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Survival and maturation of human embryonic stem cell-derived cardiomyocytes in rat hearts
(Elsevier, 2007) Dai, Wangde; Field, Loren J.; Rubart, Michael; Reuter, Sean; Hale, Sharon L.; Zweigerdt, Robert; Graichen, Ralph E.; Kay, Gregory L.; Jyrala, Aarne J.; Colman, Alan; Davidson, Bruce P.; Pera, Martin; Kloner, Robert A.; Pediatrics, School of Medicine
Purpose:
Human embryonic stem cell (hESC)-derived cardiomyocytes are a promising cell source for cardiac repair. Whether these cells can be transported long distance, survive, and mature in hearts subjected to ischemia/reperfusion with minimal infarction is unknown. Taking advantage of a constitutively GFP-expressing hESC line we investigated whether hESC-derived cardiomyocytes could be shipped and subsequently form grafts when transplanted into the left ventricular wall of athymic nude rats subjected to ischemia/reperfusion with minimal infarction. Co-localization of GFP-epifluorescence and cardiomyocyte specific marker staining was utilized to analyze hESC-derived cardiomyocyte fate in a rat ischemia/reperfused myocardium.
Methods:
Differentiated, constitutively green fluorescent protein (GFP) expressing hESCs (HES3-GFP; Envy) containing about 13% cardiomyocytes were differentiated in Singapore, and shipped in culture medium at 4°C to Los Angeles (shipping time ~3 days). The cells were dissociated and a cell suspension (2×106 cells for each rat, n=10) or medium (n=10) was injected directly into the myocardium within the ischemic risk area 5 minutes after left coronary artery occlusion in athymic nude rats. After 15 minutes of ischemia the coronary artery was reperfused. The hearts were harvested at various time points later and processed for histology, immunohistochemical staining, and fluorescence microscopy. In order to assess whether the hESC-derived cardiomyocytes might evade immune surveillance, 2×106 cells were injected into immune competent Sprague-Dawley rat hearts (n=2), and the hearts were harvested at 4 weeks after cell injection and examined as in the previous procedures.
Results:
Even following 3 days of shipping, the hESC-derived cardiomyocytes within embryoid bodies (EBs) showed active and rhythmic contraction after incubation in the presence of 5% CO2 at 37°C. In the nude rats, following cell implantation, H&E, immunohistochemical staining and GFP epifluorescence demonstrated grafts in 9 out of 10 hearts. Cells that demonstrated GFP epifluorescence also stained positive (co-localized) for the muscle marker alpha-actinin and exhibited cross striations (sarcomeres). Furthermore cells that stained positive for the antibody to GFP (immunohistochemistry) also stained positive for the muscle marker sarcomeric actin and demonstrated cross striations. At 4 weeks engrafted hESCs expressed connexin 43, suggesting the presence of nascent gap junctions between donor and host cells. No evidence of rejection was observed in nude rats as determined by inspection for lymphocytic infiltrate and/or giant cells. In contrast, hESC-derived cardiomyocytes injected into immune competent Sprague-Dawley rats resulted in an overt lymphocytic infiltrate.
Conclusions:
hESCs-derived cardiomyocytes can survive several days of shipping. Grafted cells survived up to 4 weeks after transplantation in hearts of nude rats subjected to ischemia/reperfusion with minimal infarction. They continued to express cardiac muscle markers, exhibit sarcomeric structure, and were well interspersed with the endogenous myocardium. However, hESC-derived cells did not escape immune surveillance in the xenograft setting in that they elicited a rejection phenomenon in immune competent rats.
A Novel High Throughput Immunomagnetic Cell Sorting System for Potential Clinical Scale Depletion of T Cells for Allogeneic Stem Cell Transplantation
(Elsevier, 2007) Tong, Xiaodong; Xiong, Ying; Zborowski, Maciej; Farag, Sherif S.; Chalmers, Jeffrey J.; Medicine, School of Medicine
Objective: To develop an immunomagnetic cell separation system for allogeneic hematopoietic stem cell (HSC) transplantations, which can achieve a high level of T-cell depletion (at least 4.0 log(10)), high level of recovery of hematopoietic stem cells (>90%), with a high throughput (>10(6) cells/second).
Methods: Peripheral blood leukocytes (PBLs) from buffy coats were spiked with CD34-expressing cells (KG1a) to mimic a leukaphoresis product containing stimulated HSCs. T cells were labeled with anti-CD3(+) Dynabeads and separated in a quadrupole magnetic cell sorter (QMS). The performance of the system with respect to T-cell depletion and recovery of non-T cells and spiked KG1a was determined using four-color, flow cytometry analysis, with the aid of Trucount cell-concentration calibration beads. Limiting dilution assays were also performed to quantify the log(10) depletion of clonable T cells.
Results: While the general performance of the QMS system is governed by proven theoretical principles, significant system variability exist, not all of which can be explained by our current understanding. Consequently, a factorial design was employed, guided by JMP software, to optimize the labeling conditions and operation of the QMS focused on maximizing the depletion of T cell, and recovery of unlabeled cells including KG1a cells. From these studies, an optimized, no wash, immunomagnetic labeling protocol and optimized QMS operating conditions were developed. For an average initial cell concentration of 1.7 x 10(8) total cells, an average 3.96 +/- 0.33 log(10) depletion (range, 3.53-4.34) of CD3(+)CD45(+) cells with a mean 99.43% +/- 4.23% recovery of CD34(+)CD45(+) cells (range, 94.38-104.90%) was achieved at a sorting speed of 10(6) cells/s (n = 6). Limiting dilution assays on the T-cell depleted fractions, which gave a log(10) depletion of 3.51 for the clonable T cells.
