Xiaoqiang Han

Northwestern University, Evanston, Illinois, United States

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Publications (8)123.2 Total impact

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    ABSTRACT: No current therapy for relapsing-remitting multiple sclerosis (MS) results in significant reversal of disability. To determine the association of nonmyeloablative hematopoietic stem cell transplantation with neurological disability and other clinical outcomes in patients with MS. Case series of patients with relapsing-remitting MS (n = 123) or secondary-progressive MS (n = 28) (mean age, 36 years; range, 18-60 years; 85 women) treated at a single US institution between 2003 and 2014 and followed up for 5 years. Final follow-up was completed in June 2014. Treatment with cyclophosphamide and alemtuzumab (22 patients) or cyclophosphamide and thymoglobulin (129 patients) followed by infusion of unmanipulated peripheral blood stem cells. Primary end point was reversal or progression of disability measured by change in the Expanded Disability Status Scale (EDSS) score of 1.0 or greater (score range, 0-10). Secondary outcomes included changes in the Neurologic Rating Scale (NRS) score of 10 or greater (score range, 0-100), Multiple Sclerosis Functional Composite (MSFC) score, quality-of-life Short Form 36 questionnaire scores, and T2 lesion volume on brain magnetic resonance imaging scan. Outcome analysis was available for 145 patients with a median follow-up of 2 years and a mean of 2.5 years. Scores from the EDSS improved significantly from a pretransplant median of 4.0 to 3.0 (interquartile range [IQR], 1.5 to 4.0; n = 82) at 2 years and to 2.5 (IQR, 1.9 to 4.5; n = 36) at 4 years (P < .001 at each assessment). There was significant improvement in disability (decrease in EDSS score of ≥1.0) in 41 patients (50%; 95% CI, 39% to 61%) at 2 years and in 23 patients (64%; 95% CI, 46% to 79%) at 4 years. Four-year relapse-free survival was 80% and progression-free survival was 87%. The NRS scores improved significantly from a pretransplant median of 74 to 88.0 (IQR, 77.3 to 93.0; n = 78) at 2 years and to 87.5 (IQR, 75.0 to 93.8; n = 34) at 4 years (P < .001 at each assessment). The median MSFC scores were 0.38 (IQR, -0.01 to 0.64) at 2 years (P < .001) and 0.45 (0.04 to 0.60) at 4 years (P = .02). Total quality-of-life scores improved from a mean of 46 (95% CI, 43 to 49) pretransplant to 64 (95% CI, 61 to 68) at a median follow-up of 2 years posttransplant (n = 132) (P < .001). There was a decrease in T2 lesion volume from a pretransplant median of 8.57 cm3 (IQR, 2.78 to 22.08 cm3) to 5.74 cm3 (IQR, 1.88 to 14.45 cm3) (P < .001) at the last posttransplant assessment (mean follow-up, 27 months; n = 128). Among patients with relapsing-remitting MS, nonmyeloablative hematopoietic stem cell transplantation was associated with improvement in neurological disability and other clinical outcomes. These preliminary findings from this uncontrolled study require confirmation in randomized trials.
    JAMA The Journal of the American Medical Association 01/2015; 313(3):275-84. DOI:10.1001/jama.2014.17986 · 30.39 Impact Factor
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    ABSTRACT: Rationale: Efficient clearance of apoptotic cells (efferocytosis) is a prerequisite for inflammation resolution and tissue repair. Following myocardial infarction (MI), phagocytes are recruited to the heart and promote clearance of dying cardiomyocytes (CMs). The molecular mechanisms of efferocytosis of CMs and in the myocardium are unknown. The injured heart provides a unique model to examine relationships between efferocytosis and subsequent inflammation resolution, tissue remodeling, and organ function. Objective: We set out to identify mechanisms of dying cardiomyocyte (CM) engulfment by phagocytes and to for the first time assess the causal significance of disrupting efferocytosis during MI. Methods and Results: In contrast to other apoptotic cell receptors, macrophage MER tyrosine kinase (MER-TK) was necessary and sufficient for efferocytosis of CMs ex vivo. In mice, Mertk was specifically induced in Ly6cLO myocardial phagocytes after experimental coronary occlusion. Mertk deficiency led to an accumulation of apoptotic CMs, independent of changes in non-CMs, and a reduced index of in vivo efferocytosis. Importantly, suppressed efferocytosis preceded increases in myocardial infarct size and led to delayed inflammation resolution and reduced systolic performance. Reduced cardiac function was reproduced in chimeric mice deficient in bone marrow Mertk; reciprocal transplantation of Mertk+/+ marrow into Mertk-/- mice corrected systolic dysfunction. Interestingly, an inactivated form of MERTK, known as solMER, was identified in infarcted myocardium, implicating a natural mechanism of MERTK inactivation post MI. Conclusions: These data collectively and directly link efferocytosis to wound healing in the heart and identify Mertk as a significant link between acute inflammation resolution and organ function.
