Optimizing allogeneic grafts in hematopoietic stem cell transplantation

Microvesicles and exosomes isolated from murine bone marrow-derived mesenchymal stromal cells primed with p38MAPK inhibitor differentially regulate hematopoietic stem cell function

The signaling mechanisms active within mesenchymal stromal cells (MSCs) influence the composition of microvesicles (MVs) and exosomes (Exos) secreted by them. Previously, we showed that priming MSCs with a p38 pharmacological inhibitor (pMSCs) rejuvenates them and improves their ability to promote ex vivo hematopoietic stem cell (HSC) expansion. This study examined whether pMSCs exerted HSC-supportive ability via MVs (pMVs) and Exos (pExos). Our findings demonstrate distinct regulation of HSC fate by pMVs and pExos. pMVs promoted the expansion of long-term HSCs (LT-HSCs), distinguished by their robust self-renewal capacity and superior engraftment ability. In contrast, pExos facilitated expansion of short-term HSCs (ST-HSCs) with high proliferative and differentiation potential. Infusing a combination of pMVs- and pExos-expanded HSCs as a composite graft resulted in significantly higher HSC engraftment, emphasizing the synergistic interaction between LT- and ST-HSC populations. Gene expression studies, functional and phenotypic experiments showed that pMVs regulate HSC quiescence via the Egr1/Cdkn1a axis, while pExos control HSC proliferation via the Nfya/Cdkn1a axis. These findings provide insights into the molecular mechanisms underlying the differential regulation of HSC function by pMVs and pExos. It also proposes a composite graft strategy of using pMVs and pExos as "MSC-derived biologics" for improving the HSC transplantation success.

CRISPR/nCas9-Edited CD34+ Cells Rescue Mucopolysaccharidosis IVA Fibroblasts Phenotype

Mucopolysaccharidosis (MPS) IVA is a bone-affecting lysosomal storage disease (LSD) caused by impaired degradation of the glycosaminoglycans (GAGs) keratan sulfate (KS) and chondroitin 6-sulfate (C6S) due to deficient N-acetylgalactosamine-6-sulfatase (GALNS) enzyme activity. Previously, we successfully developed and validated a CRISPR/nCas9-based gene therapy (GT) to insert an expression cassette at the AAVS1 and ROSA26 loci in human MPS IVA fibroblasts and MPS IVA mice, respectively. In this study, we have extended our approach to evaluate the effectiveness of our CRISPR/nCas9-based GT in editing human CD34+ cells to mediate cross-correction of MPS IVA fibroblasts. CD34+ cells were electroporated with the CRISPR/nCas9 system, targeting the AAVS1 locus. The nCas9-mediated on-target donor template insertion, and the stemness of the CRISPR/nCas-edited CD34+ cells was evaluated. Additionally, MPS IVA fibroblasts were co-cultured with CRISPR/nCas-edited CD34+ cells to assess cross-correction. CRISPR/nCas9-based gene editing did not affect the stemness of CD34+ cells but did lead to supraphysiological levels of the GALNS enzyme. Upon co-culture, MPS IVA fibroblasts displayed a significant increase in the GALNS enzyme activity along with lysosomal mass reduction, pro-oxidant profile amelioration, mitochondrial mass recovery, and pro-apoptotic and pro-inflammatory profile improvement. These results show the potential of our CRISPR/nCas9-based GT to edit CD34+ cells to mediate cross-correction.

Examining the effect of intermittent cycling throughout a 3-h period on peripheral blood concentrations of haemopoietic stem and progenitor cells and cytolytic natural killer cells

BACKGROUND

Peripheral blood stem cell (PBSC) donation is the primary procedure used to collect haemopoietic stem and progenitor cells (HSPCs) for haemopoietic stem cell transplants (HSCT), however there is a clinical need to reduce collection times and achieve sufficient HSPC doses for successful engraftment. Short bouts of interval cycling transiently enrich peripheral blood with HSPCs and cytolytic natural killer (CD56dim NK) cells, which predict engraftment success and prevent post-transplant complications respectively. Despite this, feasible protocols for use during PBSC collections (≈ 3 h) have yet to be evaluated.

