Repurposing prolactin as a promising immunomodulator for the treatment of COVID-19: Are common Antiemetics the wonder drug to fight coronavirus?

Abstract

Prolactin (PRL), the well-known lactogenic hormone, plays a crucial role in immune function given the fact that long term hypoprolactinemia (serum prolactin level below normal) can even lead to death from opportunistic infection. High blood PRL level is known to provide an immunological advantage in many pathological conditions (with some exceptions like autoimmune diseases) and women, because of their higher blood PRL level, get an advantage in this regard. It has been reported that by controlled enhancement of blood PRL level (within the physiological limit and in some cases a little elevated above the normal to induce mild hyperprolactinemia) using dopamine antagonists such immune-stimulatory advantage can led to survival of the patients in many critical conditions. Here it is hypothesized that through controlled augmentation of blood PRL level using dopamine antagonists like domperidone/metoclopramide, which are commonly used drugs for the treatment of nausea and vomiting, both innate and adaptive immunity can be boosted to evade or tone down COVID-19. The hypothesis is strengthened from the fact that at least seven little-understood salient observations in coronavirus patients can apparently be explained by considering the role of enhanced PRL in line with the proposed hypothesis and hence, clinical trials (both therapeutic and prophylactic) on the role of enhanced PRL on the course and outcome of coronavirus patients should be conducted accordingly.

The crucial role of prolactin-lactogenic hormone in Covid-19

“…Hence, Sen proposed that dopamine antagonists could improve and boost the immune function in Covid-19 through augmentation release of immune-stimulant PRL [62]. Also, high PRL serum level in pregnant women, children, and cigarette smokers could be a protective factor against Covid-19 [62].…”

“…Hence, Sen proposed that dopamine antagonists could improve and boost the immune function in Covid-19 through augmentation release of immune-stimulant PRL [62]. Also, high PRL serum level in pregnant women, children, and cigarette smokers could be a protective factor against Covid-19 [62]. Interestingly, there is a significant controversy regarding PRL serum level in pregnant women, children, and cigarette smokers that might be normal, reduced, or elevated in these conditions [63].…”

Attenuation of COVID-19-induced cytokine storm in a young male patient with severe respiratory and neurological symptoms

“…The dopamine agonist metoclopramide, which was administered prior to hospital admission, is able to intensify extrapyramidal symptoms in patients with Parkinson’s disease. While no adverse events in COVID-19 patients have been published to date, metoclopramide was recently even identified as a protective factor [ 10 ].…”

Features of the Course of Covid-19 in Women With Hyperprolactinemia

“…Research in recent years has established that PRL, except for the pituitary gland, is secreted in almost all tissues of the body [7]. PRL receptors have also been identified in all tissues, which indicates that PRL, in addition to hormonal, also exhibits paracrine or autocrine effects and performs the role of a cytokine [4].…”