Recombinant vascular endothelial growth factor165 gene therapy improves anastomotic healing in an animal model of ischemic esophagogastrostomy.

Proper anastomotic healing is dependent upon many factors including adequate blood flow to healing tissue. The aim of this study was to investigate the impact of vascular endothelial growth factor (VEGF(165)) transfection on anastomotic healing in an ischemic gastrointestinal anastomosis model. Utilizing an established opossum model of esophagogastrectomy followed by esophageal-gastric anastomosis, the gastric fundus was transfected with recombinant human vascular endothelial growth factor via direct injection of a plasmid-based nonviral delivery system. Twenty-nine animals were divided into three groups: two concentrations of VEGF and a control group. Outcomes included VEGF mRNA transcript levels, neovascularization, tissue blood flow, and anastomotic bursting pressure. To determine whether local injection resulted in a systemic effect, distant tissues were evaluated for VEGF transcript levels. Successful gene transfection was demonstrated by quantitative polymerase chain reaction analysis of anastomotic tissue, with significantly higher VEGF mRNA expression in treated animals compared to controls. At the gastric side of the anastomosis, there was significantly increased neovascularization, blood flow, and bursting pressure in experimental animals compared to controls. There were no differences in outcome measures between low- and high-dose VEGF groups; however, the high-dose group demonstrated increased VEGF mRNA expression across the anastomosis. VEGF production was not increased at distant sites in treated animals. In this animal model, VEGF gene therapy increased VEGF transcription at a healing gastrointestinal anastomosis without systemic VEGF upregulation. This treatment led to improved healing and strength of the acutely ischemic anastomosis. These findings suggest that VEGF gene therapy has the potential to reduce anastomotic morbidity and improve surgical outcomes in a wide array of patients.

Connective tissue growth factor-(CTGF, CCN2)--a marker, mediator and therapeutic target for renal fibrosis.

Connective tissue growth factor (CTGF, CCN2) is a key mediator of tissue fibrosis. CCN2 plays an important role in the development of glomerular and tubulointerstitial fibrosis in progressive kidney diseases. In this review, we discuss the biology of CCN2 with a focus on the regulation of CCN2 gene, cellular mechanisms of profibrotic CCN2 effects and the current in vivo and in vitro evidence for the role of CCN2 in the development of renal fibrosis. We also discuss the therapeutic potential of targeting CCN2 for the treatment of renal fibrosis.

Cost-effectiveness of capsule endoscopy in screening for colorectal cancer.

BACKGROUND AND STUDY AIMS: Capsule endoscopy (Pillcam Colon) has recently shown acceptable accuracy in detecting colonic lesions when compared with colonoscopy. The aim of this analysis is to provide a model to assess the cost and effectiveness of population-based screening for colorectal cancer (CRC) using capsule endoscopy and to compare the cost-effectiveness with that of a colonoscopy screening program. METHODS: The cost-effectiveness of two screening strategies using colonoscopy or capsule endoscopy were compared by a computer model based on a Markov process. In this model, a hypothetical population of 100,000 individuals aged 50 years and over, undergoes a 10 yearly screening procedure. Different thresholds for postcapsule polypectomy referral were simulated. RESULTS: At baseline, the incremental cost-effectiveness (compared with no screening) of colonoscopy and capsule endoscopy was $ 16,165 and $ 29,244 per life-year saved, respectively. When equal compliance was simulated, the colonoscopy program was more effective and less costly than a strategy based on capsule endoscopy. When simulating an initial compliance to capsule endoscopy 30% better than colonoscopy, capsule endoscopy became the more effective and more cost-effective option. A 20% better compliance was sufficient when a higher accuracy of capsule endoscopy for polyps was assumed. A 6 mm threshold for polypectomy referral was associated with a substantial cost reduction in the capsule endoscopy program with only a small loss of efficacy. CONCLUSIONS: The cost-effectiveness of capsule endoscopy depends mainly on its ability to improve compliance to CRC screening.

The colorectal malignant polyp: scoping a dilemma.

Colorectal adenomas containing invasive carcinoma represent the majority of early colorectal cancers. The malignant polyp carries a significant risk of lympho-haematic metastasis and mortality due to the penetration of cancerous cells into the submucosal layer. The therapeutic dilemma is whether to perform endoscopic or surgical resection. A thorough assessment of the endoscopic, histological and clinical variables is needed to unravel the best treatment for each patient. In particular, a unique staging of such lesions, based on certain histopathological features, has been deeply implicated in the therapeutic choice. Aim of this article is to review the main endoscopic, histological and clinical features of the malignant polyp in order to propose a systematic management of this lesion.

