Inflammatory Bone Marrow Research Articles

The role of inflammation in hematopoiesis and bone marrow failure: What can we learn from mouse models?

Hematopoiesis is a remarkable system that plays an important role in not only immune cell function, but also in nutrient transport, hemostasis and wound healing among other functions. Under inflammatory conditions, steady-state hematopoiesis switches to emergency myelopoiesis to give rise to the effector cell types necessary to fight the acute insult. Sustained or aberrant exposure to inflammatory signals has detrimental effects on the hematopoietic system, leading to increased proliferation, DNA damage, different forms of cell death (i.e., apoptosis, pyroptosis and necroptosis) and bone marrow microenvironment modifications. Together, all these changes can cause premature loss of hematopoiesis function. Especially in individuals with inherited bone marrow failure syndromes or immune-mediated aplastic anemia, chronic inflammatory signals may thus aggravate cytopenias and accelerate disease progression. However, the understanding of the inflammation roles in bone marrow failure remains limited. In this review, we summarize the different mechanisms found in mouse models regarding to inflammatory bone marrow failure and discuss implications for future research and clinical practice.

Novel imaging techniques for sacroiliac joint assessment.

Imaging of the sacroiliac joints is one of the cornerstones in the diagnosis and monitoring of axial spondyloarthritis. We aim to present an overview of the emerging imaging techniques for sacroiliac joint assessment and provide an insight into their relevant benefits and pitfalls. Evaluation of structural and active inflammatory lesions in sacroiliitis are both important for understanding the disease process. Dual-energy computed tomography (CT) can detect inflammatory bone marrow edema in the sacroiliac joints and provides an alternative for magnetic resonance imaging (MRI). Three-dimensional gradient echo sequences improve the visualization of erosions on MRI. Susceptibility weighted MRI and deep learning-based synthetic CT are innovative MRI techniques that allow for generating 'CT-like' images and better depict osseous structural lesions than routine MRI sequences. New imaging innovations and developments result in significant improvements in the imaging of spondyloarthritis. Advanced MRI techniques enhance its potential for the accurate detection of structural and active inflammatory lesions of sacroiliitis in one single imaging session.

Correlation of bone marrow 2-deoxy-2-[ 18 F]fluoro-D-glucose uptake with systemic inflammation in patients with newly diagnosed endometrial cancer.

To clarify the relationship between 2-deoxy-2-[ 18 F]fluoro-D-glucose (FDG) uptake of bone marrow and systemic inflammation in patients with newly diagnosed endometrial cancer. A total of 119 patients with untreated endometrial cancer underwent FDG PET/computed tomography (CT). For bone marrow FDG uptake, the mean standardized uptake value (SUVmean) of the five vertebrae (T11-12 and L3-L5) was measured and averaged (bone marrow SUV). The bone marrow-to-liver ratio (BLR) was calculated by dividing the bone marrow SUV by the SUVmean of the normal liver. FDG PET parameters were correlated with white blood cell count, neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and C-reactive protein (CRP), albumin, and hemoglobin levels. They were also correlated with FIGO stage. Bone marrow SUV and BLR showed significant positive correlations with white blood cell count, NLR, and CRP level and significant negative correlations with albumin level. BLR also showed a significant positive correlation with PLR. No significant differences in bone marrow SUV and BLR were apparent according to FIGO stage. Pretreatment FDG PET/CT in patients with newly diagnosed endometrial cancer may provide information on host systemic inflammation as assessed by bone marrow FDG uptake.

Myeloablative Conditioning for Transplantation Induces State of Sterile Inflammation in the Bone Marrow: Implications for Optimizing Homing and Engraftment of Hematopoietic Stem Cells.

