Browsing by Author "Tracy, Elisabeth T"
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Item Open Access Gallbladder abnormalities in children with metachromatic leukodystrophy.(The Journal of surgical research, 2017-02) Kim, Jina; Sun, Zhifei; Ezekian, Brian; Schooler, Gary R; Prasad, Vinod K; Kurtzberg, Joanne; Rice, Henry E; Tracy, Elisabeth TBackground
Metachromatic leukodystrophy (MLD) is a lysosomal storage disease that leads to neurological deterioration and visceral involvement, including sulphatide deposition in the gallbladder wall. Using our institution's extensive experience in treating MLD, we examined the incidence of gallbladder abnormalities in the largest cohort of children with MLD to date.Methods
We conducted a retrospective review of all children with MLD, adrenoleukodystrophy (ALD), or Krabbe disease who underwent hematopoietic stem cell transplantation (HSCT) at our institution between 1994 and 2015. Baseline characteristics and unadjusted outcomes were compared using the Kruskal-Wallis test for continuous variables and Pearson χ2 test for categorical variables, with significance defined as P < 0.05.Results
In total, 87 children met study criteria: 29 children with MLD and 58 children with ALD or Krabbe disease. Children with MLD were more likely to demonstrate gallbladder abnormalities on imaging, both before HSCT (41.4% versus 5.2%, P < 0.001) and after HSCT (75.9% versus 41.4%, P = 0.002). Consequently, a larger proportion of children with MLD underwent surgical or interventional management of biliary disease (10.3% versus 3.4%, P = 0.03).Conclusions
Children with MLD have a significantly greater incidence of gallbladder abnormalities than children with other lysosomal storage diseases. Biliary disease should be considered in children with MLD who develop abdominal pain, and cholecystectomy should be considered for persistent, symptomatic gallbladder abnormalities.Item Open Access Isolation and expansion of oligodendrocyte progenitor cells from cryopreserved human umbilical cord blood.(Cytotherapy, 2011-07) Tracy, Elisabeth T; Zhang, Claire Y; Gentry, Tracy; Shoulars, Kevin W; Kurtzberg, JoanneBackground aims
Oligodendrocyte precursor cells (OPC) hold promise as a cellular therapy for demyelinating diseases. The feasibility of using OPC-based therapies in humans depends upon a reliable, readily available source. We have previously described the isolation, expansion and characterization of oligodendrocyte-like cells from fresh human umbilical cord blood (UCB). We now describe the isolation and expansion of OPC from thawed, cryopreserved UCB.Methods
We thawed cryopreserved UCB units employing a standard clinical protocol, then isolated and plated mononuclear cells under previously established culture conditions. All OPC cultures were trypsinized at 21 days, counted, then characterized by flow cytometry after fixation, permeablization and labeling with the following antibodies: anti-oligodendrocyte marker 4 (O4), anti-oligodendrocyte marker 1 (O1) and anti-myelin basic protein (MBP). OPC were also placed in co-culture with shiverer mouse neuronal cells then stained in situ for beta tubulin III (BT3) and MBP as a functional assay of myelination.Results
The average OPC yield per cryopreserved UCB unit was 64% of that seen with fresh UCB. On flow cytometric analysis, 74% of thawed UCB units yielded cells with an O4-expression level of at least 20% of total events, compared with 95% of fresh UCB units. We observed myelination of shiverer neurons in our functional assay, which could be used as a potency assay for release of OPC cells in phase I human clinical trials.Conclusions
Our results demonstrate that OPC can be derived reliably from thawed, cryopreserved UCB units, and support the feasibility of using these cells in human clinical trials.Item Open Access Partial splenectomy but not total splenectomy preserves immunoglobulin M memory B cells in mice.(Journal of pediatric surgery, 2011-09) Tracy, Elisabeth T; Haas, Karen M; Gentry, Tracy; Danko, Melissa; Roberts, Joseph L; Kurtzberg, Joanne; Rice, Henry EPurpose
The mechanism by which partial splenectomy preserves splenic immune function is unknown. Immunoglobulin (Ig) M memory B cells are critical for the immune response against encapsulated bacteria and are reduced in asplenic patients, although it is unknown whether partial splenectomy can preserve memory B cells. We hypothesized that IgM memory B cells (murine B-1a cells) would be preserved after partial splenectomy but not after total splenectomy in mice.Methods
We performed total splenectomy (n = 17), partial splenectomy (n = 10), or sham laparotomy (n = 16) on C57BL/6J mice. Mice were killed on postoperative day 10 or 30, and peritoneal washings were analyzed by multiparameter flow cytometry for expression of murine B-1a cells (IgM(pos)IgD(dull)CD5(pos)B220(dull)).Results
We found that B-1a cells were significantly reduced after both total and partial splenectomies compared with sham laparotomy in the early postoperative period, although normal levels of B-1a cells returned by postoperative day 30 in mice undergoing partial splenectomy but not total splenectomy.Conclusion
Partial splenectomy but not total splenectomy preserves the B-1a B-cell population in mice within 30 days after surgery. Maintenance of these critical B cells may contribute to the preservation of a splenic-dependent immune response after partial splenectomy.Item Open Access Splenectomy and partial splenectomy improve hematopoietic stem cell engraftment in hypersplenic mice.(Journal of pediatric surgery, 2010-06) Tracy, Elisabeth T; Talbot, Lindsay J; Kurtzberg, Joanne; Rice, Henry EBackground
Hematopoietic stem cell (HSC) engraftment is delayed after transplantation in children with hypersplenism, increasing the morbidity and costs of care. Preliminary clinical data suggest that splenectomy before HSC transplantation may improve HSC engraftment, although this observation has not been tested in an animal model.Methods
We performed total splenectomy (n = 22), partial splenectomy (n = 16), or sham laparotomy (n = 21) on erythrocyte protein 4.2 knockout mice, a murine model of hereditary spherocytosis with hypersplenism. After 10 days, we lethally irradiated the mice, transplanted 3 x 10(6) allogeneic bone marrow cells, and then assessed engraftment using serial complete blood counts. Successful engraftment was defined as recovery of hemoglobin, neutrophil, or platelet counts. We compared engraftment rate using chi(2) test and time to engraftment using Student's t test analysis, with significance defined as P < .05.Results
Total splenectomy increased the rate of successful HSC engraftment and decreased the interval to HSC engraftment compared with controls. Similarly, partial splenectomy decreased the interval to HSC engraftment, with a nonsignificant trend toward improved overall rate of successful HSC engraftment.Conclusion
Partial or total splenectomy before HSC transplantation improves HSC engraftment in hypersplenic mice. This model supports consideration of splenic resection in hypersplenic children requiring HSC transplantation.