Colon cancer prevention in Italy: cost-effectiveness analysis with CT colonography and endoscopy.

BACKGROUND: Colorectal cancer (CRC) is a major cause of mortality in Italy. Although prevention of CRC is possible, its cost-effectiveness when applied to the Italian population is unknown. Recently, computerized tomographic colonography (CTC) has been proposed for CRC screening. AIM: To compare the efficacy and cost-effectiveness of CTC screening in a simulated Italian population with those of colonoscopy and flexible sigmoidoscopy (FS). METHODS: The cost-effectiveness of different screening strategies was compared using a Markov process computer model, in which in a hypothetical population of 100,000 50 year-olds were investigated by CTC, colonoscopy or FS every decade. Outcomes were projected to the Italian national level. RESULTS: CRC incidence reduction was calculated at 40.9%, 38.2%, and 31.8% with colonoscopy, CTC and FS, respectively. As compared to no screening, all screening programs were shown to be cost-saving, allowing a saving of 11 Euro, 17 Euro, and 48 Euro per person with colonoscopy, FS and CTC, respectively. FS appeared to be less cost-effective than CTC, whilst colonoscopy appeared to be an expensive option as compared to CTC. Undiscounted national expenditure was calculated to be 1,042,489,512 Euro, 1,093,268,285 Euro, and 1,198,783,428 Euro for FS, CTC and colonoscopy, respectively, as compared to 695,818,078 Euro without screening. CONCLUSION: CRC screening is cost-saving in Italy, irrespective of the technique applied. CTC appeared to be more cost-effective than FS, and it may also become a valid alternative to colonoscopy.

Motivation to change in recent onset and long-standing bulimia nervosa: are there differences?

UNLABELLED: REASON FOR THE STUDY: Little is known about how motivation to change evolves over the course of an eating disorder. The present study compared 'stage of change' and motivation, confidence and readiness to change in two groups of patients with bulimia nervosa (BN), adolescents with a short duration of illness and adults with a long duration of illness. METHOD: Patients completed the Severity of eating disorder symptomatology scale, Hospital Anxiety and Depression Scale and measures of stage of change and motivation, readiness and confidence to change their bulimic symptomatology at pre-treatment. MAIN FINDINGS: Short- and long duration groups did not differ in illness severity, comorbidity, stage of change, motivation, readiness, and confidence to change. There were, however, some differences between groups in terms of the relationship between motivational measures, illness severity, duration and comorbidity. CONCLUSIONS: There seem to be more similarities than differences between adolescents with short duration of illness and those with well-established BN in terms of their motivation to change.

Establishing an immortalized human osteoprecursor cell line: OPC1.

The present studies evaluated the feasibility of establishing a conditionally immortalized osteoprecursor cell line derived from human fetal bone tissue. Primary cultures were transfected with a plasmid in which the Mx-1 promoter drives the expression of SV40 T-antigen when activated by human A/D interferon. Several neomycin (G418)-resistant colonies were characterized for cell growth and alkaline phosphatase (ALP) enzyme activity. The clone, designated OPC1 (osteoblastic precursor cell line 1), which exhibited the highest ALP enzyme activity at passage 10 (P10), was selected for additional osteogenic phenotypic characterization. Reverse transcription-polymerase chain reaction (RT-PCR) phenotyping revealed abundant mRNA for osteocalcin (OC), osteonectin (ON), osteopontin (OP), parathyroid hormone receptor (PTHr), ALP, and procollagen type I (ProI). In addition, the levels of quantitative RT-PCR product of ON, OP, PTHr, and ProI mRNAs exhibited a marked up-regulation when maintained in medium containing an osteogenic supplement (OS). The ability to stimulate osteogenic differentiation was characterized in postconfluent OPC1 cells maintained in tissue culture medium supplemented with recombinant human bone morphogenetic protein-2 (rhBMP-2) either with or without an OS. All treatment groups exhibited a striking up-regulation of ALP enzyme activity that coincided with ALP histochemical observations. Postconfluent cells also exhibited the ability to form mineralized nodules under all treatments (confirmed by von Kossa histochemical staining and calcium deposition). An enzyme immunosorbent assay (EIA) was utilized to measure intact human OC from the OPC1 line under the various treatments. Abundant OC was evident in the tissue culture medium indicating de novo sythesis and release from the OPC1 line under appropriate conditions. The clonal human-derived OPC1 line represents a homogeneous osteogenic cell line that not only has maintained a consistent bone phenotype from P10 to at least P30, but has also exhibited the capacity to generate programmed differentiation in the presence of low dose rhBMP-2 (10 ng/ml). Thus, the OPC1 line is a human-derived osteoprecursor that provides a sensitive in vitro cell culture system to evaluate bone development, cell/biomaterial interactions, and may be a useful screen for putative bone differentiating factors.

