Pulmonary Arteriovenous Malformations in Dyskeratosis Congenita.

Pulmonary arteriovenous malformations (PAVMs) are rare lesions known to cause cyanosis due to abnormal communication between the pulmonary arteries and veins. They are commonly seen in association with hereditary hemorrhagic telangiectasia, congenital heart disease, hepatopulmonary syndrome, and portopulmonary shunting, but rarely in patients with dyskeratosis congenita (DC). We describe a patient previously diagnosed with DC confirmed to have microscopic PAVMs after bone marrow transplantation and discuss possible pathogenic mechanisms.

Risk factors associated with pediatric intensive care unit admission and mortality after pediatric stem cell transplant: possible role of renal involvement.

BACKGROUND: Hematopoietic stem-cell transplant (HSCT) is associated with many risk factors for life-threatening complications. Post-transplant critical illness often requires admission to the pediatric intensive care unit (PICU). METHODS: A retrospective analysis was made on the risk factors associated with PICU admission and mortality of all HSCT patients at Helen DeVos Children's Hospital from October 1998 to November 2008. RESULTS: One hundred and twenty-four patients underwent HSCT, with 19 (15.3%) requiring 29 PICU admissions. Fifty patients received autologous, 38 matched sibling, and 36 matched un-related donor HSCT, with 10%, 13% and 25% of these patients requiring PICU admission, respectively (P=0.01). Among the HSCT patients, those who were admitted to the PICU were more likely to have renal involvement by either malignancy requiring nephrectomy or a post transplant complication increasing the likelihood of decreased renal function (21.1% vs. 4.8%, P=0.03). PICU admissions were also more likely to receive pre-transplant total body irradiation (52.6% vs. 27.6%, P=0.03). Among 29 patients with PICU admission, 3 died on day 1 after admission, and 5 within 30 days (a mortality rate of 17%). Thirty days after PICU admission, non-survivors had a higher incidence of respiratory failure and septic shock on admission compared with survivors (80% vs. 16.7%, P=0.01 and 80% vs. 4.2%, respectively, P=0.001). Two survivors with chronic renal failure underwent renal transplantation successfully. CONCLUSIONS: Total body irradiation and renal involvement are associated with higher risk for PICU admissions after HSCT in pediatric patients, while septic shock upon admission and post-admission respiratory failure are associated with mortality.

Isolation of large numbers of mesenchymal stem cells from the washings of bone marrow collection bags: characterization of fresh mesenchymal stem cells.

BACKGROUND: Bone marrow (BM) is an excellent source of mesenchymal stem cells (MSC) which can be expanded in vitro for further use. However, large volumes of BM specimens are not routinely available. We hypothesized that the normally discarded BM collection kits might be a convenient source of large numbers of MSC. METHODS: Marrow specimens were isolated from used Fenwal collection kits. Purified mononuclear cells (MNC) were screened by multiparameter flow cytometry to identify MSC, which were later expanded by in vitro culture. Immunophenotyping and differentiation assays were performed initially and at subculture. Both fresh and frozen BM were tested. RESULTS: An average of 9.62E+08 MNC were collected. In this, a cell population was identified that was CD44+, CD73+, CD90+ and CD105+, but negative for hematopoietic markers. This population represented on average 0.015% of the total BM MNC fraction, or on average 1 in 6,666 MNC. The population was considered to be MSC based on its immunophenotype profile, suppressive ability in mixed lymphocyte cultures, morphology, and ability to differentiate into bone and fat cells. CONCLUSIONS: This study demonstrates that large numbers of MSC can be obtained from the normally discarded collection devices following harvest of BM for clinical transplant. This novel method offers potential for obtaining large numbers of MSC for potential therapeutic or investigational purposes following their in vitro expansion.