New Insights into Osteogenic and Chondrogenic Differentiation of Human Bone Marrow Mesenchymal Stem Cells and Their Potential Clinical Applications for Bone Regeneration in Pediatric Orthopaedics

Human mesenchymal stem cells (hMSCs) are pluripotent adult stem cells capable of being differentiated into osteoblasts, adipocytes, and chondrocytes. The osteogenic differentiation of hMSCs is regulated either by systemic hormones or by local growth factors able to induce specific intracellular signal pathways that modify the expression and activity of several transcription factors. Runt-related transcription factor 2 (Runx2) and Wnt signaling-related molecules are the major factors critically involved in the osteogenic differentiation process by hMSCs, and SRY-related high-mobility-group (HMG) box transcription factor 9 (SOX9) is involved in the chondrogenic one. hMSCs have generated a great interest in the field of regenerative medicine, particularly in bone regeneration. In this paper, we focused our attention on the molecular mechanisms involved in osteogenic and chondrogenic differentiation of hMSC, and the potential clinical use of hMSCs in osteoarticular pediatric disease characterized by fracture nonunion and pseudarthrosis

New Insights into Osteogenic and Chondrogenic Differentiation of Human Bone Marrow Mesenchymal Stem Cells and Their Potential Clinical Applications for Bone Regeneration in Pediatric Orthopaedics

Human mesenchymal stem cells (hMSCs) are pluripotent adult stem cells capable of being differentiated into osteoblasts, adipocytes, and chondrocytes. The osteogenic differentiation of hMSCs is regulated either by systemic hormones or by local growth factors able to induce specific intracellular signal pathways that modify the expression and activity of several transcription factors. Runt-related transcription factor 2 (Runx2) and Wnt signaling-related molecules are the major factors critically involved in the osteogenic differentiation process by hMSCs, and SRY-related high-mobility-group (HMG) box transcription factor 9 (SOX9) is involved in the chondrogenic one. hMSCs have generated a great interest in the field of regenerative medicine, particularly in bone regeneration. In this paper, we focused our attention on the molecular mechanisms involved in osteogenic and chondrogenic differentiation of hMSC, and the potential clinical use of hMSCs in osteoarticular pediatric disease characterized by fracture nonunion and pseudarthrosis

Immunity to infections after haploidentical hematopoietic stem cell transplantation

The advantage of using a Human Leukocyte Antigen (HLA)-mismatched related donor is that almost every patient who does not have an HLA-identical donor or who urgently needs hematopoietic stem cell transplantation (HSCT) has at least one family member with whom shares one haplotype (haploidentical) and who is promptly available as a donor. The major challenge of haplo-HSCT is intense bi-directional alloreactivity leading to high incidences of graft rejection and graft-versus-host disease (GVHD). Advances in graft processing and pharmacologic prophylaxis of GVHD have reduced these risks and have made haplo-HSCT a viable alternative for patients lacking a matched donor. Indeed, the haplo-HSCT has spread to centers worldwide even though some centers have preferred an approach based on T cell depletion of G-CSF-mobilized peripheral blood progenitor cells (PBPCs), others have focused on new strategies for GvHD prevention, such as G-CSF priming of bone marrow and robust post-transplant immune suppression or post-transplant cyclophosphamide (PTCY). Today, the graft can be a megadose of T-cell depleted PBPCs or a standard dose of unmanipulated bone marrow and/or PBPCs. Although haplo-HSCT modalities are based mainly on high intensity conditioning regimens, recently introduced reduced intensity regimens (RIC) showed promise in decreasing early transplant-related mortality (TRM), and extending the opportunity of HSCT to an elderly population with more comorbidities. Infections are still mostly responsible for toxicity and non-relapse mortality due to prolonged immunosuppression related, or not, to GVHD. Future challenges lie in determining the safest preparative conditioning regimen, minimizing GvHD and promoting rapid and more robust immune reconstitution

Maintenance of renal function in a patient with a history of acute paroxysmal nocturnal hemoglobinuria-associated kidney injury

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening blood disorder characterized by intravascular hemolysis, thrombosis and bone marrow failure. Acute kidney injury, including acute renal failure, have been reported in patients with PNH. We report the case of a 36-year-old male patient with PNH who developed acute kidney injury following an infection of undetermined diagnosis. Although hemolysis was initially controlled and renal function stabilized following packed red blood cell transfusion and empirical levofloxacin and prednisone, he later experienced recurrent episodes of hemolysis and hematuria requiring monthly red blood cell support. Given the high risk of thromboembolic events, treatment with standard-dose eculizumab was started. The patient's hematologic values improved, renal function was maintained, and no thromboembolic events occurred

Noncanonical Fungal Autophagy Inhibits Inflammation in Response to IFN-γ via DAPK1