Significance: The success rate of hematopoietic stem cell transplantation depends mainly on the number of transplanted hematopoietic stem/progenitor cells (HSPCs) followed by the speed of their engraftment in the myeloablated transplant recipient. Therefore, clinical outcomes will significantly benefit from accelerating the homing and engraftment of these cells. This is, in particular, important when the number of cells available for the transplantation of HSPCs is limited. Recent Advances: We postulated that myeloablative conditioning for hematopoietic transplantation by radio- or chemotherapy induces a state of sterile inflammation in transplant recipient peripheral blood (PB) and bone marrow (BM). This state is mediated by activation of the BM stromal and innate immunity cells that survive myeloablative conditioning and respond to danger-associated molecular patterns released from the cells damaged by myeloablative conditioning. As a result of this, several factors are released that promote proper navigation of HSPCs infused into PB of transplant recipient and prime recipient BM to receive transplanted cells. Critical Issues: We will present data that cellular innate immunity arm and soluble arm comprised complement cascade proteins, promoting the induction of the BM sterile inflammation state that facilitates the navigation, homing, and engraftment of HSPCs. Future Directions: Deciphering these mechanisms would allow us to better understand the mechanisms that govern hematopoietic recovery after transplantation and, in parallel, provide important information on how to optimize this process in the clinic by employing small molecular modifiers of innate immunity and purinergic signaling. Antioxid. Redox Signal. 37, 1254-1265.

Intravital lipid droplet labeling and imaging reveals the phenotypes and functions of individual macrophages in vivo

Macrophages play pivotal roles in the maintenance of tissue homeostasis. However, the reactivation of macrophages toward proinflammatory states correlates with a plethora of inflammatory diseases, including atherosclerosis, obesity, neurodegeneration, and bone marrow (BM) failure syndromes. The lack of methods to reveal macrophage phenotype and function in vivo impedes the translational research of these diseases. Here, we found that proinflammatory macrophages accumulate intracellular lipid droplets (LDs) relative to resting or noninflammatory macrophages both in vitro and in vivo, indicating that LD accumulation serves as a structural biomarker for macrophage phenotyping. To realize the staining and imaging of macrophage LDs in vivo, we developed a fluorescent fatty acid analog-loaded poly(lactic-co-glycolic acid) nanoparticle to label macrophages in mice with high efficiency and specificity. Using these novel nanoparticles, we achieved in situ functional identification of single macrophages in BM, liver, lung, and adipose tissues under conditions of acute or chronic inflammation. Moreover, with this intravital imaging platform, we further realized in vivo phenotyping of individual macrophages in the calvarial BM of mice under systemic inflammation. In conclusion, we established an efficient in vivo LD labeling and imaging system for single macrophage phenotyping, which will aid in the development of diagnostics and therapeutic monitoring. Moreover, this method also provides new avenues for the study of lipid trafficking and dynamics in vivo.

Skeletal muscle mitoribosomal defects are linked to low bone mass caused by bone marrow inflammation in male mice.

BackgroundMitochondrial oxidative phosphorylation (OxPhos) is a critical regulator of skeletal muscle mass and function. Although muscle atrophy due to mitochondrial dysfunction is closely associated with bone loss, the biological characteristics of the relationship between muscle and bone remain obscure. We showed that muscle atrophy caused by skeletal muscle‐specific CR6‐interacting factor 1 knockout (MKO) modulates the bone marrow (BM) inflammatory response, leading to low bone mass.MethodsMKO mice with lower muscle OxPhos were fed a normal chow or high‐fat diet and then evaluated for muscle mass and function, and bone mineral density. Immunophenotyping of BM immune cells was also performed. BM transcriptomic analysis was used to identify key factors regulating bone mass in MKO mice. To determine the effects of BM‐derived CXCL12 (C–X–C motif chemokine ligand 12) on regulation of bone homeostasis, a variety of BM niche‐resident cells were treated with recombinant CXCL12. Vastus lateralis muscle and BM immune cell samples from 14 patients with hip fracture were investigated to examine the association between muscle function and BM inflammation.ResultsMKO mice exhibited significant reductions in both muscle mass and expression of OxPhos subunits but increased transcription of mitochondrial stress response‐related genes in the extensor digitorum longus (P < 0.01). MKO mice showed a decline in grip strength and a higher drop rate in the wire hanging test (P < 0.01). Micro‐computed tomography and von Kossa staining revealed that MKO mice developed a low mass phenotype in cortical and trabecular bone (P < 0.01). Transcriptomic analysis of the BM revealed that mitochondrial stress responses in skeletal muscles induce an inflammatory response and adipogenesis in the BM and that the CXCL12–CXCR4 (C–X–C chemokine receptor 4) axis is important for T‐cell homing to the BM. Antagonism of CXCR4 attenuated BM inflammation and increased bone mass in MKO mice. In humans, patients with low body mass index (BMI = 17.2 ± 0.42 kg/m2) harboured a larger population of proinflammatory and cytotoxic senescent T‐cells in the BMI (P < 0.05) and showed reduced expression of OxPhos subunits in the vastus lateralis, compared with controls with a normal BMI (23.7 ± 0.88 kg/m2) (P < 0.01).ConclusionsDefects in muscle mitochondrial OxPhos promote BM inflammation in mice, leading to decreased bone mass. Muscle mitochondrial dysfunction is linked to BM inflammatory cytokine secretion via the CXCL12–CXCR4 signalling axis, which is critical for inducing low bone mass.