METHODS

In a randomised crossover design, 18 adults (9 young: 22.7 ± 3.2 years, 9 older: 65.2 ± 12.9 years) completed 3 × 3-h trials: high-intensity interval exercise (HIIE, 9 × 2-min cycling at 80-85% heart rate (HR)max/9 × 18 min rest), moderate-intensity interval exercise (MIIE, 9 × 4-min cycling at 65-70% HRmax/9 × 16 min rest) and REST (180 min). Immune cell subsets, including HSPCs and CD56dim NK concentrations (cells/µL) were determined across 18 timepoints and area under the curve (AUC, cells/µL x minutes) and total cell dose (cells/kg) were estimated.

RESULTS

By design, MIIE elicited lower average and peak HR and rating of perceived exertion than HIIE and was reported as more enjoyable. All cell subset concentrations increased following each interval of MIIE and HIIE. Across all participants, the estimated cell dose of total lymphocytes, monocytes, T cells, CD56bright and CD56dim NK was greater in MIIE and HIIE versus REST (p < 0.03), but there were no differences between MIIE and HIIE. The magnitude of change versus REST was greatest for CD56dim NK versus all cell subsets, and AUC was significantly greater in HIIE versus REST for this cell type only (p < 0.0001). There were no statistically significant differences in HSPC AUC (p = 0.77) or cell dose (p = 0.0732) in MIIE and HIIE versus REST. Age did not predict any changes across trials or timepoints for any cell type.

CONCLUSION

Persistent mobilisation of peripheral blood immune cells throughout 3 h of MIIE and HIIE evoked sustained numbers of CD56dim NK cells, but there was no reliable difference in HSPCs compared to a time-matched period of rest.

Innovative approaches in stem cell therapy: revolutionizing cancer treatment and advancing neurobiology - a comprehensive review

Stem cell therapy represents a transformative frontier in medical science, offering promising avenues for revolutionizing cancer treatment and advancing our understanding of neurobiology. This review explores innovative approaches in stem cell therapy that have the potential to reshape clinical practices and therapeutic outcomes in cancer and neurodegenerative diseases. In this dynamic and intriguing realm of cancer research, recent years witnessed a surge in attention toward understanding the intricate role of mesenchymal stem cells (MSCs). These cells, capable of either suppressing or promoting tumors across diverse experimental models, have been a focal point in the exploration of exosome-based therapies. Exosomes released by MSCs have played a pivotal role, in unraveling the nuances of paracrine signaling and its profound impact on cancer development. Recent studies have revealed the complex nature of MSC-derived exosomes, showcasing both protumor and antitumor effects. Despite their multifaceted involvement in tumor growth, these exosomes show significant promise in influencing both tumor development and chemosensitivity, acting as a pivotal factor that increases stem cells' potential for medicinal use. Endogenous MSCs, primarily originating from the bone marrow, exhibited a unique migratory response to damaged tissue sites. The genetic modification of stem cells, including MSCs, opened avenues for the precise delivery of therapeutic payloads in the milieu around the tumor (TME). Stem cell therapy offers groundbreaking potential for treating neurodegenerative and autoimmune disorders by regenerating damaged tissues and modulating immune responses. This approach aims to restore lost function and promote healing through targeted cellular interventions. In this review, we explored the molecular complexities of cancer and the potential for breakthroughs in personalized and targeted therapies. This analysis offers hope for transformative advancements in both cancer treatment and neurodegenerative disorders, highlighting the promise of precision medicine in addressing these challenging conditions.

Advances in hematopoietic stem cells ex vivo expansion associated with bone marrow niche

Hematopoietic stem cells (HSCs) are an ideal source for the treatment of many hematological diseases and malignancies, as well as diseases of other systems, because of their two important features, self-renewal and multipotential differentiation, which have the ability to rebuild the blood system and immune system of the body. However, so far, the insufficient number of available HSCs, whether from bone marrow (BM), mobilized peripheral blood or umbilical cord blood, is still the main restricting factor for the clinical application. Therefore, strategies to expand HSCs numbers and maintain HSCs functions through ex vivo culture are urgently required. In this review, we outline the basic biology characteristics of HSCs, and focus on the regulatory factors in BM niche affecting the functions of HSCs. Then, we introduce several representative strategies used for HSCs from these three sources ex vivo expansion associated with BM niche. These findings have deepened our understanding of the mechanisms by which HSCs balance self-renewal and differentiation and provided a theoretical basis for the efficient clinical HSCs expansion.

