Biomedical subjects

James J Yoo

Publications and source records attributed to James J Yoo.

At least 19 recordsLinked to original sources

PubMed2007

Isolation of amniotic stem cell lines with potential for therapy.

Stem cells capable of differentiating to multiple lineages may be valuable for therapy. We report the isolation of human and rodent amniotic fluid-derived stem (AFS) cells that express embryonic and adult stem cell markers. Undifferentiated AFS cells expand extensively without feeders, double in 36 h and are not tumorigenic. Lines maintained for over 250 population doublings retained long telomeres and a normal karyotype. AFS cells are broadly multipotent. Clonal human lines verified by retroviral marking were induced to differentiate into cell types representing each embryonic germ layer, including cells of adipogenic, osteogenic, myogenic, endothelial, neuronal and hepatic lineages. Examples of differentiated cells derived from human AFS cells and displaying specialized functions include neuronal lineage cells secreting the neurotransmitter L-glutamate or expressing G-protein-gated inwardly rectifying potassium channels, hepatic lineage cells producing urea, and osteogenic lineage cells forming tissue-engineered bone.

Amniotic Fluid↗

PubMed2006

Tissue-engineered autologous bladders for patients needing cystoplasty.

BACKGROUND: Patients with end-stage bladder disease can be treated with cystoplasty using gastrointestinal segments. The presence of such segments in the urinary tract has been associated with many complications. We explored an alternative approach using autologous engineered bladder tissues for reconstruction. METHODS: Seven patients with myelomeningocele, aged 4-19 years, with high-pressure or poorly compliant bladders, were identified as candidates for cystoplasty. A bladder biopsy was obtained from each patient. Urothelial and muscle cells were grown in culture, and seeded on a biodegradable bladder-shaped scaffold made of collagen, or a composite of collagen and polyglycolic acid. About 7 weeks after the biopsy, the autologous engineered bladder constructs were used for reconstruction and implanted either with or without an omental wrap. Serial urodynamics, cystograms, ultrasounds, bladder biopsies, and serum analyses were done. RESULTS: Follow-up range was 22-61 months (mean 46 months). Post-operatively, the mean bladder leak point pressure decrease at capacity, and the volume and compliance increase was greatest in the composite engineered bladders with an omental wrap (56%, 1.58-fold, and 2.79-fold, respectively). Bowel function returned promptly after surgery. No metabolic consequences were noted, urinary calculi did not form, mucus production was normal, and renal function was preserved. The engineered bladder biopsies showed an adequate structural architecture and phenotype. CONCLUSIONS: Engineered bladder tissues, created with autologous cells seeded on collagen-polyglycolic acid scaffolds, and wrapped in omentum after implantation, can be used in patients who need cystoplasty.

Adolescent↗

PubMed2006

In vitro evaluation of a poly(lactide-co-glycolide)-collagen composite scaffold for bone regeneration.

Numerous materials have been proposed for bone tissue regeneration. However, none has been shown to be entirely satisfactory. In this study we fabricated a hybrid composite scaffold composed of poly(D,L-lactide-co-glycolide) (PLGA) and a naturally derived collagen matrix derived from porcine bladder submucosa matrix (BSM), and evaluated the biological activities and physical properties of the scaffold for use in bone tissue regeneration. The BSM-PLGA composite scaffolds are able to promote cellular interactions and possess uniformly interconnected pores with adequate structural integrity. The composite scaffolds were tested with both human embryonic stem (hES) cells and bovine osteoblasts (bOB). Cells seeded on the composite scaffolds readily attached, infiltrated and proliferated, as confirmed by cell viability and mitochondrial metabolic activity. Use of the composite scaffolding system with cells may enhance the formation of bone tissue for therapeutic regeneration.

Animals↗

PubMed2006

Engineering of blood vessels from acellular collagen matrices coated with human endothelial cells.

