Biological basis for the use of autologous bone marrow stromal cells in the treatment of congenital pseudarthrosis of the tibia

The study was designed to establish the biological basis for the use of autologous bone-marrow stromal cells (MSC) in order to improve the curing opportunities of congenital pseudarthrosis of the tibia (CPT). The investigation was planned by taking into account that the pathophysiology of bone healing mainly depends on the osteogenic potential of the resident cells, although several factors play a crucial role in restoring the normal bone structure. Bone marrow samples were collected from the lesion site (P) and the iliac crest (IC) of 7 patients affected by CPT and type 1 neurofibromatosis (NF1+) and 6 patients affected by CPT without NF1 (NF1-). Four patients without CPT served as control group. Biochemical, functional and molecular assays showed that the ability to generate bone-forming cells was higher in IC-MSC than in P-MSC, but lower in CPT patients than in control group. We evaluated whether host factors, such as autologous serum and the microenvironment surrounding the pseudarthrosis lesion, could impair the osteogenic differentiation of IC-MSC. Autologous serum was less effective than FBS in promoting the IC-MSC differentiation, but the damage was more evident in NF1- than in NF1+ patients. Additionally, the supernatant of osteoblast cultures obtained from bone fragments close to the lesion site favoured the differentiation of IC-MSC in NF1- patients. In summary, our results suggest that MSC transplantation could be a promising strategy for the therapy of CPT. Further studies are warranted to confirm the clinical effectiveness in comparison to standard surgical treatment.

Osteo-Odonto-Keratoprosthesis: A Human Model of Autotransplant

We evaluated the microscopical changes that occurred when bone and dental tissue were exposed to such a foreign environment as the ocular surface and anterior chamber in 17 osteo-odonto-keratoprostheses removed from the recipient's eye after 1 to 20 years. Histochemical methods were performed to demonstrate elastic and precursor fibers, while immunohistochemical procedures were used to study the distribution of collagen types I to VI. Islands of heterotopic, newly formed bone were observed in the dentin and the periodontal space, leading to focal dentoalveolar ankylosis. Remodelling and disappearance of the periodontal ligament was never diffuse.

Islet surface heparinization prevents the instant blood-mediated inflammatory reaction in islet transplantation

OBJECTIVE

In clinical islet transplantation, the instant blood-mediated inflammatory reaction (IBMIR) is a major factor contributing to the poor initial engraftment of the islets. This reaction is triggered by tissue factor and monocyte chemoattractant protein (MCP)-1, expressed by the transplanted pancreatic islets when the islets come in contact with blood in the portal vein. All currently identified systemic inhibitors of the IBMIR are associated with a significantly increased risk of bleeding or other side effects. To avoid systemic treatment, the aim of the present study was to render the islet graft blood biocompatible by applying a continuous heparin coating to the islet surface.

RESEARCH DESIGN AND METHODS

A biotin/avidin technique was used to conjugate preformed heparin complexes to the surface of pancreatic islets. This endothelial-like coating was achieved by conjugating barely 40 IU heparin per full-size clinical islet transplant.

RESULTS

Both in an in vitro loop model and in an allogeneic porcine model of clinical islet transplantation, this heparin coating provided protection against the IBMIR. Culturing heparinized islets for 24 h did not affect insulin release after glucose challenge, and heparin-coated islets cured diabetic mice in a manner similar to untreated islets.

CONCLUSIONS

This novel pretreatment procedure prevents intraportal thrombosis and efficiently inhibits the IBMIR without increasing the bleeding risk and, unlike other pretreatment procedures (e.g., gene therapy), without inducing acute or chronic toxicity in the islets.

Quantitative 3D MR evaluation of autologous chondrocyte implantation in the knee: feasibility and initial results

OBJECTIVE

To evaluate the feasibility of quantitative magnetic resonance imaging (MRI) based follow-up of cartilage volumetric data in patients after autologous chondrocyte implantation (ACI). To provide results from a 1-year follow-up study.

METHODS

From 21 ACI patients sagittal FS 3D FLASH (50/11/30; 0.6x0.6x1.5mm(3)) MRI knee data sets were obtained pre and 1-year post-ACI surgery in the femoral condyles. After semi-automated segmentation and 3D reconstruction of the cartilage plates, cartilage volume, mean thickness and size of the cartilage-bone interface were calculated. Susceptibility artifacts were evaluated in all, intra-observer reproducibility was evaluated in six of the patients. Volumetric parameters were compared during follow-up and sensitivity to change was assessed for the total femur vs the separately evaluated medial/lateral portions of the femur.

RESULTS

Reproducibility error (coefficient of variation %) was 3.9%/4.4% for the med./lat. tibial and 5.1% for the femoral cartilage volume. Susceptibility artifacts led to the exclusion of three out of the 21 patients, but were moderate in the remaining 18 patients, not preventing reproducible segmentation. In contrast to lack of significant change in the (non-operated) tibiae, a mean 6% increase of volume and thickness in the treated femora (P<0.001 Wilcoxon) relative to the pre-OP data was observed. Sensitivity to change for the femur ranged from 0.74 to 2.60 for cartilage volume and thickness and was improved when evaluating only the treated portion of the femur in contrast to the total femur.

CONCLUSION

Our data indicate that despite postoperative susceptibility artifacts quantitative evaluation of cartilage volumetric parameters can be performed in ACI patients. The technique is able to describe changes of these parameters over 1 year. Volumetric follow-up may help to identify altered disease progression.

Vertical and horizontal dimensional evaluation of free gingival grafts in the anterior mandible: a case report series

The shrinkage of free gingival grafts (FGGs) is a well-known clinical phenomenon but there are limited studies demonstrating the dimensional changes during healing in FGGs. The aim of the study is to examine the shrinkage of FGG in both horizontal and vertical dimensions and calculate the changes in the surface area of the graft at early and delayed periods of healing. The FGG procedure was applied to 15 consecutive patients in their mandibular anterior area. The graft sizes and areas were measured and the shrinkage of the graft was calculated at baseline and days 10, 21 and 180. Hemorrhage, sense alteration and pain symptoms were also examined. Change in the horizontal direction was not statistically significant during the whole study period (p > 0.05). However, there was a statistically significant reduction in the vertical direction in all visits, except day 10 (p < 0.05). Calculated graft area was also significantly reduced during the study period at all time-points compared to the baseline (p < 0.001). At day 10, 4 (26.7%) recipient sites and 5 (33%) donor sites demonstrated paresthesia. Only one (0.07%) recipient site demonstrated paresthesia at day 21 where the donor site resulted with an uneventful healing. At day 10, 5 (33%) patients demonstrated bleeding at their donor regions and resulted with a complete cessation of bleeding at day 21. Pain symptom was found in 8 (53.3%) recipient sites where 3 (20%) donor regions presented pain symptom at day 10. Graft shrinkage in the vertical dimension seems to affect the clinical outcomes of the FGG procedure. However, the influence of horizontal graft shrinkage was minimal.