Antibiotic Prophylaxis During Allogeneic Stem Cell transplantation-A Comprehensive Single Center Retrospective Analysis

BACKGROUND

Prophylactic antibiotics are still controversial during allogeneic hematopoietic stem cell transplantation (allo-HSCT). In our transplant center, we suspended antibiotic prophylaxis during allo-HSCT in 2017.

OBJECTIVE

The main objective of this study was the detailed analysis of the potentially beneficial impact of omittance of standard antibiotic prophylaxis during allo-HSCT in survival and Graft-versus-Host disease (GvHD) development, especially with consideration of confounding factors and competing events. Secondary objectives were the evaluation of the risk of severe infections and transplant-related mortality without antibiotic prophylaxis, the detailed assessment of bacterial and viral infections including multiresistant pathogens as well as occurrence of relapse in both groups. This study aims to support the development of future antibiotic strategies in allo-HSCT.

STUDY DESIGN

We retrospectively analyzed patient outcome in the time periods before (between December 2012 and February 2017) and after suspension (between March 2017 and June 2020) of antibiotic prophylaxis during allo-HSCT. Relevant clinical outcome parameters of the patients (n = 221) were collected by chart-review in the two groups (with antibiotic prophylaxis n = 101 versus without antibiotic prophylaxis n = 120). All patients were 18 years or older. Propensity score methods were used to adjust for potentially confounding patient characteristics. To address competing events, transitions between moderate/severe acute and chronic GvHD, relapse and death were analyzed using an inverse-propensity score weighted multistate modeling approach.

RESULTS

While we observed a trend towards an improved outcome in the cohort without antibiotic prophylaxis, the inverse-propensity-score-weighted analyses did not show significant differences between the two groups in overall survival (OS) (P = .811) or development of acute GvHD (aGvHD) grade 3/4 (P = .158) and chronic moderate/severe GvHD (cGvHD) (P = .686). Multistate analysis respecting competing events revealed comparable estimated probabilities without antibiotic prophylaxis versus with antibiotic prophylaxis in OS (35.0% [95% CI: 28.2%-42.7%] versus 35.3% [95% CI: 27.8%-41.1%]) as well as development of aGvHD grade 3/4 (7.7% [95% CI: 5.9%-12.2%] vs. 10.6% [95% CI: 7.7%-15.7%]) and moderate/severe cGvHD (21.0% [95% CI: 17.7%-30.0%] vs. 23.8% [95% CI: 19.6%-31.4%]). Similar analyses showed also no significant differences in relapse rate, transplant-related mortality, relapse-related mortality, or GvHD-free/relapse-free survival between the two groups. An observed increase in severe infections without antibiotic prophylaxis did not lead to a significantly higher mortality rate. Viral reactivation and detection of multiresistant bacteria were comparable, yet a higher incidence of Clostridioides difficile infections was observed in patients receiving antibiotic prophylaxis.

CONCLUSION

Our study supports previous reports of noninferiority of allo-HSCT without use of antibiotic prophylaxis with close monitoring and rapid intervention, if infection is suspected. The trend towards improved outcomes without antibiotic prophylaxis, however, might not only be due to the absence of antibiotic prophylaxis but also due to additional progresses in the field over the recent years. While the present study is too small to draw definite conclusions, these results strongly warrant further multicenter studies addressing the potential benefit of omitting antibiotic prophylaxis during allo-HSCT.

Hematopoietic stem cell transplantation therapy for refractory' Crohn disease: A systematic review and meta-analysis

BACKGROUND

Despite the availability of numerous treatments for Crohn disease, there are patients who do not respond to any therapy, thereby diminishing their quality of life. The aim of this review is to analyze the efficacy and safety of autologous hematopoietic stem cell transplantation therapy for refractory Crohn disease.

METHODS

This work is a systematic review with meta-analysis conducted in accordance with the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analyses. Electronic databases such as PubMed, Scopus, Web of Science, and ClinicalTrials were consulted. The searches were carried out in August 2024. To evaluate the efficacy of autologous hematopoietic stem cell transplantation in inducing remission, the mean and standard deviation of the Crohn's Disease Activity Index pre- and post- treatment were used, and a fixed-effects meta-analysis was conducted. Additionally, to assess the efficacy in perianal fistulas, a random-effects meta-analysis was performed, collecting data on the number of subjects with fistulas at the beginning and end of the intervention. All 95% confidence intervals were calculated, and the I2 statistic was used to assess the heterogeneity of the outcome variables.