Cell delivery to the central nervous system.

A dysfunctional central nervous system (CNS) resulting from neurological disorders and diseases impacts all of humanity. The outcome presents a staggering health care issue with a tremendous potential for developing interventive therapies. The delivery of therapeutic molecules to the CNS has been hampered by the presence of the blood-brain barrier (BBB). To circumvent this barrier, putative therapeutic molecules have been delivered to the CNS by such methods as pumps/osmotic pumps, osmotic opening of the BBB, sustained polymer release systems and cell delivery via site-specific transplantation of cells. This review presents an overview of some of the CNS delivery technologies with special emphasis on transplantation of cells with and without the use of polymer encapsulation technology.

Gene therapy approaches for modulating bone regeneration.

Following injury, bone has the ability to regenerate itself to a form and function nearly indistinguishable from the pre-injury state. However, if the injury is beyond a critical limit, recovery will not occur without therapeutic interventions. Autografts and implants with banked bone continue as the treatments of choice, although each exhibits limitations and liabilities. Alternatives have included the utilization of bone-graft substitutes that may incorporate bone derivatives and soluble signaling molecules such as mitogens and morphogens. In addition, an evolving treatment modality, gene therapy, offers an exciting avenue for bone regeneration. This review presents some of the current concepts for developing a rational gene therapy approach in bone regeneration.

A novel approach to neural transplantation in Parkinson's disease: use of polymer-encapsulated cell therapy.

Transplantation of dopaminergic neurons derived from fetal or adrenal tissue into the striatum is a potentially useful treatment for Parkinson's disease (PD). Although initially promising, recent clinical studies using adrenal autografts have demonstrated limited efficacy. The use of human fetal cells, despite promising preliminary results, is complicated by tissue availability and ethical concerns. An attractive alternative is based on encapsulating dopamine-producing cells into polymer capsules prior to transplantation. Polymer capsules can be fabricated to surround the cells with a semi-permeable and immunoprotective barrier. The semi-permeable membrane allows nutrients to enter the capsule, so the encapsulated cells will survive and function, and dopamine and other low molecular weight constituents to diffuse out into the host tissue. Thus, the technique allows use of unmatched human tissue (allografts), or even animal tissue (xenografts) without immunosuppression of the recipient. Cell-loaded polymer capsules can also be retrieved if necessary or desired. The demonstration that striatal implants of encapsulated dopamine-producing cells promote behavioral recovery in rodent and primate models of PD further suggests that cellular encapsulation may be a useful strategy for ameliorating the behavioral consequences of PD.

The effects of antidepressants on the thyroid axis in depression.

Thirty-nine patients with major depression were studied to determine the differential effects of desipramine (DMI) and fluoxetine (FLU) on thyroid hormones. Twenty-six percent showed some abnormality in baseline thyroid hormone levels. There were no demonstrable differences for any of the thyroid indices from baseline to the 3- or 6-week samples for the total group or for either drug by repeated measures analysis of variance. There was a significant group by time interaction for total thyroxine (TT4) between the drug treatment groups, which was caused by a small but significant increase in TT4 in the DMI sample. Correlations were performed between the change in hormones over the 6 week period and treatment response. There was a significant association between a decline in triiodothyronine (T3) levels and response to FLU but not DMI. The implications of these findings for the pathophysiology of depression and antidepressant drug mechanisms are discussed.

Critical aspects of tissue-engineered therapy for bone regeneration.

Recent advances in bone tissue engineering are established on the understanding of an engineered scaffold, the molecular milieu within the osteogenic site, and the cell(s) predisposed to an osteogenic lineage. Advances in the incorporation of a generative vehicle into a skeletal defect require temporal and spatial distribution of the scaffold, growth factor, and cell compatible with enhanced bone healing. Monitoring events culminating in osteogenesis has focused on phenotypic and intracellular indicators. Phenotypic and intracellular indicators include the presence of receptors and intracellular signals that enable cell proliferation and differentiation. Progress in the areas of scaffold design, growth factor utilization, bone cell lineage, and intracellular signaling are reviewed.