Small-caliber synthetic grafts used for coronary bypass artery grafting are compromised by thrombogenicity and accelerated intimal thickening, resulting in early graft occlusion. Herein we describe the fabrication and physical properties of small-caliber blood vessels using decellularized porcine aortic segments. These vessels were further coated with human saphenous vein endothelial cells (HSVECs) for future clinical applications. Chemical staining of decellularized vessels showed that they preserved their native matrix architecture, including several collagen layers in between internal and external elastin layers. The burst pressure for the decellularized vessels was higher than 1,000 mmHg. HSVECs, seeded on the luminal side, adhered to the matrix and formed a uniform monolayer. HSVEC-seeded vessels produced prostaglandin I2 and released vasoactive agents in response to the calcium ionophore A23187. These results show that engineered blood vessels coated with the host endothelial cells possess morphologic and functional characteristics of human small-caliber vessels. Tissue-engineered vessels may potentially be useful clinically as vascular grafts.

Animals↗

PubMed2005

Controlled fabrication of a biological vascular substitute.

Autologous and synthetic vessel grafts have been used as a vascular substitute for cardiovascular bypass procedures. However, these materials are limited by the availability of appropriate caliber autologous vessels, increased susceptibility to thrombosis and intimal hyperplasia following surgery. Electrospinning technology offers the potential for controlling composition, structure and mechanical properties of biomaterials. Vascular graft scaffolds have been fabricated using electrospun polymer blends of Type I collagen, elastin from ligamentum nuchae, and poly (d,l-lactide-co-glycolide). This study demonstrates improved electrospinning characteristics versus previous studies by increasing polymer concentration and adding PLGA to the polymer blend. Additionally, new in vitro biocompatibility and mechanical testing data is presented. The scaffolds possess tissue composition and mechanical properties similar to native vessels. The electrospun vessel matrix is biocompatible and does not elicit local or systemic toxic effects when implanted in vivo. This study demonstrates the promise of electrospinning as a fabrication process for a functional vascular graft for clinical use.

Animals↗

PubMed2005

Failure of differentiation into mature myotubes by muscle precursor cells with the side-population phenotype after injection into irreversibly damaged striated urethral sphincter.

We previously showed that the injection of a heterogeneous population of muscle precursor cells (MPCs) into striated urethral sphincter irreversibly damaged by electrocoagulation results in the formation of functional myotubes. To gain further insights into the role played by the different types of MPCs, we elected to sort the MPCs by Hoechst 33342 staining/fluorescence-activated cell-sorter analysis before injection. We found that the side population (SP) cells (muscle stem cells) injected in isolation survived, whereas the main population (MP) cells did not. However, the SP cells failed to differentiate into mature myotubes, as observed previously with unfractionated MPCs containing both SP and MP cells. This result suggests that interactions between SP and MP cells are required for the formation of myotubes in a nonregenerating muscle. In the setting of sphincter insufficiency, injection of MPCs at different stages of maturation may be a better option than purified muscle stem cells.

Animals↗

PubMed2005

Propagation, expansion, and multilineage differentiation of human somatic stem cells from dermal progenitors.

We isolated multipotential mesenchymal stem cells (MSC) from human postnatal dermal tissues. The isolated cells were expanded and maintained for over 100 population doublings with retention of their chromosomal complement and potential for multilineage differentiation. Progeny of cell lines established from a single dermal MSC could be differentiated into adipogenic, osteogenic, and myogenic lineages, consistent with the conclusion that we established a clonal, multipotential, somatic MSC cell line. This study is the first to show potential growth of multipotential human MSC cell lines from a single cell that can be used for the engineering of tissues in vivo. Clonal growth of MSCs presents profound implications in our understanding of differentiation and development, and should provide a valuable resource for tissue repair.

Adipocytes↗

PubMed2005

Tissue engineering of functional salivary gland tissue.