Presence of subclinical inflammation in axial spondyloarthritis patients with NSAID/anti-TNF-α drug-induced clinical remission.

To investigate the rate of subclinical inflammation in patients with axial spondyloarthritis (axSpA) with nonsteroidal anti-inflammatory drug (NSAID)/anti-tumor necrosis factor (TNF)-α drug-induced clinical remission and to explore factors influencing clinical and imaging remission. One hundred twenty-five patients with axSpA followed up for at least 6months were enrolled in this prospective study and randomly divided into two groups. Ninety patients were treated with anti-tumor necrosis factor (TNF)-α or anti-TNF-α combined with nonsteroidal anti-inflammatory drugs (NSAIDs) (anti-TNF-α treatment group), and thirty-five patients were treated with only NSAIDs (non anti-TNF-α treatment group). The improvements in the clinical remission rate, imaging remission rate, and disease parameters before and after the different treatments were compared. Risk factors for clinical and imaging remission were analyzed by multivariate logistic regression analysis. The clinical and imaging remission rate was increased after treatment especially in the anti-TNF-α group (P < 0.001). The remission rate of imaging in the group with clinical remission was higher than that in the group with clinical non-remission (P < 0.05). After treatment, the remission rates of imaging in the clinical remission and non-remission group were significantly higher than those before treatment (P < 0.0001). The results of multivariate logistic regression analysis showed that higher CRP was a risk factor for failure of clinical remission in axSpA (OR = 2.034, 95% CI:1.595 ~ 2.617, P < 0.001), while higher ASDAScrp was a risk factor for failure of imaging remission (OR = 1.306, 95% CI:1.026 ~ 1.688, P < 0.05). Anti-TNF-α treatment was a protective factor for both clinical (OR = 0.234, 95% CI:0.091 ~ 0.605, P < 0.05) and imaging remission (OR = 0.511, 95% CI:0.286 ~ 0.914, P < 0.05). Even after regular treatment, some clinical remission patients continued to have evidence of subclinical inflammation. Higher CRP and ASDAScrp are risk factors for clinical and imaging non-remission in axSpA respectively, Continuous NSAID treatment (more than 1year) can effectively improve clinical and MRI inflammation in patients, but anti-TNF-α treatment is more beneficial for clinical and imaging remission. Key Points • Some patients achieving ASDAScrp remission status continue to have inflammation when assessed with objective imaging techniques. • MRI can sensitively measure bone marrow inflammation and may provide a more accurate assessment of remission. • Controlling inflammation, especially reducing CRP and ASDAScrp levels, is a key factor for achieving clinical and imaging remission in patients with axSpA.

VEXAS syndrome : when do we have to consider it ?

VEXAS syndrome was recently discovered in patients who developed late in adulthood an inflammatory syndrome with fever, cytopenias, dysplastic bone marrow, cutaneous and pulmonary neutrophilic inflammation, arthritis, chondritis, or vasculitis. It is the result of an inactivating somatic mutation affecting methionine codon 41 of the UBA1 gene which encodes an ubiquitin activating enzyme (E1). Systemic corticosteroids generally reduce symptoms, while other immunosuppressive drugs only have limited long-term effects. Azacitidine is a promising treatment, but further studies are warranted. Here, we describe 2 new cases including one associated with pyoderma gangrenosum and cryoglobulinemia.