Autologous chondrocyte implantation: natural history of postimplantation periosteal hypertrophy and effects of repair-site debridement on outcome

PURPOSE

Our purposes were to report the clinical outcome of autologous chondrocyte implantation (ACI) patients with graft hypertrophy compared with that of unoperated ACI patients and to longitudinally assess the effects of graft hypertrophy debridement.

METHODS

We divided 170 knee ACI patients with a minimum of 2 years' follow-up into groups according to the need for reoperation after ACI and the findings at surgery. Group A (n = 73) comprised patients who did not undergo reoperation, group B (n = 61) comprised patients who underwent reoperation and had findings unrelated to the repair, and group C (n = 36) comprised patients who underwent reoperation and had isolated graft hypertrophy. The International Knee Documentation Committee, modified Cincinnati knee rating, and Short Form 36 physical component scores for the 3 groups were compared. Of the repairs debrided because of graft hypertrophy, 41 were longitudinally assessed with arthroscopy or magnetic resonance imaging.

RESULTS

The mean follow-up was 42.2 months. Patch-related problems were seen in 73.7% of cases undergoing reoperation less than 2 years after implantation, whereas cartilage-related problems were the dominant finding more than 2 years after implantation (70.2%). Group A patients fared significantly better than group B or C patients with regard to all 3 parameters measured, with no difference between groups B and C. Longitudinal assessment of 41 hypertrophied repairs revealed 18 with signs of pathology after graft debridement.

CONCLUSIONS

This study shows that reoperation is frequent after ACI and is associated with a less satisfying outcome. Furthermore, debridement of a hypertrophied ACI graft appears to be detrimental as shown by longitudinal assessment of repairs.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Comparison of fresh osteochondral autografts and allografts: a canine model

BACKGROUND

Osteochondral autografts and allografts have been widely used in the treatment of isolated grade IV articular cartilage lesions of the knee. However, the authors are not aware of any study that has prospectively compared fresh osteochondral autografts to fresh allografts with regard to imaging, biomechanical testing, and histology.

HYPOTHESIS

The imaging, biomechanical properties, and histologic appearance of fresh osteochondral autograft and fresh allograft are similar with respect to bony incorporation into host bone, articular cartilage composition, and biomechanical properties.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eighteen adult dogs underwent bilateral knee osteochondral graft implantation after creation of an Outerbridge grade IV cartilage defect. One knee received an autograft, and the contralateral knee received a fresh allograft. Nine dogs were sacrificed at 3 months, and 9 dogs were sacrificed at 6 months. Graft analysis included gross examination, radiographs, magnetic resonance imaging, biomechanical testing, and histology.

RESULTS

Magnetic resonance imaging demonstrated excellent bony incorporation of both autografts and allografts. Biomechanical testing demonstrated no significant difference between autografts versus allografts versus control at 3 or 6 months (P = .36-.91). A post hoc calculation showed 80% power to detect a 30% difference between allograft and control. Histologic examination showed normal cartilage structure for both autografts and allografts.

CONCLUSION

Fresh osteochondral autograft and fresh allograft tissues are not statistically different with respect to bony incorporation, articular cartilage composition, or biomechanical properties up to 6 months after implantation.

CLINICAL RELEVANCE

The use of fresh allograft tissue to treat osteochondral defects eliminates morbidity associated with harvesting autograft tissue without compromising the results of the surgical procedure.

Osteochondral autograft transplantation in the porcine knee

BACKGROUND

Knee articular cartilage defects are not an uncommon problem. Because articular cartilage is limited in its ability to heal, these defects are difficult to manage.

HYPOTHESIS

Osteochondral autografts will provide less of a cavitary defect and more viable hyaline articular cartilage than will control knees.

STUDY DESIGN

Controlled laboratory study.

METHODS

Osteochondral autografts were grossly and microscopically evaluated in the porcine knee and compared with a control at 6 weeks, 3 months, and 6 months. In 18 porcine specimens, a 1-stage surgical procedure was performed to harvest an osteochondral graft from a nonweightbearing articular cartilage surface, and the graft was transplanted into a defect created in the weight-bearing region of the medial femoral condyle. In the opposite control knee, a similar defect was created in the medial femoral condyle; an osteochondral transplant was not performed. Six pigs each were sacrificed at 6 weeks, 3 months, and 6 months.

RESULTS

Gross inspection of the control knees showed a cavitary defect. The defect grossly decreased in size with fibrous ingrowth seen on microscopic analysis. An increasing amount of fibrous tissue and fibrocartilage was present at the 3 time periods. Gross inspection of the graft knee showed a healed osteochondral plug with no obvious displacement, cavitary defects, or surrounding necrotic tissue at each time interval. Microscopic analysis revealed the graft knee contained viable hyaline cartilage and healed viable subchondral bone. At all time intervals, 75% to 100% of the hyaline cartilage was viable in all specimens. In 6-month specimens, bridging cartilage at the autograft-host junction was incomplete in 50%, partial in 33%, and complete in 17%.

CONCLUSION

Osteochondral autografts in the porcine knee resulted in viable hyaline cartilage for up to 6 months; there was inconsistent bridging hyaline cartilage at the periphery. Grafts appeared to heal into existing subchondral bone without displacement or evidence of necrosis.

CLINICAL RELEVANCE

This type of osteochondral transplant can be used as a reliable reconstructive alternative for osteochondral defects.

Beneficial effects of concurrent autologous bone marrow cell therapy and metabolic intervention in ischemia-induced angiogenesis in the mouse hindlimb

Lower-limb ischemia is a major health problem. Because of the absence of effective treatment in the advanced stages of the disease, amputation is undertaken to alleviate unbearable symptoms. Novel therapeutic approaches include the intramuscular use of autologous bone marrow cells (BMCs). Because tissue ischemia is associated with an overwhelming generation of oxygen radicals and negative effects due to perturbed shear-stress, metabolic intervention with antioxidants and l-arginine could potentially induce beneficial effects beyond those achieved by BMCs. The protective effect of autologous BMCs and vascular protection by metabolic cotreatment (1.0% vitamin E added to the chow and 0.05% vitamin C and 6% l-arginine added to the drinking water) were examined in ischemia-induced angiogenesis in the mouse hindlimb, a model of extensive acute peripheral arterial occlusion. i.v. BMC therapy improved blood flow and increased capillary densities and expression of Ki-67, a proliferation-associated protein. This beneficial effect was amplified by metabolic cotreatment, an intervention inducing vascular protection, at least in part, through the nitric oxide pathway, reduction of systemic oxidative stress, and macrophage activation. Therefore, although a cautious approach is mandatory when experimental findings are extended to human diseases, autologous BMCs together with metabolic intervention could be an effective clinical treatment for peripheral arterial disease.