Defects in a form of noncanonical autophagy, known as LC3-associated phagocytosis (LAP), lead to increased inflammatory pathology during fungal infection. Although LAP contributes to fungal degradation, the molecular mechanisms underlying LAP-mediated modulation of inflammation are unknown. We describe a mechanism by which inflammation is regulated during LAP through the death-associated protein kinase 1 (DAPK1). The ATF6/C/EBP-β/DAPK1 axis activated by IFN-γ not only mediates LAP to Aspergillus fumigatus but also concomitantly inhibits Nod-like receptor protein 3 (NLRP3) activation and restrains pathogenic inflammation. In mouse models and patient samples of chronic granulomatous disease, which exhibit defective autophagy and increased inflammasome activity, IFN-γ restores reduced DAPK1 activity and dampens fungal growth. Additionally, in a cohort of hematopoietic stem cell-transplanted patients, a genetic DAPK1 deficiency is associated with increased inflammation and heightened aspergillosis susceptibility. Thus, DAPK1 is a potential drugable player in regulating the inflammatory response during fungal clearance initiated by IFN-γ

Haploidentical hematopoietic stem cell transplantation in adults using the αβTCR/CD19-based depletion of G-CSF-mobilized peripheral blood progenitor cells

In patients with hematological malignancies at high risk for relapse, a mismatched hematopoietic stem cells transplants can be offered with no undue delay between decision-making and transplantation as virtually all patients have a full-haplotype mismatched member who could serve immediately as a donor. Using a T-cell depletion approach, these patients can benefit from a graft-vs-leukemia effect in the absence of both acute and chronic graft-vs-host disease. Over the past decade, efforts have concentrated on developing new conditioning regimens, optimizing the graft processing and improving the posttransplant immunological recovery. The innovative strategy based on the selective depletion of alpha/beta-positive T lymphocytes from G-CSF-mobilized peripheral blood precursor cells has shown very promising results in the setting of the pediatric transplantation. This paper reports the outcome in adult patients with hematological malignancies

Bloodstream infections due to Gram-negative bacteria in patients with hematologic malignancies: updated epidemiology and risk factors for multidrug-resistant strains in an Italian perspective survey

: Bloodstream infections (BSI) caused by Gram-negative bacteria (GNB) in patients with hematological malignancies (HM) have been associated with high mortality rates, particularly with infections caused by antibiotic-resistant strains. A multicenter cohort study including all consecutive episodes of GNB BSI in HM patients was conducted to update the epidemiology and antibiotic resistance patterns (compared to our previous survey conducted between 2009 and 2012) and investigate risk factors for GNB BSI due to multidrug-resistant (MDR) isolates. A total of 834 GNB were recovered in 811 BSI episodes from January 2016 to December 2018. Compared to the previous survey, there was a significant reduction in use of fluoroquinolone prophylaxis and a significant recovery in susceptibility rates to ciprofloxacin among Pseudomonas aeruginosa, Escherichia coli and Enterobacter cloacae isolates. In addition, there was a shift to a significantly increased susceptibility of P. aeruginosa isolates to ceftazidime, meropenem, and gentamicin. A total of 256/834 (30.7%) isolates were MDR. In multivariable analysis, MDR bacteria culture-positive surveillance rectal swabs, previous therapy with aminoglycosides and carbapenems, fluoroquinolone prophylaxis, and time at risk were independently associated with MDR GNB BSI. In conclusion, despite the persistence of a high prevalence of MDR GNB, there was a shift to a reduced use of fluoroquinolone prophylaxis and increased rates of susceptibility to fluoroquinolones in almost all isolates and to almost all antibiotics tested among P. aeruginosa isolates, compared to our previous survey. Fluoroquinolone prophylaxis and previous rectal colonization by MDR bacteria were independent risk factors for MDR GNB BSI in the present study

Rhodotorula infection in haematological patient: risk factors and outcome

Rhodotorula spp are uncommon yeasts able to cause infections with high mortality rates. Rhodotorula infections have been associated with the presence of central venous catheter (CVC), immunosuppression, exposure to antifungals and the presence of either solid or hematologic malignancies. However, in this latter setting, only a few cases have so far been reported

SEIFEM 2017: from real life to an agreement on the use of granulocyte transfusions and colony-stimulating factors for prophylaxis and treatment of infectious complications in patients with hematologic malignant disorders

The rapid spread of severe infections mainly due to resistant pathogens, justifies the search for therapies aiming to restore immune functions severely compromised in patients with hematologic malignancies. Areas covered: The present review summarizes the current knowledge on the role of granulocyte transfusions and colony-stimulating factors as treatment strategy for hematologic patients with serious infectious complications. In addition, a survey among 21 hematologic centers, to evaluate the clinical practice for the use of G-CSF originator and biosimilars was performed. Expert commentary: Granulocyte transfusions with a target dose of at least 1.5-3 7 108 cells/kg, may be considered as an approach to bridge the gap between marrow suppression and recovery of granulocytes. G-CSF shortens the period of neutropenia, the hospitalization, the use of antibiotics and the rate of febrile neutropenia (FN) in adult and pediatric patients with non-Hodgkin lymphoma, and in adults with acute myeloid leukemia where these advantages nevertheless, did not translate into a clinical benefit. G-CSF biosimilar showed equivalence or non-inferiority to filgrastim. There are no data supporting the use of GM-CSF, eltrombopag and erythropoietin for preventing or treating infectious complications in patients with hematologic disorders