OBJECTIVES: Treatment of conditions that lead to salivary hypofunction, such as radiation induced xerostomia, is currently limited to the administration of saliva substitutes and sialogogues. The transient effect of these medications necessitates frequent administration, and systemic side effects may be intolerable. The creation of implantable, functional salivary gland tissue from autologous glandular cells would provide a physiologic solution to this problem. We investigated the feasibility of engineering such tissue in vivo. METHODS: Primary human salivary gland cells were grown, expanded, and seeded on biodegradable polymer scaffolds. A total of 48 scaffolds with cells and 16 control polymers without cells were implanted subcutaneously in athymic mice. The implants were retrieved 2, 4, and 8 weeks after the implantation for phenotypic and functional analyses. RESULTS: Human salivary gland epithelial cells retained their phenotypic and functional characteristics at all culture stages. Histologically, formation of acinar gland-like structures was observed within the engineered tissue by 4 weeks after implantation. Immunocytochemical and Western blot analyses of the implanted tissues demonstrated the expression of human a-amylase, cytokeratins AE1/AE3, and aquaporin-5 using cell-specific antibodies. Reverse-transcription polymerase chain reaction analyses confirmed the expression of human salivary type of alpha-amylase (sigma-amylase) mRNA. The retrieved tissues demonstrated the production of human alpha-amylase over time using a biochemical amylase detection system.

Animals↗

PubMed2004

Peripheral nerve regeneration using acellular nerve grafts.

Long gap peripheral nerve injuries usually require a graft to facilitate axonal regeneration into the distal nerve stump. The use of autografts is often limited because of graft availability and donor-site morbidity. We investigated whether acellular nerve allografts would provide an appropriate channel for the promotion and induction of sciatic nerve regeneration in rats. Axons sprouted from the proximal portion and reached the distal portion in the 1 cm-long grafts by 1 month. The number of axons in the regenerated nerves was similar to that of normal nerves at 1 month. Loading the grafts with betaNGF and VEGF increased the number and mean diameter of axons and neovascularization in the regenerated nerves at 1 month. The motor conduction velocity increased over time and reached 63 +/- 10% of that of normal nerves at 6 months. The nerve injuries treated with the acellular grafts had a significant improvement in motor, nociception, and proprioception function compared to untreated nerves. The results from this study suggest that acellular nerve allografts may be a useful biomaterial for functional peripheral nerve regeneration.

Animals↗

PubMed2003

Cell cycle checkpoint function in bladder cancer.

BACKGROUND: Cell cycle checkpoints function to maintain genetic stability by providing additional time for repair of DNA damage and completion of events that are necessary for accurate cell division. Some checkpoints, such as the DNA damage G1 checkpoint, are dependent on p53, whereas other checkpoints, such as the decatenation G(2) checkpoint, are not. Because bladder transitional cell carcinomas (TCCs) often contain numerous chromosomal aberrations and appear to have highly unstable genomes, we analyzed cell cycle checkpoint functions in a panel of TCC lines. METHODS: Cell cycle arrest was induced in normal human fibroblasts (NHF1-hTERT) and normal human uroepithelial cells (HUCs), and TCC lines and checkpoint functions were quantified using flow cytometry and fluorescence microscopy. The inducers and checkpoints were ionizing radiation (i.e., DNA damage) (G1 and G2 checkpoints), the mitotic inhibitor colcemid (polyploidy checkpoint), or the topoisomerase II catalytic inhibitor ICRF-193 (decatenation G2 checkpoint). Four of the five TCC lines expressed mutant p53. RESULTS: HUCs had an effective G1 checkpoint response to ionizing radiation, with 68% of cells inhibited from moving from G1 into S phase. By contrast, G1 checkpoint function was severely attenuated (<15% inhibition) in three of the five TCC lines and moderately attenuated (<50% inhibition) in the other two lines. NHF1-hTERT had an effective polyploidy checkpoint response, but three of five TCC lines were defective in this checkpoint. HUCs had effective ionizing radiation and decatenation G2 checkpoint responses. All TCC lines had a relatively effective G2 checkpoint response to DNA damage, although the responses of two of the TCC lines were moderately attenuated relative to HUCs. All TCC lines had a severe defect in the decatenation G2 checkpoint response. CONCLUSION: Bladder TCC lines have defective cell cycle checkpoint functions, suggesting that the p53-independent decatenation G2 checkpoint may cooperate with the p53-dependent G1 checkpoints to preserve chromosomal stability and suppress bladder carcinogenesis.

