Platelet-rich concentrate in serum-free medium enhances cartilage-specific extracellular matrix synthesis and reduces chondrocyte hypertrophy of human mesenchymal stromal cells encapsulated in alginate

Platelet-rich concentrate (PRC), used in conjunction with other chondroinductive growth factors, have been shown to induce chondrogenesis of human mesenchymal stromal cells (hMSC) in pellet culture. However, pellet culture systems promote cell hypertrophy and the presence of other chondroinductive growth factors in the culture media used in previous studies obscures accurate determination of the effect of platelet itself in inducing chondrogenic differentiation. Hence, this study aimed to investigate the effect of PRC alone in enhancing the chondrogenic differentiation potential of human mesenchymal stromal cells (hMSC) encapsulated in three-dimensional alginate constructs. Cells encapsulated in alginate were cultured in serum-free medium supplemented with only 15% PRC. Scanning electron microscopy was used to determine the cell morphology. Chondrogenic molecular signature of hMSCs was determined by quantitative real-time PCR and verified at protein levels via immunohistochemistry and enzyme-linked immunosorbent assay. Results showed that the cells cultured in the presence of PRC for 24 days maintained a chondrocytic phenotype and demonstrated minimal upregulation of cartilaginous extracellular matrix (ECM) marker genes (SOX9, TNC, COL2, ACAN, COMP) and reduced expression of chondrocyte hypertrophy genes (Col X, Runx2) compared to the standard chondrogenic medium (p < 0.05). PRC group had correspondingly higher levels of glycosaminoglycan and increased concentration of chondrogenic specific proteins (COL2, ACAN, COMP) in the ECM. In conclusion, PRC alone appears to be very potent in inducing chondrogenic differentiation of hMSCs and offers additional benefit of suppressing chondrocyte hypertrophy, rendering it a promising approach for providing abundant pool of chondrogenic MSCs for application in cartilage tissue engineering.     

Design of a Traumatic Injury Simulator for Assessing Lower Limb Response to High Loading Rates

Current military conflicts are characterized by the use of the improvised explosive device. Improvements in personal protection, medical care, and evacuation logistics have resulted in increasing numbers of casualties surviving with complex musculoskeletal injuries, often leading to life-long disability. Thus, there exists an urgent requirement to investigate the mechanism of extremity injury caused by these devices in order to develop mitigation strategies. In addition, the wounds of war are no longer restricted to the battlefield; similar injuries can be witnessed in civilian centers following a terrorist attack. Key to understanding such mechanisms of injury is the ability to deconstruct the complexities of an explosive event into a controlled, laboratory-based environment. In this article, a traumatic injury simulator, designed to recreate in the laboratory the impulse that is transferred to the lower extremity from an anti-vehicle explosion, is presented and characterized experimentally and numerically. Tests with instrumented cadaveric limbs were then conducted to assess the simulator’s ability to interact with the human in two mounting conditions, simulating typical seated and standing vehicle passengers. This experimental device will now allow us to (a) gain comprehensive understanding of the load-transfer mechanisms through the lower limb, (b) characterize the dissipating capacity of mitigation technologies, and (c) assess the bio-fidelity of surrogates.     

Meniscal Root Repair Along with Auxiliary Procedures for Joint Preservation: Current Concepts

Meniscal root repair and joint preservation surgeries have gained increased interest in the last decade, from a better interpretation of the role of meniscal functions, from the biomechanical studies. Several published results from both biomechanical and clinical studies has proven the effectiveness of meniscal root repairs and has led to a unanimous international consensus for the need for root repair surgery. Meniscal repair by suture pull-out technique is widely followed around the world and leads to adequate healing and good clinical outcome. There are auxiliary procedures like centralization sutures (to reduce the meniscal extrusion), high tibial osteotomy, cartilage repair procedures, meniscal root reconstruction and ligament reconstructions are performed along with meniscal root repair, especially in the younger patients and recently sub-chondroplasty for the bone marrow lesions (BMLs) are also executed. This review article discusses the anatomy, types of root tears, evaluation, treatment, outcomes of root repair, and the need for additional procedures, which are imperative for joint preservation and restoration of the biomechanics of the knee.     

Why should we screen for male fertility?

An increasing number of studies show declining sperm counts; however, semen analyses are uncommon until the evaluation for infertility. Semen analysis is a safe, reliable and relatively inexpensive screening test, assessing male fertility and directing further work-up. In young men, the use of semen analysis may identify disease prior to attempted conception and result in improved fertility potential when combined with lifestyle changes, medical or surgical therapy. Furthermore, if sperm counts are significantly low, evaluation and management for genetic causes can be initiated. Our commentary outlines why screening for male infertility in young adult men may be beneficial. We discuss options for early intervention, including sperm cryopreservation, if defects in sperm parameters are identified.     

Activation of plasmacytoid dendritic cells promotes AML-cell fratricide

Acute myeloid leukemia (AML) is characterized by the proliferation of immature myeloid blasts and a suppressed immune state. Interferons have been previously shown to aid in the clearance of AML cells. Type I interferons are produced primarily by plasmacytoid dendritic cells (pDCs). However, these cells exist in a quiescent state in AML. Because pDCs express TLR 7–9, we hypothesized that the TLR7/8 agonist R848 would be able to reprogram them toward a more active, IFN-producing phenotype. Consistent with this notion, we found that R848-treated pDCs from patients produced significantly elevated levels of IFNβ. In addition, they showed increased expression of the immune-stimulatory receptor CD40. We next tested whether IFNβ would influence antibody-mediated fratricide among AML cells, as our recent work showed that AML cells could undergo cell-to cell killing in the presence of the CD38 antibody daratumumab. We found that IFNβ treatment led to a significant, IRF9-dependent increase in CD38 expression and a subsequent increase in daratumumab-mediated cytotoxicity and decreased colony formation. These findings suggest that the tolerogenic phenotype of pDCs in AML can be reversed, and also demonstrate a possible means of enhancing endogenous Type I IFN production that would promote daratumumab-mediated clearance of AML cells.