Histological findings in a human autogenous pasteurized bone graft

BACKGROUND

Autogenous bone graft after pasteurization is one of the most valuable procedures for reconstruction of large bone defects following excision of malignant musculoskeletal tumors. To date, there have been no documented histological reports on pasteurized bone grafts, apart from short-term histological results.

CASE REPORT

We treated a 27-year-old male with a periosteal chondrosarcoma of the tibia by wide excision and reimplantation of the large pasteurized bone. Biopsy specimens harvested from the pasteurized bone over 3 years after reimplantation were evaluated histologically. The graft cortices remained totally necrotic with empty osseous lacuna, whereas the architecture of the acellular cortical bones was still maintained without microfractures. Deposited seams of woven bone existed focally on the surface of the acellular trabeculae.

CONCLUSION

Our medium-term histological outcome suggests the limitations of incorporating a pasteurized hone graft, but also advocates its role as a useful temporary material for the reconstruction of massive bone defects.

Influence of autograft removal on rabbit patellar tendon length

Twelve adult New Zealand white rabbits were randomly divided into two groups. In group 1, 30% of the central mass of the right patellar tendon was removed. In group 2, 60% was removed. The left knees served as controls. The animals were killed 1 year later. The patella-patellar tendon-tibial tuberosity units of all knees were studied using histological and morphometric analysis. In both groups, the tendons had lengthened. Lengthening average was 2.50 mm in group 1 and 8.17 mm in group 2. In both groups, histology revealed poor alignment of the collagen fibres and high cellularity, although the findings in group 1 were nearer the normal histological pattern. The results suggest that removal of significant portions of the patellar tendon leads to lengthening of the resulting tendon. In clinical practice, it seems prudent to pay attention to the dimensions of the patellar tendon when harvesting a graft.

Bone ingrowth characteristics of porous tantalum and carbon fiber interbody devices: an experimental study in pigs

BACKGROUND CONTEXT

In preclinical and clinical joint replacement applications, porous tantalum has been shown to be osteoconductive and effective for biological fixation. Relatively little research has been undertaken to investigate the porous tantalum implants for potential application in intervertebral spinal fusion.

PURPOSE

The current study was designed to assess the radiographic and histological performance of porous tantalum and carbon fiber devices in the porcine anterior lumbar interbody fusion (ALIF) model.

STUDY DESIGN

A total of 10 Danish Landrace pigs underwent a three-level anterior intervertebral lumbar arthrodeses at L2-L3, L4-L5 and L6-L7. Each level was randomly allocated to one of three implants: a solid piece of porous tantalum, a porous tantalum ring packed with autograft or a carbon fiber cage, likewise packed with autograft. Two staples for fixation were supplemented in front of implant.

METHODS

Pigs were sacrificed 3 months after operation. Specimens were evaluated by plain radiography, conventional tomography and histology.

RESULTS

Bone graft filled into the central hole of the porous tantalum ring was less than that of the carbon fiber cage (p<.001). Radiolucencies around the porous tantalum solid were significantly higher than the carbon fiber cage (p=.02) and were not different between the porous tantalum ring and the carbon fiber cage. The bone volume in the hole of implants, within the pores of the porous tantalum and in the implant interface did not differ between implants. Bone volume in the hole of the porous tantalum ring did not differ from that of the adjacent vertebral bone; however, it was significantly different in the carbon fiber cage and the adjacent vertebral bone (p=.005).

CONCLUSIONS

In this porcine ALIF model, the radiographic and histological appearances of the porous tantalum ring were equivalent to those of the carbon fiber cage. The high presence of radiolucencies and fibrous tissue layer at the vertebrae-implant interface suggests that an initial stabilizing biomechanical environment is important in order to achieve bone ingrowth in the interbody fusion devices in this ALIF model.

Hematological, hemorheological, immunological, and morphological studies of spleen autotransplantation in mice: Preliminary results

Using a spleen autotransplantation model, we conducted hematological, hemorheological, immunological, and morphological studies in mice 6 weeks after splenectomy. Sixty male and female A/J inbred mice were equally divided into 3 groups: 1) SE group, splenectomy was performed; 2) AU group, spleen chips were autotransplanted into the omentum without vascular anastomosis following splenectomy; and 3) C group (controls), no intervention in these mice. At postoperative week 6, the following studies were performed: 1) measurement of hematological parameters; 2) hemorheological studies, including relative cell transit time (RCTT) and fibrinogen levels; and 3) activity of peripheral phagocytes, measured by zymozan-induced chemiluminescence, which was calculated in stimulation index values (SI). In addition, histological investigations of autotransplants were conducted. Erythrocyte mean cell volume and platelet counts, RCTT, fibrinogen levels, and activity of phagocytes were significantly higher in the SE group, compared to those in the C group. In the AU group, these parameters were similar to those in the C group. Morphologically, the transplanted spleen showed normal histology. These data indicate that the transplanted spleens restored their function. We conclude that spleen autotransplantation reserves the normal morphology of spleen and restores most of the spleen's hematological, hemorheological, and immunological functions. Both SI index and erythrocyte deformability can be an informative detection of decreasing splenic function. These data suggest that spleen autotransplantation may provide a useful tool to prevent complications following splenectomy in a clinical setting.

Long-term function and morphology of intestinal autografts and allografts in outbred dogs

Although small bowel transplantation (SBTx) has become a clinical option, there have been few studies of long-term function and histopathology of intestinal grafts. Unrelated mongrel dogs received autologous (n = 4) or allogeneic (n = 11) orthotopic SBTx under oral cyclosporine. Intestinal graft function and routine/immunohistopathology of full-thickness intestine were studied. Six allograft and all isograft recipients had comparable body weight gain and are currently alive (> 420 days). Five allograft recipients were sacrificed because of significant body weight loss and malnutrition at a median of 119 days. Analyses of intestinal function in long-surviving recipients revealed marginal reduction of D-xylose/cyclosporine absorption, intestinal transit time, in vitro muscle contractility, and mucosal enzyme activity compared with normal dogs. However, these changes were insignificant and no statistical difference was seen between auto and long-surviving allografts. In histopathological analysis, long-surviving allografts had normal mucosa with submucosal, muscularis propria, and perineural (Auerbach's plexus) inflammation. Five allorecipients with malnutrition had mucosal atrophy/erosion and significantly reduced intestinal absorption and motility. Thus, denervated intestinal allografts are able to efficiently digest and absorb nutrients to support life. Results also indicate that these allografts experienced low-grade chronic rejection as evidenced in the submucosa and muscle layers, despite the lack of clinical symptoms.

