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PubMed2006

Interface tissue engineering and the formulation of multiple-tissue systems.

Interface tissue engineering is an exciting field which focuses on the development of tissue engineered grafts capable of promoting integration between different types of tissue and between the implant and surrounding tissue. Focusing on interface tissue engineering, and using the insertion site between the anterior cruciate ligament and bone as an example, this chapter discusses strategies in soft tissue to bone integration as well as current tissue engineering efforts in this area. This review begins with the clinical significance of this problem, followed by a review of existing fixation methods, and tissue engineering efforts aimed at addressing this critical issue. The development of multiphased scaffolds designed for the replacement of more than one type of tissue, as well as novel in vitro co-culture systems will be introduced. Future directions in the field of interface tissue engineering will also be discussed.

Animals↗
PubMed2002

[Transplantation and donation of tissues--six years with the new law. Experiences from the tissue bank in Lund].

Tissue transplantation is more common than organ transplantation. Legislative changes in 1996 transformed tissue banking and conditions for tissue transplantation in Sweden. After an initial decrease in donated tissue, heart valves are now available in sufficient numbers, but there is sometimes a shortage of valves the right size for pediatric cardiac surgery. Since the new transplantation legislation was implemented there has been an increase in the number of valves from neonatal donation and after sudden infant death. The number of donated corneas does not correspond to the number required for transplantation. A number of tissue coordinators have been established throughout the country and recently some new tissue banks were founded to increase the amount of tissue available for transplantation. The organization of the tissue bank in Lund is described. There is a lack of knowledge about tissue transplantation and donation among health professionals as well as the general public, and more education is warranted.

Bone Transplantation↗
PubMed1992

The structural integrity of glial scar tissue associated with a chronic spinal cord lesion can be altered by transplanted fetal spinal cord tissue.

The potential for fetal spinal cord (FSC) tissue transplants to modify an established glial scar or to restrict the reformation of a scar following surgical manipulation of a chronic lesion site was studied in the injured rat spinal cord. Six to eight weeks after preparation of a hemisection lesion cavity, glial scar tissue was left intact in one group, whereas in a second group it was excised prior to transplantation of a suspension of FSC tissue. From the first group, examination of serial sections through the graft-host interface that had been immunoreacted for glial fibrillary acidic protein (GFAP) demonstrated that in many cases the glial scar no longer was a continuous wall separating the two tissues. Quantitation of the area occupied by these discrete gaps in the scar provided an Index of Fusion, indicating the extent of direct contact between the transplant and host spinal cord. In some animals this constituted as much as 60% of the interface, while in others there were no breaks in the scar (0% fusion). Reinjury of the spinal cord lead to a rapid astrocytic response culminating in the reestablishment of a dense matrix of glial cells and processes covered by a basal lamina. This reformed scar effectively isolated the spinal cord from the external environment of the cavity. When FSC tissue was transplanted after first removing scar tissue the continuity of reformed glial scarring at the graft-host interface was altered. Distinct gaps in the scar appeared randomly along the interface. The mean Index of Fusion for animals receiving a moderate reinjury (removal of scar tissue only) was not as high as for those animals in which a more severe reinjury (expansion of the cavity by 0.5 mm) was performed before transplantation. The extent of graft-host fusion was not significantly improved when scar tissue was removed prior to transplantation. These findings support the hypothesis that the presence of FSC tissue will have an effect on the persistence of glial scar tissue in a chronic lesion site as well as limit the extent to which a new scar is formed in response to a second injury to the spinal cord.

Animals↗
PubMed2005

Tissue-type plasminogen activator activity in morphologically normal tissues adjacent to gastrointestinal carcinomas is associated with the degree of tumor progression.

