Biomedical subjects

Reza Jarrahy

Publications and source records attributed to Reza Jarrahy.

6 recordsLinked to original sources

PubMed2006

Osteogenic potentiation of human adipose-derived stem cells in a 3-dimensional matrix.

Adipose-derived stem cells (ADSCs) hold promise for use in tissue engineering. Despite growing enthusiasm for use of ADSCs, there is limited research that has examined their behavior in different in vitro and in vivo systems. The purpose of our study was to evaluate the effect of the extracellular matrix structure and composition on osteogenic differentiation by comparing the osteogenic marker expression of ADSCs grown under 2-dimensional or 3-dimensional cell culture conditions. Group 1 (2-D) included ADSCs raised under conventional cell culture conditions (cells in a 2-D monolayer configuration) (n = 24), and group 2 (3-dimensional) included ADSCs seeded in a collagen gel (cells within a 3-dimensional, biologically active environment) (n = 24). Comparison of ADSC behavior between the 2 groups was analyzed during a 14-day time frame. Osteogenic marker expression (CBFA-1, alkaline phosphatase, osteonectin, osteopontin, Collagen I, and JNK2) was quantified by real-time PCR, and histologic analysis was performed. Histologically, group 1 (2-D) showed cell spreading and deposition of a calcified extracellular matrix. Group 2 (3-dimensional) assumed a disorganized state in the collagen gel, with extension of pseudopodia throughout the matrix. Expression of CBFA-1 was up-regulated immediately in both groups. However, cells in group 2 (3-dimensional) had a more rapid and greater overall expression compared with cells in group 1 (2-D) (250-fold greater at 4 days). At day 14, cells in group 2 (3-dimensional) showed greater expression of all other osteogenic markers than cells in group 1 (2-D) (2.3-fold greater expression of alkaline phosphatase [P < 0.05], 8.4-fold greater expression of osteonectin [P < 0.05], 6.4-fold greater expression of osteopontin [P < 0.05], 2.9-fold greater expression of collagen I [P < 0.05], and 2.5-fold greater expression of JNK2 [P < 0.05]). Our data showed there was a progressive stimulatory effect on ADSCs with regard to osteogenesis when cultured in a 3-dimensional gel compared with a 2-D monolayer.

Adipose Tissue↗

PubMed2005

Characterization of growth and osteogenic differentiation of rabbit bone marrow stromal cells.

BACKGROUND: The rabbit is recognized as an excellent model to study the repair of bony defects with tissue engineered constructs. However, the use of rabbit bone marrow stromal cells (RBMSCs) has been limited despite the proven benefits of autologous BMSCs in the formation of bone. The purpose of this study was to characterize the growth and differentiation pattern of RBMSCs and their response to growth factors. MATERIAL AND METHODS: BMSCs were isolated from New Zealand White rabbits and cultured. Serial cell counts of parallel cultures were taken daily to determine cell growth. Response of RBMSCs to varying doses of recombinant human BMP-2 (rhBMP-2) and their time course was gauged by alkaline phosphatase (ALP) activity. The osteoblastic differentiation potential of RBMSCs in response to rhBMP-2 treatment was determined by evaluating the expression pattern of various genes involved with osteogensis using northern analysis. Von Kossa staining was performed to determine the effect of rhBMP-2 on the mineralization capabilities of RBMSCs. RESULTS: The growth rate of RBMSCs severely declined after first passage and this rate was further suppressed by TGF-beta1. The optimal dose response of rhBMP-2 was determined to be 50 ng/ml and its time course displayed increasing alkaline phosphatase activity over time. Two osteogenic markers, collagen I and osteopontin, were up regulated by rhBMP-2 treatment. Finally, the mineralization capability of RBMSCs was determined to be enhanced by rhBMP-2 treatment. CONCLUSION: Our work indicates that RBMSCs possess strong osteogenic potential and can be successfully applied toward bone tissue engineering in a rabbit model.

Animals↗

PubMed2005

The application of craniofacial techniques and intracranial endoscopy to pituitary surgery.

