A purified population of multipotent cardiovascular progenitors derived from primate pluripotent stem cells engrafts in postmyocardial infarcted nonhuman primates

Cell therapy holds promise for tissue regeneration, including in individuals with advanced heart failure. However, treatment of heart disease with bone marrow cells and skeletal muscle progenitors has had only marginal positive benefits in clinical trials, perhaps because adult stem cells have limited plasticity. The identification, among human pluripotent stem cells, of early cardiovascular cell progenitors required for the development of the first cardiac lineage would shed light on human cardiogenesis and might pave the way for cell therapy for cardiac degenerative diseases. Here, we report the isolation of an early population of cardiovascular progenitors, characterized by expression of OCT4, stage-specific embryonic antigen 1 (SSEA-1), and mesoderm posterior 1 (MESP1), derived from human pluripotent stem cells treated with the cardiogenic morphogen BMP2. This progenitor population was multipotential and able to generate cardiomyocytes as well as smooth muscle and endothelial cells. When transplanted into the infarcted myocardium of immunosuppressed nonhuman primates, an SSEA-1⁺ progenitor population derived from Rhesus embryonic stem cells differentiated into ventricular myocytes and reconstituted 20% of the scar tissue. Notably, primates transplanted with an unpurified population of cardiac-committed cells, which included SSEA-1^– cells, developed teratomas in the scar tissue, whereas those transplanted with purified SSEA-1⁺ cells did not. We therefore believe that the SSEA-1⁺ progenitors that we have described here have the potential to be used in cardiac regenerative medicine.     

Bone Marrow-derived Myofibroblasts Are the Providers of Pro-invasive Matrix Metalloproteinase 13 in Primary Tumor

Carcinoma-associated fibroblasts are key contributors of the tumor microenvironment that regulates carcinoma progression. They consist of a heterogeneous cell population with diverse origins, phenotypes, and functions. In the present report, we have explored the contribution of bone marrow (BM)-derived cells to generate different fibroblast subsets that putatively produce the matrix metalloproteinase 13 (MMP13) and affect cancer cell invasion. A murine model of skin carcinoma was applied to mice, irradiated, and engrafted with BM isolated from green fluorescent protein (GFP) transgenic mice. We provide evidence that one third of BM-derived GFP⁺ cells infiltrating the tumor expressed the chondroitin sulfate proteoglycan NG2 (pericytic marker) or α-smooth muscle actin (α-SMA, myofibroblast marker), whereas almost 90% of Thy1⁺ fibroblasts were originating from resident GFP-negative cells. MMP13producing cells were exclusively α-SMA⁺ cells and derived from GFP⁺ BM cells. To investigate their impact on tumor invasion, we isolated mesenchymal stem cells (MSCs) from the BM of wild-type and MMP13-deficient mice. Wild-type MSC promoted cancer cell invasion in a spheroid assay, whereas MSCs obtained from MMP13-deficient mice failed to. Our data support the concept of fibroblast subset specialization with BM-derived α-SMA⁺ cells being the main source of MMP13, a stromal mediator of cancer cell invasion.     

Species identification of clinical Prevotella isolates by matrix-assisted laser desorption ionization-time of flight mass spectrometry

The performance of matrix-assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF MS) for species identification of Prevotella was evaluated and compared with 16S rRNA gene sequencing. Using a Bruker database, 62.7% of the 102 clinical isolates were identified to the species level and 73.5% to the genus level. Extension of the commercial database improved these figures to, respectively, 83.3% and 89.2%. MALDI-TOF MS identification of Prevotella is reliable but needs a more extensive database.     

Potential role of tocilizumab in severe gastrointestinal barrier damage after CAR T-cell therapy

We report a septicemia and disseminated candidiasis due to delayed gastrointestinal mucosae repair in a patient treated with tocilizumab after anti-CD19 CAR T-cell therapy. Tocilizumab could have inhibited intestinal tissue repair and furthered bacteria translocation leading to the invasion of intestinal mucosa by yeasts as IL-6 is known to be involved in mucosal wound healing.     

Palivizumab prophylaxis of respiratory syncytial virus disease in 2000-2001: results from The Palivizumab Outcomes Registry

The objective of the Registry was to characterize the population of infants receiving prophylaxis for respiratory syncytial virus (RSV) disease by describing the patterns and scope of usage of palivizumab in a cross section of US infants. RSV hospitalization outcomes were also described. The Palivizumab (Synagis, MedImmune, Inc., 25 West Watkins Mill Road, Gaithersburg, MD 20878) Outcomes Registry was a prospective multicenter survey conducted at 63 sites. Demographics, injection history, and RSV hospitalization outcomes were collected on 2,116 infants receiving palivizumab. Infants were enrolled in the Registry between September 1, 2000-March 1, 2001, at the time of their first injection. Infants born at less than 32 weeks of gestation accounted for 47% of infants enrolled, and those between 32-35 weeks accounted for 45%; approximately 8% were greater than 35 weeks of gestation. Lower RSV hospitalization rates were observed in infants who had greater adherence to regularly scheduled injections. Nearly one-half of all hospitalizations occurred within the first and second injection intervals, suggesting the importance of early RSV protection. The confirmed RSV hospitalization rate of all infants in the Registry was 2.9%; the rate was 5.8% in infants with chronic lung disease of infancy, and 2.1% in premature infants without chronic lung disease. In conclusion, these data support the continued effectiveness of palivizumab prophylaxis for severe RSV lower respiratory tract disease in a large cohort of high-risk infants from geographically diverse pediatric offices and clinics. The Palivizumab Outcomes Registry provides an opportunity to assess palivizumab utilization and clinical effectiveness in the US.