PURPOSE: To investigate whether the level of plasminogen activator (PA) activity assayed in gastrointestinal carcinomas and the "morphologically normal tissues" adjacent to them is associated with the degree of tumor progression. METHODS: Tumor and "normal tissues" were obtained from gastrointestinal surgical samples to assess urokinase-type (u-PA) and tissue-type plasminogen activator (t-PA) activities by radial caseinolytic assay and the expression of PA inhibitor-1 (PAI-1) by ELISA. We compared the PA system between the tumor and "normal tissues" and we investigated the existence of correlations between: (a) PA production in the tumor and "normal tissues", (b) different components of the PA system, and (c) PA system and the degree of tumor progression. RESULTS: (1) Total PA activity, u-PA activity and PAI-1 expression are significantly higher in tumor than in "normal tissues", whereas t-PA activity does not differ between them. (2) Total PA activity mainly correlates with u-PA activity in tumor tissues and similarly with u-PA and t-PA activities in "normal tissues". (3) There is a significant association between t-PA activity in tumor and "normal tissues" and the degree of tumor progression. CONCLUSIONS: "Morphologically normal tissues" adjacent to carcinomas present abnormal t-PA activity that is associated with the degree of tumor progression. Assaying of this activity could be useful as a predictive parameter.

Adult↗
PubMed2003

A closer view of tissue engineering in China: the experience of tissue construction in immunocompetent animals.

Tissue engineering started in late 1980s and is now well established and progressing rapidly in Western developed countries. However, the development of tissue-engineering research in China remains relatively unknown to the international society of tissue engineering. Although involved in all areas of tissue-engineering research, including the creation of new scaffold materials, in vitro studies of seed cells, application of growth factors, and modification of seed cells and scaffold materials, China has put special emphasis on tissue construction in large mammalian animals in order to establish a solid scientific basis for clinical application of engineered tissues. To provide a closer view of tissue-engineering research in China, this article reviews our experience in tissue construction and tissue repair using immunocompetent animals such as sheep, pig, and dog as well as hen and rabbit. The engineered tissues include bone, cartilage, tendon, skin, blood vessels, cornea, and peripheral nerves.

Animals↗
PubMed2006

Embryonic myocardium shows increased longevity as a functional tissue when cultured in the presence of a noncardiac tissue layer.

A major aim of regenerative medicine is the construction of bioengineered organs and tissue for transplantation into human patients; yet living tissue is dynamic, and thus arranging cellular and extracellular constituents into an architecture resembling normal adult organs may not be sufficient to maintain tissue stability. In this study, we used cultures of embryonic chick heart tissue as a model to explore how newly formed cardiac tissue constructs can sustain their morphological structure and functional capabilities over extended periods. During the initial days of incubation, embryonic cardiac explants will thrive as beating three-dimensional tissue aggregates. However, within the first week of culture, cardiac aggregates lose their contractile function and flatten. After 2 weeks of incubation, the cardiac cells will have spread out into a homogeneous monolayer and dedifferentiated to a noncardiac phenotype. In contrast, when the embryonic heart tissue was co-cultured with a noncardiac cell layer obtained from adult bone marrow, the cardiac aggregates maintained their contractile function, three-dimensional tissue morphology, and myocyte phenotype for a full month of incubation. The capacity of this noncardiac cell layer to sustain the phenotype and morphology of the cardiac explants was partially replicated by treatment of the heart tissue with conditioned media from bone marrow cells. These findings are discussed in regard to the importance of adjacent cell layers for facilitating organogenesis in the developing embryo and having potential utility in producing stable bioengineered tissue constructs.

Animals↗
PubMed2005

Organization of secondary lymphoid tissue and local IgE formation to Staphylococcus aureus enterotoxins in nasal polyp tissue.

BACKGROUND: Bilateral nasal polyposis (NP) is characterized by high concentrations of IgE in NP tissue, which show no relation to the atopic status. We aimed to study the relationship between systemic and local IgE formation, nasal carriage of Staphylococcus aureus and nasal polyposis. METHODS: In serum and nasal tissue homogenates from 24 NP patients and 12 controls, we determined concentrations of total IgE and IgE antibodies to inhalant allergens and S. aureus enterotoxins (SAEs; A,B,C,D,E,TSST) by ImmunoCAP. Tissue cryosections were stained for CD3, CD20, CD38, CD23, FcepsilonRI, IgE and SEA/SEB. RESULTS: We demonstrated a higher incidence of S. aureus colonization (17/24) and IgE antibodies to SAEs in NP tissue (12/24) compared with controls (3/12 and 0/12, respectively). Total IgE and IgE antibodies in serum and NP tissue were dissociated because of local polyclonal IgE formation in NP tissue. Staining of NP tissue revealed follicular structures characterized by B and T cells, and lymphoid accumulations with diffuse plasma cell infiltration. CONCLUSIONS: We demonstrated the organization of secondary lymphoid tissue in polyp tissue and a polyclonal hyper-immunoglobulinemia E associated with the presence of IgE antibodies to SAEs, colonization with S. aureus, and tissue eosinophilia in a relevant subgroup of polyp patients.

