Cellular senescence in brain aging and cognitive decline

Cellular senescence is a biological aging hallmark that plays a key role in the development of neurodegenerative diseases. Clinical trials are currently underway to evaluate the effectiveness of senotherapies for these diseases. However, the impact of senescence on brain aging and cognitive decline in the absence of neurodegeneration remains uncertain. Moreover, patient populations like cancer survivors, traumatic brain injury survivors, obese individuals, obstructive sleep apnea patients, and chronic kidney disease patients can suffer age-related brain changes like cognitive decline prematurely, suggesting that they may suffer accelerated senescence in the brain. Understanding the role of senescence in neurocognitive deficits linked to these conditions is crucial, especially considering the rapidly evolving field of senotherapeutics. Such treatments could help alleviate early brain aging in these patients, significantly reducing patient morbidity and healthcare costs. This review provides a translational perspective on how cellular senescence plays a role in brain aging and age-related cognitive decline. We also discuss important caveats surrounding mainstream senotherapies like senolytics and senomorphics, and present emerging evidence of hyperbaric oxygen therapy and immune-directed therapies as viable modalities for reducing senescent cell burden

Insight into the molecular pathophysiology of myelodysplastic syndromes: targets for novel therapy

Myelodysplastic syndromes (MDS) are clonal hematopoietic stem cell disorders characterized by abnormal cellular differentiation and maturation with variable progression to acute leukemia. Over the last decade, scientific discoveries have unraveled specific pathways involved in the complex pathophysiology of MDS. Prominent examples include aberrations in cytokines and their signaling pathways (such as tumor necrosis factor-alpha, interferon-gamma, SMAD proteins), mutations in genes encoding the RNA splicing machinery (SF3B1, SRSF2, ZRSR2, and U2AF1 genes), mutations in genes disrupting the epigenetic machinery (TET2, DNMT3A, DNMT3B, EZH2, ASXL1). In addition, abnormalities in regulatory T-cell dynamics and atypical interactions between the bone marrow microenvironment, stroma and progenitor cells, and abnormal maintenance of telomeres are also notable contributors to the complex pathogenesis of MDS. These pathways represent potential targets for novel therapies. Specific therapies include drugs targeting aberrant DNA methylation and chromatin remodeling, modulating/activating the immune system to enhance tumor-specific cellular immune responses and reduce anomalous cytokine signaling, and blocking abnormal interaction between hematopoietic progenitors and stromal cells

Role of gene therapy in fanconi anemia: A systematic and literature review with future directions

Gene therapy (GT) has been reported to improve bone marrow function in individuals with Fanconi anemia (FA); however, its clinical application is still in the initial stages. We conducted this systematic review, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, to assess the long-term safety and clinical outcomes of GT in FA patients. Electronic searches from PubMed, Web of Science, Cochrane Library, and Google Scholar were conducted and full texts of articles meeting our inclusion criteria were reviewed. Three clinical trials were included, with a total of nine patients and mean age of 10.7 ± 5.7 years. All patients had lentiviral-mediated GT. A 1-year follow-up showed stabilization in blood lineages, without any serious adverse effects from GT. A metaregression analysis could not be conducted, as very little long-term follow-up data of patients was observed, and the median survival rate could not be calculated. Thus, we can conclude that GT seems to be a safe procedure in FA; however, further research needs to be conducted on the longitudinal clinical effects of GT in FA, for a better insight into its potential to become a standard form of treatment

Worldwide network for blood and marrow transplantation recommendations for establishing a hematopoietic stem cell transplantation program in countries with limited resources, part II: Clinical, technical, and socioeconomic considerations

The development of hematopoietic stem cell transplantation (HSCT) programs can face significant challenges in most developing countries because such endeavors must compete with other government health care priorities, including the delivery of basic services. Although this is may be a limiting factor, these countries should prioritize development of the needed expertise to offer state-of-the-art treatments, including transplantation, by providing financial, technological, legal, ethical, and other needed support. This would prove beneficial in providing successful programs customized to the needs of their population and potentially provide long-term cost savings by circumventing the need for their citizens to seek care abroad. The costs of establishing an HSCT program and the costs of the HSCT procedure itself can be substantial barriers in developing countries. In addition, socioeconomic factors intrinsic to specific countries can influence access to HSCT, patient eligibility for HSCT, and timely utilization of HSCT center capabilities. This report describes recommendations from the Worldwide Network for Blood and Marrow Transplantation for establishing HSCT programs, with a specific focus on developing countries, and identifies challenges and opportunities for providing this specialized procedure in resource-constrained settings

Venous thromboembolism following hematopoietic stem cell transplantation-a systematic review and meta-analysis