Autologous adult bone marrow stem cell transplantation in an animal model of huntington's disease: behavioral and morphological outcomes

We investigated the effects of autologous bone marrow stem cell transplantation in a rat model of Huntington's Disease. Thirteen days after bilateral quinolinic lesions (QA), bone marrow was implanted into the damaged striatum. The ability of the transplants to reverse QA-induced cognitive deficits in the radial-arm water maze (RAWM) was examined. The transplants significantly reduced working memory deficits. Most of the transplanted cells appeared quite primitive. Because only a few cells expressed neural phenotypes, we suggest that the release of growth factors by the transplants allowed surviving cells within the caudate to function more efficiently and to facilitate other compensatory responses.

Cytokine and chemokine profiles in autologous graft-versus-host disease (GVHD): interleukin 10 and interferon gamma may be critical mediators for the development of autologous GVHD

Administration of the immunosuppressive drug cyclosporine A (CsA) following autologous stem cell transplantation paradoxically elicits a systemic autoimmune syndrome resembling graft-versus-host disease (GVHD). This syndrome, termed autologous GVHD, is associated with autoreactive CD8(+) T cells that recognize major histocompatibility complex (MHC) class II determinants in association with a peptide from the invariant chain. To investigate the potential role of cytokines and chemokines in autologous GVHD, interleukin 2 (IL-2), IL-4, IL-10, interferon gamma (IFN-gamma), and macrophage inflammatory protein-1alpha (MIP-1alpha) gene expression in peripheral blood mononuclear cells (PBMCs) was determined in 36 patients treated with CsA following transplantation and correlated with the induction of cytolytic activity against autologous phytohemagglutinin-stimulated lymphocytes (PHA-blasts) and the breast cancer cell line (T47D). The determination of gene expression by real-time polymerase chain reaction (PCR) revealed that IL-10 mRNA levels by PBMCs in patients with autologous GVHD were 29-fold higher than in healthy individuals. IFN-gamma (4-fold), IL-2 (3-fold), and MIP-1alpha (44-fold) mRNA levels were also increased in GVHD-induced patients compared with healthy individuals. The ability of PBMCs to lyse autologous PHA-blasts and T47D tumor cells exhibited an identical temporal relationship with expression of IL-10 and IFN-gamma during autologous GVHD. Moreover, the susceptibility to autologous GVHD as assessed in 75 patients was significantly associated with the IL-10(-1082) G/G polymorphic alleles, allelic variants in the promoter region that govern IL-10 production. These findings indicate that IL-10 may play an unexpected but critical role in autologous GVHD and could be utilized to enhance a graft-versus-tumor effect after transplantation. Interestingly, polymorphisms in the IL-10 promoter region may also explain differences in the susceptibility of patients to autologous GVHD induction.

Dermatome setting for autografts to cover INTEGRA

Using the INTEGRA Dermal Regeneration Template requires the outer silastic layer to be replaced with an autograft. We followed the manufacturer's directions for epidermal autografting and frequently obtained shredded, useless grafts, therefore, it seemed important to determine the proper dermatome setting. We evaluated dermatome settings from 0.002 to 0.012 inches. First, with feeler gauges, we verified the dermatome settings. Second, we harvested skin at various dermatome settings and measured the thickness histologically. We found that 1) the dermatome settings are reasonably accurate; 2) harvesting useful sheets at 0.002 and 0.004 inches is virtually impossible; 3) the variability of histologic graft thickness is enormous; and 4) a dermatome setting of 0.006 inches yields useful grafts. We no longer use the term epidermal autografting but rather ultrathin split-thickness grafting. To harvest these grafts, we now merely set the dermatome to 0.006 inches and make whatever midcourse corrections are necessary to obtain translucent grafts.

Dermatome setting for autografts to cover INTEGRA

Using the INTEGRA Dermal Regeneration Template requires the outer silastic layer to be replaced with an autograft. We followed the manufacturer's directions for epidermal autografting and frequently obtained shredded, useless grafts, therefore, it seemed important to determine the proper dermatome setting. We evaluated dermatome settings from 0.002 to 0.012 inches. First, with feeler gauges, we verified the dermatome settings. Second, we harvested skin at various dermatome settings and measured the thickness histologically. We found that 1) the dermatome settings are reasonably accurate; 2) harvesting useful sheets at 0.002 and 0.004 inches is virtually impossible; 3) the variability of histologic graft thickness is enormous; and 4) a dermatome setting of 0.006 inches yields useful grafts. We no longer use the term epidermal autografting but rather ultrathin split-thickness grafting. To harvest these grafts, we now merely set the dermatome to 0.006 inches and make whatever midcourse corrections are necessary to obtain translucent grafts.

Chimerism and minimal residual disease monitoring after reduced intensity conditioning (RIC) allogeneic transplantation

Since graft-versus-leukemia (GVL) is the main weapon for disease eradication after reduced intensity conditioning (RIC) allogeneic SCT, the availability of sensitive and specific techniques to monitor changes in tumor load after transplant are especially helpful. These minimal residual disease techniques would allow an early intervention in the event of low tumor burden, for which immunotherapy is highly effective. Some authors have found an association between persistence of MRD, mixed chimerism and risk of relapse. Nevertheless, data from the literature remain contradictory and further correlations should be established, especially in RIC transplants. In this study we have analyzed the impact of MRD and chimerism monitoring on the outcome of 34 patients undergoing RIC allogeneic SCT who were considered poor candidates for conventional transplantation due to advanced age or other concurrent medical conditions. At day +100 25 (75%) patients reached complete remission (CR), there were five (15%) partial responses and three patients progressed. Incidence of grade 2-4 aGVHD and extensive cGVHD were 35% and 58%, respectively. Sixteen percent of patients developing aGVHD relapsed as compared to 47% in those without aGVHD (P = 0.03) and also 10% of patients developing cGVHD relapsed as compared to 50% relapses in those without cGHVD (P = 0.03). Four patients (12%) died due to early (n = 1) and late (n = 3) transplant-related mortality. After a median follow-up of 15 months, 24 out of the 34 patients remain alive. Projected overall survival and disease-free survival at 3 years are 68% and 63%, respectively. Early chimerism analysis showed 67% of patients with complete chimerism (CC) in bone marrow (BM), 86% in peripheral blood (PB), 89% in granulocytes and 68% in T lymphocytes. On day +100, these figures were 68%, 79%, 90% and 73%, respectively, and on day +180 there were 83% patients with CC in BM, 100% in PB, 100% in granulocytes and 100% in T lymphocytes. We observed a trend to a higher incidence of relapse in patients with mixed chimerism (MC) as compared to patients with CC. MRD monitoring by flow cytometry and/or RT-PCR analysis was performed in 23 patients. MRD assessment on days +21 to +56 after transplant allowed identification of patients at risk of relapse. In this sense, seven out of 12 patients (58.3%) who had positive MRD on days +21 to +56 relapsed as compared to none out of 11 patients who had negative MRD (P = 0.002). Of the seven patients with criteria to monitor MRD who relapsed after transplant, all but one remained MRD positive until relapse. By contrast, 10 patients remained MRD negative and all of them are in continuous CR. In nine additional patients, persistence of MRD or mixed chimerism was observed after transplant and withdrawal of cyclosporin with or without DLI was performed. Only two out of these nine patients relapsed. MRD clearance was preceded by CC and GVHD. In conclusion, in our study we found that RIC allogeneic transplantation can be used in patients considered poor candidates for conventional transplantation due to advanced age or other concurrent medical conditions with both low toxicity and low transplant-related mortality. Simultaneous studies of both chimerism and MRD are a useful tool in order to predict risk of relapse in patients undergoing RIC transplants and so can be helpful for individualizing treatment strategies after transplant.