Adult↗
PubMed2005

A correlation study of organochlorine levels in serum, breast adipose tissue, and gluteal adipose tissue among breast cancer cases in India.

We used data from a breast cancer pilot study carried out in Kerala, India in 1997, for which organochlorine levels were measured in three biological media, blood serum, breast adipose tissue, and gluteal adipose tissue, of 37 fasting breast cancer cases (pretreatment). Our objective was to investigate the relationships between organochlorine concentrations in different biological media. Gas-liquid chromatography determined serum, breast adipose, and gluteal adipose tissue levels of dichlorodiphenyltricholorethane, dichlorodiphenyldichloroethane, beta-benzene hexachloride, and polychlorinated biphenyl (PCB) congeners, PCB-153 and PCB-180. Correlation plots were made and Spearman correlation coefficients (r) calculated for breast adipose tissue versus serum, gluteal adipose tissue versus serum, and breast adipose versus gluteal adipose tissue. We also examined paired ratios of all summary statistics. There were strong correlations among serum, breast adipose tissue, and gluteal adipose tissue concentrations for most organochlorines analyzed, one exception being gluteal versus serum for PCB-153. The correlations for all other comparisons ranged from r = 0.65 to 0.94. Serum (ng/g) versus adipose ratios approached 1:1 for most of the organochlorine pesticide comparisons and did not vary by summary statistic. To our knowledge, this is the first study to use three different media from fasting subjects and to comprehensively investigate the relationship between organochlorines measured across the three media for both organochlorine pesticides and PCBs. These data indicate that blood serum reflects the present body burden of a range of organochlorines to the same extent as adipose tissue, and they support the view that serum may be collected in lieu of adipose tissue to obtain similar information. However, such measurements are a combination of both recent exposures and past exposures, which have metabolized slowly and may still persist. Therefore, investigators should use caution when assigning a level as lifetime body burden.

Adipose Tissue↗
PubMed2000

Alterations in fetal adipose tissue leptin expression correlate with the development of adipose tissue.

Control pig fetuses and fetuses hypophysectomized (hypox) at 70 days of gestation were treated with hormones on day 90. At 105 days of gestation, subcutaneous adipose tissue was prepared for morphological studies, leptin Northern blot and Western blot analysis. Fetal ontogeny studies showed that leptin mRNA in adipose tissue increased with morphological development, and the highest level of leptin mRNA was observed in 105-day fetal pigs. In hypox fetuses, levels of leptin mRNA were similar to those in controls. Treatment with either hydrocortisone (HC) or thyroxine (T(4)) resulted in a slight increase in leptin mRNA levels in hypox fetuses but not in intact fetuses. Supplementation with both HC and T(4) markedly stimulated leptin mRNA expression in both hypox and intact fetuses. Morphological data showed that hypox slightly enhanced lipid accretion and treatment of hypox fetuses with HC and T(4) increased lipid accretion to a greater degree than did either HC or T(4) alone. However, serum leptin levels were not influenced by age, hypox or hormone treatment. Leptin protein expression was not detected in adipose tissue of hypox or intact fetuses regardless of hormone treatment. Leptin protein was detected in adipose tissue of 7-day-old pigs and placenta. As compared to 7-day postnatal adipose tissue, placenta showed a higher level of leptin protein expression. Leptin mRNA expression in fetal adipose tissue was not correlated with body weight and organ weight. The expression of long-form leptin receptor mRNA was detected in fetal adipose tissue. Our results indicate that adipose tissue leptin may not be the main source of serum leptin in the fetus and may not be involved in general prenatal growth and development. But adipose tissue leptin may act as an autocrine or paracrine factor in the development of fetal adipose tissue.

Adipose Tissue↗
PubMed2000

Distribution of uridine diphosphate-glucuronosyltransferase (UGT) expression and activity in cynomolgus monkey tissues: evidence for differential expression of steroid-conjugating UGT enzymes in steroid target tissues.