Implants of polymer-encapsulated human NGF-secreting cells in the nonhuman primate: rescue and sprouting of degenerating cholinergic basal forebrain neurons.

Baby hamster kidney (BHK) cells were genetically modified to secrete high levels of human nerve growth factor (BHK-hNGF). Following polymer encapsulation, these cells were implanted into the lateral ventricle of four cynomolgus monkeys immediately following a unilateral transection/aspiration of the fornix. Three control monkeys received identical implants, with the exception that the BHK cells were not genetically modified to secrete hNGF and thus differed only by the hNGF construct. One monkey received a fornix transection only. All monkeys displayed complete transections of the fornix as revealed by a comprehensive loss of acetylcholinesterase-containing fibers within the hippocampus ipsilateral to the lesion. Control monkeys that were either unimplanted or received BHK-control (non-NGF secreting) cell implants did not differ from each other and displayed extensive losses of choline acetyltransferase and p75 NGF receptor (NGFr)-immunoreactive neurons within the medial septum (MS; 53 and 54%, respectively) and vertical limb of the diagonal band (VLDB; 21 and 30%, respectively) ipsilateral to the lesion. In contrast, monkeys receiving implants of BHK-hNGF cells exhibited a only a modest loss of cholinergic neurons within the septum (19 and 20%, respectively) and VLDB (7%). Furthermore, only implants of hNGF-secreting cells induced a dense sprouting of cholinergic fibers within the septum, which ramified against the ependymal lining of the ventricle adjacent to the transplant site. Examination of the capsules retreived from monkeys just prior to their death revealed an abundance of cells that produced detectable levels of hNGF in a sufficient concentration to differentiate PC12A cells in culture. These findings support the use of polymer-encapsulated cell therapy as a potential treatment for neurodegenerative diseases such as Alzheimer disease where basal forebrain degeneration is a consistent pathological feature. Moreover, this encapsulated xenogeneic system may provide therapeutically effective levels of a number of neurotrophic factors, alone or in combination, to select populations of neurons within the central nervous system.

Intrastriatal implants of polymer encapsulated cells genetically modified to secrete human nerve growth factor: trophic effects upon cholinergic and noncholinergic striatal neurons.

Nerve growth factor selectively prevents the degeneration of cholinergic neurons following intrastriatal infusion but rescues both cholinergic and noncholinergic striatal neurons if the nerve growth factor is secreted from grafts of genetically modified fibroblasts. The present study evaluated whether grafted fibroblasts genetically modified to secrete human nerve growth factor could provide trophic influences upon intact cholinergic and noncholinergic striatal neurons. Unilateral striatal grafts of polymer-encapsulated cells genetically modified to secrete human nerve growth factor induced hypertrophy and significantly increased the optical density of choline acetyltransferase-immunoreactive striatal neurons one, two, and four weeks post-transplantation relative to rats receiving identical grafts missing only the human nerve growth factor construct. Nerve growth factor secreting grafts also induced a hypertrophy of noncholinergic neuropeptide Y-immunoreactive striatal neurons one, two, and four weeks post-transplantation. Glutamic acid decarboxylase-immunoreactive neurons were unaffected by the human nerve growth factors secreting grafts. The effects upon choline acetyltransferase-immunoreactive and neuropeptide Y-immunoreactive striatal neurons dissipated following retrieval of the implants. Immunocytochemistry for nerve growth factor revealed intense graft-derived immunoreactivity for up to 1000 microns from the capsule extending along the dorsoventral axis of the striatum. Nerve growth factor-immunoreactivity was also observed within a subpopulation of striatal neurons and may represent nerve growth factor consumer neurons which retrogradely transported graft-derived nerve growth factor. When explanted, grafts produced 2-4 ng human nerve growth factor/24 h over the time course of this study indicating that this level of continuous human nerve growth factor secretion was sufficient to mediate the effects presently observed.

Immunoisolation cell therapy for CNS diseases.

Delivery of potentially therapeutic drugs to the brain is hindered by the blood-brain barrier (BBB), which restricts the diffusion of drugs from the vasculature to the brain parenchyma. One means of overcoming the BBB is with cellular implants that produce and deliver therapeutic molecules directly into the CNS region of interest. In this paper we describe the current status of one iteration of cell-based therapy that uses xenogeneic cells encased within a selectively permeable polymeric membrane; this is known as immunoisolation. For the purposes of this review, cell immunoisolation for treating CNS diseases is presented in terms of device configurations, membrane manufacturing, characterization in relevant preclinical model systems, and the current status of clinical trials.

