Differential Expression of Adhesion-Related Proteins and MAPK Pathways Lead to Suitable Osteoblast Differentiation of Human Mesenchymal Stem Cells Subpopulations.

Cellular adhesion enables communication between cells and their environment. Adhesion can be achieved throughout focal adhesions and its components influence osteoblast differentiation of human mesenchymal stem cells (hMSCs). Because cell adhesion and osteoblast differentiation are closely related, this article aimed to analyze the expression profiles of adhesion-related proteins during osteoblastic differentiation of two hMSCs subpopulations (CD105(+) and CD105(-)) and propose a strategy for assembling bone grafts based on its adhesion ability. In vitro experiments of osteogenic differentiation in CD105(-) cells showed superior adhesion efficiency and 2-fold increase of α-actinin expression compared with CD105(+) cells at the maturation stage. Interestingly, levels of activated ß1-integrin increased in CD105(-) cells during the process. Additionally, the CD105(-) subpopulation showed 3-fold increase of phosphorylated FAK(Y397) compared to CD105(+) cells. Results also indicate that ERK1/2 was activated during CD105(-) bone differentiation and participation of mitogen-activated protein kinase (MAPK)-p38 in CD105(+) differentiation through a focal adhesion kinase (FAK)-independent pathway. In vivo trial demonstrated that grafts containing CD105(-) showed osteocytes embedded in a mineralized matrix, promoted adequate graft integration, increased host vascular infiltration, and efficient intramembranous repairing. In contrast, grafts containing CD105(+) showed deficient endochondral ossification and fibrocartilaginous tissue. Based on the expression of α-actinin, FAKy,(397) and ERK1/2 activation, we define maturation stage as critical for bone graft assembling. By in vitro assays, CD105(-) subpopulation showed superior adhesion efficiency compared to CD105(+) cells. Considering in vitro and in vivo assays, this study suggests that integration of a scaffold with CD105(-) subpopulation at the maturation stage represents an attractive strategy for clinical use in orthopedic bioengineering.

Mucormycosis in a Non-Hodgkin Lymphoma Patient Caused by Syncephalastrum racemosum: Case Report and Review of Literature.

Mucormycosis is a rare opportunistic fungal infection caused by saprophytic zygomycetes. These fungal infections are caused by members of the mucorales. The clinical importance of zygomycosis, an emerging and frequently fatal mycotic disease, has increased during recent years, due to several risk factors such as (a) the use of broad-spectrum antibiotic, (b) use of empirical antifungal treatment (mainly triazoles), and (c) aggressive chemotherapy and sustained leucopenia (i.e., peripheral stem cell transplantation). An almost fulminant pneumonia caused by Syncephalastrum racemosum in an immunocompromised patient with an aggressive non-Hodgkin lymphoma (NHL) is described. Despite treatment with amphotericin B, deoxycholate, caspofungin, and surgical resection of fungal bodies from both lungs, and survival of 10 months without relapsing from fungal infection, the patient died due to hematological complications from an unresponsive disease. Herein is the description of the first case of pulmonary infection caused by Syncephalastrum racemosum.

Characterization of mesenchymal stem cell subpopulations from human amniotic membrane with dissimilar osteoblastic potential.

Human fetal mesenchymal stem cells can be isolated from the amniotic membrane (AM-hMSCs) by enzymatic digestion. The biological properties of this cell population have been characterized; however, few studies have focused on the presence of stem cell subpopulations and their differentiation potential. The aim of the present study was to isolate homogeneous AM-hMSC subpopulations based on the coexpression of surface markers. In addition, we aimed to characterize stem cell subpopulations through the detection of typical stem cell markers and its differentiation potential. In this study, fluorescence-activated cell sorting (FACS) was used to positively select for the surface markers CD44, CD73, and CD105. Two subpopulations were isolated: CD44+ / CD73+ / CD105+ (CD105+), and CD44+ / CD73+ / CD105- (CD105-). To characterize the cell subpopulations, the expression of pluripotency-associated markers was analyzed by reverse transcriptase-polymerase chain reaction and immunofluorescence. Our results showed positive expression of SOX2, SOX3, PAX6, OCT3/4, and NANOG in the CD105+ and CD105(-) cell subpopulations. In contrast, we did not detect expression of SSEA4 or FOXD3 in either subpopulation. Immunophenotypes, such as mesenchymal and hematopoietic markers, were studied by FACS analyses. Our data revealed the expression of the CD49a, CD49d, CD29, integrin α9ß1, CD44, CD73, and CD105 antigens in both subpopulations. In contrast, CD90, CD45, CD34, CD14, and HLA-DR expression was not detected. The ability of both subpopulations to differentiate into osteoblasts, adipocytes, and chondrocytes was evidenced using Alizarin red, Oil-Red, and Alcian blue staining, respectively. Furthermore, neuronal differentiation was demonstrated by the expression of GFAP and NEURO-D. Interestingly, we observed a dissimilar osteoblastic differentiation potential between the subpopulations. CD105- cells showed stronger expression of secreted protein acidic and rich in cysteine (SPARC) and osteonectin, which was associated with more effective calcium deposition, than CD105+ cells. In conclusion, we described a systematic method for the isolation of hMSCs that was highly reproducible and generated homogeneous cultures for osteoblast differentiation with an efficient capacity for mineralization.

Mycobacterium avium subsp. paratuberculosis detection in individual and bulk tank milk samples from bovine herds and caprine flocks.

Paratuberculosis, or Johne's disease, is caused by Mycobacterium avium subsp. paratuberculosis (Map), and it generates great economic losses for the dairy industry worldwide. In humans, Map has been associated with Crohn's disease. Mexico has unknown paratuberculosis prevalence, and yet, control programs have not been applied. This study aimed to determine the presence of Map in milk samples from seropositive goats and cows and bulk tank milk samples from herds previously designated Map-infected using indirect enzyme-linked immunosorbent assay. Map DNA was detected in 100% of the bulk tank milk samples of 14 bovine herds and 3 caprine flocks using a modified insertion sequence 900 polymerase chain reaction (PCR). Additionally, Map DNA was detected in 100% of the individual milk samples from 10 cows and 8 goats. Further, based on the findings of the experimental insertion sequence 900 PCR assessment, evaluation of bulk tank and individual milk samples through a type-specific PCR was performed, which confirmed our previous findings and revealed that 56.25% cow and 63.63% goat milk had concurrent infections of the C, I, and S types. Out of 14 bulk tank milk samples, 10 had viable mycobacteria. Paratuberculosis was detected at a high frequency in cow and goat milk, which suggests that raw milk ingestion represents a potential risk of Map infection.