New insights into the bone marrow niche in multiple myeloma revealed by single-cell profiling technologies

Several types of nonhematopoietic cells, including mesenchymal stem or progenitor cells, mature mesenchymal cells, and endothelial cells, and mature hematopoietic cells such as monocytes, macrophages, NK cells, T cells, and B cells regulate the proliferation and survival of myeloma cells. The cell functions adjacent to myeloma cells is specialized by the location of these cells, called a niche. This review focuses on the role and interaction of cellular components of the myeloma-specific niche revealed by studies that utilized the recently developed experimental techniques of single-cell RNA sequencing and high-parameter cytometry. In the myeloma niche, immune cells and mesenchymal cells regulate tumor proliferation. Bone marrow inflammation induced by multiple myeloma, tumor cells, mesenchymal stromal cells, and immune cells interact, results in the dysregulation of anti-tumor immunity. This complex network could affect tumorigenesis, disease progression, and treatment resistance of multiple myeloma.

Terpene Lactucopicrin Limits Macrophage Foam Cell Formation by a Reduction of Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 in Lipid Rafts.

Sustained inflammation promotes macrophage foam cell formation by promoting cholesterol influx and impairing cholesterol efflux. Terpene lactucopicrin, affluent in vegetables of the Asteraceae family (e.g., chicory, curly escarole, and lettuce) can inhibit atherogenesis in mice. However, it remains unknown whether and how lactucopicrin regulates macrophage foam cell formation. Lactucopicrin at physiologically reachable concentrations inhibits oxidized low-density lipoprotein (oxLDL)-induced foam cell formation in inflammatory mouse bone marrow derived macrophages established by 50 pg mL-1 of LPS, reachable level in patients with metabolic endotoxemia. This effect is not due to modulation of cholesterol efflux, but reliant on a reduction in lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1)-mediated cholesterol influx. Mechanistically, lactucopicrin does not affect LOX-1 expression, cellular oxidative stress, and exocytosis, known mechanisms regulating LOX-1 function in cholesterol influx. Strikingly, lactucopicrin selectively decreases LOX-1 content in lipid rafts, an effect responsible for the lactucopicrin effect on cholesterol influx. Moreover, ApoE-/- mice fed a high fat diet supplemented with lactucopicrin for 12 weeks display fewer macrophage foam cells within atherosclerotic plaques relative to the control mice. Lactucopicrin limits macrophage foam cell formation through a reduction of LOX-1 distribution in lipid rafts, thus contributing to its atheroprotective effect.

Physiotherapy Rehabilitation in Idiopathic Chronic Osteomyelitis: A Case Report

Osteomyelitis is an infection-related inflammation of the bones and bone marrow. Generally in the legs, arms, spine. Foot and ankle osteomyelitis can be excruciatingly painful for patients and a difficult management challenge for orthopedic surgeons. Acute staphylococcal osteomyelitis had a 50% death rate in the pre-antibiotic era. Osteomyelitis of the foot and ankle can occur due to a variety of reasons, with diabetic foot infections being one of the most common. Osteomyelitis is a bone marrow inflammation which progression, involving the cortical plates and frequently periosteal tissues, along with the majority of cases occurring after bone trauma or surgery, or as a result of vascular insufficiency. Chronic nonbacterial osteomyelitis is an autoinflammatory disease that primarily affects children and adolescents and is characterized by recurrent or persistent osteitic foci. The symptom is bone pain, which may or may not be accompanied by soft tissue tenderness. Chronic osteomyelitis is related with avascular necrosis of bone along with the establishment or formation of sequestrum (dead bone), and surgical debridement, in addition to antibiotic therapy, is required for cure. Physiotherapy has effect in improving the quality of life of the patient with osteomyelitis.