Carcinoma, Transitional Cell↗

PubMed2003

Restoration of functional motor units in a rat model of sphincter injury by muscle precursor cell autografts.

BACKGROUND: Urinary incontinence is a debilitating condition that affects primarily elderly individuals. One major mechanism results from chronic denervation of the striated urethral sphincter with associated fibrosis. The authors investigated the fate of muscle precursor cells (MPC) injected into a model of striated urethral sphincter injury that reproduces the histopathologic changes of sphincter insufficiency. METHODS: The striated urethral sphincter of older male rats was damaged by electrocoagulation. MPC were isolated from limb myofiber explants, infected with an adenovirus carrying the transgene encoding beta-galactosidase, and injected into the sphincter of the same animal 37 days after injury. Animals were killed 5 and 30 days after injection for assessment of sphincter function and the formation of motor units. RESULTS: Electrocoagulation resulted in an irreversible destruction of both sphincteric myofibers and nerve endings, with a functional incapacity of the damaged sphincter to sustain an increase in bladder pressure; atrophy and fibrosis developed after 1 month. Injection of MPC resulted in the formation of beta-galactosidase-expressing myotubes in the sphincter that persisted beyond 30 days. The regenerated myotubes carried acetylcholine receptors associated with a nerve ending and were thus considered to form anatomic motor units. Urodynamic studies confirmed the restoration of 41% of sphincter function 1 month after MPC injection. CONCLUSIONS: The authors showed that MPC isolated from limb muscles of an older animal can recapitulate a myogenic program when injected into an irreversibly injured sphincter. The maturation of MPC activates nerve regeneration and restores functional motor units.

Animals↗

PubMed2003

Urethral stricture repair with an off-the-shelf collagen matrix.

PURPOSE: In select patients with urethral strictures in whom genital skin is insufficient alternative tissues are needed for urethral reconstruction. We explored the feasibility of using a bladder submucosa collagen based inert matrix as a free graft substitute for urethral stricture repair. MATERIALS AND METHODS: A total of 28 patients 22 to 61 years old with a diagnosis of urethral stricture underwent reconstructive surgery using a collagen based inert matrix for urethral repair. The inert collagen matrix was trimmed to size as needed for each patient and the neourethra was created by anastomosing the matrix in an onlay fashion to the urethral plate with continuous 6-zero absorbable sutures. The size of the created neourethra ranged from 1.5 to 16 cm. A voiding history, physical examination, retrograde urethrography, uroflowmetry and cystoscopic examinations were performed preoperatively and postoperatively. Random urethral biopsies were also performed. RESULTS: After a 36 to 48-month followup (mean 37) 24 of the 28 patients had a successful outcome. The remaining 4 patients had a slight caliber decrease at the anastomotic sites on urethrography. A subcoronal fistula developed in 1 patient which closed spontaneously 1 year after repair. Mean maximum urine flow rate increased from the preoperative value of 9 +/- 1.29 to 19.7 +/- 3.07 ml. per second postoperatively. Cystoscopic studies revealed adequate caliber conduits and normal appearing urethral tissues. Histological examination of the biopsy specimens showed the typical urethral stratified epithelium. CONCLUSIONS: Use of an off-the-shelf collagen inert matrix appears to be beneficial for patients with urethral strictures and obviates the need for obtaining an autologous graft, thus eliminating donor site morbidity.

Adult↗

PubMed2003

Formation of corporal tissue architecture in vivo using human cavernosal muscle and endothelial cells seeded on collagen matrices.