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.

Morphometric analysis of early regeneration of motor axons through motor and cutaneous nerve grafts

Peripheral nerve damage is a frequent consequence of trauma, tumor surgery or diseases. Clinical results of functional reinnervation after the application of cutaneous grafts are still unsatisfactory. Differences in the extracellular matrix are considered to be one of the factors responsible for poor results of motor axon reinnervation through the cutaneous graft. To verify these differences, we compared morphological features of the motor axons regenerating through the graft prepared from the saphenous nerve and the motor branch of the femoral nerve. Eighteen female adult rats (Wistar) were used in experiments. The saphenous nerve, the femoral nerve, and its main motor branch were exposed under deep anesthesia with ketamine and xylazine. The nerve graft (10 mm) prepared from the saphenous nerve was applied between the stumps of the transected motor branch of the femoral nerve in the 6 rats. In the next 6 rats, the nerve graft (10 mm) harvested from the motor branch of the femoral nerve was inserted between stumps of the transected motor branch of the femoral nerve on the contralateral side. All rats were perfused with Zamboni's fixative solution 14 days after grafting. The samples of grafts and the intact motor branch (n = 6) were dissected and embedded in Durcupan ACM. Semithin sections stained with Toluidine Blue were used for morphometric analysis of myelinated axons by means of computer-assisted image analysis system. Ultrathin sections counterstained with uranyl acetate were viewed and photographed in an electron microscope. The number of myelinated motor axons showing early regeneration under conditions of the cutaneous and motor nerve grafts was similar. The diameter of axons and thickness of their myelin sheaths were significantly smaller when the axons regenerated into the saphenous nerve in contrast to the motor graft. Morphometric analysis of early regeneration of myelinated motor axons suggests that the cutaneous and motor branches of the femoral nerve provide different conditions not for the growth but for the maturation of motor axons.

Muscle differentiation after sciatic nerve transection and reinnervation in adult rats

Reinnervation after peripheral nerve transections generally leads to poor functional recovery. In order to study whether changes in muscles might be a contributing factor in this phenomenon we studied muscle morphology and fibre type distributions after sciatic nerve transection in the rat hind limb. Proximally, before the bifurcation in the tibial and common peroneal nerve, a 12 mm segment of the sciatic nerve was resected, reversed and re-implanted as an autologous nerve graft. After survival periods of 7, 15 and 21 weeks the lateral gastrocnemius, tibialis anterior and soleus muscles were dissected, stained with mATP-ase, and fibre type distributions were studied. In addition, numbers of muscle fibres were counted, and cross sectional areas were calculated. After 7 weeks, cross sectional areas were decreased in all muscles. In the gastrocnemius and tibialis anterior muscles the fibre number remained unaltered but the hypotrophy had been reversed at later ages. The number of muscle fibres in the soleus muscle remained decreased over the entire period of observation. The percentages of type II fibres in the gastrocnemius and tibialis anterior muscles were decreased at 7 and 15 weeks but these again approached normal values at 21 weeks. The type I fibres, however, remained arranged in groups. In the soleus muscle a large increase in the percentage of type II muscle fibres was observed and this remained until 21 weeks. We conclude that a non-selective reinnervation and later readjustments by regression of polyneural innervation may in part explain the changes in distributions of various fibre types.

Effects of collagen gel mixed with hydroxyapatite powder on interface between newly formed bone and grafted Achilles tendon in rabbit femoral bone tunnel

The Achilles tendon was implanted into a bone tunnel made in the femoral condyle of 20 rabbits. In the left femur, collagen gel mixed with hydroxyapatite powder (C-HAp) was injected between the graft and the bone tunnel. On the other hand, as a control, simple saline was injected in the right femur. Five rabbits were sacrificed at 4, 8, 12, and 16 weeks after surgery. Histological findings showed that in the C-HAp group, the grafted tendon came in direct contact with new bone, and Sharpey-like collagen fibers arising from the grafted tendon were observed to penetrate new bone by 4 weeks after surgery. In the control group, however, fibrous tissue was observed between new bone and the grafted tendon, but no penetrating fibers from the grafted tendon into the new bone were observed until 16 weeks. The area of new bone in the C-HAp group was significantly greater than that in the control group 4, 8, and 12 weeks after surgery (p < 0.0001, p < 0.0007, p < 0.0013, respectively).

Obliterative airway disease in a porcine heterotopic bronchial allograft model

Representative animal models are needed for the study of posttransplant obliterative bronchiolitis (OB). Because human OB originates in terminal bronchi, the validity of tracheal models can be questioned. Using our hetrotopic model, we implanted pieces of a lobar bronchus subcutaneously into domestic pigs. Five groups were included: autograft implants, allograft implants, allograft implants with 2 regimens of cyclosporine (CsA)azathioprine (AZA)-methylprednisolone (MP), and allograft implants with CsA-SDZ RAD-MP. Samples were harvested at 2 weeks and at 1, 2, and 3 months. The histological findings were graded from 0 to 3. Following initial ischemic epithelial damage, autograft implants recovered, but untreated allografts and those treated with CsA-AZA-MP were totally and permanently damaged within one month. In the group treated with CsA-SDZ RAD-MP, a maximal grade 1.5 +/- 0.5 epithelial injury was seen at one month. Epithelial damage preceded and correlated with luminal obliteration. The obliterative lesions histologically resembled human OB. Differences from our previous findings with terminal bronchioles were minor. This study supports the use of larger-size airways in the study of OB.

