Effect of Smoking on Outcomes of Allogeneic Transplantation: A Single-Center Analysis

Cigarette smoke impairs the hematopoietic supportive property of mesenchymal stem cells via the production of reactive oxygen species and NLRP3 activation

BACKGROUND

Mesenchymal stem cells (MSCs) play important roles in tissue homeostasis by providing a supportive microenvironmental niche for the hematopoietic system. Cigarette smoking induces systemic abnormalities, including an impeded recovery process after hematopoietic stem cell transplantation. However, the role of cigarette smoking-mediated alterations in MSC niche function have not been investigated.

METHODS

In the present study, we investigated whether exposure to cigarette smoking extract (CSE) disrupts the hematopoietic niche function of MSCs, and pathways impacted. To investigate the effects on bone marrow (BM)-derived MSCs and support of hematopoietic stem and progenitor cells (HSPCs), mice were repeatedly infused with the CSE named 3R4F, and hematopoietic stem and progenitor cells (HSPCs) supporting function was determined. The impact of 3R4F on MSCs at cellular level were screened by bulk-RNA sequencing and subsequently validated through qRT-PCR. Specific inhibitors were treated to verify the ROS or NLRP3-specific effects, and the cells were then transplanted into the animal model or subjected to coculture with HSPCs.

RESULTS

Both direct ex vivo and systemic in vivo MSC exposure to 3R4F resulted in impaired engraftment in a humanized mouse model. Furthermore, transcriptomic profile analysis showed significantly upregulated signaling pathways related to reactive oxygen species (ROS), inflammation, and aging in 3R4F-treated MSCs. Notably, ingenuity pathway analysis revealed the activation of NLRP3 inflammasome signaling pathway in 3R4F-treated MSCs, and pretreatment with the NLRP3 inhibitor MCC950 rescued the HSPC-supporting ability of 3R4F-treated MSCs.

CONCLUSION

In conclusion, these findings indicate that exposure to CSE reduces HSPCs supportive function of MSCs by inducing robust ROS production and subsequent NLRP3 activation.

Clinical Impact of Pretransplantation Physical Function on Transplantation after Allogeneic Hematopoietic Cell Transplantation in Older Adults

Clinical research regarding the impact of pretransplantation physical function on transplantation outcomes in older adults remains limited. We retrospectively reviewed the charts of 150 consecutive patients age >55 years who underwent their first allogeneic hematopoietic cell transplantation (HCT) at our center between 2010 and 2021. We evaluated the clinical impact of pretransplantation physical function, including hand grip strength (HGS), knee extension strength (KES), and distance covered in a 6-minute walk test (6MWT), along with other clinical factors, on transplantation outcomes such as overall survival (OS), nonrelapse mortality (NRM), and cumulative incidence of disease relapse (CIR). There was no difference in OS, NRM, or CIR among the 3 age groups studied (56 to 60 years, 61 to 65 years, and 66 to 70 years). With regard to physical function tests, we divided the study patients into 2 groups based on the median HGS, KES, and 6MWT values: higher physical function and lower physical function groups. Because there were significant differences in HGS and KES between male and female patients, sex-specific threshold values were used. In a univariate analysis, OS tended to be better in the higher physical function group compared with the lower physical function group (4-year OS, 42.0% versus 32.0% in HGS, P = .14; 44.8% versus 37.8% in KES, P = .17; 46.7% versus 30.5% in 6MWT, P = .099). NRM was significantly lower in the higher physical function group (4-year NRM, 25.5% versus 39.9% in HGS, P = .045; 17.7% versus 38.0% in KES, P = .005; 22.5% versus 43.4% in 6MWT, P = .033). There was no significant difference in CIR between the higher and lower physical function groups (4-year CIR, 34.6% versus 28.7% in HGS, P = .38; 38.5% versus 25.8% in KES, P = .20; 33.0% versus 27.0% in 6MWT, P = .42). In multivariate analysis, the higher KES group (hazard ratio [HR], .54; 95% confidence interval [CI], .32 to .90) was significantly associated with better OS, as were female sex (HR, .48; 95% CI, .26 to .89) and low/intermediate Disease Risk Index (HR, 3.59; 95% CI, 2.04 to 6.31). Higher KES (HR, .37; 95% CI, .17 to .83) and female sex (HR .36; 95% CI, .13 to .998) were significantly associated with a reduced risk of NRM. Higher HGS and higher 6MWT tended to be associated with a reduced risk of NRM, but this trend was not statistically significant. Pretransplantation physical function, particularly the strength of the lower extremities, but not chronological age, is associated with NRM and OS after allogeneic HCT in adults age >55 years.

Association between the kinetics of cytomegalovirus reactivation in terms of the area under the curve of cytomegalovirus antigenemia and non-relapse mortality after allogeneic hematopoietic stem cell transplantation

BACKGROUND

We assessed the kinetics of cytomegalovirus (CMV) reactivation using the area under the curve (AUC), which simultaneously reflects both the viral load at each time point and the duration of CMV antigenemia (CMV-AG).

METHODS

We performed a single-institute retrospective analysis in patients who received allogeneic hematopoietic stem cell transplantation (HSCT) between 2007 and 2017 and survived more than 100 days after HSCT. The AUC of CMV-AG (CMV-AUC) was calculated by a trapezoidal method using the number of CMV-AG tested by the C10/C11 method after logarithmic transformation, and plotted weekly up to day 100.

RESULTS

CMV reactivation was observed in 195 cases and the median CMV-AUC for CMV-reactivated patients was 8.7 (range 0.5-30.7). Older age, corticosteroid administration, CMV-seropositive transplant recipients, HSCT from an unrelated donor, and underlying diseases were independent predictive factors for higher CMV-AUC. Higher CMV-AUC was associated with poor overall survival (OS) with borderline significance in a univariate analysis (p = .07), but was not significant in a multivariate analysis. Older age, high-risk disease status, and female gender were identified as significant factors associated with poor OS in this study. On the other hand, CMV-AUC (hazard ratio: no reactivation reference, low 0.98, high 2.49, p < .01), older age, HCT-CI ≥3, and corticosteroid administration were identified as significant factors associated with increased incidence of non-relapse mortality (NRM).

CONCLUSIONS

The kinetics of CMV reactivation in terms of CMV-AUC reflect both the severity and duration of CMV reactivation. High CMV-AUC was associated with an increased incidence of NRM in survivors over 100 days.