Computed and magnetic resonance imaging for osteomyelitis in children

Introduction. The frequency of osteomyelitis in pediatric population is approximately 1:5000, and the mortality rate is from 0.2% to 17.0%. In children, acute bone infection is most often of hematogenous origin. Transition from the classical radiography and radionuclide examination to computed tomography (CT) and magnetic resonance imaging (MRI) has been completed.Purpose. To demonstrate potentials of CT and MRI in the diagnostics of osteomyelitis in children.Material and methods. 238 children with osteomyelitis, aged 1-17 years (average 9.1 ± 4.9 years), were examined for the last ten years. There were 126 boys (53%) and 112 girls (47%). Depending on the disease nosology, patients were divided as follows: hematogenous osteomyelitis (n = 112 children, 47%), BCG-osteomyelitis (n = 20, 8.4%), post-traumatic osteomyelitis (n = 67, 28.2%). 138 children (58%) were treated surgically. CT scanning was performed in 174 patients using Brilliance 16 scanners. MRI was performed using Philips AchievadStream 3.0 T scanner to obtain multi-planar STIR, T1-, T2- and PD weighted images (SE and GE). In addition, new MRI methods were used: diffusion-weighted images (DWI), Dixon, dynamic MRI with contrast enhancement (DCE).Results. CT examination, which was performed in 174 patients at the same terms as radiography, confirmed density decrease ( though not large). Periosteal changes were better visualized at CT examination in 107 out of 174 patients (61.5%) including those who had changes at the classical radiography. MRI was performed in 51 patients ( including those with intravenous contrast enchancement) on Day 2-3 since the disease onset. This examination was effective in all cases (sensitivity 100%). T2WI and STIR with fat suppression (FS) clearly revealed edema of the bone marrow and surrounding muscles as well as small changes.Conclusion. MRI is the most informative diagnostic technique in acute osteomyelitis at its early period because main signs of the initial stage of this disease - edema of bone marrow, periosteum and soft tissues - are detected during the first days. In addition, MRI reveals details of bone and soft tissues damages, including abscess and sequester formation, especially in spinal and pelvic lesions. MRI sensitivity in osteomyelitis reaches up to 100%. Sequences with the fat suppression (FS) can better detect bone marrow edema and inflammation than radiography. MRI is a preferable technique in diagnostics of infectious lesions of the spine, pelvis, and limbs.

Novel Evidence That Alternative Activation Pathway of Complement Cascade (ComC) Regulates Optimal Homing and Engraftment of Hematopoietic Stem/Progenitor Cells (HSPCs) in Reactive Oxygen Species (ROS) - Nlrp3 Inflammasome-Dependent Manner

Background. We reported in the past that activation of the third (C3) and fifth element (C5) of complement cascade (ComC) is required not only for mobilization of hematopoietic stem progenitor cells (HSPCs) but also for their proper homing and engraftment after transplantation to bone marrow (BM) (Leukemia 2012; 26:106-16). The ComC consists of zymogen proteins that become activated in a cascade-mediated manner by the i) classical, ii) mannan-binding lectin (MBL), or iii) alternative pathway. However, it is not clear which of these pathways plays a crucial role in inducing state of sterile inflammation in recipient BM conditioned for transplantation. Interestingly, the alternative pathway of ComC activation, in contrast to the other two pathways, is not triggered by antibodies or specific structures expressed on the surface of invading microorganisms, but is continuously activated and “ticking” by the spontaneous hydrolysis of the third component of the ComC (C3), which is the most abundant complement protein present in blood plasma. This process of C3 hydrolysis is hyperactivated in response to tissue/organ damage and changes the structure of C3 in order to promote binding of factor B (FB) that initiates the amplification process by which more C3b molecules and C3b-Bb convertases are created responsible for activation of the ComC. We also recently demonstrated that homing and engraftment of HSPCs to BM is mediated by activation of innate immunity pattern recognition receptor Nlrp3 inflammasome (Leukemia 2020; 34:1512-1523). On the other hand reactive oxygen species (ROS) are known activators of Nlrp3 inflammasome. Hypothesis. We hypothesized that sensitive and “continuously ticking” in peripheral blood (PB) alternative pathway of ComC activation facilitates homing and engraftment of HSPCs in response to myeloablation triggered sterile inflammation of hematopoietic microenvironment in donor BM. We also hypothesized that this depends on the activation of the Nlrp3 inflammasome in ROS-dependent manner. Materials and Methods. Activation of ComC and Nlrp3 inflammasome in BM of conditioned for hematopoietic transplantation by lethal irradiation mice was evaluated by C5a ELISA assay and immunofluorescence glow assay measuring activation of Nlrp3 inflammasome product that is activated caspase-1, respectively. We also run shotgun proteomic analysis with BM conditioned media and BMMNCs extracts. The release of ROS was measured by a colorimetric assay. To assess the involvement of alternative pathway of ComC activation, we performed homing and engraftment experiments in wild-type (WT) and FB-deficient mice, that have defect in alternative pathway of ComC activation. FB-KO and WT animals were transplanted with WT BMMNC. We also analyzed changes in the BM microenvironment in response to lethal irradiation in WT and FB-KO mice at mRNA and protein level. Results. We demonstrate for a first time that conditioning for transplantation by myeloablative irradiation induces in BM state of sterile inflammation reflected by activation of ComC, the release of reactive oxygen species (ROS), and activation of Nlrp3 inflammasome in ROS-dependent manner. Moreover, as compared to WT animals, all these pathways were significantly inhibited in FB-KO mice. As a result of this FB-KO animals displayed defective homing and engraftment after transplantation of WT BMMNC. This correlated at molecular level by the decreased expression of cell adhesion molecules and group of structural proteins involved in so called “docking structures” necessary for cell migration and homing as well as for Nlrp3 inflammasome complex and caspase 1, 2, 4 and 6. Moreover, FB-KO mice demonstrated lower level of SDF-1 and KL in BM after myeloablative conditioning for transplantation. Conclusions. We provide for a first time an evidence that myeloablative conditioning for transplantation by lethal irradiation activates in ComC-ROS-Nlrp3 inflammasome - dependent manner a state of sterile inflammation in the BM microenvironment, required for optimal homing and engraftment. This data also explains this phenomenon at molecular level and provides an evidence for a crucial involvement of alternative pathway of ComC activation. DisclosuresNo relevant conflicts of interest to declare.