We explored the feasibility of developing corporal tissue, consisting of human cavernosal smooth muscle and endothelial cells in vivo, using three-dimensional acellular collagen matrices, which are similar in architecture to native corpora. Acellular collagen matrices were derived from processed donor rabbit corpora, using cell lysis techniques. Human corpus cavernosal muscle and endothelial cells were seeded on the acellular matrices. A total of 80 matrices, 20 without cells and 60 with cells, were implanted subcutaneously in athymic mice. An additional 36 matrices seeded with cells were maintained in culture for up to 4 weeks. Hydroxyproline quantification, Western blot analysis, RT-PCR, and scanning electron microscopy of the matrices, with and without cells, were performed at various time points. Animals were killed 3 days and 1, 2, 3, 4, 6, and 8 weeks after implantation. Immunocytochemical and histological analyses were performed to confirm the muscle and endothelial phenotype. Organ bath studies were performed in order to determine the degree of tissue contraction. Western blot analysis detected alpha-actin, myosin, and tropomyosin proteins from human corporal smooth muscle cells. Expression of muscarinic acetylcholine receptor (mAChR) subtype m4 mRNA was demonstrated by RT-PCR from corporal muscle cells before and 8 weeks after seeding. The implanted matrices showed neovascularity into the sinusoidal spaces by 1 week after implantation. Increasing organization of smooth muscle and endothelial cells lining the sinusoidal walls was observed at 2 weeks and continued with time. The matrices were covered with the appropriate cell architecture 4 weeks after implantation. The matrices showed a stable collagen concentration over 8 weeks, as determined by hydroxyproline quantification. Immunocytochemical studies using alpha-actin and factor VIII antibodies confirmed the presence of corporal smooth muscle and endothelial cells, both in vitro and in vivo, at all time points. There was no evidence of cellular organization in the control matrices. Organ bath studies showed that the cell-seeded corporal tissue matrices responded to electrical field stimulation, whereas the unseeded implants failed to respond. This study demonstrates that human cavernosal smooth muscle and endothelial cells seeded on three-dimensional acellular collagen matrices derived from donor corpora are able to form well-vascularized corporal tissues in vivo.

Animals↗

PubMed2003

Engineering of vaginal tissue in vivo.

Congenital vaginal anomalies and cloacal malformations may require extensive surgical reconstruction. Surgical challenges are often encountered because of the limited amounts of native tissue available. We investigated the feasibility of using vaginal epithelial and smooth muscle cells for the engineering of vaginal tissues in vivo. Vaginal epithelial and smooth muscle cells of female rabbits were grown, expanded in culture, and characterized immunocytochemically. Vaginal epithelial and smooth muscle cells were seeded on polyglycolic acid (PGA) scaffolds at 10 x 10(6) and 20 x 10(6) cells/cm(3), respectively. The cell-seeded scaffolds were subcutaneously implanted into nude mice. The animals were killed 1, 4, and 6 weeks after implantation. Immunocytochemical and histochemical analyses were performed with pancytokeratins AE1/AE3 and with smooth muscle-specific alpha-actin antibodies to confirm the reconstituted tissue phenotype. Western blot analyses and electrical field stimulation studies were also performed to further characterize the tissue-engineered constructs. Vaginal epithelial cells were serially identified with anti-pancytokeratins AE1/AE3 at all culture stages. Smooth muscle cells in culture stained positively with alpha-smooth muscle actin antibodies. One week after implantation in vivo, the retrieved polymer scaffolds demonstrated multilayered tissue strips of both cell types, and penetrating native vasculature was also noted. Increased organization of the smooth muscle and epithelial tissue was evident by 4 weeks. There was no evidence of tissue formation in the controls. Immunocytochemical analyses using anti-pancytokeratins confirmed the presence of vaginal epithelial cells in each of the constructs. Anti-alpha-actin smooth muscle antibodies also confirmed the presence of multilayered smooth muscle fibers and tissue at each time point. Western blot analyses of the scaffolds confirmed the expression of cytokeratin and smooth muscle actin proteins when compared with controls. The contractile properties of the tissue-engineered vaginal constructs in response to electrical field stimulation were similar to those of normal vaginal tissue. Vaginal epithelial and smooth muscle cells can be easily cultured and expanded in vitro. Cell-seeded polymer scaffolds are able to form vascularized vaginal tissue in vivo that have phenotypic and functional properties similar to those of normal vaginal tissues. This is the first demonstration in tissue engineering wherein vaginal epithelial and smooth muscle cells are reconstituted in vivo into vaginal tissue. This technology may be pursued further experimentally in order to achieve the engineering of vaginal tissues for clinical applications.