    Circulation Research 07/2013; 113(8). DOI:10.1161/CIRCRESAHA.113.301198 · 11.09 Impact Factor
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    ABSTRACT: BACKGROUND: Autologous haemopoietic stem-cell transplantation (HSCT) benefits patients with systemic sclerosis but has been associated with significant treatment-related mortality and failure to improve diffusion capacity of carbon monoxide (DLCO). We aimed to assess efficacy of HSCT and use of rigorous cardiac screening in this group. METHODS: We assessed patients with diffuse systemic sclerosis or limited systemic sclerosis and interstitial lung disease who were treated with HSCT as part of a study or on a compassionate basis at Northwestern University (Chicago, IL, USA) or the University of São Paulo (Ribeirão Preto, Brazil). Unselected peripheral blood stem cells were harvested with cyclophosphamide (2 g/m(2)) and filgrastim. The transplant regimen was a non-myeloablative regimen of cyclophosphamide (200 mg/kg) and rabbit anti-thymocyte globulin (rATG; 4·5-6·5 mg/kg). We followed patients up to 5 years for overall survival, relapse-free survival, modified Rodnan skin score, and pulmonary function tests. FINDINGS: Five (6%) of 90 patients died from treatment-related causes. Despite standard guidelines that recommend echocardiogram for screening before transplantation, four treatment-related deaths occurred because of cardiovascular complications (one constrictive pericarditis, two right heart failures without underlying infection, and one heart failure during mobilisation), and one death was secondary to sepsis without documented underlying heart disease. Kaplan-Meier analysis showed survival was 78% at 5 years (after eight relapse-related deaths) and relapse-free survival was 70% at 5 years. Compared with baseline, we noted improvements after HSCT in modified Rodnan skin scores at 1 year (58 patients; p<0·0001), 2 years (42 patients; p<0·0001), and 3 years (27 patients; p<0·0001) and forced vital capacity at 1 year (58 patients; p=0·009), 2 years (40 patients; p=0·02), and 3 years (28 patients; p=0·004), but total lung capacity and DLCO were not improved significantly after HSCT. Overall mean DLCO was significantly improved in patients with normal baseline echocardiograms (p=0·005) or electrocardiographs (p=0·05). INTERPRETATION: Autologous HSCT with a non-myeloablative regimen of cyclophosphamide and rATG with a non-selected autograft results in sustained improvement in skin thickness and forced vital capacity. DLCO is affected by baseline cardiac function. Guidelines for cardiac screening of patients with systemic sclerosis to assess treatment-related risk from pulmonary artery hypertension, primary cardiac involvement, or pericardial disease should be reconsidered and updated. FUNDING: None.
    The Lancet 01/2013; 381(9872). DOI:10.1016/S0140-6736(12)62114-X · 45.22 Impact Factor
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    ABSTRACT: Rationale: Various types of viable stem cells have been reported to result in modest improvement in cardiac function after acute myocardial infarction (AMI). The mechanisms for improvement from different stem cell populations remain unknown. Objective: To determine if irradiated (non-viable) embryonic stem cells (iESC) improve post ischemic cardiac function without adverse consequences. Methods and Results: After coronary artery ligation-induced cardiac infarction either conditioned media or male murine or male human iESC were injected into the penumbra of ischemic myocardial tissue of female mice or female rhesus macaque monkeys, respectively. Murine and human iESC, despite irradiation doses that prevented proliferation and/ or induced cell death, significantly improved cardiac function and decreased infarct size compared to untreated or media treated controls. Fluorescent in situ hybridization (FISH) for the y-chromosome revealed disappearance of iESC within the myocardium, while 5-bromo-2'-deoxyuridine assays revealed de novo in vivo cardiomyocyte DNA synthesis. Microarray gene expression profiling demonstrated an early increase in metabolism, DNA proliferation, and chromatin remodeling pathways, and decrease in fibrosis and inflammatory gene expression compared to media treated controls. Conclusions: Due to irradiation prior to injection, ex vivo and in vivo iESC existence is transient, yet iESC provide a significant improvement in cardiac function after AMI. The mechanism(s) of action of iESC appears to be related to cell-cell exchange, paracrine factors, and or a scaffolding effect between iESC and neighboring host cardiomyocytes.
