Risk Factors for Hematopoietic Stem Cell Transplantation-Associated Bone Loss

Bone remodeling in survivors of pediatric hematopoietic stem cell transplantation: Impact of heavy resistance training

BACKGROUND

Early-onset osteoporosis is a frequent late effect after pediatric hematopoietic stem cell transplantation (HSCT). It remains unknown if physical training can improve bone formation in these patients, as the transplantation procedure may cause sustained dysregulation of the bone-forming osteoblast progenitor cells.

OBJECTIVE

We aimed to explore the effect of resistance training on bone remodeling in long-term survivors of pediatric HSCT.

PROCEDURE

In this prospective, controlled intervention study, we included seven HSCT survivors and 15 age- and sex-matched healthy controls. The participants completed a 12-week heavy load, lower extremity resistance training intervention with three weekly sessions. We measured fasting serum levels of the bone formation marker "N-terminal propeptide of type I procollagen" (P1NP), and the bone resorption marker "C-terminal telopeptide of type I collagen" (CTX). The hypothesis was planned before data collection began. The trial was registered at Clinicaltrials.gov before including the first participant, with trial registration no. NCT04922970.

RESULTS

Resistance training led to significantly increased levels of fasting P1NP in both patients (from 57.62 to 114.99 ng/mL, p = .03) and controls (from 66.02 to 104.62 ng/mL, p < .001). No significant changes in fasting CTX levels were observed.

CONCLUSIONS

Despite previous high-dose cytotoxic therapy, long-term survivors of pediatric HSCT respond to resistance training with improvement of bone formation, comparable to that of healthy controls. This suggests that resistance training might be a promising non-pharmacological approach to prevent the early decline in bone mass, and should be considered as part of a follow-up program to counteract long-term sequela after pediatric HSCT.

Increased risk of hip and major osteoporotic fractures in 8463 patients who have undergone stem cell transplantation, a Swedish population-based study

In this retrospective cohort study of adult stem cell transplanted patients (n = 8463), a significant increased risk of both MOF and hip fractures was seen compared with the Swedish population and occurred in mean more than 2 years after stem cell transplantation.

PURPOSE

To explore the risk for osteoporotic fracture in patients who have undergone hematopoietic stem cell transplantation (HSCT) compared with the Swedish population.

METHODS

The risk of osteoporotic fractures was determined in a retrospective population cohort study of adult (≥ 18 years) Swedish patients (n = 8463), who were transplanted with HSCT 1997-2016 and compared with all adults living in Sweden during the same period.

RESULTS

In the total study group (n = 8463), 90 hip fractures (1.1% both in males and females) and 361 major osteoporotic fractures (MOF) (3.2% in men and 6.0% in women) were identified. In the total study population, the ratio of observed and expected number of hip fracture for women was 1.99 (95% CI 1.39-2.75) and for men 2.54 (95% CI 1.91-3.31). The corresponding ratio for MOF in women was 1.36 (CI 1.18-1.56) and for men 1.61 (CI 1.37-1.88). From 2005 onwards, when differentiation in the registry between allo- and auto-HSCT was possible, the observed number of hip fracture and MOF in allo-HSCT (n = 1865) were significantly increased (observed/expected hip fracture 5.24 (95% CI 3.28-7.93) and observed/expected MOF 2.08 (95% CI 1.63-2.62)). Fractures occurred in mean 2.7 (hip) and 2.5 (MOF) years after allo-HSCT. Graft-versus-host disease (GVHD) was not associated with an increased risk of fracture.

CONCLUSION

Patients who underwent HSCT had an increased risk of both hip and major osteoporotic fracture compared with the Swedish population and occurred in 4.3% of patients. GVHD was not statistically significantly associated with fracture risk.

Prevalence of osteoporosis among patients after stem cell transplantation: a systematic review and meta-analysis

The prevalence of osteoporosis in post stem cell transplantation (SCT) is poorly defined. We performed a systematic review and meta-analysis to determine the prevalence of osteoporosis in patients with hematologic diseases who underwent SCT. PubMed, EMBASE, and Web of Science were searched (from inception to 30th April 2023) using Medical Subject Headlines to find studies that assessed the prevalence of osteoporosis among post SCT. Thirteen articles meeting the inclusion criteria were included in the analysis. The pooled prevalence rates of osteoporosis, osteopenia, and decreased bone mineral density (BMD) were determined to be 14.2% (95% CI 9.7-18.8), 36.0% (95% CI 23.8-48.2), and 47.8% (95% CI 36.6-58.9), respectively. Substantial heterogeneity was observed among the included studies (I² values ranged from 81% to 99%). Subgroup analyses revealed variations in prevalence based on gender, follow-up duration, age, region, sample size, and study quality. These findings suggest a high prevalence of osteoporosis in post-SCT patients. Given the negative impact of osteoporosis on prognosis and recipient survival, clinicians should prioritize preventive measures, early diagnosis, and effective treatments to minimize its impact.

Endocrine sequelae of hematopoietic stem cell transplantation: Effects on mineral homeostasis and bone metabolism

Hematopoietic stem cell transplantation (HSCT) is an established therapeutic strategy for the treatment of malignant (leukemia and lymphoma) and non-malignant (thalassemia, anemia, and immunodeficiency) hematopoietic diseases. Thanks to the improvement in patient care and the development of more tolerable conditioning treatments, which has extended the applicability of therapy to the elderly, a growing number of patients have successfully benefited from HSCT therapy and, more importantly, HSCT transplant-related mortality has consistently reduced in recent years. However, concomitantly to long term patient survival, a growing incidence of late HSCT-related sequelae has been reported, being variably associated with negative effects on quality of life of patients and having a non-negligible impact on healthcare systems. The most predominantly observed HSCT-caused complications are chronic alterations of the endocrine system and metabolism, which endanger post-operative quality of life and increase morbidity and mortality of transplanted patients. Here, we specifically review the current knowledge on HSCT-derived side-effects on the perturbation of mineral metabolism; in particular, the homeostasis of calcium, focusing on current reports regarding osteoporosis and recurrent renal dysfunctions that have been observed in a percentage of HSC-transplanted patients. Possible secondary implications of conditioning treatments for HSCT on the physiology of the parathyroid glands and calcium homeostasis, alone or in association with HSCT-caused renal and bone defects, are critically discussed as well.

Bioengineered 3D microfibrous-matrix modulates osteopontin release from MSCs and facilitates the expansion of hematopoietic stem cells

The osteopontin released from mesenchymal stem cells (MSC) undergoing lineage differentiation can negatively influence the expansion of hematopoietic stem cells (HSCs) in co-culture systems developed for expanding HSCs. Therefore, minimising the amount of osteopontin in the co-culture system is important for the successful ex vivo expansion of HSCs. Towards this goal, a bioengineered 3D microfibrous-matrix that can maintain MSCs in less osteopontin-releasing conditions has been developed, and its influence on the expansion of HSCs has been studied. The newly developed 3D matrix significantly decreased the release of osteopontin, depending on the MSC culture conditions used during the priming period before HSC seeding. The culture system with the lowest amount of osteopontin facilitated a more than 24-fold increase in HSC number in 1 week time period. Interestingly, the viability of expanded cells and the CD34+ pure population of HSCs were found to be the highest in the low osteopontin-containing system. Therefore, bioengineered microfibrous 3D matrices seeded with MSCs, primed under suitable culture conditions, can be an improved ex vivo expansion system for HSC culture. This article is protected by copyright. All rights reserved.