Bone Marrow Cell Transplant From Donors With Cardiovascular Risk Factors Increases the Pro-atherosclerotic Phenotype in the Recipients

Endothelial dysfunction and vascular complications after allogeneic hematopoietic cell transplantation: an expert analysis

Allogeneic hematopoietic cell transplantation (alloHCT) is the standard of care for many diseases. However, survivors often present with serious complications resulting from acute and chronic toxicities and it is crucial to increase consciousness from treating physicians. We performed a comprehensive review of the literature and critically examined recent available data, mostly using the PubMed and Medline search engines for original articles published over the last decade. Better understanding of many alloHCT-related disorders has shown that endothelial injury and vascular damage plays a critical role. The most widely studied endothelial injury syndromes (EIS) are veno-occlusive disease/sinusoidal obstruction syndrome (SOS/VOD), graft-versus-host-disease (GVHD), and transplant-associated thrombotic microangiopathy (TA-TMA). TA-TMA, frequently underdiagnosed, needs to be clarified using certain criteria and, as a life-threatening condition, requires immediate and intensive treatment. The first-in-class complement inhibitor eculizumab has significantly improved outcomes in both the pediatric and adult population. Cardiovascular (CV) events are the second major cause of morbidity and mortality of alloHCT survivors, after GVHD. Long-term monitoring and management of CV risk is expected to also incorporate patient stratification with CV risk prediction models, early markers of vascular dysfunction or procoagulant activity, subclinical target organ damage, arterial stiffness, and subclinical atherosclerosis.

Impact of Diabetes Mellitus on the Potential of Autologous Stem Cells and Stem Cell-Derived Microvesicles to Repair the Ischemic Heart

Ischemic heart disease remains the leading cause of morbidity and mortality worldwide. Despite the advances in medical management and catheter-based therapy, mortality remains high, as does the risk of developing heart failure. Regenerative therapies have been widely used as an alternative option to repair the damaged heart mainly because of their paracrine-related beneficial effects. Although cell-based therapy has been demonstrated as feasible and safe, randomized controlled trials and meta-analyses show little consistent benefit from treatments with adult-derived stem cells. Mounting evidence from our group and others supports that cardiovascular risk factors and comorbidities impair stem cell potential thus hampering their autologous use. This review aims to better understand the influence of diabetes on stem cell potential. For this purpose, we will first discuss the most recent advances in the mechanistic understanding of the effects of diabetes on stem cell phenotype, function, and molecular fingerprint to further elaborate on diabetes-induced alterations in stem cell extracellular vesicle profile. Although we acknowledge that multiple sources of stem or progenitor cells are used for regenerative purposes, we will focus on bone marrow hematopoietic stem/progenitor cells, mesenchymal stem cells residing in the bone marrow, and adipose tissue and briefly discuss endothelial colony-forming cells.

Bone marrow deficiency of mRNA decaying protein Tristetraprolin increases inflammation and mitochondrial ROS but reduces hepatic lipoprotein production in LDLR knockout mice

Tristetraprolin (TTP), an mRNA binding and decaying protein, plays a significant role in controlling inflammation by decaying mRNAs encoding inflammatory cytokines such as TNFalpha. We aimed to test a hypothesis that TTP in bone marrow (BM) cells regulates atherogenesis by modulating inflammation and lipid metabolism through the modulation of oxidative stress pathways by TTP target genes. In a BM transplantation study, lethally irradiated atherogenic LDLR^-/- mice were reconstituted with BM cells from either wild type (TTP^+/+) or TTP knockout (TTP^-/-) mice, and fed a Western diet for 12 weeks. We made the following observations: (1) TTP^-/- BM recipients display a significantly higher systemic and multi-organ inflammation than TTP^+/+ BM recipients; (2) BM TTP deficiency modulates hepatic expression of genes, detected by microarray, involved in lipid metabolism, inflammatory responses, and oxidative stress; (3) TTP^-/- BM derived macrophages increase production of mitochondrial reactive oxygen species (mtROS); (4) BM-TTP^-/- mice display a significant reduction in serum VLDL/LDL levels, and attenuated hepatic steatosis compared to controls; and (5) Reduction of serum VLDL/LDL levels offsets the increased inflammation, resulting in no changes in atherosclerosis. These findings provide a novel mechanistic insight into the roles of TTP-mediated mRNA decay in bone marrow-derived cells in regulating systemic inflammation, oxidative stress, and liver VLDL/LDL biogenesis.

Highlights from the 2019 International Aspirin Foundation Scientific Conference, Rome, 28 June 2019: benefits and risks of antithrombotic therapy for cardiovascular disease prevention

At the 2019 International Aspirin Foundation Scientific Conference 'Benefits and Risks of Antithrombotic Therapy for Cardiovascular Disease Prevention', held in Rome, Italy, international experts sought to discuss and debate the optimal antithrombotic strategy for the secondary prevention of cardiovascular disease (CVD) and to seek agreement around dosing and target populations for aspirin use in primary disease prevention. Getting the best evidence to support real-life decisions in the clinic can be complex, and individualising management in order to balance both the risks and benefits of different disease prevention strategies appears to be the best approach. It is hoped that future decision-making tools and biomarkers will help direct treatments at those most likely to benefit.

Early Prediction of Cardiovascular Risk after Hematopoietic Cell Transplantation: Are We There Yet?

Cardiovascular (CV) events have emerged as a major cause of morbidity and mortality among hematopoietic cell transplantation (HCT) survivors. Accumulating evidence supports the presence of increased CV risk in HCT recipients. Most studies have focused mainly on traditional CV risk factors, such as the metabolic syndrome and hypertension. However, detection of these factors suggests the development of irreversible overt clinical atherosclerosis. Therefore, earlier prediction of CV risk is needed to prevent CV morbidity and mortality in these patients. In the field of CV research, endothelial dysfunction is considered an early event in the pathophysiology of CV risk factors, and a number of markers have been proposed for its assessment. In addition, markers of subclinical target organ damage have been introduced to implement CV risk prediction and early preventive or intensive therapeutic interventions. Furthermore, a number of CV models have been suggested aiming for optimal stratification of patients. Preliminary studies have indicated excess CV risk using these early markers in HCT recipients. However, their role in the pathophysiology and clinical practice in HCT survivors remains largely understudied. Taking into account the need for increased awareness from treating physicians in this evolving setting, we conducted a state-of-the-art review aiming to summarize current knowledge on endothelial dysfunction, subclinical target organ damage, and CV risk prediction in HCT survivors.

Acquired Complement Regulatory Gene Mutations and Hematopoietic Stem Cell Transplant-Related Thrombotic Microangiopathy

Hematopoietic stem cell transplant-related thrombotic microangiopathy (HSCT-TMA) is a severe complication whose pathophysiology is unknown. We describe 6 patients in which the disease was associated with complement regulatory gene abnormalities received from their respective donors. It is suggested that mutated and transplanted monocyte-derived cells are responsible for production of abnormal proteins, complement dysregulation, and, ultimately, for the disease. This observation might have important drawbacks as far as HSCT-TMA pathophysiology and treatment are concerned.