Ascorbic acid and intestinal metaplasia in the stomach: a prospective, randomized study.

BACKGROUND: Intestinal type metaplasia plays a role in intestinal type gastric carcinoma development. Ascorbic acid demonstrates a protective effect against gastric carcinogenesis, due to its ability to inactivate oxygen free-radicals as well as its nitrite-scavenging effects. AIM: To assess whether long-term ascorbic acid administration following Helicobacter pylori eradication could affect intestinal metaplasia regression in the stomach. METHODS: Sixty-five patients were included in the study. The inclusion criterion was the presence of intestinal metaplasia on the gastric mucosa after H. pylori eradication. An upper gastrointestinal endoscopy was performed and 3 biopsy specimens were taken in the antrum, 3 in the gastric body, and 2 in the incisura angularis. Patients were randomized to receive 500 mg of ascorbic acid o.d., after lunch (32 patients) for 6 months or no treatment (33 patients). All patients underwent to endoscopic control at the end of the 6 months. RESULTS: H. pylori infection recurrence was detected in 6 (9.4%) patients (three from each group), and these patients were excluded from further analysis. We were unable to find evidence of intestinal metaplasia in any biopsied site of the gastric mucosa in 9/29 (31%) patients from the ascorbic acid group and in 1/29 (3.4%) of the patients from the control group (P=0.006). Moreover, a further six (20.7%) patients from the ascorbic acid group presenting chronic inactive pangastritis with widespread intestinal metaplasia at entry, showed less extensive antritis with intestinal metaplasia at control, whilst a similar finding was only seen in one patient from the control group (P=0.051). CONCLUSION: The administration of ascorbic acid significantly helps to resolve intestinal metaplasia of the gastric mucosa following H. pylori eradication, and its use as a chemoprevention treatment should be considered.

A new highly effective short-term therapy schedule for Helicobacter pylori eradication.

BACKGROUND: Although triple therapy regimens suggested in the Current European guidelines give fairly good results, several studies have reported an unsatisfactory Helicobacter pylori eradication rate (< 80%). AIM: To evaluate the efficacy of a new short-term treatment sequence on H. pylori eradication. METHODS: A total of 52 patients with H. pylori infection and either non-ulcer dyspepsia (34 patients) or peptic ulcer (18 patients) were enrolled to receive a 10-day therapy: omeprazole 20 mg b.d. plus amoxycillin 1 g b.d. for the first 5 days, followed by omeprazole 20 mg b.d., clarithromycin 500 mg b.d. and tinidazole 500 mg b.d. for the remaining 5 days. H. pylori infection at entry was assessed by rapid urease test and histology on biopsies from the antrum and the corpus. Bacterial eradication was assessed by endoscopy (peptic ulcer patients) or 13C urea breath test (non-ulcer dyspepsia patients) 4-6 weeks after therapy had ended. RESULTS: All patients completed the study. H. pylori eradication was achieved in all but one patient, with an eradication rate of 98% (95% CI: 94.3-100) with intention-to-treat analysis. Patient compliance was good (consumption of prescribed drugs > 95%) for all but one patient, who took the triple therapy regimen for 4 days instead of 5 days. No major side-effects were reported but three (6%) patients complained of mild side-effects. CONCLUSIONS: The use of this 'five plus five' therapy schedule as an initial treatment for H. pylori deserves further investigation.

Helicobacter pylori eradication with proton pump inhibitor-based triple therapies and re-treatment with ranitidine bismuth citrate-based triple therapy.