Conclusion: We suggest that this system will provide superior performance with respect to T-cell depletion and CD34(+) recovery for clinical allogeneic bone marrow transplants. Ongoing studies, on a clinical scale, are being conducted to demonstrate this claim.
Vaccinia virus infection induces dendritic cell maturation but inhibits antigen presentation by MHC class II
(Elsevier, 2007) Yao, Yongxue; Li, Ping; Singh, Pratibha; Thiele, Allison T.; Wilkes, David S.; Renukaradhya, Gourapura J.; Brutkiewicz, Randy R.; Travers, Jeffrey B.; Luker, Gary D.; Hong, Soon-Cheol; Blum, Janice S.; Chang, Cheong-Hee; Microbiology and Immunology, School of Medicine
Vaccinia virus (VV) infection is known to inhibit dendritic cells (DC) functions in vitro. Paradoxically, VV is also highly immunogenic and thus has been used as a vaccine. In the present study, we investigated the effects of an in vivo VV infection on DC function by focusing on early innate immunity. Our data indicated that DC are activated upon in vivo VV infection of mice. Splenic DC from VV-infected mice expressed elevated levels of MHC class I and co-stimulatory molecules on their cell surface and exhibited the enhanced potential to produce cytokines upon LPS stimulation. DC from VV-infected mice also expressed a high level of interferon-beta. However, a VV infection resulted in the down-regulation of MHC class II expression and the impairment of antigen presentation to CD4 T cells by DC. Thus, during the early stage of a VV infection, although DC are impaired in some of the critical antigen presentation functions, they can promote innate immune defenses against viral infection.
The Indiana University telephone-based assessment of neuropsychological status: a new method for large scale neuropsychological assessment
(Cambridge University Press, 2007) Unverzagt, Frederick W.; Monahan, Patrick O.; Moser, Lyndsi R.; Zhao, Qianqian; Carpenter, Janet S.; Sledge, George W., Jr.; Champion, Victoria L.; Psychiatry, School of Medicine
Sensitive measures of neuropsychological function were adapted to a telephone administration format for use in a large survey of quality of life in breast cancer survivors (BCS). Healthy controls (HC) and BCS were recruited from the community and administered the same neuropsychological test battery on two occasions separated by 1 week. Subjects were randomly assigned to conditions, stratified by diagnosis: In-person at Time-1 and In-person at Time-2 (P-P); Telephone at Time-1 and Telephone at Time-2 (T-T); T-P; and P-T. Four cognitive (Rey Auditory Verbal Learning Test, Controlled Oral Word Association, Digit Span, Symbol Digit) and two self-report measures (Squire Memory Self-Report Scale, Center for Epidemiological Studies Depression Scale) were used. The 106 subjects were randomized (54 HC and 52 BCS). Test-retest reliabilities (intraclass correlations) did not differ significantly by condition across the cognitive or self-report measures and ranged from moderate to near perfect (r's .43-.93; p's<.05). Mean scores at Time-1, practice effects (Time-1 to Time-2), and standard errors of measurement were comparable between In-person and Telephone administration formats. Results suggest that memory, attention, information processing speed, verbal fluency, and self-report of mood and memory can be measured reliably and precisely over the telephone.
Thymic selection pathway regulates the effector function of CD4 T cells
(Rockefeller University Press, 2007) Li, Wei; Sofi, M. Hanief; Yeh, Norman; Sehra, Sarita; McCarthy, Brian P.; Patel, Dipak R.; Brutkiewicz, Randy R.; Kaplan, Mark H.; Chang, Cheong-Hee; Microbiology and Immunology, School of Medicine
Recently, a new developmental pathway for CD4 T cells that is mediated by major histocompatibility complex class II-positive thymocytes was identified (Choi, E.Y., K.C. Jung, H.J. Park, D.H. Chung, J.S. Song, S.D. Yang, E. Simpson, and S.H. Park. 2005. Immunity. 23:387-396; Li, W., M.G. Kim, T.S. Gourley, B.P. McCarthy, D.B. Sant'angelo, and C.H. Chang. 2005. Immunity. 23:375-386). We demonstrate that thymocyte-selected CD4 (T-CD4) T cells can rapidly produce interferon gamma and interleukin (IL) 4 upon in vivo and in vitro T cell receptor stimulation. These T-CD4 T cells appear to be effector cells producing both T helper type 1 (Th1) and Th2 cytokines, and they maintain a potential to produce Th2 cytokines under Th1-skewing conditions in a signal transducer and activator of transcription 6-independent manner. The IL-4 mRNA level is high in CD4 single-positive thymocytes if they are selected on thymocytes, which is at least partly caused by enhanced histone acetylation of the IL-4 locus. However, mice that can generate T-CD4 T cells showed attenuated immune responses in an allergen-induced airway inflammation model, suggesting a protective role for T-CD4 T cells during an airway challenge. Our results imply that this thymic selection pathway plays an important role in determining the effector function of the resulting CD4 cells and in regulating immune response.