Actins↗

PubMed2002

Generation of histocompatible tissues using nuclear transplantation.

Nuclear transplantation (therapeutic cloning) could theoretically provide a limitless source of cells for regenerative therapy. Although the cloned cells would carry the nuclear genome of the patient, the presence of mitochondria inherited from the recipient oocyte raises questions about the histocompatibility of the resulting cells. In this study, we created bioengineered tissues from cardiac, skeletal muscle, and renal cells cloned from adult bovine fibroblasts. Long-term viability was demonstrated after transplantation of the grafts into the nuclear donor animals. Reverse transcription-PCR (RT-PCR) and western blot analysis confirmed that the cloned tissues expressed tissue-specific mRNA and proteins while expressing a different mitochondrial DNA (mtDNA) haplotype. In addition to creating skeletal muscle and cardiac "patches", nuclear transplantation was used to generate functioning renal units that produced urinelike fluid and demonstrated unidirectional secretion and concentration of urea nitrogen and creatinine. Examination of the explanted renal devices revealed formation of organized glomeruli- and tubule-like structures. Delayed-type hypersensitivity (DTH) testing in vivo and Elispot analysis in vitro suggested that there was no rejection response to the cloned renal cells. The ability to generate histocompatible cells using cloning techniques addresses one of the major challenges in transplantation medicine.

Animals↗

PubMed2002

Reconstitution of human corpus cavernosum smooth muscle in vitro and in vivo.

A large number of congenital and acquired abnormalities of the genitalia would benefit from the availability of transplantable, autologous corpus cavernosum tissue for use in reconstructive procedures. We describe the results of preliminary experiments designed to determine the feasibility of using cultured human corporal smooth muscle cells seeded onto biodegradable polymer scaffolds for the formation of corpus cavernosum smooth muscle in vitro and in vivo. Primary cultures of human corpus cavernosum smooth muscle cells were derived from operative biopsies obtained during penile prosthesis implantation. Cells were characterized in vitro and seeded as a contiguous multilayered sheet onto polymers of non-woven polyglycolic acid. The seeded polymer constructs were then implanted subcutaneously in athymic mice. Animals were killed 7, 14, and 24 days after surgery and implants were examined via histology, immunocytochemistry, and Western blot analyses. Cultured cell multilayers were identified as smooth muscle before implantation via phase-contrast microscopy, immunocytochemistry and Western blot analyses. Retrieved implants from all time points demonstrated corporal smooth muscle tissue grossly, and histologically, at the time of sacrifice. Intact smooth muscle cell multilayers were observed growing along the surface of the polymers. There was evidence of early vascular ingrowth at the periphery of the implants by 7 days. By 24 days, there was evidence of polymer degradation. Maintenance of the smooth muscle phenotype in vivo was confirmed immunocytochemically and by Western blot analyses with antibodies to alpha-smooth muscle actin. This study provides evidence that cultured human corporal smooth muscle cells may be used in conjunction with biodegradable polymer scaffolds to create corpus cavernosum smooth muscle tissue in vitro and in vivo.

Animals↗

PubMed2002

Urethral replacement using cell seeded tubularized collagen matrices.

