Supervivenica de hepatocitos alogénicos trasplantados en timo, en ausencia de terapia inmunosupresora / Survival o fallogeneic hepatocytes transplanted into thymus, without immunossuprresive therapy

El trasplante hepático constituye actualmente, una realidad clínica en situaciones de fallo hepático. Por otro lado, en el caso de diversos errores congénitos del metabolismo, en los cuales un solo fallo en una reacción de una ruta metabólica, conducea un fallo multiorgánico, la sustitución de un hígado morfológicamente normal parece una medida demasiado agresiva. Por ello, el uso de terapias celulares para el tratamiento de estas entidades está cada vez mas presente. Sin embargo, ambas estrategias terapéuticas se asocian a los efectos derivados de la inmunosupresión. La búsqueda de métodos que eliminen la necesidad de inmunosupresión es uno de los principales objetivos dentro del campode los trasplantes. La inyección intratímica de aloantígenos ha demostrado, en ciertos modelos experimentales, inducir tolerancia inmunológica. Sin embargo, los resultados con el trasplante intratímico de hepatocitos son contradictorios. Por este motivo, el objetivo de nuestro estudio ha sido estudiar el trasplante de hepatocitos en un órgano inmunológicamente privilegiado, como es el timo, donde se puede estudiar la funcionalidad y supervivencia de las células trasplantadas, así como estudiar la hipótesis de que el trasplante intratímico podría inducir un cierto grado de inmunomodulación en las células del sistemainmune. Se realizó trasplante de hepatocitos procedentes de ratas Fisher 344, en timo de ratas Gunn que habían recibido una dosis previa única de ciclosporina A. Después del trasplante, las ratas no recibieron nuevas dosis de ciclosporina, y fueron sacrificadas a diferentes tiempos. Se realizó microscopia óptica y se determinaron los niveles séricos y biliares de bilirrubina. También se estudió la presencia de mRNAs específicos y las poblaciones linfocitarias CD4 y CD8 en timo y sangre. Los datos obtenidos demuestran que los hepatocitos trasplantados sobreviven al menos 6 semanas, en los animales que habían recibido una dosis de ciclosporina A, antes del trasplante (AU)

Liver transplantation is currently a clinical reality, and it is well established as a treatment for acute organ failure. On the other hand, in the case of inborn errors of metabolism, in which a single step in a metabolic pathway leads to multiple organ failure, the replacement of a morphologically normal liver would be an aggressive measure. Thus, the use of cell therapy in these diseases is being considered. However, both strategies are associated with the effects derived from immunosuppression. The search for methods resulting in the avoidance of immunosupression is nowadays one of the main objectives within the field of transplantation. Intrathymic alloantigen injection has proved to induce immunological tolerance in certain experimental models. However, the results of intrathymic hepatocyte transplantation are contradictory. For this reason our objective was to study the transplantation of hepatocytes into an immunologically privileged organ such as the thymus, where we could assess the functionality and survival of the transplanted cells, as well as test the hypothesis that the intrathymic transplant could induce a certain immunomodulation in the cells of the immune system. Gunn rats, half of which received a single pre-transplant dose of cyclosporine A, were transplanted into the thymus with hepatocytes from Fisher 344 rats. After the transplant, rats did not receive any further dose of cyclosporine A, and they were sacrificed at different times. Light microscopy, bilirubin levels in both serum and bile, and presence of specific mRNAs were determined. Also, CD4 and CD8 lymphocyte subsets were studied in both thymus and blood. The results demonstrated thattransplanted hepatocytes survive for six weeks in animals which had been given cyclosporine A prior to the transplant (AU)

Optimization of the technique to isolate fetal hepatocytes, and assessment of their functionality by transplantation.

In contrast to adult hepatocytes, fetal hepatocytes (FH) are thought to be highly proliferative less immunogenic and more resistant to both cryopreservation and ischemic injury. In the present study, we describe the method for isolation of FH and the relationship between the transplantability of FH into the spleen of analbuminemic rats and expression of albumin mRNA. Rat FH were obtained using the nonperfusion collagenase/DNase digestion method. Nagase analbuminemic rats (NAR), a strain which bears a mutation that determines the impossibility of the normal splicing of the albumin mRNA were used as recipients. The transplanted FH immediately migrated to the liver via portal vein, and anchored there. To assess the functional state of the transplanted cells, one month after transplantation, the expression of the albumin gene was studied in the liver of the recipients.

