H.J. Duckers

Similar effect of autologous and allogeneic cell therapy for ischemic heart disease : Systematic review and meta-analysis of large animal studies

Rationale: In regenerative therapy for ischemic heart disease, use of both autologous and allogeneic stem cells has been investigated. Autologous cell can be applied without immunosuppression, but availability is restricted, and cells have been exposed to risk factors and aging. Allogeneic cell therapy enables preoperative production of potent cell lines and immediate availability of cell products, allowing off-the-shelf therapy. It is unknown which cell source is preferred with regard to improving cardiac function. Objective: We performed a meta-analysis of preclinical data of cell therapy for ischemic heart disease. Methods and Results: We conducted a systematic literature search to identify publications describing controlled preclinical trials of unmodified stem cell therapy in large animal models of myocardial ischemia. Data from 82 studies involving 1415 animals showed a significant improvement in mean left ventricular ejection fraction in treated compared with control animals (8.3%, 95% confidence interval, 7.1–9.5; P <0.001). Meta-regression revealed a similar difference in left ventricular ejection fraction in autologous (8.8%, 95% confidence interval, 7.3–10.3; n=981) and allogeneic (7.3%, 95% confidence interval, 4.4–10.2, n=331; P =0.3) cell therapies. Conclusions: Autologous and allogeneic cell therapy for ischemic heart disease show a similar improvement in left ventricular ejection fraction in large animal models of myocardial ischemia, compared with placebo. These results are important for the design of future clinical trials. # Novelty and Significance {#article-title-48}Rationale: In regenerative therapy for ischemic heart disease, use of both autologous and allogeneic stem cells has been investigated. Autologous cell can be applied without immunosuppression, but availability is restricted, and cells have been exposed to risk factors and aging. Allogeneic cell therapy enables preoperative production of potent cell lines and immediate availability of cell products, allowing off-the-shelf therapy. It is unknown which cell source is preferred with regard to improving cardiac function. Objective: We performed a meta-analysis of preclinical data of cell therapy for ischemic heart disease. Methods and Results: We conducted a systematic literature search to identify publications describing controlled preclinical trials of unmodified stem cell therapy in large animal models of myocardial ischemia. Data from 82 studies involving 1415 animals showed a significant improvement in mean left ventricular ejection fraction in treated compared with control animals (8.3%, 95% confidence interval, 7.1–9.5; P<0.001). Meta-regression revealed a similar difference in left ventricular ejection fraction in autologous (8.8%, 95% confidence interval, 7.3–10.3; n=981) and allogeneic (7.3%, 95% confidence interval, 4.4–10.2, n=331; P=0.3) cell therapies. Conclusions: Autologous and allogeneic cell therapy for ischemic heart disease show a similar improvement in left ventricular ejection fraction in large animal models of myocardial ischemia, compared with placebo. These results are important for the design of future clinical trials.

Clinical Study Using Adipose-Derived Mesenchymal-Like Stem Cells in Acute Myocardial Infarction and Heart Failure

Adipose tissue represents an abundant, accessible source of regenerative cells that can be easily obtained in sufficient amount for therapy. Adipose-derived regenerative cells (ADRC) are comprised of leukocytes, smooth muscles, endothelial cells, and mesenchymal stem cells. In contrast to bone-marrow-derived MSC, the abundance of adipose tissue in patients and the higher frequency per unit mass of regenerative cells allow for the isolation of cells in therapeutic meaningful amounts in less than 2h after donor tissue acquisition.Harvest of adipose tissue can thus follow primary PCI, allowing efficient treatment within 24h. This obviates the need for extensive cell culturing in GMP clean room facilities and makes ADSCs a promising and practical autologous cell source. In the following chapter, we will describe the liposuction procedure for stem cell harvest, two cell delivery techniques, and pressure/volume loop analysis for the follow-up of our patients enrolled in the clinical studies.