Circulating Tumor Cells (CTCs) in Smoldering and Active Multiple Myeloma (MM): Mechanism of Egression, Clinical Significance and Therapeutic Endpoints

Circulating Tumor Cells (CTCs) in Smoldering and Active Multiple Myeloma (MM): Mechanism of Egression, Clinical Significance and Therapeutic Endpoints

Gasdermin D Mediates Inflammation-Driven Pathogenesis of the Myelodysplastic Syndromes

The myelodysplastic syndromes (MDS) are a group of clonal hematopoietic stem cell diseases characterize by cytopenia(s), dysplasia in one or more of the major myeloid cell lines, ineffective hematopoiesis, and increased risk of development of acute myeloid leukemia (AML). Growing evidence revealed the significance of pyroptotic cell death in the inflammatory bone marrow in MDS. However, the detailed mechanisms of pyroptosis in the pathogenesis and progression of MDS remain unknown.Gasdermin D is a pore-forming protein that is cleaved upon inflammasome assembly by inflammatory caspases at the linker between the N-terminus pore-forming domain and the C-terminus autoinhibitory domain. The activation of gasdermin D results in increased cell permeability, cell pyroptosis, and the release of cytokines including Interleukin 1 (IL-1) family. Binding of these cytokines to the IL-1 receptor triggers the activation and release of other pro-inflammatory cytokines, including IL-6 and tumor necrosis factor (TNF).Our group recently established a Diap1 (encoding mDia1) and miR-146a double knockout (DKO) mouse model phenocopying MDS. These two genes are involved in the innate immune signaling and inflammation. DKO mice develop aging-related anemia and thrombocytopenia with over-secretion of pro-inflammatory cytokines. Many DKO mice progress to acute myeloid leukemia (AML) with monocytic differentiation and bone marrow fibrosis at 12 months of age. We found that gasdermin D is upregulated and activated (cleaved) in the bone marrow and spleens of the DKO mice. To study the role of gasdermin D in MDS, we crossed DKO mice with gasdermin D knock out mice to generate gasdermin D, mDia1, miR-146a triple knock out (TKO) mice. Gasdermin D knock out in the background of DKO significantly antagonized the increase of leukocyte count, especially the monocyte count, in the aging mice, and partially rescued the anemia. We transplanted bone marrow from 5-month-old TKO, DKO, and wildtype mice to 5-month-old lethally irradiated mice, respectively, to investigate whether the rescue effect of gasdermin D knock out was hematopoietic cell intrinsic. As expected, TKO bone marrow transplanted (BMT) mice had significantly less leukocyte count compared with DKO BMT mice, the anemia was also ameliorated in TKO BMT mice. More importantly, gasdermin D depletion in hematopoietic cells significantly extended the survival of DKO mice and reverted the progression to AML, suggesting a critical role of GSDMD in the pathogenesis of MDS.These findings indicate that gasdermin D plays a pivotal role in inflammation related MDS development and progression. This is further supported by the evidence that gasdermin D is highly upregulated in patients with MDS in our preliminary immunohistochemical studies in the bone marrow from patients with different types of MDS. Therefore, targeting gasdermin D could be a novel therapeutic approach in the management of MDS. DisclosuresNo relevant conflicts of interest to declare.

