Probiotics: An adjuvant treatment strategy for chronic respiratory diseases.

Chronic respiratory disease is considered by reduced airflow and heightened airway inflammation, a pattern that has progressively increased in past few decades. Currently, chronic respiratory disease is considered one of the main leading causes of death worldwide. The gut-lung axis, which connects these two organs, facilitates bidirectional communication and may be influenced by microbiome populations in the context of disease interactions. The human microbiome, particularly in the gastrointestinal tract is thought to play a pivotal role in affecting diseases and maintaining homeostasis. Dysbiosis, defined as an imbalance in the gut microbiota, is associated with an elevated risk of lung infections. Studies have shown that modifying the gut microbiota by the use of probiotics, prebiotics, and synbiotics can reduce the duration and extent of respiratory infections. Probiotics have been observed to significantly alter serum cytokine and IgE levels in allergic conditions, as well as reduce eosinophilia in individuals with asthma. However, there has been no discernible improvement in clinical symptoms, although this approach may diminish eosinophilia in chronic obstructive pulmonary disease (COPD) patients and mitigate serum cytokine and IgE levels. Several factors such as illness severity, treatment duration, patient-specific, environmental characteristics, and treatment regimen seem to influence the effectiveness of these interventions. Research indicates that direct interaction and colonization of respiratory epithelial cells by probiotic microbes can enhance the success of intranasal probiotic delivery compared to oral administration. Although allergic rhinitis is a chronic inflammatory ailment, nasal probiotics have been utilized to address acute infections and respiratory disorders, offering a promising therapeutic avenue for a range of chronic inflammatory conditions.