PURPOSE: Acellular collagen matrices derived from bladder submucosa have been used successfully as an off-the-shelf biomaterial for urethral replacement, experimentally and clinically in an onlay fashion. We investigated whether collagen matrices, either alone or with autologous cells, could be used for tubularized urethral replacement. MATERIALS AND METHODS: Acellular collagen matrices were processed and tubularized. Ten rabbits underwent an open bladder biopsy with subsequent cell expansion. Autologous bladder cells were grown and seeded onto the pre-configured tubular matrices. A 1 cm. long urethral segment was excised in 24 male rabbits. Urethroplasty was performed with the tubularized collagen matrices seeded with cells in 12 animals and without cells in 12. Serial urethrography was performed preoperatively and at 1, 2, 3 and 6 months postoperatively. Retrieved urethras were analyzed grossly, histologically, immunocytochemically and with Western blots. Contractility and the presence of neurotransmitter receptors were confirmed with organ bath studies. RESULTS: Serial urethrography confirmed the maintenance of a wide urethral caliber without any signs of strictures in animals implanted with the cell seeded matrices. The urethral segments replaced with the collagen scaffolds without cells demonstrated strictures and graft collapse at all time points. The implanted cell seeded matrices had a normal urethral architecture by 1 month, consisting of a transitional cell layer surrounded by muscle cell fiber bundles with increasing cellular organization with time. Epithelial and smooth muscle phenotypes were confirmed immunocytochemically and with Western blot analyses using pancytokeratins AE1/AE3 and smooth muscle specific alpha-actin antibodies. Formation of a transitional cell layer was confirmed in the matrices implanted without cells but only scant unorganized muscle fiber bundles were present, mostly at the anastomotic sites. Organ bath studies demonstrated the capacity for contractility along with cholinergic and adrenergic specific receptors in the tissue engineered scaffolds compared to controls. CONCLUSIONS: These results show that collagen matrices seeded with cells form normal urethral tissue can be used for tubularized replacement, whereas tubularized collagen matrices alone without cells lead to poor tissue formation and strictures. The collagen matrices seeded with cells may offer a useful alternative in the future for patients requiring a tubularized urethral segment replacement.

Animals↗

PubMed2002

Engineering of human cartilage rods: potential application for penile prostheses.

PURPOSE: Natural penile prostheses created from the patient's own cells may eliminate the biocompatibility risks associated with artificial prostheses. We previously demonstrated that autologous cartilaginous rods could be created in animal corpus cavernosum as penile prostheses in situ by transplanting autologous chondrocytes on biodegradable polymer scaffolds. In the present study we investigated the possibility of engineering human cartilage rods for potential use as penile prostheses. MATERIALS AND METHODS: Chondrocytes isolated from human ear were seeded on rod shaped biodegradable polymer scaffolds (1.2 cm. in diameter, 6.0 cm. long). The seeded scaffolds were maintained in stirred bioreactors for 1 month. Subsequently, the seeded scaffolds were implanted subcutaneously into athymic rats. The specimens were retrieved 2 months after implantation, and histological, structural and mechanical properties were analyzed. The mechanical properties of the engineered prostheses were compared to those of silicone prostheses. RESULTS: Human chondrocytes seeded onto polymer scaffolds formed milk-white cartilaginous rods of the same size as the initial implants. Histological analyses using hematoxylin and eosin, toluidine blue and alcian blue showed mature and well-formed chrondrocytes in the retrieved implants. The engineered human cartilaginous rods were flexible, elastic and able to withstand high degrees of compressive forces. The mechanical properties were comparable to those of commercially available silicone prostheses. CONCLUSIONS: Transplantation of chrondrocytes isolated from human ear on polymer scaffolds resulted in the formation of human cartilage rods with the appropriate mechanical properties required for use as penile prostheses. This study demonstrates the feasibility of creating human cartilage rods with a large dimension. This technology may be useful for patients who need penile reconstruction.

Biomechanical Phenomena↗