Adoptive Therapy with Allogeneic Cord Blood T Regulatory Cells Improves Transfusion Requirement in Bone Marrow Failure Syndromes

Adoptive Therapy with Allogeneic Cord Blood T Regulatory Cells Improves Transfusion Requirement in Bone Marrow Failure Syndromes

Vitamin D Deficiency, Osteoporosis and Effect on Autoimmune Diseases and Hematopoiesis: A Review.

Vitamin D (VD) is essential for bone homeostasis, but it is also involved in pleiotropic effects on various organs and tissues. In adults, VD deficiency can cause or exacerbate osteoporosis and induce osteomalacia. However, every tissue and cell in the body has a VD receptor, including the brain, heart, stomach, pancreas, skin, gonads, and immune cells, and a deficiency may modify the function of these organs. Thus, the wide-ranging actions of VD help to explain why a reduction in VD amount has been correlated with numerous chronic diseases. In fact, VD deficiency increases the risk of osteoporosis and several other diseases and complications characterized by impaired bone metabolisms, such as autoimmune diseases, inflammatory bowel diseases, allergy, endocrinological diseases, hematological malignancies, and bone marrow transplantation. This review aims to investigate the link between VD deficiency, osteoporosis, and its concomitant diseases. Further epidemiological and mechanistic studies are necessary in order to ascertain the real role of hypovitaminosis in causing the reported diseases; however, adequate vitamin supplementation and restoration of metabolic normality could be useful for better management of these pathologies.

CAR-HEMATOTOX: a model for CAR T-cell–related hematologic toxicity in relapsed/refractory large B-cell lymphoma

AbstractHematotoxicity represents a frequent chimeric antigen receptor (CAR) T-cell–related adverse event and remains poorly understood. In this multicenter analysis, we studied patterns of hematopoietic reconstitution and evaluated potential predictive markers in 258 patients receiving axicabtagene ciloleucel (axi-cel) or tisagenlecleucel (tisa-cel) for relapsed/refractory large B-cell lymphoma. We observed profound (absolute neutrophil count [ANC] <100 cells per µL) neutropenia in 72% of patients and prolonged (21 days or longer) neutropenia in 64% of patients. The median duration of severe neutropenia (ANC < 500 cells per µL) was 9 days. We aimed to identify predictive biomarkers of hematotoxicity using the duration of severe neutropenia until day +60 as the primary end point. In the training cohort (n = 58), we observed a significant correlation with baseline thrombocytopenia (r = −0.43; P = .001) and hyperferritinemia (r = 0.54; P < .0001) on univariate and multivariate analysis. Incidence and severity of cytokine-release syndrome, immune effector cell–associated neurotoxicity syndrome, and peak cytokine levels were not associated with the primary end point. We created the CAR-HEMATOTOX model, which included markers associated with hematopoietic reserve (eg, platelet count, hemoglobin, and ANC) and baseline inflammation (eg, C-reactive protein and ferritin). This model was validated in independent cohorts, one from Europe (n = 91) and one from the United States (n = 109) and discriminated patients with severe neutropenia ≥14 days to <14 days (pooled validation: area under the curve, 0.89; sensitivity, 89%; specificity, 68%). A high CAR-HEMATOTOX score resulted in a longer duration of neutropenia (12 vs 5.5 days; P < .001) and a higher incidence of severe thrombocytopenia (87% vs 34%; P < .001) and anemia (96% vs 40%; P < .001). The score implicates bone marrow reserve and inflammation prior to CAR T-cell therapy as key features associated with delayed cytopenia and will be useful for risk-adapted management of hematotoxicity.

Proerythroblast Cells of Diamond-Blackfan Anemia Patients With RPS19 and CECR1 Mutations Have Similar Transcriptomic Signature.