Based on the similarity of pathways and enzymes involved in steroid metabolism, simians represent a relevant animal model to study steroid elimination by glucuronidation. In this study the tissue distribution of UDP-glucuronosyltransferase (UGT) transcripts, proteins, and enzymatic activities were examined in 24 different cynomolgus monkey tissues. RT-PCR and Western blot analysis on total RNA and microsomal proteins demonstrated the presence of UGT1A and UGT2B transcripts and proteins in a wide range of tissues including steroid target tissues. Glucuronidation activity on eugenol, 5alpha-androstane-3alpha,17beta-diol, androsterone, and 4-hydroxyestradiol was measured using tissue homogenates and radiolabeled [14C]UDP-glucuronic acid. All tissues contained conjugation activity on these substrates, but glucuronidation rates were significantly lower in steroid target tissues than in liver, kidney, or gut. However, the ratio of steroid glucuronidation vs. eugenol glucuronidation was higher in steroid target tissues, suggesting a differential expression of steroid-conjugating enzymes in these tissues. Taken together, these results clearly demonstrate the presence of steroid glucuronidation enzymes in extrahepatic steroid target tissues and support the hypothesis that steroid glucuronidation is an important intracrine pathway involved in termination of steroid signaling.

Animals↗
PubMed1994

Insulin receptor ribonucleic acid levels and alternative splicing in human liver, muscle, and adipose tissue: tissue specificity and relation to insulin action.

The absolute levels and alternative splicing of insulin receptor RNA molecules were determined in samples from liver, muscle, and adipose tissue from 17 nondiabetic individuals. Both the absolute levels and alternative splicing varied in a tissue-specific manner. In all tissues, a majority of the insulin receptor RNA molecules contained exon 11. Liver tissue had a lower percentage of RNA molecules without exon 11 (Ex 11-) than muscle and adipose tissue, but the absolute number of Ex 11- RNA copies was higher due to higher overall levels of insulin receptor RNA. Insulin receptor RNA levels in adipose tissue showed significant correlation with obesity, expressed as body mass index (kilograms per m2) as well as with in vivo insulin action, as measured by the insulin tolerance test. In this study, obesity and insulin action were not correlated with insulin receptor RNA expression in liver or muscle. Within individuals, no relation was detected between the number of insulin receptor RNA copies in a tissue and the number or percent Ex 11- RNA in the same tissue. Also, the absolute levels or Ex 11- percentages in one tissue could not predict corresponding measurements in the other two investigated tissues from the same individual.

Adipose Tissue↗
PubMed1987

Age-dependent changes in phenytoin tissue bindings in rats: comparison between in vivo and in vitro tissue-to-blood partition coefficients (Kp values) of phenytoin.

Age-dependent changes in phenytoin tissue bindings in rats were investigated by equilibrium dialysis using serum and 10% tissue (brain, lung, liver, kidney and muscle) homogenates. All percentages of phenytoin bound to serum and tissue homogenates were independent of the initial phenytoin concentration (2 to 25 micrograms/ml) in 1-d, 1-, 3- and 8-week-old rats. The percentages bound to serum, brain, liver, kidney and muscle in newborn rats (1-d-old rats) were lower than those in 8-week-old rats and the percentages bound increased gradually in the growth process. However, those in lungs were constant in all ages of rats. It was assumed that the age-dependent changes in phenytoin tissue binding were caused by the changes in the quantities of tissue constituents to which phenytoin bound in the growth process. Tissue-to-blood partition coefficients (Kp values) were calculated from in vitro tissue binding data and the pH-difference across the cell membrane. These Kp values were in good agreement with the in vivo Kp values reported previously. It was concluded that the age-dependent changes in phenytoin tissue distribution were caused by the age-dependent changes in phenytoin binding to blood constituents and tissues but that the change of phenytoin blood binding contributed to the age-dependent changes in Kp values of phenytoin more than to phenytoin tissue binding and consequently the Kp values of phenytoin decreased as rats grew.

Aging↗
PubMed2003

The lipolytic responsiveness to endotoxin in subcutaneous adipose tissue is greater than mesenteric adipose tissue.