The evolution of pituitary surgery during the last century is characterized by the development of progressively less invasive approaches to the pituitary gland that have been facilitated by simultaneous advances in medical technology. Once performed via an open transcranial operation involving prolonged brain retraction, resection of pituitary tumors can now be performed via a direct transnasal approach entirely under endoscopic imaging. This review discusses the evolution of pituitary surgery from open transcranial techniques to the fully endoscopic transnasal procedure. However, in certain cases, with large pituitary tumors that have a significant extrasellar portion, a transcranial approach offers the greatest chance of complete tumor removal and often is reserved for the second stage of a two-staged operation. Recently, an endoscopic transglabellar minimally invasive approach has been reported, which could be used in place of the traditional transcranial approach.

Endoscopy↗

PubMed2005

Osteogenic differentiation is inhibited and angiogenic expression is enhanced in MC3T3-E1 cells cultured on three-dimensional scaffolds.

Osteogenic differentiation of osteoprogenitor cells in three-dimensional (3D) in vitro culture remains poorly understood. Using quantitative real-time RT-PCR techniques, we examined mRNA expression of alkaline phosphatase, osteocalcin, and vascular endothelial growth factor (VEGF) in murine preosteoblastic MC3T3-E1 cells cultured for 48 h and 14 days on conventional two-dimensional (2D) poly(l-lactide-co-glycolide) (PLGA) films and 3D PLGA scaffolds. Differences in VEGF secretion and function between 2D and 3D culture systems were examined using Western blots and an in vitro Matrigel-based angiogenesis assay. Expression of both alkaline phosphatase and osteocalcin in cells cultured on 3D scaffolds was significantly downregulated relative to 2D controls in 48 h and 14 day cultures. In contrast, elevated levels of VEGF expression in 3D culture were noted at every time point in short- and long-term culture. VEGF protein secretion in 3D cultures was triple the amount of secretion observed in 2D controls. Conditioned medium from 3D cultures induced an enhanced level of angiogenic activity, as evidenced by increases in branch points observed in in vitro angiogenesis assays. These results collectively indicate that MC3T3-E1 cells commit to osteogenic differentiation at a slower rate when cultured on 3D PLGA scaffolds and that VEGF is preferentially expressed by these cells when they are cultured in three dimensions.

Alkaline Phosphatase↗

PubMed2003

Craniofacial and skull base trauma.

BACKGROUND: Traumatic craniofacial and skull base injuries require a multidisciplinary team approach. Trauma physicians must evaluate carefully, triage properly, and maintain a high index of suspicion to improve survival and enhance functional recovery. Frequently, craniofacial and skull base injuries are overlooked while treating more life-threatening injuries. Unnoticed complex craniofacial and skull base fractures, cerebrospinal fluid fistulae, and cranial nerve injuries can result in blindness, diplopia, deafness, facial paralysis, or meningitis. Early recognition of specific craniofacial and skull base injury patterns can lead to identification of associated injuries and allow for more rapid and appropriate management. CONCLUSION: Early detection and treatment of craniofacial and skull base traumatic injuries should lead to decreased morbidity and mortality. This review discusses the most common of these injuries, their possible complications, and treatment.

Accidents, Traffic↗

PubMed2002

Fully endoscopic vascular decompression of the glossopharyngeal nerve.

Microvascular decompression of the glossopharyngeal nerve is an effective treatment of patients with glossopharyngeal neuralgia in whom compression of the nerve by a blood vessel is implicated in the pathogenesis of the disease. The standard surgical technique uses a binocular operating microscope for intra-operative visualization. Growing experience with posterior fossa endoscopy, however, has suggested that endoscopes may provide more comprehensive anatomical views of cerebellopontine angle. This report describes the case of a patient suffering from glossopharyngeal neuralgia who underwent fully endoscopic vascular decompression of the glossopharyngeal nerve. During this procedure the endoscope was used to survey the posterior fossa, guide the placement of insulating sponges, and conduct a final assessment of the intervention. We found the endoscope ideally suited to the constricted operating space of the posterior fossa, allowing for accurate localization and careful separation of the pathological vascular conflict with minimal brain retraction and no damage to surrounding structures. The versatility of endoscopy allows for superior visual appreciation of neurovascular conflicts in the posterior fossa. To date, endoscopy has primarily been used to supplement microscopy in cranial nerve decompression surgery. This report demonstrates how the endoscope can be used as the sole imaging modality in glossopharyngeal nerve decompression, with excellent results.

Adult↗