucocorticoid hormones during NSAID treatment

COVID-19 and corticosteroids: a narrative review

It has been reported that corticosteroid therapy was effective in the management of severe acute respiratory syndrome (SARS) and the Middle East Respiratory Syndrome (MERS), and recently in coronavirus disease 2019 (COVID-19). Corticosteroids are potent anti-inflammatory drugs that mitigate the risk of acute respiratory distress syndrome (ARDS) in COVID-19 and other viral pneumonia, despite a reduction of viral clearance; corticosteroids inhibit the development of cytokine storm and multi-organ damage. The risk-benefit ratio should be assessed for critical COVID-19 patients. In conclusion, corticosteroid therapy is an effective way in the management of COVID-19, it reduces the risk of complications primarily acute lung injury and the development of ARDS. Besides, corticosteroid therapy mainly dexamethasone and methylprednisolone are effective in reducing the severity of COVID-19 and associated comorbidities such as chronic obstructive pulmonary diseases (COPD), rheumatoid arthritis, and inflammatory bowel disease (IBD).

Protective effects of perindopril against indomethacin-induced gastric mucosal damage through modulation of DDAH-1/ADMA and ACE-2/ANG-(1-7) signaling pathways

Indomethacin is a widely used nonsteroidal anti-inflammatory drug; however, its clinical utility is accompanied by serious adverse reactions including peptic ulcers. The current study aims to investigate the protective potential of perindopril against indomethacin-induced gastric injury in rats. Perindopril (4 mg/kg) was administered orally for 7 days and indomethacin (60 mg/kg, single oral dose) was administered on the 7^th day, 1 h after perindopril administration. Pantoprazole was used as a standard agent. Ulcer index (UI), preventive index ratio (PI), histopathological examination, oxidative stress, and inflammatory biomarkers were investigated. Perindopril significantly decreased UI while increased PI and counteracted histopathological aberrations induced by indomethacin. It alleviated indomethacin-induced oxidative stress by lowering NO while increasing GSH content and superoxide dismutase activity. Perindopril significantly downregulated TNF-α and asymmetric dimethylarginine (ADMA), while significantly upregulated COX-2, PGE-2, dimethylarginine dimethylaminohydrolase-1 (DDAH-1), ANG-(1-7), and ACE-2 expression. Together, these findings suggest the gastroprotective effects of perindopril through modulation of DDAH-1/ADMA and ACE-2/ANG-(1-7) signaling.HIGHLIGHTSPerindopril attenuated gastric histopathological damage.It increased GSH content and SOD activity while decreased NO content.It modulated gastric ADMA and DDAH-1 activity.It reduced TNF-α, while increased COX-2 and PGE-2 expression.It upregulated ACE-2 activity and ANG-(1-7) protein expression.

Gut-Brain Axis in Gastric Mucosal Damage and Protection

BACKGROUND

The gut-brain axis plays a potential role in numerous physiological and pathological conditions. Several substances link stomach with central nervous system. In particular, hypothalamo-pituitary-adrenocortical axis, thyrotropinreleasing factor-containing nerve fibers and capsaicin-sensitive nerves are principal mediators of the harmful and protective central nervous system-mediated effects on gastric mucosa. Also, existing evidence indicates that nitric oxide, prostaglandins and calcitonin gene-related peptide play a role as final effectors of gastric protection.

METHODS

We undertook a structured search of bibliographic databases for peerreviewed research literature with the aim of focusing on the role of gut-brain axis in gastric damage and protection. In particular, we examined manuscripts dealing with the role of steroids, thyrotropin-releasing hormone, prostaglandins, melatonin, hydrogen sulfide and peptides influencing food intake (i.e. leptin, cholecystokinin, peptide YY, central glucagon-like peptide-1, and ghrelin). Also, the role of GABAergic and glutamatergic pathways in gastric mucosal protection have been examined.

RESULTS

We found and reviewed 61 peer-reviewed papers dealing with the major aspects related to the role of gut brain axis in gastric mucosal damage and protection.

CONCLUSIONS

A dense neuronal network links stomach with central nervous system and a number of neurotransmitters and peptides functionally and anatomically related to central nervous system play a major role in contributing to gastric mucosal integrity. Exploiting the mechanisms underlying the connection between brain and gut may lead to a better understanding of the pathophysiology of gastric mucosal injury and to an improvement in the prevention and, eventually, management of gastric damage.