RESULTS

A total of 609 records were identified from databases, with 12 studies selected for inclusion in the review. Immediate intervention proved effective in inducing a decrease in the Crohn Disease Activity Index compared to late intervention with conventional therapies. Moreover, the meta-analysis demonstrated efficacy for Crohn disease and associated fistulas with a mean decrease in the CDAI of -217.53 ± 14.3. When evaluating the efficacy of the procedure in perianal fistulas, a risk ratio of 0.47 with a 95% CI of [0.26, 0.86] was obtained. However, the procedure showed adverse effects, such as infections, acute renal failure or deaths.

CONCLUSION

Systemic autologous hematopoietic stem cell transplantation has shown efficacy in patients who fail to achieve remission of their Crohn disease with conventional therapies. This procedure has also demonstrated efficacy in treating perianal fistulas. However, it is essential to carefully evaluate de implementation of this procedure due to the associated risks.

Insights into gut microbiomes in stem cell transplantation by comprehensive shotgun long-read sequencing

The gut microbiome is a diverse ecosystem, dominated by bacteria; however, fungi, phages/viruses, archaea, and protozoa are also important members of the gut microbiota. Exploration of taxonomic compositions beyond bacteria as well as an understanding of the interaction between the bacteriome with the other members is limited using 16S rDNA sequencing. Here, we developed a pipeline enabling the simultaneous interrogation of the gut microbiome (bacteriome, mycobiome, archaeome, eukaryome, DNA virome) and of antibiotic resistance genes based on optimized long-read shotgun metagenomics protocols and custom bioinformatics. Using our pipeline we investigated the longitudinal composition of the gut microbiome in an exploratory clinical study in patients undergoing allogeneic hematopoietic stem cell transplantation (alloHSCT; n = 31). Pre-transplantation microbiomes exhibited a 3-cluster structure, characterized by Bacteroides spp. /Phocaeicola spp., mixed composition and Enterococcus abundances. We revealed substantial inter-individual and temporal variabilities of microbial domain compositions, human DNA, and antibiotic resistance genes during the course of alloHSCT. Interestingly, viruses and fungi accounted for substantial proportions of microbiome content in individual samples. In the course of HSCT, bacterial strains were stable or newly acquired. Our results demonstrate the disruptive potential of alloHSCTon the gut microbiome and pave the way for future comprehensive microbiome studies based on long-read metagenomics.

DNA methylation of hematopoietic stem/progenitor cells from donor peripheral blood to patient bone marrow: implications for allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (AHSCT) is a life-saving treatment for selected hematological malignancies. So far, it remains unclear whether transplanted hematopoietic stem/progenitor cells (HSPCs) undergo epigenetic changes upon engraftment in recipient bone marrow (BM) after AHSCT and whether these changes might be useful in the transplant diagnostics. The purpose of this study was to characterize the whole genome methylation profile of HSPCs following AHSCT. Moreover, the relationship between the observed methylation signature and patient outcome was analyzed. Mobilized peripheral blood (mPB)-HSPCs from seven donors and BM-HSPCs longitudinally collected from transplanted patients with hematological malignancies up to one year from AHSCT (a total of twenty-eight samples) were analyzed using DNA methylation based-arrays. The obtained data showed that DNA methylation of mPB-HSPCs differs between young and adult donors and changes following HSPC engraftment in the BM of recipient patients. Looking at methylation in promoter regions, at 30 days post-AHSCT, BM-HSPCs showed a higher number of differentially methylated genes (DMGs) compared to those of mPB-HSPCs, with a prevalent hyper-methylation. These changes were maintained during all the analyzed time points, and methylation became like the donors after one year from transplant. Functional analysis of these DMGs showed an enrichment in cell adhesion, differentiation and cytokine (interleukin-2, -5 and -7) production and signaling pathways. Of note, DNA methylation analysis allowed to identify a potential "cancer/graft methylation signature" of transplant failure. It was evident in the latest available post-transplant BM-HSPC sample (at 160 days) and surprisingly already in early phase (at 30 days) in patients whose transplant was doomed to fail. Overall, the analysis of HSPC methylation profile could offer useful prognostic information to potentially assess engraftment success and predict graft failure in AHSCT.