Immunohistochemical phenotypic alterations of rabbit autologous vein grafts implanted under arterial circulation with or without poor distal runoff-implications of vein graft remodeling

Although intimal hyperplasia is a major cause limiting the long-term patency of the vein grafts, its precise mechanisms, including the effect of poor runoff, has not yet been well characterized. We thus designed the present study to try to determine the effect of poor runoff arterial flow to the phenotypic alterations of the graft wall by immnohistochemistry using anti-intermediate filaments (alpha-SM actin, desmin, and vimentin) and anti-myosin heavy chain (SM1, SM2, and SMemb) specific antibodies. Vein grafts implanted under the poor runoff hind limb of rabbits showed enhanced intimal hyperplasia, however, no apparent difference in the cytoskeleton expression, including intermediate filaments and MHC, between two groups until 4 weeks. Interestingly, six of eight vein grafts at 2 weeks after implantation in both groups showed the accumulations of perivascular fibroblast-like phenotype (negative for SM1, alpha-SM actin, and desmin) in some parts of the outer neointima, whereas the inner neointima at 2 weeks and the whole neointima at 4 weeks were mainly occupied by a smooth muscle phenotype (positive for these three). Although the cellular origin of these cells is still unknown, these results suggest that the migration of non-muscle mesenchymal cells is involved in the neointima and thus may provide a clue for better understanding vein graft remodeling.

Pulmonary T cell repertoire in patients with graft-versus-host disease following blood and marrow transplantation

Pulmonary inflammation is one of the risk factors associated with blood and marrow transplantation (BMT). To determine the potential role of T cells in pulmonary complications after transplantation, we analyzed the T-cell repertoire expressed in bronchoalveolar lavage fluids from eleven patients with graft-versus-host disease following BMT. A reverse transcriptase-polymerase chain reaction was used to amplify rearranged TCR transcripts in unfractionated, CD4+, and CD8+ T cells from bronchoalveolar lavage fluids. The relative expression of TCR variable (V) gene families and the diversity of junctional region lengths associated with different AV and BV gene families were analyzed. Nearly all TCR AV and BV gene families were detected in bronchoalveolar lavage cells from BMT recipients. Oligoclonal patterns of TCR junctional region lengths were observed in unfractionated, CD4+, and CD8+ bronchoalveolar T cells. The oligoclonal expansion of bronchoalveolar T cells in patients was confirmed by DNA sequencing. TCRV gene expression is almost completely restored in the lungs of BMT recipients as early as two weeks after transplantation. Increased oligoclonality among TCR gene families suggests either an incomplete restoration of TCR diversity or an antigen-driven expansion of T cells in the lungs of BMT recipients with graft-versus-host disease, not necessarily related to pulmonary infection.

Vascular osteomuscular autograft prefabrication using coral, type I collagen and recombinant human bone morphogenetic protein-2

In 20 male Sprague-Dawley rats, 10 pieces of L-shaped coral combined with type I collagen and recombinant human bone morphogenetic protein-2 (rhBMP-2) and 10 discs (diameter 5 mm) were wrapped in the gracilis muscle, and left pedicled on the femoral vessels. Untreated coral was buried in muscle at a distant control site in 4 animals. After 3 weeks, autografts were examined for the shape of new bone, vascular patency, and induction of bone. In all grafts in viable tissue, heterotopic bone was formed. The shape of the new bone was the same as that of the coral, and there was no significant inflammatory reaction. Part of the coral in the composite was absorbed. Bone was not formed in any of the control sites. Coral and type 1 collagen are effective as a carrier for BMP to prefabricate vascular osteomuscular autografts with designed shape. There is a potential clinical application for BMP to bioengineer microvascular free flaps with intrinsic skeletal muscle for maxillofacial reconstruction.

The control of epidermal stem cells (holoclones) in the treatment of massive full-thickness burns with autologous keratinocytes cultured on fibrin

BACKGROUND

Cell therapy is an emerging therapeutic strategy aimed at replacing or repairing severely damaged tissues with cultured cells. Epidermal regeneration obtained with autologous cultured keratinocytes (cultured autografts) can be life-saving for patients suffering from massive full-thickness burns. However, the widespread use of cultured autografts has been hampered by poor clinical results that have been consistently reported by different burn units, even when cells were applied on properly prepared wound beds. This might arise from the depletion of epidermal stem cells (holoclones) in culture. Depletion of holoclones can occur because of (i) incorrect culture conditions, (ii) environmental damage of the exposed basal layer of cultured grafts, or (iii) use of new substrates or culture technologies not pretested for holoclone preservation. The aim of this study was to show that, if new keratinocyte culture technologies and/or "delivery systems" are proposed, a careful evaluation of epidermal stem cell preservation is essential for the clinical performance of this life-saving technology.

METHODS

Fibrin was chosen as a potential substrate for keratinocyte cultivation. Stem cells were monitored by clonal analysis using the culture system originally described by Rheinwald and Green as a reference. Massive full-thickness burns were treated with the composite allodermis/cultured autograft technique.

RESULTS

We show that: (i) the relative percentage of holoclones, meroclones, and paraclones is maintained when keratinocytes are cultivated on fibrin, proving that fibrin does not induce clonal conversion and consequent loss of epidermal stem cells; (ii) the clonogenic ability, growth rate, and long-term proliferative potential are not affected by the new culture system; (iii) when fibrin-cultured autografts bearing stem cells are applied on massive full-thickness burns, the "take" of keratinocytes is high, reproducible, and permanent; and (iv) fibrin allows a significant reduction of the cost of cultured autografts and eliminates problems related to their handling and transportation.

CONCLUSION

Our data demonstrate that: (i) cultured autografts bearing stem cells can indeed rapidly and permanently cover a large body surface; and (ii) fibrin is a suitable substrate for keratinocyte cultivation and transplantation. These data lend strength to the concept that the success of cell therapy at a clinical level requires cultivation and transplantation of stem cells. We therefore suggest that the proposal of a culture system aimed at the replacement of any severely damaged self-renewing tissue should be preceded by a careful evaluation of its stem cell population.

Transplantation of autologous iris pigment epithelium to the subretinal space in rabbits

BACKGROUND

Transplantation of autologous iris pigment epithelium (IPE) into the subretinal space has been suggested as one approach for the treatment of age-related macular degeneration. Autologous rabbit IPE cells were transplanted to the subretinal space to define the technique of transplantation and examine the survival of the transplanted cells.

METHODS

Autologous IPE cells were harvested by iridectomy and transplanted directly to the subretinal space of the fellow eye in 25 rabbits, using the parsplana approach. Animals were killed over a period of 5 months, and the retinas were examined morphologically by light and electron microscopy.