Cadmium chloride-induced dysplastic changes in the ventral rat prostate: an immunohistochemical and quantitative study.

BACKGROUND: Cadmium chloride is an environmental toxic that might be implicated in human prostate carcinogenesis. The study was directed: 1) to evaluate the immunoexpression of markers for cell proliferation, apoptosis, and resistance to apoptosis, and 2) to estimate the size of premalignant cell population in the preneoplastic changes induced in ventral prostates of rats treated with cadmium chloride administered in drinking water. METHODS: The following parameters were calculated in the ventral prostatic lobe of normal rats and rats that received cadmium in drinking water during 18 months: total volume, epithelial volume, total number of epithelial cells, numerical density of epithelial cells, percentage of cells that immunostained to the proliferating cell nuclear antigen (PCNA), percentage of apoptotic cells (evaluated by a DNA fragmentation method), and absolute volume and volume fraction of immunostaining to bcl-2. RESULTS: The percentage of PCNA immunoreactive nuclei, the bcl-2 expression, and the numerical density of epithelial cells were significantly (P < 0.05) increased in the dysplastic prostatic acini of treated rats in comparison with the normal acini of treated rats and control animals. The percentage of apoptotic nuclei from ventral dysplastic acini was significantly (P < 0.05) decreased in comparison with that of normal acini. A negative correlation between proliferation and apoptosis was found in dysplastic lesions. CONCLUSIONS: Prostate epithelial dysplasia induced in rats by cadmium presents an increased proliferative activity and high expression of bcl-2 protein, as was described in human prostate intraepithelial neoplasia. However, the rate of apoptosis in rat dysplasia was importantly decreased, in contrast to that observed in some human preneoplastic changes. This decrease might be related to the increase of bcl-2 expression.

Liver gene expression and increase in albumin synthesis by fetal hepatocytes transplanted into analbuminemic rats.

This report describes the evolution of hepatocytes isolated from 21-day fetuses and transplanted into spleens of Nagase analbuminemic rats which have negligible serum albumin levels due to a mutation affecting albumin mRNA processing. Albumin and alpha-fetoprotein expression, in addition to other parameters related to cellular proliferation status (thymidine kinase and proliferating cell nuclear antigen expression) were studied as indicative of the behavior and evolution of the cells. In recipient rats, only a few clusters of hepatocytes could be observed in the red pulp of the spleen 24 h after transplantation. The fetal hepatocytes migrated to the liver and could be seen in portal branches immediately after transplantation. Fifteen days later, albumin mRNA was detected in recipient livers and was expressed throughout the entire 3-month study. Alpha-fetoprotein was not detected. Cell proliferation was not relevant, although 3 months after transplantation, the proliferation rates appeared to show a tendency to increase. These data demonstrate that fetal hepatocytes transplanted into spleen migrate to liver, settle there and acquire an adult phenotype free of malignant transformation. Our study is a first step towards the thorough understanding of fetal hepatocyte transplantation. The next steps will involve in-depth studies of the possibilities of genetic manipulation to achieve a high degree of repopulation/expression, employing the least possible number of donor cells, and of how the cells reach the liver parenchyma, overcoming the endothelial barrier.

Comparative effect of growth hormone and plerocercoid growth factor in the intestinal resection in rat.