The next horizon now that everyone has a donor: Precision allogeneic transplantation

Post-transplant cyclophosphamide (PTCy) allows safe and effective partially matched donor allogeneic blood or marrow transplantation (alloBMT), so that almost everyone in need of the procedure now has a donor. Moreover, PTCy and other recent advances have lowered alloBMT mortality rates to less than half of that seen before the turn of the century, at costs that are substantially less than most newly approved anticancer agents. These advances also make tailoring BMT based on patients' unique diseases and characteristics now feasible for further improving outcomes. Personalizing every aspect of alloBMT, including conditioning, donor, graft type, and post-transplant maintenance is now possible. For example, alloBMT's antitumor activity historically was restricted to the allogeneic graft-versus-tumor effect directed against histocompatibility antigens. However, replacing exhausted immune systems with healthy non-exhausted, non-tolerant ones likely can enhance the activity of novel targeted therapies. The impressive results seen with tyrosine kinase inhibitors after alloBMT for patients with both Ph+ acute lymphoblastic leukemia and FLT/ITD+ acute myeloid leukemia herald the potential of precision BMT.

Development of Nonwoven Fibrous Materials Based on Poly-3-Hydroxybutyrate with a High Content of α-Tricalcium Phosphate

α-tricalcium (α-TCP) phosphate is widely used as an osteoinductive biocompatible material, serving as an alternative to synthetic porous bone materials. The objective of this study is to obtain a highly filled fibrous nonwoven material composed of poly-3-hydroxybutyrate (PHB) and α-TCP and to investigate the morphology, structure, and properties of the composite obtained by the electrospinning method (ES). The addition of α-TCP had a significant effect on the supramolecular structure of the material, allowing it to control the crystallinity of the material, which was accompanied by changes in mechanical properties, FTIR spectra, and XRD curves. The obtained results open the way to the creation of new osteoconductive materials with a controlled release of the source of calcium into the living organism.

Haploidentical donor stem cell transplantation had a lower incidence of bronchiolitis obliterans syndrome compared with HLA-matched sibling donor transplantation in patients with hematologic malignancies: Benefit from ATG?

Background

Haploidentical donor stem cell transplantation (HID-SCT) based on antithymocyte globulin (ATG) for graft-versus-host disease (GVHD) prophylaxis had achieved a similar incidence of chronic graft-versus-host disease (cGVHD) with human leukocyte antigen (HLA)-matched sibling donor stem cell transplantation (MSD-SCT). However, bronchiolitis obliterans syndrome (BOS), which serves as pulmonary cGVHD, was rarely compared between HID and MSD transplantation.

Methods

One thousand four hundred five patients with hematologic malignancies who underwent allogeneic SCT were enrolled in this retrospective study. Based on donor type, we divided the patients into three groups: HID, MSD, and match unrelated donor (MUD) groups. The cumulative incidences and risk factors of BOS were analyzed.

Results

The 5-year cumulative incidence of BOS was 7.2% in the whole population. HID transplantation had a lower 5-year cumulative incidence of BOS than MSD transplantation (4.1% vs. 10.0%, p < 0.001) and a similar incidence with MUD transplantation (4.1% vs. 6.2%, p = 0.224). The 5-year cumulative incidence of BOS was lower in the ATG group than that in the non-ATG group in both the whole and MSD populations (4.6% vs. 11.2%, p < 0.001, and 4.1% vs. 11.2%, p = 0.042, respectively). The 5-year incidence of BOS in mixed grafts [peripheral blood stem cell (PBSC) plus bone marrow] group was also lower than that in the PBSC group (4.2% vs. 9.1, p = 0.001). Multivariate analysis showed that HID, ATG, and mixed grafts were protective factors for BOS [odds ratio (OR) 0.3, 95% CI 0.2-0.6, p < 0.001; OR 0.3, 95% CI 0.2-0.7, p = 0.001; OR 0.3, 95% CI 0.1-0.8, p = 0.013], and acute graft-versus-host disease (aGVHD) and cGVHD were independent risk factors for BOS (OR 2.1, 95% 1.1-4.3, p = 0.035; OR 10.1, 95% CI 4.0-25.0, p < 0.001).

Conclusions

HID transplantation had a lower incidence of BOS than MSD transplantation, which might be associated with ATG and mixed grafts.