BACKGROUND: It has been suggested that short-term triple therapy comprising a proton pump inhibitor, plus clarithromycin and amoxycillin be used as first choice in treating H. pylori infection, while eradication failure patients should be further treated with a quadruple therapy. Nevertheless, conflicting results have been reported using these treatment regimens in different countries. METHODS: A total of 278 patients with H. pylori infection were randomised to receive one-week triple therapy, comprising clarithromycin 500 mg b.d., amoxycillin 1 g b.d., and either omeprazole 20 mg b.d. (OAC; 90 patients), or pantoprazole 40 mg b.d. (PAC; 95 patients), or lansoprazole 30 mg b.d. (LAC; 93 patients). H. pylori infection at entry, and eradication 4-6 weeks after therapy had ended, were assessed by rapid urease test and histology on biopsies from the antrum and the corpus. When eradication did not occur, patients were given a 2-week treatment comprising ranitidine bismuth citrate 400 mg b.d., tetracycline 500 mg t.d.s. and tinidazole 500 mg b.d. (RBTT). Eradication in these patients was assessed 4-6 weeks after conclusion of treatment by a further endoscopy. RESULTS: Six patients were lost to the follow-up. At the end of the first course of treatment, the overall H. pylori eradication rate was 78% (95% CI: 73-83) and 79% (95% CI: 75-84) at 'intention-to-treat' (ITT) and 'per protocol' (PP) analysis, respectively, without any statistically significant difference between treatment regimens, although a trend for better results with the omeprazole combination was observed. Moreover, H. pylori eradication was achieved in 82% (95% CI: 75-97) (ITT) and 86% (95% CI: 69-94) (PP) of 38 patients re-treated with RBTT regimen. CONCLUSIONS: Our data found that this short-term triple therapy is not a satisfactory treatment (< 80% eradication rate) for H. pylori infection. The 2-week triple therapy used as re-treatment in eradication failure patients yielded more promising results.

Polymer encapsulated dopaminergic cell lines as "alternative neural grafts".

Our preliminary findings (Jaeger et al., 1988; Aebischer et al., 1989; Tresco et al., 1989) and the studies in progress show that encapsulated dopaminergic cell lines survive enclosure within a semi-permeable membrane. The encapsulated cells remained viable for extended time periods when maintained in vitro. Moreover, encapsulated PC12 and T28 cells have the potential to survive following their implantation into the forebrain of rats. Cell lines are essentially "immortal" because they continue to divide indefinitely. This property allows perpetual "self-renewal" of a given cell population. However, the capacity of continuous uncontrolled cell division may also lead to tumor formation. This in fact is the case for unencapsulated PC12 cell implants placed into the brain of young Sprague Dawley rats (Jaeger, 1985). Cell line encapsulation has the potential to prevent tumor growth (Jaeger et al., 1988). Survival for 6 months in vitro suggests that encapsulation does not preclude long-term maintenance of an homogeneous cell line like PC12 cells. The presence of mitotic figures in the capsules further supports the likelihood of propagation and self renewal of the encapsulated population. Another significant property of cell lines is that they consist of a single, genetically homogeneous cell type. They do not require specific synaptic interactions for their survival. In the case of PC12 and T28 lines, the cells synthesize and release neurotransmitters. Our data show that PC12 and T28 cells continue to release dopamine spontaneously and to express specific transmitters and enzymes following encapsulation. Thus, cell lines such as these may constitute relatively simple "neural implants" exerting their function via humoral release.(ABSTRACT TRUNCATED AT 250 WORDS)

An osteogenic cell culture system to evaluate the cytocompatibility of Osteoset, a calcium sulfate bone void filler.

The purpose of the study was to describe a convenient, reliable and quantitative in vitro assay system to assess the cytocompatibility of a calcium sulfate bone filler on two osteogenic cell lines and primary osteoblasts. The hypothesis was that the bone void filler, OsteoSet pellets, would not impact adversely on cell proliferation kinetics or osteogenic potential of selected cells. The hypothesis was tested by standard in vitro methodology of placing OsteoSet pellets either directly in contact with osteogenic cells, or by compartmentalizing within transwell - clear microporous membrane inserts. Data analyses were accomplished with appropriate post hoc statistics (p < or = 0.05). In the presence of the OsteoSet pellets, the cell lines exhibited a decrease in cell proliferation at days 4 and 7, independent of either cell type or tissue culture medium. A decrease in the alkaline phosphatase enzyme activity occurred in the osteogenic cell lines maintained for 9 and 16 days in the presence of the OsteoSet pellets. However, with the exception of the MC3T3E-1 line, no differences were observed with respect to calcium deposition (mineralization) by day 16. Intact human osteocalcin release data for the human-derived OPC1 line and the primary osteoblasts was inconclusive as the OsteoSet pellets may interact with the osteocalcin secreted into the tissue culture medium. The present studies describe a cell culture system to assess the cytocompatibility of bone-graft substitutes with osteogenic cells by compartmentalizing material from direct cell contact (in transwells), and additionally, by evaluating direct cell/biomaterial interactions.