Longitudinal in vivo magnetic resonance imaging studies in experimental allergic encephalomyelitis: Effect of a neurotrophic treatment on cortical lesion development

Proton magnetic resonance imaging enables non-invasive monitoring of lesion formation in multiple sclerosis and has an important role in assessing the potential effects of therapy. T2-weighted and short tau inversion recovery magnetic resonance imaging were used to assess the effect of a neurotrophic adrenocorticotrophic hormone analogue [H-Met(O(2))-Glu-His-Phe-D-Lys-Phe-OH] on the volume of lesions in the brains of rats suffering from chronic experimental allergic encephalomyelitis, an animal equivalent of multiple sclerosis. Lesion volume was monitored during a five-month period. Magnetic resonance imaging indicated that treatment with the adrenocorticotrophic hormone analogue significantly reduced the lesion volume by 84 and 85% 10 and 20 weeks after lesion induction, respectively. Furthermore, peptide treatment significantly reduced chronic experimental allergic encephalomyelitis-related neurological symptoms during the chronic phase of the disease (week 3 until week 20 after lesion induction). Both functional and morphological recovery were considerably advanced by peptide treatment. Twenty weeks after lesion induction rats with chronic experimental allergic encephalomyelitis were killed for histological analysis, to correlate magnetic resonance imaging findings with morphological changes. The regions of abnormally high signal intensities on T2-weighted magnetic resonance images coincided with areas of demyelination and concomitant widespread inflammatory infiltration, oedema formation and enlarged ventricles. The improved neurological status and the 84% reduction in the lesion volume in the cerebrum of rats chronic experimental allergic encephalomyelitis point to the potential value of trophic peptides in the development of strategies for limiting the damage caused by central demyelinating lesions in syndromes such as multiple sclerosis.

Functional and neurophysiological evidence of the efficacy of trophic pharmacotherapy using an adrenocorticotrophic hormone4–9 analog in experimental allergic encephalomyelitis, an animal model of multiple sclerosis

Chronic experimental allergic encephalomyelitis (CEAE) is a well-established animal model for the human syndrome, multiple sclerosis. CEAE has striking histological, electrophysiological and clinical analogies with multiple sclerosis and is a valuable animal model for the preclinical pharmacotherapeutical development of new putative therapeutic agents. In this paper, we describe a neurotrophic repair approach in Lewis rats suffering from CEAE. The neurotrophic peptide used is a degradation resistant adrenocorticotrophic hormone4-9 analog. The development of CEAE was examined using a combination of clinical, functional and electrophysiological parameters including somatosensory and motor evoked potentials. The latencies and amplitudes of the various evoked potentials can provide quantitative, objective data regarding the involvement of different nerve tracts in CEAE and the effectiveness of the neurotrophic peptide. Repeated subcutaneous injections of the neurotrophic peptide suppressed the development of CEAE-related clinical symptoms, markedly improved motor performance and reduced the reaction time upon thermal stimulation as compared to saline-treated CEAE animals during a 17 week follow-up study. Prolonged onset latencies of corticomotor evoked potentials and peak latencies of somatosensory evoked potentials due to the demyelination were normalized upon peptide treatment. In addition, peptide treatment substantially prevented total blocking of the corticomotor pathway in CEAE-animals and reduced the attenuation of sensory evoked potentials-related peak amplitudes as compared to saline-treated animals. The functional and electrophysiological improvements observed in CEAE-animals treated with the adrenocorticotrophic hormone4-9 analog, suggest that a neurotrophic repair approach could be of great value to promote the restoration of function in a disabling demyelinating disorder.

Current outlook of cardiac stem cell therapy towards a clinical application

Cardiovascular diseases are the major cause of death worldwide and currently affect 36.3% of the US population.w1 The majority of this population comprises patients with acute myocardial infarction (AMI) and chronic ischaemic heart failure. Despite the considerable contribution of percutaneous coronary revascularisation and coronary artery bypass grafting (CABG) in coronary artery disease (CAD) patients, the long term benefits remain unsatisfactory. Moreover, heart transplantation, as a last resort, is available for a very limited patient population. Cell transplantation emerged initially as a potential therapy to treat heart failure. Cardiomyocytes are generally considered to be post-mitotic, and do not regenerate upon loss or damage. However, recently Bergmann and co-workers were able to demonstrate that 50% of adult cardiomyocytes are exchanged during a normal lifespan,1 which has propelled investigations into the potential use of cardiovascular regenerative therapy. Moreover, recent improvements in preparation techniques of stem cells, the creation of stable stem cell lines (master cell banks), as well as the isolation of omnipotent embryonic stem cells (ESCs) and induced pluripotent stem (iPS) cells, underscore the potential of stem cell therapy as a viable new avenue in the treatment regimen of cardiac patients. The majority of preclinical studies and clinical trials to date have evaluated the efficacy of cell therapy mainly in AMI. Cell therapy in the acute phase of a myocardial infarction (MI) is geared towards prevention of cardiomyocyte apoptosis, promotion of local neoangiogenesis, improving myocardial perfusion, and reduction of the local inflammatory response. These will all result in sustained contractile function and a reduction of adverse post-AMI cardiac remodelling, ultimately decreasing major adverse cardiac events and progression into overt chronic heart failure. Numerous preclinical studies and meta-analyses of randomised controlled clinical trials suggest that stem cell therapy by either intravascular or intramyocardial injection in ischaemic heart disease is safe, feasible …