In sepsis and endotoxemia, metabolism is characterized by accelerated catabolism. In the present study, lipolytic responsiveness of subcutaneous and mesenteric adipose tissue to the sub-lethal dose of endotoxin injection (5 mg/kg) was evaluated using microdialysis techniques in rats. All rats were urethane-anesthetized and implanted with microdialysis probes in their subcutaneous and mesenteric adipose tissue. Lipolysis in each adipose tissue was assessed by measuring the glycerol concentration (an index of lipolysis) in the dialysate from the microdialysis probe. Lipolysis was continuously monitored for 7-hours, prior to and following the injection of endotoxin. The control animals were injected with only saline. Lipolysis in subcutaneous adipose tissue began to increase by 1-hours after endotoxin injection, and reached a peak 60% higher than the basal level by 2-hours after injection. This activated lipolysis after endotoxin was markedly greater than that in the control animals and maintained for 5 hours. In mesenteric adipose tissue, lipolysis after endotoxin injection was greater than in the control animals, but not significant. The endotoxin-induced lipolysis in the subcutaneous adipose tissue was significantly greater than that in the mesenteric adipose tissue. We conclude that the sub-lethal dose of endotoxin injection cause active lipolysis in adipose tissues, and that the lipolytic responsiveness to endotoxin in subcutaneous adipose tissue is greater than in mesenteric adipose tissue.

Adipose Tissue↗
PubMed1999

The relative amount of epithelium, muscle, connective tissue and lumen in prostatic hyperplasia as a function of the mass of tissue resected.

PURPOSE: The relative amounts of epithelium, connective tissue, muscle and gland lumen in benign prostatic hyperplasia have been reported but they have not been correlated with prostate size. We determine if the relative amount of prostatic tissue varies with prostate size. MATERIALS AND METHODS: Paraffin blocks of transurethrally resected prostate tissue were randomly chosen from the archives of 58 patients with benign prostatic hyperplasia. Two new slides per patient were made and stained with prostate specific antigen or Masson trichrome, respectively. A total of 20 images from each slide were captured using a high resolution camera, digitized and analyzed with computer software for the relative percentage of the various tissue components. RESULTS: As the amount of prostate tissue resected increased from less than 10 to greater than 70 gm. the epithelium had a 4-fold increase from 5.37 to 21.92%, the muscle component had a 42% decrease from 28.46 to 16.62%, the lumen doubled from 7.05 to 14.01% and the connective tissue remained relatively unchanged from 35.58 to 31.53%. There was a statistically significant difference in all components of prostatic tissue except for connective tissue when comparing prostates less than 30 versus greater than 30 gm., including epithelium 6.52 versus 16.10% (p <0.01), muscle 28.45 versus 20.78% (p <0.01), lumen 7.42 versus 14.58% (p <0.01) and connective tissue 35.74 versus 32.45% (p <0.06). The stroma-to-epithelium and muscle-to-epithelium ratios each had a 9-fold decline (p = 0.01). CONCLUSIONS: As the prostate increases in size, there is statistically significant more epithelium and lumen, and less muscle tissue.

Connective Tissue↗
PubMed2003

[Detection of collagenase activity and tissue inhibitor of metalloproteinase-1 expression level in the urethral scar tissue].

OBJECTIVE: To find the difference between the collagenase activity and tissue inhibitor of metalloproteinase-1 (TIMP-1) expression level in normal urethral tissue and in urethral scar tissue, and to study the effect of collagenase activity and TIMP-1 expression level on the degradation of urethral scar. METHODS: The urethral tissues were derived from 10 human surgical specimens of urethral stricture scar and 10 human normal urethral specimens from patients with brain death. The collagenase activity was detected by ELISA assay, and the TIMP-1 mRNA level by RTPCR. RESULTS: The collagenase activity of urethral scar tissue was (15.32 +/- 2.29) U and lower than that of normal urethral tissue (24.67 +/- 6.78) U, there was significant difference between them (P < 0.01). The TIMP-1 expression level of urethral scar tissue was higher than that of normal urethral tissue, there was significant difference between them (P < 0.05). CONCLUSION: The high level of TIMP-1 expression and the low collagenase activity in urethral scar tissue may inhibit the degradation of urethral scar, and may be one of important causes of the scar tissue hyperplasia.