Venous thromboembolism (VTE) is a common complication of hematopoietic stem cell transplantation (HSCT). Graft-versus-host disease (GVHD) is another complication of HSCT that may modify the risk of VTE. Our objective was to explore the incidence of VTE (deep venous thrombosis and pulmonary embolism) following HSCT and to evaluate its association with GVHD. A comprehensive search of Medline In-Process & Other Non-Indexed Citations, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Scopus was conducted to search for both retrospective and prospective HSCT studies which had reported VTE. Random-effects meta-analysis was used to pool incidence rates. We included 17 studies reporting on allogeneic- and 10 on autologous-HSCT; enrolling 6693 patients; of which 5 were randomized. The overall incidence of VTE after HSCT was 5%(4-7%). Incidence in allogeneic-HSCT was 4%(2-6%) and in autologous-HSCT was 4%(1-15%). Eleven and nine studies reported data on acute and chronic GVHD, respectively. The incidence of VTE in chronic GVHD was 35%(20-54%), whereas in acute GVHD it was 47%(32-62%). Based on the results of this meta-analysis, VTE is a fairly common complication after HSCT, emphasizing the importance of assimilating guidelines for both treatment and prophylaxis in this patient population

Determining the Quantitative Principles of T Cell Response to Antigenic Disparity in Stem Cell Transplantation

Alloreactivity compromising clinical outcomes in stem cell transplantation is observed despite HLA matching of donors and recipients. This has its origin in the variation between the exomes of the two, which provides the basis for minor histocompatibility antigens (mHA). The mHA presented on the HLA class I and II molecules and the ensuing T cell response to these antigens results in graft vs. host disease. In this paper, results of a whole exome sequencing study are presented, with resulting alloreactive polymorphic peptides and their HLA class I and HLA class II (DRB1) binding affinity quantified. Large libraries of potentially alloreactive recipient peptides binding both sets of molecules were identified, with HLA-DRB1 generally presenting a greater number of peptides. These results are used to develop a quantitative framework to understand the immunobiology of transplantation. A tensor-based approach is used to derive the equations needed to determine the alloreactive donor T cell response from the mHA-HLA binding affinity and protein expression data. This approach may be used in future studies to simulate the magnitude of expected donor T cell response and determine the risk for alloreactive complications in HLA matched or mismatched hematopoietic cell and solid organ transplantation

Should Healthcare Organisations Offer Ongoing Rehabilitation Services for Patients Undergoing Haematopoietic Cell Transplant? A Narrative Review

Purpose: Hematopoietic stem cell transplant (HSCT) patients can suffer from long-term transplant-related complications that affect their quality of life and daily activities. This study, a narrative review, aims to report the impact of HCT complications, the benefits of rehabilitation intervention, the need for long-term care and highlights the research gap in clinical trials involving rehabilitation. Design/methodology/approach: A comprehensive search strategy was performed on several databases to look for relevant articles published from 1998 to 2018. Articles published in English with the following terms were used: hematopoietic stem cell transplant, chronic graft-versus-host disease, rehabilitation, exercise, physical therapy, occupational therapy. A patient/population, intervention, comparison, and outcomes (PICO) framework was employed to ensure that the search strategies were structured and precise. Study year, design, outcome, intervention, sample demographics, setting and study results were extracted. Findings: Of the 1,411 records identified, 51 studies underwent title/abstract screening for appropriateness, 30 were reviewed in full, and 19 studies were included in the review. The review found that, for the majority of patients who underwent HSCT and developed treatment-related complications, rehabilitation exercises had a positive impact on their overall quality of life. However, exercise prescription in this patient group has not always reflected the scientific approach; there is a lack of high-quality clinical trials in general. The review also highlights the need to educate healthcare policymakers and insurance companies responsible for rationing services to recognise the importance of offering long-term follow-up care for this patient group, including rehabilitation services. Practical implications: A large number of HSCT patients require long-term follow-up from a multidisciplinary team, including rehabilitation specialists. It is important for healthcare policymakers and insurance companies to recognise this need and take the necessary steps to ensure that HSCT patients receive adequate long-term care. This paper also highlights the urgent need for high-quality rehabilitation trials to demonstrate the feasibility and importance of rehabilitation teams. Originality/value: Healthcare policymakers and insurance companies need to recognise that transplant patients need ongoing physiotherapy for early identification of any functional impairments and appropriate timely intervention

Cost and quality issues in establishing hematopoietic cell transplant program in developing countries

The hematopoietic cell transplant (HCT) activity has grown significantly over the past two decades in both developing and developed countries. Many challenges arise in establishing new HCT programs in developing countries, due to scarcity of resources and manpower in expertise in HCT. While cost issues can potentially hinder establishment of new HCT programs in certain regions, the focus on quality and value should be included in the general vision of leadership before establishing an HCT program. The main challenge in most developing countries is the lack of trained/qualified personnel, enormous start-up costs for a tertiary care center, and quality maintenance. Herein, we discuss the main challenges from a cost and quality perspective which occur at initiation of a new HCT program. We give real world examples of two developing countries that have recently started new HCT programs despite significant financial constraints. We also portray recommendations from the Worldwide Network of Blood and Marrow Transplantation for levels of requirements for a new HCT program. We hope that this review will serve as a general guide for new transplant program leadership with respect to the concerns of balancing high quality with concurrently lowering costs