THSD1 preserves vascular integrity and protects against intraplaque haemorrhaging in ApoE−/− mice

AIMS Impairment of the endothelial barrier leads to microvascular breakdown in cardiovascular disease and is involved in intraplaque haemorrhaging and the progression of advanced atherosclerotic lesions that are vulnerable to rupture. The exact mechanism that regulates vascular integrity requires further definition. Using a microarray screen for angiogenesis-associated genes during murine embryogenesis, we identified thrombospondin type I domain 1 (THSD1) as a new putative angiopotent factor with unknown biological function. We sought to characterize the role of THSD1 in endothelial cells during vascular development and cardiovascular disease. METHODS AND RESULTS Functional knockdown of Thsd1 in zebrafish embryos and in a murine retina vascularization model induced severe haemorrhaging without affecting neovascular growth. In human carotid endarterectomy specimens, THSD1 expression by endothelial cells was detected in advanced atherosclerotic lesions with intraplaque haemorrhaging, but was absent in stable lesions, implying involvement of THSD1 in neovascular bleeding. In vitro, stimulation with pro-atherogenic factors (3% O2 and TNFα) decreased THSD1 expression in human endothelial cells, whereas stimulation with an anti-atherogenic factor (IL10) showed opposite effect. Therapeutic evaluation in a murine advanced atherosclerosis model showed that Thsd1 overexpression decreased plaque vulnerability by attenuating intraplaque vascular leakage, subsequently reducing macrophage accumulation and necrotic core size. Mechanistic studies in human endothelial cells demonstrated that THSD1 activates FAK-PI3K, leading to Rac1-mediated actin cytoskeleton regulation of adherens junctions and focal adhesion assembly. CONCLUSION THSD1 is a new regulator of endothelial barrier function during vascular development and protects intraplaque microvessels against haemorrhaging in advanced atherosclerotic lesions.

Effect of shear stress alteration on atherosclerotic plaque vulnerability in cholesterol-fed rabbits

Previously, we created an experimental murine model for the induction of vulnerable plaque (VP). Although this murine model offers the opportunity to study the different molecular biological pathways that regulate plaque destabilization, the size of the animals severely limits the use of the model for in vivo diagnostics and percutaneous interventions. This study aimed to create a VP model in the rabbit, based on the murine model, to aid the assessment and development of novel diagnostic and interventional tools. New Zealand white rabbits were fed on a 2% cholesterol diet. After 1 week, a shear stress-altering device was implanted around the right carotid artery. Twelve weeks after cast placement, the carotid artery was isolated and processed for (immuno-)histological analysis to evaluate the presence of a VP phenotype. Atherosclerotic plaques with high lipid and macrophage content, low vascular smooth muscle cell content and intimal neovascularization were located upstream and downstream of the cast. The plaques lacked a significant necrotic core. In conclusion, we were able to create atherosclerotic plaques with a phenotype beyond that of a fatty streak, with a high percentage of lipids and macrophages, a thick cap with some vascular smooth muscle cells and neovascularization. However, as there was only a small necrotic core, the overall phenotype seems less vulnerable as compared to the thin fibrous cap atheroma in patients.

Efficiency of statin treatment on EPC recruitment depends on baseline EPC titer and does not improve angiographic outcome in coronary artery disease patients treated with the Genous™ stent

