Mohammad Sahebjam

Bio: Mohammad Sahebjam is an academic researcher from Tehran University of Medical Sciences. The author has contributed to research in topics: Ejection fraction & Medicine. The author has an hindex of 10, co-authored 43 publications receiving 294 citations. Previous affiliations of Mohammad Sahebjam include University of Tehran.

Induction of angiogenesis via topical delivery of basic-fibroblast growth factor from polyvinyl alcohol-dextran blend hydrogel in an ovine model of acute myocardial infarction

Abstract: Hydrogels are currently used as interesting constructs for the delivery of proteins. In this study, a novel polyvinyl alcohol-dextran (PVA-Dex) blend hydrogel was used for controlled delivery of basic-fibroblast growth factor (bFGF). These biocompatible constructs were sutured to the epicardium as patches on the heart surface to provide slow release of bFGF to the infarcted site in an ovine model of myocardial infarction (MI). Eighteen sheep were randomly divided into three groups (n = 6 each), including group I (control without any patch and bFGF), group II (patch without bFGF) and group III (patch incorporating 100 µg bFGF). They were subjected to coronary artery ligation after lateral thoracotomy, and then in groups II and III the patches were implanted 20-30 min after MI. Cardiac function was assessed by both echocardiography and magnetic resonance imaging (MRI) 2 months after implantation. Then the animals were sacrificed and the hearts subjected to histopathological examination, immunohistochemistry and electron microscopy. Heart lysates were subject to protein expression analysis through western blotting. The results showed that sustained release of bFGF using PVA-Dex blend hydrogel strongly stimulated angiogenesis and increased wall thickness index in the infarcted myocardium. The patch also significantly attenuated the increase in left ventricular end-systolic diameter, but it did not improve cardiac function within 2 months of myocardial infarction. In conclusion, PVA-Dex gel incorporating bFGF can be used as a sustained release construct for therapeutic angiogenesis in ischaemic heart disease.

The similar effect of transplantation of marrow-derived mesenchymal stem cells with or without prior differentiation induction in experimental myocardial infarction.

Abstract: Marrow-derived mesenchymal stem cells (MSCs) have been heralded as a source of great promise for the regeneration of the infarcted heart. There is no clear data indicating whether or not in vitro differentiation of MSCs into major myocardial cells can increase the beneficial effects of MSCs. The aim of this study is to address this issue. To induce MSCs to transdifferentiate into cardiomyocyte-like and endothelial-like cells, 5-azacytidine and vascular endothelial growth factor (VEGF) were used, respectively. Myocardial infarction in rabbits was generated by ligating the left anterior descending coronary artery. Animals were divided into three experimental groups: I, control group; II, undifferentiated mesenchymal stem cell transplantation group; III, differentiated mesenchymal stem cell transplantation group; which respectively received peri-infarct injections of culture media, autologous undifferentiated MSCs and autologous differentiated MSCs. General pathology, immunohistochemistry, electron microscopy and echocardiography were performed in order to search for myocardial regeneration and improvement of cardiac function. In Groups II and III, implanted cells transdifferentiate into myocardial cells within 28 days post injection in a similar manner, and well-developed ultra structures formed within transplanted cells. Improvements in left ventricular function and reductions in infarcted area were observed in both cell-transplanted groups to the same degree. Vascular density was similar in Groups II and III and significantly higher in these groups compared with the control group. There is no need for prior differentiation induction of marrow-derived MSCs before transplantation and peri-infarct implantation of MSCs can efficiently regenerate the infarcted myocardium and improve cardiac function.

Development of an ovine model of myocardial infarction.

Abstract: Background: We report experimental myocardial infarction by occluding coronary arteries in ovine models. Methods: Twelve ewes were included in the study. After the chest was opened by left lateral thoracotomy incision, the second diagonal branch of the left anterior descending coronary artery was ligated at a point approximately 40% distant from its base. Prophylactic anti-arrhythmics were given. Animals were mechanically ventilated during surgery and stayed in intensive care unit for 24 h postoperation. Experiments were then evaluated by echocardiographic, electrocardiographic, haemodynamic, serological and morphological investigations. Echocardiographic measurements were repeated after 2 months and animals were then killed for post-mortem cardiac examinations. Results: All animals survived the surgical procedure. Cyanotic discoloration and hypokinesia in the cardiac tissue in an area of (30 ± 2) × (4 ± 2) mm plus ST-segment elevations was detected immediately after vessel ligation. Moreover, there were pathological Q-waves 2 months later. Echocardiographic evaluations showed an average of 30% relative decrease in cardiac ejection fraction. Wall motion analysis showed anteroseptal hypokinesia and akinesia in all animals 1 day and 2 months after operation, respectively. Thin-walled infarcted areas with tissue fibrosis were evident in pathological investigations 2 months after surgery. Conclusion: In conclusion, we developed a practical and safe method for producing myocardial infarction in large animal models.