Diamond Blackfan Anemia (DBA) is an inherited bone marrow (BM) failure syndrome, characterized by a paucity of erythroid differentiation. DBA is mainly caused by the mutations in ribosomal protein genes, hence classified as ribosomopathy. However, in approximately 30% of patients, the molecular etiology cannot be discovered. RPS19 germline mutations caused 25% of the cases. On the other hand, CECR1 mutations also cause phenotypes similar to DBA but not being a ribosomopathy. Due to the blockade of erythropoiesis in the BM, we investigated the transcriptomic profile of three different cell types of BM resident cells of DBA patients and compared them with healthy donors. From BM aspirates BM mononuclear cells (MNCs) were isolated and hematopoietic stem cells (HSC) [CD71–CD34+ CD38mo/lo], megakaryocyte–erythroid progenitor cells (MEP) [CD71–CD34+ CD38hi] and Proerythroblasts [CD71+ CD117+ CD38+] were sorted and analyzed with a transcriptomic approach. Among all these cells, proerythroblasts had the most different transcriptomic profile. The genes associated with cellular stress/immune responses were increased and some of the transcription factors that play a role in erythroid differentiation had altered expression in DBA proerythroblasts. We also showed that gene expression levels of ribosomal proteins were decreased in DBA proerythroblasts. In addition to these, colony formation assay (CFU-E) provided functional evidence of the failure of erythroid differentiation in DBA patients. According to our findings that all patients resembling both RPS19 and CECR1 mutations have common transcriptomic signatures, it may be possible that inflammatory BM niche may have a role in DBA pathogenesis.

Exercise of high intensity ameliorates hepatic inflammation and the progression of NASH

ObjectiveNon-alcoholic fatty liver disease (NAFLD) covers a wide spectrum of liver pathology ranging from simple fatty liver to non-alcoholic steatohepatitis (NASH). Notably, immune cell-driven inflammation is a key mechanism in the transition from fatty liver to the more serious NASH. Although exercise training is effective in ameliorating obesity-related diseases, the underlying mechanisms of the beneficial effects of exercise remain unclear. It is unknown whether there is an optimal modality and intensity of exercise to treat NAFLD. The objective of this study was to determine whether high-intensity interval training (HIIT) or moderate-intensity continuous training (MIT) is more effective at ameliorating the progression of NASH. MethodsWild-type mice were fed a high-fat, high-carbohydrate (HFHC) diet for 6 weeks and left sedentary (SED) or assigned to either an MIT or HIIT regimen using treadmill running for an additional 16 weeks. MIT and HIIT groups were pair-fed to ensure that energy intake was similar between the exercise cohorts. To determine changes in whole-body metabolism, we performed insulin and glucose tolerance tests, indirect calorimetry, and magnetic resonance imaging. NASH progression was determined by triglyceride accumulation, expression of inflammatory genes, and histological assessment of fibrosis. Immune cell populations in the liver were characterized by cytometry by time-of-flight mass spectrometry, and progenitor populations within the bone marrow were assessed by flow cytometry. Finally, we analyzed the transcriptional profile of the liver by bulk RNA sequencing. ResultsCompared with SED mice, both HIIT and MIT suppressed weight gain, improved whole-body metabolic parameters, and ameliorated the progression of NASH by reducing hepatic triglyceride levels, inflammation, and fibrosis. However, HIIT was superior to MIT at reducing adiposity, improving whole-body glucose tolerance, and ameliorating liver steatosis, inflammation, and fibrosis, without any changes in body weight. Improved NASH progression in HIIT mice was accompanied by a substantial decrease in the frequency of pro-inflammatory infiltrating, monocyte-derived macrophages in the liver and reduced myeloid progenitor populations in the bone marrow. Notably, an acute bout of MIT or HIIT exercise had no effect on the intrahepatic and splenic immune cell populations. In addition, bulk mRNA sequencing of the entire liver tissue showed a pattern of gene expression confirming that HIIT was more effective than MIT in improving liver inflammation and lipid biosynthesis. ConclusionsOur data suggest that exercise lessens hepatic inflammation during NASH by reducing the accumulation of hepatic monocyte-derived inflammatory macrophages and bone marrow precursor cells. Our findings also indicate that HIIT is superior to MIT in ameliorating the disease in a dietary mouse model of NASH.