Depressive symptoms in lung transplant recipients: trajectory and association with mortality and allograft dysfunction

The gut microbiome in end-stage lung disease and lung transplantation

Gut dysbiosis has been associated with impaired outcomes in liver and kidney transplant recipients, but the gut microbiome of lung transplant recipients has not been extensively explored. We assessed the gut microbiome in 64 fecal samples from end-stage lung disease patients before transplantation and 219 samples from lung transplant recipients after transplantation using metagenomic sequencing. To identify dysbiotic microbial signatures, we analyzed 243 fecal samples from age-, sex-, and BMI-matched healthy controls. By unsupervised clustering, we identified five groups of lung transplant recipients using different combinations of immunosuppressants and antibiotics and analyzed them in relation to the gut microbiome. Finally, we investigated the gut microbiome of lung transplant recipients in different chronic lung allograft dysfunction (CLAD) stages and longitudinal gut microbiome changes after transplantation. We found 108 species (58.1%) in end-stage lung disease patients and 139 species (74.7%) in lung transplant recipients that were differentially abundant compared with healthy controls, with several species exhibiting sharp longitudinal increases from before to after transplantation. Different combinations of immunosuppressants and antibiotics were associated with specific gut microbial signatures. We found that the gut microbiome of lung transplant recipients in CLAD stage 0 was more similar to healthy controls compared to those in CLAD stage 1. Finally, the gut microbial diversity of lung transplant recipients remained lower than the average gut microbial diversity of healthy controls up to more than 20 years post-transplantation. Gut dysbiosis, already present before lung transplantation was exacerbated following lung transplantation.IMPORTANCEThis study provides extensive insights into the gut microbiome of end-stage lung disease patients and lung transplant recipients, which warrants further investigation before the gut microbiome can be used for microbiome-targeted interventions that could improve the outcome of lung transplantation.

Depression in transplantation

PURPOSE OF REVIEW

To review and summarize the literature published between 1 January 2020 and 30 June 2022, on the prevalence, risk factors and impact of depression in transplant population.

RECENT FINDINGS

Depression is common in transplantation candidates and recipients, with a prevalence up to 85.8% in kidney recipients. Multiple studies have indicated after transplantation depression correlates with increased mortality and with higher healthcare utilization. Social risk factors for posttransplant depression include financial difficulties and unemployment, while less is understood about the biological substrate of depression in this population. There is evidence that dynamic psychotherapy is effective for depression in organ transplant recipients, while cognitive behavioral therapy or supportive therapy did not lead to improvement of depression in transplant recipients. For living organ donors, the rates of depression are similar to the general population, with financial factors and the clinical status of the recipient playing a significant role.

SUMMARY

Depression is a common finding in transplant population. More research is needed to understand the biological substrate and risk factors and to develop effective treatment interventions.