Inflammatory myofibroblastic tumor of the right ventricle causing tricuspid valve regurgitation.

Abstract: Cardiac inflammatory myofibroblastic tumor is a rare lesion consisting of inflammatory cells and myofibroblastic spindle cells. We describe a case of inflammatory myofibroblastic tumor that involved the right ventricle, thereby causing tricuspid valve regurgitation in an 18-year-old man who presented with a fever of unknown origin and of 1 month's duration. With the patient on cardiopulmonary bypass, we excised the lesion and replaced the tricuspid valve without serious intraoperative or postoperative sequelae. The patient had a favorable outcome.

Valvular heart disease

Abstract: This unique text covers all aspects of valvular heart disease, including normal valve anatomy and physiology, pathophysiology, modes of investigation, assessment and treatment of specific valve lesions, valve surgery (both medical and surgical aspects), treatment in pregnancy or during non-cardiac surgery, and the devastating complication of infective endocarditis, in an easy-to-read, accessible format.

Concise review: mesenchymal stromal cells: potential for cardiovascular repair.

Abstract: Cellular therapy for cardiovascular disease heralds an exciting frontier of research. Mesenchymal stromal cells (MSCs) are present in adult tissues, including bone marrow and adipose, from which they can be easily isolated and cultured ex vivo. Although traditional isolation of these cells by plastic adherence results in a heterogeneous composite of mature and immature cell types, MSCs do possess plasticity of differentiation and under appropriate in vitro culture conditions can be modified to adopt cardiomyocyte and vascular cell phenotypic characteristics. In vivo preclinical studies have demonstrated their capacity to facilitate both myocardial repair and neovascularization in models of cardiac injury. The mechanisms underlying these effects appear to be mediated predominantly through indirect paracrine actions, rather than direct regeneration of endogenous cells by transdifferentiation, especially because current transplantation strategies achieve only modest engraftment of cells in the host myocardium. Currently, published clinical trial experience of MSCs as cardiac therapy is limited, and the outcomes of ongoing studies are keenly anticipated. Of relevance to clinical application is the fact that MSCs are relatively immunoprivileged, potentially enabling their allogeneic therapeutic use, although this too requires further investigation. Overall, MSCs are an attractive adult-derived cell population for cardiovascular repair; however, research is still required at both basic and clinical levels to resolve critical areas of uncertainty and to ensure continued development in cell culture engineering and cell transplantation technology.

Inflammatory Pseudotumor: The Great Mimicker

Abstract: OBJECTIVE. The purpose of this review is to describe the pathophysiologic findings, differential diagnosis, imaging features, and management of inflammatory pseudotumor in various locations throughout the body. CONCLUSION. Inflammatory pseudotumor is a rare benign process mimicking malignant processes and has been found in almost every organ system. Radiologists should be familiar with this entity as a diagnostic consideration to avoid unnecessary surgery.

Growth factor regulation of proliferation and survival of multipotential stromal cells

Abstract: Multipotential stromal cells (MSCs) have been touted to provide an alternative to conservative procedures of therapy, be it heart transplants, bone reconstruction, kidney grafts, or skin, neuronal and cartilage repair. A wide gap exists, however, between the number of MSCs that can be obtained from the donor site and the number of MSCs needed for implantation to regenerate tissue. Standard methods of MSC expansion being followed in laboratories are not fully suitable due to time and age-related constraints for autologous therapies, and transplant issues leave questions for allogenic therapies. Beyond these issues of sufficient numbers, there also exists a problem of MSC survival at the graft. Experiments in small animals have shown that MSCs do not persist well in the graft environment. Either there is no incorporation into the host tissue, or, if there is incorporation, most of the cells are lost within a month. The use of growth and other trophic factors may be helpful in counteracting these twin issues of MSC expansion and death. Growth factors are known to influence cell proliferation, motility, survival and morphogenesis. In the case of MSCs, it would be beneficial that the growth factor does not induce differentiation at an early stage since the number of early-differentiating progenitors would be very low. The present review looks at the effect of and downstream signaling of various growth factors on proliferation and survival in MSCs.