Abstract
ObjectiveAlthough many works have been done, the objectively measured diagnostic biomarkers are not available. Thus, we conducted this study to identify potential biomarkers for objectively diagnosing depression and explore the role of gut microbiota in the onset of depression.MethodsMajor depressive disorder (MDD) patients (n=56) and demographic data-matched healthy controls (HCs) (n=56) were included in this study. The gut microbiota in fecal samples and inflammation-related factors in serum were measured. Both univariate and multivariate statistical analyses were performed to identify the differential gut microbiota and inflammation-related factors.ResultsFinally, 46 differential operational taxonomic units (OTUs) (60.9% OTUs belonging to Firmicutes) and ten differential inflammation-related factors were identified. Correlation analysis showed that there were significant correlations between 14 differential OTUs (9 OTUs belonging to Firmicutes and 5 OTUs belonging to family Lachnospiraceae under Firmicutes) and seven differential inflammation-related factors. Meanwhile, 14 differential OTUs (9 OTUs belonging to Firmicutes and 5 OTUs belonging to family Lachnospiraceae under Firmicutes) and five differential inflammation-related factors (adiponectin, apolipoprotein A1, alpha 1-antitrypsin, neutrophilicgranulocyte count/white blood cell count and basophil count) were significantly correlated to depression severity. A panel consisting of these five differential inflammation-related factors could effectively diagnose MDD patients from HCs.ConclusionsOur results suggested that Firmicutes, especially family Lachnospiraceae, might play a role in the onset of depression via affecting the inflammation levels of host, and these five differential inflammation-related factors could be potential biomarkers for objectively diagnosing MDD.
Highlights
We found that some inflammation-related serum metabolites were significantly correlated with gut microbiota and could be the potential biomarkers for major depressive disorder (MDD) (Bai et al, 2021b)
The results of orthogonal partial least squares discriminant analysis (OPLS-DA) showed that the two groups were obviously separated, suggesting the significantly divergent gut microbiota compositions at operational taxonomic units (OTUs) level between MDD patients and healthy controls (HCs) (Figure 1B)
We found that APN was significantly correlated to five differential OTUs belonging to Firmicutes, and both apolipoprotein A1 (APOA1) and Basophil count (BASO) were significantly correlated to five OTUs (60% of them belonging to Firmicutes)
Summary
Depression is a common mental disorder characterized by depressed mood, loss of appetite, and high suicide rates (Hidaka, 2012; Wachowska and Gałecki, 2021). It causes harmful effects on individuals, and challenges the public health system with massive social and economic impacts (Rana et al, 2022). Depressive disorder has the most extensive heterogeneity of clinical diseases, which greatly increasing the difficulty of research on this type of disease. The identification and research of depression is the most complicated field of clinical scientific research, and a major problem that needs to be solved in global life science research. Further studies are urgently needed to identify potential biomarkers for diagnosing depression and explore novel molecular mechanisms of depression
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