RESULTS

Autologous IPE cells survived and formed a polarized monolayer above the retinal pigment epithelium in the subretinal space, with apical microvilli adjacent to photoreceptors. Fragments of phagocytosed photoreceptor rod outer segments were observed in phagosomes in the cytoplasm of IPE cells. Adjacent rod outer segments remained healthy throughout the experimental period. No signs of a cell-mediated immunologic response were observed.

CONCLUSIONS

Our results show that in rabbits, autologous IPE cells transplanted to the subretinal space survive and do not adversely affect the photoreceptors. These results suggest that in humans, IPE cells might provide a substitute for retinal pigment epithelium cells as autologous transplants for the treatment of age-related macular degeneration.

Interphase FISH: a rapid method for detecting malignant plasma cells in multiple myeloma patients submitted to autologous transplantation

Fluorescence in situ hybridization (FISH) on interphase nuclei has been shown to be an efficient method for detecting aneuploidy in multiple myeloma (MM). The aim of this study was to test the feasibility of FISH techniques for detecting malignant cells in the harvests of MM patients submitted to autologous transplantation. As trisomy 9 (T9) is a frequent event in MM, we used it as a genetic marker of malignant plasma cells. T9 was detected in 45 out of 55 MM bone marrow samples (81.8%) using a chromosome 9 centromeric (C9C) probe. Twenty-four of the 55 MM patients were subjected to high-dose therapy followed by autologous unselected progenitor cell transplantation. Trisomy 9 was detected in 20 patients and was used as a marker of malignant cells. Upon karyotypic analysis, three of the four remaining patients without T9 showed an unbalanced translocation leading to a complete trisomy of the long arm of chromosome 1 (T1q). We thus used a 1q juxtacentromeric probe, pUC1.77, as another genetic marker of malignant plasma cells in these three further patients. FISH with C9C or pUC1.77 probes was performed on the harvests of these 23 patients and detected clonal cells in 11 transplants. The disease-free survival from graft was significantly longer for the patients who had no malignant cells in their transplant (P=0.009). The median disease-free survival was 23 months in these patients, as compared to 12 months in the patients whose transplant was contaminated. As almost all MM are cytogenetically abnormal, FISH with adequate probes represents a simple, quantitative tool for rapid detection of malignant cells in the harvests. Our results also suggest that the presence of MM cells in the transplant may be predictive of poor outcome.

Revascularization and new bone formation in heat-treated bone grafts

Human imnmunodeficiency virus (HIV) infection is one of the possible serious complications associated with bone allografts. In order to prevent infection, grafted bone is sterilized by various treatments. Heat treatment has attracted attention as a simple and practical method. We carried out a histological study of the influence of heat treatment on autogenic bone grafts. To eliminate the problem of antigenicity of grafted bone, we used autografts, not allografts. Three types of heat-treated autografts were employed: heat-treated at 60 degrees C for 30 min, at 80 degrees C for 10 min, and at 100 degrees C for 5 min; as a control, fresh autografts were replaced in the rabbits' ilium. One, 2, 4 and 8 weeks after grafting, we performed microangiography and prepared two types of samples: transparent and haematoxylin-eosin (H&E) stained. Then, using an image analyzer, we quantitatively measured revascularization and new bone formation in the grafted bone. The grafts heat-treated at 60 degrees C showed early and good revascularization and new bone formation, from 1 to 8 weeks. The grafts heat-treated at 80 degrees C showed relatively good revascularization and new bone formation. However, the grafts heat-treated at 100 degrees C showed unsatisfactory revascularization and bone formation, less than 40% of control 8 weeks after grafting. Therefore, heat treatment at 60-80 degrees C does not seriously affect revascularization and new bone formation.

Factors influencing platelet recovery after autologous transplantation of G-CSF-mobilized peripheral blood stem/progenitor cells following myeloablative therapy in 50 heavily pretreated lymphoma patients

Delayed platelet recovery following autologous PBPCs transplantation after myeloablative therapy remains an unresolved problem in lymphoma patients heavily pretreated with several chemotherapy cycles and/or radiotherapy. In the present study of 50 lymphoma patients, the factors influencing platelet recovery after myeloablative therapy followed by autologous PBPCs transplantation were analysed retrospectively. The median age was 42 years (range, 15-58). Fourteen patients had HD and 36 had NHL (13 high-grade and 23 low-grade); most (80%) had stage III or IV. Twenty-two patients had received radiotherapy to various extents before mobilization. The mean number of previous chemotherapy cycles was seven (range 3-24) of different regimens (range 1-4). A median of three leukapheresis procedures (range 1-5) was performed after G-CSF mobilization. Single leukapheresis was sufficient in only one patient. A significant correlation was found between the BFU-E content of autografts and platelet recovery after transplantation. Neither the patient's age and sex nor the stage and grade of lymphoma had any effect on platelet recovery after transplantation. Neither the type of myeloablative therapy used or the dose of G-CSF administered after transplantation had any effect on platelet recovery after transplantation. The type of previous chemotherapy cycles was a major adverse factor affecting the progenitor cell yield in the autografts. Lymphoma patients previously treated with ASHAP and/or Dexa-BEAM cycles had less progenitor cell yield. The chemotherapeutic agents used in previous cycles also had a clear adverse effect on the progenitor cell yield in the autografts. Lymphoma patients previously treated with cycles including cytarabine and/or cisplatin showed significantly less progenitor cell yield and slower platelet recovery after transplantation. All seven patients with delayed platelet recovery had received cytarabine and/or cisplatin in several previous ASHAP and/or Dexa-BEAM cycles. All seven patients had a BFU-E count of less than 1 x 10(5)/kg yield in the autografts.

Superior autologous blood stem cell mobilization from dose-intensive cyclophosphamide, etoposide, cisplatin plus G-CSF than from less intensive chemotherapy regimens

The study purpose was to determine if G-CSF plus dose-intensive cyclophosphamide 5.25 g/m2, etoposide 1.05 g/m2 and cisplatin 105 mg/m2 (DICEP) results in superior autologous blood stem cell mobilization (BSCM) than less intensive chemotherapy. From January 1993 until May 1997, 152 consecutive patients with non-Hodgkin's lymphoma (n = 55), breast cancer (n = 47), Hodgkin's disease (n = 14), multiple myeloma (n = 9), AML (n = 9), or other cancers (n = 18) initially underwent BSCM by one of three methods: Group 1: G-CSF alone x 4 days (n = 30). Group 2: disease-oriented chemotherapy, dosed to avoid blood transfusions, followed by G-CSF starting day 7 or 8, and apheresis day 13 or 14 (n = 82). Group 3: DICEP days 1-3, G-CSF starting day 14, and apheresis planned day 19, 20 or 21 (n = 40). A multivariate analysis was performed to determine which factors independently predicted BSCM. The median peripheral blood CD34+ (PB CD34+) cell count the morning of apheresis linearly correlated with the number of CD34+ cells removed per litre of apheresis that day. The median PB CD34+ cell count and median CD34+ cells x 10(6) removed per litre of apheresis were highest for Group 3, intermediate for Group 2, and lowest for Group 1. By multivariate analysis, mobilization group (3 > 2 > 1), disease other than AML, no prior melphalan or mitomycin-C, and less than two prior chemotherapy regimens predicted better BSCM. Out of 15 Group 3 patients who had infiltrated marrows, 11 had no detectable cancer in marrow and apheresis products after DICEP. These data suggest that DICEP results in superior BSCM than less intensive chemotherapy regimens.