The objective of this study was to assess the effect of high-dose atorvastatin treatment on endothelial progenitor cell (EPC) recruitment and angiographic and clinical outcome in coronary artery disease (CAD) patients treated with the Genous™ EPC-capturing stent. The HEALING IIB study was a multicenter, open-label, prospective trial that enrolled 100 patients. Patients were started on 80 mg atorvastatin qd, at least 2 weeks before the index procedure and continued for at least 4 weeks after the index procedure. Eighty-seven patients were included in this analysis. EPC levels significantly increased as early as 2 weeks after the start of atorvastatin. Remarkably, among this group, 31 patients proved to be nonresponders to atorvastatin treatment (i.e., no increase in EPC levels), while 56 patients were responders (i.e., rise in EPC count between week −2 and 0). Compared to responders, nonresponders had a significantly higher baseline EPC count (76 ± 10 vs. 41 ± 5, p < 0.01) with a lower late luminal loss (LLL) at 6- and 18-month follow-up (FU) (0.61 ± 0.07 vs. 0.88 ± 0.08, p < 0.05, and 0.50 ± 0.08 vs. 0.82 ± 0.08, p < 0.01 respectively). Furthermore, baseline EPC count was inversely correlated with LLL at 6-month FU (R = −0.42, p < 0.001). Patients with a higher EPC count at baseline showed no increase in EPC recruitment in response to statin treatment but had favorable LLL at 6- and 18-month FU, whereas patients with lower EPC count were responsive to statin therapy, but EPCs might be less functional as they had higher LLL at 6- and 18-month FU. These data imply that although statin treatment can enhance EPC titer in patients with low baseline levels, there is no indication for a possible beneficial clinical effect with EPC capture stents.

Neurotrophic ACTH4-9 analogue therapy normalizes electroencephalographic alterations in chronic experimental allergic encephalomyelitis

Chronic experimental allergic encephalomyelitis (CEAE) is an established experimental model for multiple sclerosis (MS). The demyelinating lesions in the white matter of the central nervous system observed in CEAE and in MS are accompanied by various neurophysiological alterations. Among the best defined electrophysiological abnormalities are the changes in event‐related potentials, in particular evoked potentials involving the spinal cord, i.e. motor and sensory evoked potentials. Less familiar are the changes observed in the electroencephalogram of CEAE‐affected animals, which are also encountered in the human equivalent, MS. In the present experiment we evaluated the therapeutic value of a neurotrophic peptide treatment [H‐Met(O2)‐Glu‐His‐Phe‐d‐Lys‐Phe‐OH, an ACTH4–9 analogue] and its effect on the delayed flash visual evoked potentials (VEP) and power spectra of the electroencephalogram, during a 17‐week follow‐up of CEAE. CEAE animals treated with the neurotrophic peptide were protected against the development of neurological symptoms during the course of the demyelinating syndrome. VEPs of animals suffering from CEAE showed a delay of the latencies of the late components which was significantly counteracted by peptide treatment. The peak‐to‐peak amplitude of the VEP afterdischarge recorded from CEAE animals was significantly increased during the course of CEAE and correlated closely with the progression of the myelinopathy. Furthermore, CEAE animals showed an increase of electroencephalogram (EEG) beta activity of up to 500% as compared with the age‐matched control group. This increase in beta power mainly consisted of a prevailing 20–21 Hz peak, a frequency that normally is not dominant in control EEG recordings of the rat during passive wakefulness. All these electrophysiological phenomena were absent in ACTH4–9 analogue‐treated animals. The present findings underscore the potential importance of a neurotrophic peptide treatment in the pharmacotherapy of central demyelinating syndromes, and possibly of MS.

A neurotrophic ACTH(4–9) analogue prevents the formation of central demyelinating lesions in CEAE and normalizes central conduction slowing

Objective. To evaluate the efficacy of a type IV phnsphodiestegase (PDE-IV) inhibitor with a novel, ~ .c i f ic profile of tumor necrosis factor (TNF-c0 inhibitina in preventing EAE in the common marmoset C. jacchus. This model of EAE was selected because of its charsoteristics of chrmic, relapsing remitting cotnse and early and prominent demyelination closely rea~nlsc~t o( huma~ MS. Methods. Marmosets were treated for 7 weeks with either the PDE-IV inhibitor Roliwam (10mg/kg every 48 hrs suboutnocoasly) or placebo (controls), slatting at day 7 after EAE induction with human whole white matter. Assessment of EAE was done by examination of clinical status, ce~hrospinai fluid (CSF), and magnetic resonalge imaging (MRI). Results. Clinical signs of EAE (grade 2 to 3), CSF pleucytosls (150-190 WBC/mm3), and cerelmd white matter loci of Gadolinium enhancement developed within 17 days after EAE induction in 2 controls and in none of 3 Roliwam-treated animals. The drug protected against EAE as Io,g as treatment was cootinucd, but failed to s ~ antibody and T-cell responses to Myelin Basic Protein in peripheral blood. In contrast to controls, pethoiogic examination of the braid and cod in the treatment group revealed only subtle inflammation and no demyelinatico. Conclusion. Specific inhibition of TNF-a protects EAE-primed C. jacchus from blond-brein barrier breakdown and substantially suppresses CNS white matter inflammation and demyelination. Similar strategies may be considered for therapy of human MS.