Adult↗
PubMed1989

[The effect of fat tissue autotransplantation on the changes in tissue surrounding the dura mater following laminectomy].

Problems, probably caused by the adhesion of scar tissue to the dural sac or nerve roots, may appear after a laminectomy in which resection was required. In our department, free auto-fatty tissue transplantation has been clinically performed since 1979 in an effort to prevent this phenomenon, and favorable therapeutic results have been obtained. In the present study, the possible influence of extradural tissue on the dura mater over certain periods was investigated in post-laminectomized adult rabbits. Additionally, the inhibitory effect of transplanted fatty tissue on adhesion was examined. In the laminectomy-only subject group, a remarkable development of granulating tissue was observed. This tissue subsequently adhered to the dura mater, often resulting in a delayed repair of the dura mater and its surrounding tissue. In the fatty tissue transplanted group, on the other hand, the transplanted fat preserved its composition morphologically and rapid degeneration was deterred even in free grafts, so scar formation was inhibited at the site of the laminectomy. In comparison with the laminectomy-only group, furthermore, the repair of the tissue surrounding the dura mater was accelerated by the transplanted fatty tissue, beginning in the early postoperative stage.

Adipose Tissue↗
PubMed1994

Histopathology of lymphatic tissues in transgenic mice expressing human tissue kallikrein gene.

BACKGROUND: Tissue kallikrein is a member of a family of closely related serine proteinases whose genetics are currently under intense investigation, but whose functions are still poorly understood. Functions of human tissue kallikrein, other than production of inflammatory kinins, are not readily amenable to investigation. A current mechanism for examining the function of a gene product is to introduce the gene with tissue-specific and/or inducible promoters into a suitable host that can then be experimentally manipulated. EXPERIMENTAL DESIGN: Five transgenic mouse lines were established by backcross matings of transgenic founder mice containing the human tissue kallikrein gene. The inserted genomic material included the full-length kallikrein coding sequence as well as 800 bp in the upstream promoter region and 300 bp in the 3' noncoding region (PHK). Two of the five strains contained, in addition to the complete coding region and 3' flanking sequence, an upstream, zinc-inducible metallothionein promoter (MRE-PHK). Tissues from animals containing human kallikrein gene constructs (as determined by Southern blot of tail DNA) were examined histologically, and compared with control tissues from siblings negative for the gene. RESULTS: Transgenic mice exhibited tissue pathology in several lymphatic organs. Cytoarchitecture was disrupted in both thymus and spleen. The distinction between cortex and medulla in the thymus was usually blurred, and cytolysis was common. Spleens exhibited decreased T cell-dependent zones (periarteriolar sheath), with active hematopoietic foci throughout the red pulp. In lymph nodes, cortical nodules were rare. The deep cortex (paracortical area) was usually normal in heterozygotes, but often depleted in homozygous animals. Comparable results were obtained in all five transgenic strains. CONCLUSIONS: Expression of human tissue kallikrein appears to exert a profound effect on the cytoarchitecture of lymphatic tissues and a general decrease in lymphocytes, particularly in T cell-dependent areas. These findings presumably reflect altered function of lymphatic tissues in transgenic mouse strains carrying the human kallikrein gene.

Animals↗
PubMed1976

[Ectopic induction of bone and cartilaginous tissue in diffusion chambers in adult rabbits under the effect of ground bone tissue].

The possibility of induction of bony and cartilaginous tissues in the diffusion chambers inserted in the abdominal cavity of adult rabbit under the influence of crushed bone was shown. The induction occurred when the crushed bony tissue moistened with blood was autotransplanted in the chambers together with the crushed muscle. No formation of tissues do novo occurred in the chambers with the crushed bony tissue moistened with blood only. The formation of atypical islets of bony tissue was observed from time to time in the connective tissue capsule overgrowing the diffusion chambers. The bony and cartilaginous tissues were found neither in the chamber, nor on its surface when the empty diffusion chambers were inserted. The comparison of these results with the data obtained earlier allows to conclude that the crushed bony tissue is an inductor rather than a source of ectopic osteogenesis. In those cases when the bony and cartilaginous tissues formed de novo, the connective tissue elements of the crushed muscle were their source.

Abdomen↗