Characteristics of endothelin receptors in acutely rejecting transplanted lungs

Experiments were designed to characterize endothelin receptors in bronchi and parenchyma of transplanted lungs during acute rejection. Third-order bronchi from autografted or allografted lungs were either cut into rings and suspended in organ chambers for the measurement of isometric force or frozen for isolation of membrane proteins. Lung parenchyma was prepared for histology or isolation of membrane protein. The grade of rejection was 2.74+/-0.17 (n= 19) in allotransplanted lungs; evidence of infection was present in 58% of the transplanted lungs. In organ chamber experiments, endothelin 1 (which stimulates endothelin A receptors) caused comparable contraction of bronchi from autotransplanted and allotransplanted rejecting lungs. Endothelin 3 (which stimulates endothelin A and B receptors) caused contractions of bronchi from autotransplanted lungs which were not different from those caused by endothelin 1. In contrast, contractions caused by endothelin 3 were reduced in bronchi from rejecting allotransplanted lungs. The magnitude of contractions caused by endothelin 3 was reduced further when infection was present with rejection. Competitive inhibition of 125I-endothelin 1 by endothelin 3 was significant for a two-site binding model in membranes prepared from all bronchi and lung parenchyma. The total number of binding sites (Bmax) was reduced significantly in bronchi and parenchyma from rejecting lungs with or without infection. The relative proportions of high-affinity and low-affinity binding sites did not change. Affinities of both high- and low-affinity receptors were not altered with rejection. These results indicate that at least two subtypes of endothelin receptors are present on canine bronchial smooth muscle and parenchyma. The number of endothelin receptors associated with bronchial contractions is reduced with rejection of lung allografts.

Allo- and autotransplantation of carotid artery--a new model of chronic graft vessel disease: evaluation by magnetic resonance imaging and histology

BACKGROUND

Graft vessel disease is a special form of accelerated arteriosclerosis. Because immunological and nonimmunological factors can contribute to graft vessel disease, we developed a model that enables the study of both factors simultaneously.

METHODS

A carotid artery was allografted from DA to Lewis rats, with the excised native artery autografted on the contralateral side. Five groups of six to seven rats were treated for 8 weeks with vehicle (placebo) or cyclosporine (CsA) (0.3, 1, 3, and 10 mg x kg(-1) x day(-1)), which was administered using subcutaneous osmotic minipumps. The carotid lumen area was estimated in vivo at 2, 4, and 8 weeks by magnetic resonance imaging (MRI); CsA blood levels were determined twice. Carotid neointimal thickening and medial and luminal area were measured with histological techniques.

RESULTS

MRI showed bulging of the allografts but not autografts. Bulging disappeared over time with narrowing of the allograft lumina estimated by both MRI and histology. Histologically, vehicle-treated animals developed a massive neointima, which was inhibited in a dose-dependent manner by CsA. Autografts remained normal except for minimal subintimal thickening of two of four arteries in the group given the highest dose of CsA. Cellular rejection was detected in the allografts of all but the highest-dose group. The CsA blood levels were similar to those used in man at the two lower doses and about 10-fold higher at the highest dose.

CONCLUSIONS

Subintimal thickening did not correlate with in vivo lumen size, a phenomenon that we have previously described for balloon catheter-induced lesions. CsA blood concentrations similar to those used in patients suppressed neointima formation in part, and 10-fold higher concentrations almost completely suppressed neointima formation.

The effect of small bowel transplantation on the morphology and physiology of intestinal muscle: a comparison of autografts versus allografts in dogs

The effects of acute (AR) and chronic rejection (CR) on intestinal smooth muscle that are responsible for the dysmotility following small bowel transplantation (SBTX) are incompletely understood. Jejunal and ileal specimens from normal control dogs (n=7), and autotransplanted dogs were examined at 7 days (n=6) and 1 (n=7), 3 (n=6), 6 (n=6), and 12 months (n=6). Allotransplanted dogs that developed AR (n=8) and CR (n=5) were examined for gross and microscopic morphology (muscle thickness, the number and size of myocytes, and inflammatory infiltrate), and for contractile and intracellular electrical function in vitro. Auto-SBTX did not alter morphology at any period, but contractile function was impaired at 7 days (73.6%) compared with normal intestine. Acute rejection did not influence myocyte number or size, but was associated with a prominent infiltrate of neutrophils and lymphocytes, and severely impaired contractile function (20.6%) compared with auto-SBTX controls. Acute rejection also significantly inhibited the amplitude of slow waves and of inhibitory junction potentials. Chronic rejection caused thickening of muscularis propria by both hyperplasia (175.5%) and hypertrophy (202.6%) accompanied by moderate inflammatory cell infiltrate compared with auto-SBTX controls. We conclude that the marked inflammatory infiltrate into the muscularis propria indicates that the graft muscle is injured by both acute and chronic rejection; impaired function of intestinal smooth muscle following SBTX results from both rejection and the injury associated with transplantation, and chronic rejection following SBTX is associated with both hyperplasia and hypertrophy of the muscularis propria.

Use of coral grafts in anterior interbody fusion of the rabbit spine

The search for suitable bone graft substitutes has been made necessary by the problems encountered when using autogenous sources. Coral grafts have been used for the past two decades in various fields of surgery with reported good results. The aim of this study was to determine the efficacy of coral graft (Biocoral in anterior interbody fusion of rabbit spine. Fourteen rabbits underwent surgical anterior interbody fusion with autogenous, coral and Kiel grafts. At three months there was evidence of new bone formation at the graft-bone interface but no signs of osteointegration of the coral graft. The coral graft was also inert and did not evoke in any inflammatory reactions. Radiological examinations did not reveal any signs of fusion at three months. Kiel grafts only evoked a fibrous reaction. Autogenous rib grafts used has solid interbody fusion at two months as evidenced from both radiological and histological studies.