Probiotics: A potential immunomodulator in COVID-19 infection management

Novel Insights into the Role of Probiotics in Respiratory Infections, Allergies, Cancer, and Neurological Abnormalities

In recent years, probiotics have attracted public attention and transformed the social perception of microorganisms, convening a beneficial role/state on human health. With aging, the immune system, body physiology, and intestinal microbiota tend to change unfavorably, resulting in many chronic conditions. The immune-mediated disorders can be linked to intestinal dysbiosis, consequently leading to immune dysfunctions and a cluster of conditions such as asthma, autoimmune diseases, eczema, and various allergies. Probiotic bacteria such as Lactobacillus and Bifidobacterium species are considered probiotic species that have a great immunomodulatory and anti-allergic effect. Moreover, recent scientific and clinical data illustrate that probiotics can regulate the immune system, exert anti-viral and anti-tumoral activity, and shields the host against oxidative stress. Additionally, microbiota programming by probiotic bacteria can reduce and prevent the symptoms of respiratory infections and ameliorate the neurological status in humans. This review describes the most recent clinical findings, including safe probiotic therapies aiming to medicate respiratory infections, allergies, cancer, and neurological disorders due to their physiological interconnection. Subsequently, we will describe the major biological mechanism by which probiotic bacteriotherapy expresses its anti-viral, anti-allergic, anticancer, and neuro-stimulatory effects.

[How does COVID-19 affect intestinal microbiota?]

BACKGROUND

There is a bidirectional interaction between the intestines and lungs, the so-called lung-intestinal axis.

METHOD

The review article reports on studies that deal with a possible influence of the intestinal microbiota on the immune response to a SARS-CoV-2 infection.

RESULTS AND CONCLUSIONS

Studies have shown that COVID-19 is accompanied by dysbiosis that persists even after successful virus conversion (negative PCR). One study found that the severity of COVID-19 is associated with the intestinal microbiota. A dysbiosis could thus favor the so-called cytokine storm. There is indication that pre- and probiotics could boost the immune response in both the guts and lungs.

Neuropathy in COVID-19 associated with dysbiosis-related inflammation

Although COVID-19 affects mainly lungs with a hyperactive and imbalanced immune response, gastrointestinal and neurological symptoms such as diarrhea and neuropathic pains have been described as well in patients with COVID-19. Studies indicate that gut-lung axis maintains host homeostasis and disease development with the association of immune system, and gut microbiota is involved in the COVID-19 severity in patients with extrapulmonary conditions. Gut microbiota dysbiosis impairs the gut permeability resulting in translocation of gut microbes and their metabolites into the circulatory system and induce systemic inflammation which, in turn, can affect distal organs such as the brain. Moreover, gut microbiota maintains the availability of tryptophan for kynurenine pathway, which is important for both central nervous and gastrointestinal system in regulating inflammation. SARS-CoV-2 infection disturbs the gut microbiota and leads to immune dysfunction with generalized inflammation. It has been known that cytokines and microbial products crossing the blood-brain barrier induce the neuroinflammation, which contributes to the pathophysiology of neurodegenerative diseases including neuropathies. Therefore, we believe that both gut-lung and gut-brain axes are involved in COVID-19 severity and extrapulmonary complications. Furthermore, gut microbial dysbiosis could be the reason of the neurologic complications seen in severe COVID-19 patients with the association of dysbiosis-related neuroinflammation. This review will provide valuable insights into the role of gut microbiota dysbiosis and dysbiosis-related inflammation on the neuropathy in COVID-19 patients and the disease severity.

Could Probiotics and Postbiotics Function as "Silver Bullet" in the Post-COVID-19 Era?

We are currently experiencing the realities of the most severe pandemic within living memory, with major impacts on the health and economic well-being of our planet. The scientific community has demonstrated an unprecedented mobilization capability, with the rapid development of vaccines and drugs targeting the protection of human life and palliative measures for infected individuals. However, are we adequately prepared for ongoing defense against COVID-19 and its variants in the post-pandemic world? Moreover, are we equipped to provide a satisfactory quality of life for individuals who are recovering from COVID-19 disease? What are the possibilities for the acceleration of the recovery process? Here, we give special consideration to the potential and already-demonstrated role of probiotics and traditional medical approaches to the management of current and potential future encounters with our major virus adversaries.

[Diagnosis of chronic reflux esophagitis. Role of endoscopic and histological examination]

Fibroendoscopic and histobioptic study of the distal oesophageal mucosa has been carried out in a series of patients suffering from gastro-oesophageal regurgitation. The regurgitation condition was verified and its extent established by means of anamnestic, spot-fluorographic and manometric-pHmetric investigations. On the basis of the analysis of relations between the extent of the oesophagitis assessed on the basis of endoscopy and that arising out of microscopic examination of the biopsy, it is concluded that there is no complete correspondence between the two techniques insofar as endoscopy can give false positive or false negative results. On the basis of these results and of those of functional investigations, histology is considered desirable even when the oesophageal mucosa is normal, if there are clinical and/or laboratory signs of gastro-oesophageal regurgitation.