Background: Respiratory failure caused by pneumonia is the leading cause of death in coronavirus disease 2019 (COVID-19) patients; furthermore, anxiety and depression caused by this disease and its complications, as the most common psychological disorders might harm the mental health of COVID-19 patients. Objectives: This study aimed to look into the effect of a home-based pulmonary rehabilitation (HBPR) program on anxiety and depression in COVID-19 patients (severe acute respiratory syndrome). Methods: This randomized clinical trial was conducted on 70 COVID-19 patients in Kerman, Iran, in 2021, randomly allocated into 2 equal groups of control (n = 35) and intervention (n = 35). In the control group, the patients received only routine post-discharge care, and in the intervention group, the patients received HBPR procedures based on the “Guide to Restoring Movement COVID-19 Protocol” by John Hopkins University, the United States, that teaches to patients after discharge. The Hospital Anxiety and Depression Scale was used to determine anxiety and depression status and scores before and after 4-week procedures. Additionally, the chi-square, Fisher’s exact, and Mann-Whitney U tests were used to compare anxiety and depression status and scores between the 2 groups. P < 0.05 was considered statistically significant. Results: The median score of anxiety (5 vs. 14, P < 0.0001) and depression (6 vs. 10, P < 0.0001), 4 weeks after discharge from the hospital in the intervention group, was significantly lower than in the control group based on the Mann-Whitney U test (P < 0.0001). Conclusions: This rehabilitation procedure is effective in the reduction of anxiety and depression in COVID-19 patients and their pulmonary status. Therefore, it can be used as a treatment procedure for mental recovery in these patients.

Background: Exosomes are nanosized extracellular vesicles that range from 30 to 150 nm and have a bilayer lipid membrane which encapsulates proteins, lipids, and nucleic acids, first identified in the 1960s and expanded in application from disease diagnostics to targeted therapeutics. They are intercellular communicators with roles in physiological regulation and pathological progression. Results: Exosomes applications in gene therapy, drug delivery, tissue regeneration, and disease diagnostics activate signaling pathways such as Wnt/β-catenin, PI3K/Akt, etc., deliver anti-aging molecules, and promote angiogenesis refers to their properties such as biocompatibility, cross the blood-brain barrier, serving as vectors and selective cargo delivery. Altogether, these effects promote tissue regeneration, as well as its therapeutic potential in dermatology, orthopedics, cardiology, neurology, and wound healing. However the same mechanisms that promote regeneration can also drive tumor progression, induce drug resistance, suppress immune responses, and mediate the pathogenic factors spread. It means that exosome's dual nature presents challenges. On the therapeutic side, exosomes can promote tumor growth, drug resistance, and immune suppression. In contrast, the transmission of viral or pathogenic proteins, tumor progression, and so on, underscores their “Trojan horse” potential. Conclusion: Exosomes embody a biological paradox as mentioned. It is essential for developing safe and effective exosome based therapies to understanding of this duality deeper for harnessing their therapeutic potential while mitigating associated risks.