Glucocorticoids are Gastroprotective under Physiologic Conditions

Stress may contribute to the development and progression of gastrointestinal disorders. Activation of the hypothalamic-pituitary-adrenocortical (HPA) axis is one of the main characteristics of stress. For several decades it was generally accepted that glucocorticoids released during stress are ulcerogenic hormones. We designed some experimental studies in rats to clarify the validity of this widely held view. To achieve this goal, we examined the effect of glucocorticoid deficiency followed by corticosterone replacement or the glucocorticoid receptor antagonist, RU-38486, on stress-induced gastric erosion and the parameters of gastric function in rats. The data obtained shows that the reduction in the stress-induced corticosterone release, or its actions, aggravates stress-caused gastric erosion. It is suggested that an acute increase in corticosterone during stress protects the stomach against stress-induced injury. According to our results, various ulcerogenic stimuli, similar to stress, induce an increase in corticosterone that helps the gastric mucosa to resist against a harmful action of ulcerogenic stimuli. Glucocorticoids exhibit their gastroprotective effect by both maintaining local defensive factors and inhibiting pathogenic elements. Furthermore, the contribution of glucocorticoids to gastroprotection is tightly related to their contribution to general body homeostasis. Glucocorticoids provide gastroprotective actions in co-operation with prosta-glandins, nitric oxide and capsaicin-sensitive sensory neurons. The results obtained do not support the traditional paradigm and suggest that glucocorticoids released during acute activation of the HPA axis are naturally occurring gastroprotective factors. In this article, we review our recent publications on the role of glucocorticoids in gastroprotection.

High sensitivity of gastric mucosa to ulcerogenic effect of indomethacin in rats with diabetes

One week after injection of streptozotocin (60 mg/kg intravenously), rats developed diabetes associated with a significant increase of gastric mucosa sensitivity to the ulcerogenic effect of indomethacin (35 mg/kg subcutaneously). Since potentiation of the ulcerogenic effect of indomethacin was observed only in rats subjected to fasting before drug injection, we hypothesize that this effect was caused by a drop of high glucose level in the blood after fasting.

Suppression of hypothalamo-hypophyseal-adrenocortical system function as the cause of aggravation of the ulcerogenic action of indomethacin on the stomach after administration of pharmacological doses of hydrocortisone

We report testing of the suggestion that aggravation of the actions of glucocorticoid treatment on the formation of indomethacin-induced erosions may be mediated by inadequate production of glucocorticoid hormones resulting from the suppression of the hypothalamo-hypophyseal-adrenocortical system (HHACS) in these conditions. Administration of indomethacin (25 mg/kg, s.c.) to rats after 24 h of starvation was used to induce gastric erosions. The effects of hydrocortisone given at pharmacological doses on the indomethacin-induced formation of gastric erosions and plasma corticosterone levels were studied one and four weeks after hormone administration. Indomethacin induced increases in plasma corticosterone levels, which were almost completely prevented one week after hydrocortisone administration. The formation of indomethacin-induced erosions was aggravated one week after administration of hydrocortisone, though replacement therapy with corticosterone, which imitates the normal increase in corticosterone, prevented this aggravation. Return of both the increased corticosterone level and the normal sensitivity of the gastric mucosa to the ulcerogenic action of indomethacin occurred four weeks after hydrocortisone administration. These results provide evidence that suppression of HHACS function may be responsible for the aggravation of the action of glucocorticoid treatment on the formation of erosions after administration of indomethacin.

Gastroprotective role of glucocorticoid hormones

Gastric ulcer disease remains widespread; a stressful lifestyle and nonsteroidal antiinflammatory drugs (NSAIDs) make significant contributions to this pathological situation. The findings overviewed here support the idea that glucocorticoid hormones released in response to acute stress or NSAIDs act as gastroprotective substances and exert many of the same actions in the stomach as prostaglandins (PGs) and nitric oxide (NO) as well as capsaicin-sensitive afferent neurons. Glucocorticoids exert a gastroprotective effect by both maintaining local defensive factors (mucosal blood flow and mucus production) and inhibiting pathogenic elements (gastric motility and microvascular permeability). Furthermore, they exert gastroprotective actions in co-operation with PGs, NO, and the afferent neurons; and their compensatory action is observed when the protective mechanism provided by either of these factors is impaired. The gastroprotective action of glucocorticoids is also associated with maintenance of general body homeostasis, including blood glucose levels and systemic blood pressure. In conclusion, glucocorticoids released in response to acute stress or NSAIDs are naturally occurring protective factors that play an important role in maintenance of the gastric mucosal integrity. This led us to re-evaluate the traditional paradigm that glucocorticoid hormones produced during activation of the hypothalamic-pituitary-adrenocortical axis are ulcerogenic in the stomach.

Activation of the hypothalamo-hypophyseal-adrenocortical system as an important gastroprotective component of the stress reaction

This article presents an analysis of data providing evidence of the important contribution of the hypothalamo-hypophyseal-adrenocortical system (HHACS) to the processes maintaining the integrity of the gastric mucosa. According to these data, glucocorticoid hormones produced during stress-induced activation of the HHACS are gastroprotective hormones rather than ulcerogenic factors, as is widely believed. The gastroprotective influence of glucocorticoids has been demonstrated on exposure to ulcerogenic stimuli of different modalities. The gastroprotective action of glucocorticoid hormones is mediated via type II glucocorticoid receptors and may be associated with the maintenance of the blood glucose level, their calming effects on pathogenetic factors, and their favorable effects on protective factors for the gastric mucosa. Glucocorticoid hormones can compensate for the absence of the gastroprotective action of prostaglandins, nitric oxide, and capsaicin-sensitive neurons. The data lead to the conclusion that activation of the HHACS is an important gastroprotective component of the stress reaction.