Acute respiratory distress syndrome (ARDS) is a critical illness complication that is associated with high mortality. ARDS is documented in severe cases of COVID-19. No effective pharmacological treatments for ARDS are currently available. Dysfunctional immune responses and pulmonary and systemic inflammation are characteristic features of ARDS pathogenesis. Recent advances in our understanding of the regulation of inflammation point to an important role of the vagus-nerve-mediated inflammatory reflex and neural cholinergic signaling. We examined whether pharmacological cholinergic activation using a clinically approved (for myasthenia gravis) cholinergic drug, the acetylcholinesterase inhibitor pyridostigmine alters pulmonary and systemic inflammation in mice with lipopolysaccharide (LPS)-induced ARDS. Male C57Bl/6 mice received one intratracheal instillation of LPS or were sham manipulated (control). Both groups were treated with either vehicle or pyridostigmine (1.5 mg/kg twice daily, 3 mg/day) administered by oral gavage starting at 1 h post-LPS and euthanized 24 h after LPS administration. Other groups were either sham manipulated or received LPS for 3 days and were treated with vehicle or pyridostigmine and euthanized at 72 h. Pyridostigmine treatment reduced the increased total number of cells and neutrophils in the bronchoalveolar lavage fluid (BALF) in mice with ARDS at 24 and 72 h. Pyridostigmine also reduced the number of macrophages and lymphocytes at 72 h. In addition, pyridostigmine suppressed the levels of TNF, IL-1β, IL-6, and IFN-γ in BALF and plasma at 24 and 72 h. However, this cholinergic agent did not significantly altered BALF and plasma levels of the anti-inflammatory cytokine IL-10. Neither LPS nor pyridostigmine affected BALF IFN-γ and IL-10 levels at 24 h post-LPS. In conclusion, treatments with the cholinergic agent pyridostigmine ameliorate pulmonary and systemic inflammatory responses in mice with endotoxin-induced ARDS. Considering that pyridostigmine is a clinically approved drug, these findings are of substantial interest for implementing pyridostigmine in therapeutic strategies for ARDS.

Background: In this investigation, we explored the effects of pharmacological cholinergic stimulation on cardiac function and renal inflammation following acute myocardial infarction (AMI) in spontaneously hypertensive rats (SHRs). Methods: Adult male SHRs were randomized into three experimental groups: sham-operated; AMI + Veh (infarcted, treated with vehicle); and AMI + PY (infarcted, treated with the cholinesterase inhibitor, pyridostigmine bromide (PY)—40 mg/kg, once daily for seven days). Rats were euthanized 7 or 30 days post-surgery. The clinical parameters were assessed on the day before euthanasia. Subsequent to euthanasia, blood samples were collected and renal tissues were harvested for histological and gene expression analyses aimed to evaluate inflammation and injury. Results: Seven days post-surgery, the AMI + PY group demonstrated improvements in left ventricular diastolic function and autonomic regulation, and a reduction in renal macrophage infiltration compared to the AMI + Veh group. Furthermore, there was a notable downregulation in pro-inflammatory gene expression and an upregulation in anti-inflammatory gene expression. Analysis 30 days post-surgery showed that PY treatment had a sustained positive effect on renal gene expression, correlated with a decrease in biomarkers, indicative of subclinical kidney injury. Conclusions: Short-term cholinergic stimulation with PY provides both cardiac and renal protection by mitigating the inflammatory response after AMI.

Background: In this investigation, we explored the effects of pharmacological cholinergic stimulation on cardiac function and renal inflammation following acute myocardial infarction (AMI) in spontaneously hypertensive rats (SHRs). Methods: Adult male SHRs were randomized into three experimental groups: sham-operated; AMI+Veh (infarcted, treated with vehicle); and AMI+PY (infarcted, treated with the cholinesterase inhibitor pyridostigmine bromide (PY) - 40 mg/kg, once daily for seven days). Rats were euthanized 7 or 30 days post-surgery. Clinical parameters were assessed on the day before euthanasia. Subsequent to euthanasia, blood samples were collected and renal tissues were harvested for histological and gene expression analyses aimed to evaluate inflammation and injury. Results: Seven days post-surgery, the AMI+PY group demonstrated improvements in left ventricular diastolic function and autonomic regulation, and a reduction in renal macrophage infiltration compared to the AMI+Veh group. Furthermore, there was a notable downregulation of pro-inflammatory gene expression and an upregulation of anti-inflammatory gene expression. Analysis 30 days post-surgery showed that PY treatment had a sustained positive effect on renal gene expression, correlated with a decrease in biomarkers indicative of subclinical kidney injury. Conclusion: Short-term cholinergic stimulation with PY provides both cardiac and renal protection by mitigating the inflammatory response after AMI.

Extra-olfactory receptors (ORs) are expressed in multiple tissues and implicated in cardiovascular regulation and placental biology. Thyroid hormones influence olfactory function, but their role in tissue-specific OR expression during pregnancy remains unclear. Methods: Pregnant Wistar rats were assigned to control, gestational hypothyroid, and levothyroxine (LT4)-treated hypothyroid groups. Hypothyroidism was induced by administering methimazole and an iodine-deficient diet; LT4 was administered at 5.0 μg/100 g body weight. Or5t5, Or10j5, Agtr1a, Oprm1, and Pgf mRNA expressions were quantified by RT-qPCR in blood, kidney, heart, and placenta on gestational day 14. Results: No OR expression was detected in the heart, and Pgf was undetectable in the LT4-treated group. Hypothyroidism reduced renal Or10j5 expression. Placental LT4 treatment increased Or5t5 and Agtr1a and reduced Oprm1 expression compared with hypothyroid animals. Correlation analyses showed that circulating ORs correlate with each other (except in controls) and with circulating Agtr1a in all samples and subgroups. The circulating ORs correlate with placental Or10j5 in the hypothyroidism group and with kidney Or10j5 in LT4-treated animals. Conclusions: Gestational thyroid dysfunction modified OR expression in the kidney and placenta. LT4 alters placental transcriptional profiles, suggesting hormone sensitivity of extra-olfactory receptor transcripts. The small sample size and ANN-imputed TSH warrant cautious interpretation.