    Circulation Research 08/2012; 111(10). DOI:10.1161/CIRCRESAHA.111.262584 · 11.09 Impact Factor
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    ABSTRACT: The mechanism for stem cell-mediated improvement following acute myocardial infarction has been actively debated. We support hypotheses that the stem cell effect is primarily paracrine factor-linked. We used a heparin-presenting injectable nanofibre network to bind and deliver paracrine factors derived from hypoxic conditioned stem cell media to mimic this stem cell paracrine effect. Our self-assembling peptide nanofibres presenting heparin were capable of binding paracrine factors from a medium phase. When these factor-loaded materials were injected into the heart following coronary artery ligation in a mouse ischaemia-reperfusion model of acute myocardial infarction, we found significant preservation of haemodynamic function. Through media manipulation, we were able to determine that crucial factors are primarily < 30 kDa and primarily heparin-binding. Using recombinant VEGF- and bFGF-loaded nanofibre networks, the effect observed with conditioned media was recapitulated. When evaluated in another disease model, a chronic rat ischaemic hind limb, our factor-loaded materials contributed to extensive limb revascularization. These experiments demonstrate the potency of the paracrine effect associated with stem cell therapies and the potential of a biomaterial to bind and deliver these factors, pointing to a potential therapy based on synthetic materials and recombinant factors as an acellular therapy.
    Journal of Tissue Engineering and Regenerative Medicine 12/2010; 4(8):600-10. DOI:10.1002/term.273 · 4.43 Impact Factor
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    ABSTRACT: This study investigated the effects on cardiomyocyte differentiation of embryonic stem cells by the overexpression of the transcription factor, Pitx2c, and examined the effects of transplantation of these differentiated cells on cardiac function in a mouse model of myocardial infarction. Pitx2c overexpressing embryonic stem cells were characterized for cardiac differentiation by immunocytochemistry, RNA analysis, and electrophysiology. Differentiated cells were transplanted by directed injection into the infarcted murine myocardium and functional measurements of blood pressure, contractility, and relaxation were performed. Histochemistry and FISH analysis performed on these mice confirmed the engraftment and cardiac nature of the transplanted cells. Pitx2c overexpressing embryonic stem cells robustly differentiated into spontaneously contracting cells which acquired cardiac protein markers and exhibited action potentials resembling that of cardiomyocytes. These cells could also be synchronized to an external pacemaker. Significant improvements (P < 0.01) in blood pressure (56%), contractility (57%), and relaxation (59%) were observed in infarcted mice with transplants of these differentiated cells but not in mice which were transplanted with control cells. The Pitx2c overexpressing cells secrete paracrine factors which when adsorbed onto a heparinated gel and injected into the infarcted myocardium produce a comparable and significant (P < 0.01) functional recovery. Pitx2c overexpression is a valuable method for producing cardiomyocytes from embryonic stem cells, and transplantation of these cardiomyocytes into infracted myocardium restores cardiac function through multiple mechanisms.
    International Heart Journal 11/2009; 50(6):783-99. DOI:10.1536/ihj.50.783 · 1.13 Impact Factor
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    ABSTRACT: Sympathetic nervous system development depends upon many factors that mediate neuron migration, differentiation and survival. Target tissue-derived nerve growth factor (NGF) signaling-induced gene expression is required for survival, differentiation and target tissue innervation of post-migratory sympathetic neurons. However, the transcriptional regulatory mechanisms mediated by NGF signaling are very poorly defined. Here, we identify Egr3, a member of the early growth response (Egr) family of transcriptional regulators, as having an important role in sympathetic nervous system development. Egr3 is regulated by NGF signaling and it is expressed in sympathetic neurons during development when they depend upon NGF for survival and target tissue innervation. Egr3-deficient mice have severe sympathetic target tissue innervation abnormalities and profound physiological dysautonomia. Unlike NGF, which is essential for sympathetic neuron survival and for axon branching within target tissues, Egr3 is required for normal terminal axon extension and branching, but not for neuron survival. The results indicate that Egr3 is a novel NGF signaling effector that regulates sympathetic neuron gene expression required for normal target tissue innervation and function. Egr3-deficient mice have a phenotype that is remarkably similar to humans with sympathetic nervous system disease, raising the possibility that it may have a role in some forms of human dysautonomia, most of which have no known cause.
    Development 09/2008; 135(17):2949-57. DOI:10.1242/dev.023960 · 6.27 Impact Factor
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    ABSTRACT: Controlling new blood vessel formation is of interest in regenerative medicine and cancer treatment. Heparin, a biopolymer that binds to angiogenic growth factors, was used to nucleate the self-assembly of nanostructures from designed peptide amphiphile molecules. This process yields rigid nanofibers that display heparin chains to orient proteins for cell signaling. In vivo, the nanostructures stimulated extensive new blood vessel formation using nanogram amounts of growth-factor proteins that by themselves did not induce any detectable angiogenesis.
    Nano Letters 10/2006; 6(9):2086-90. DOI:10.1021/nl0613555 · 13.59 Impact Factor