OBJECTIVE: After massive bowel resection, absorption depends on how fast the mucosal adaptation takes place. This work aims at assessing the trophic effect of growth hormone (GH) and its analogue, the plerocercoid growth factor (PGF), on the intestinal mucosa after 90% small bowel resection. EXPERIMENTAL DESIGN: 24 male Wistar rats were divided into four groups of 6: Control (laparotomy), 90% small bowel resection (RID), resection and treatment with GH during 14 days (RID + GH) and resection and PGF treatment (RID + PGF). Intestinal mucosal adaptation was assessed by measuring mucosal weight and height, and evaluating the regenerative activity by measuring proliferation cell nuclear antigen (PCNA) labelling index. RESULTS: Bowel resection itself caused a significant increment of jejunal and ileal mucosal height in comparison with the control group. GH and PGF did not change this increase. Jejunal and ileal proliferation indexes were significantly higher than those in controls and they were significantly higher in both RID + GH and RID + PGF groups. CONCLUSIONS: GH and PGF cause a proliferative effect on the intestinal mucosa, even in hyperproliferative states such as the small bowel resection. This finding might have a clinic application.

Neurotensin increases intestinal adaptation and reduces enteroglucagon-like immunoreactivity after large bowel resection in rats.

OBJECTIVE: To assess the effects of giving neurotensin on intestinal adaptation after colectomy and their relation to enteroglucagon-like immunoreactivity. DESIGN: Laboratory experiment. SETTING: Teaching hospital, Spain. MATERIAL: 55 Male Wistar rats. INTERVENTIONS: All animals were anaesthetised before undergoing laparotomy; 24 animals had 75% of their colon resected. Half of the animals (12 in each group) were treated with neurotensin (600 micrograms/kg body wt/day) for 14 days. MAIN OUTCOME MEASURES: Differences in the number of mitoses and in nuclear antigen staining of proliferating cells in the intestinal mucosal crypts; plasma enteroglucagon-like immunoreactivity. RESULTS: After colon resection, the proliferative status, number of mitoses (p < 0.01), and nuclear antigen staining of proliferating cells (p < 0.001) increased significantly in the jejunum of animals treated with neurotensin (p < 0.05). Less pronounced effects were observed in colon and ileum. Plasma enteroglucagon-like immunoreactivity levels fell significantly in all animals given neurotensin (p < 0.05). CONCLUSIONS: Neurotensin increases the adaptive intestinal process after colon resection and reduces plasma enteroglucagon-like immunoreactivity in rats.

Comparative effects of growth hormone in large and small bowel resection in the rat.

Our aim was to assess the proliferative effect of human growth hormone on ileal mucosa after two different adaptation models of massive small and massive large bowel resection. Male Wistar rats were assigned to control-laparotomy, 90% small bowel resection, or 75% large bowel resection and were treated with either saline or human growth hormone daily for 7 days (total six groups; n = 8/group). Ileal proliferative status was assessed by means of histomorphometry and proliferating cell nuclear antigen. Plasma somatostatin was quantitated. Growth hormone increased (P < 0.01) mucosal height in all groups with a more marked effect on the crypt than on villus height. Proliferating cell nuclear antigen-labeled cells increased similarly (P < 0.01). Small bowel resection appears to favor a more marked increment in villus height than large bowel resection. Compared to control saline-treated group, the remaining groups showed decreases in plasma somatostatin (P < 0.01). Human growth hormone has a marked trophic effect on intestinal mucosa, even in hyperproliferative states. Decreased plasma somatostatin associated with intestinal hyperplastic mucosa suggests a possible relationship with the adaptive process.

[Effects of neurotensin on the development of suckling rats with intestinal resection]. / Efectos de la neurotensina en el desarrollo de la rata lactante con resección intestinal.

Massive intestinal resection produces malabsorption which, in the suckling rat, reduces growth. Our aim was to determine whether the proliferative action of neurotensin, can reduce the negative effects on growth induced by bowel resection. Fifteen days old suckling Wistar rats were used. Twenty rats underwent 90% midgut resection and twelve were used as controls. Half the animals were treated with neurotensin (600 micrograms/kg-day) until sacrifice 30 days later. Body and bone weight were measured and mucosal samples obtained. All resected animals lost body weight and bone weight. Neurotensin treatment reduced femur weight loss. After bowel resection, significant trophic effects were observed at mucosal level (crypt and villous size) but only in the jejunum of resected animals neurotensin treatment had a trophic effect. In conclusion, neurotensin favors intestinal adaptation after resection without improving mid-term growth in the suckling rat.

Immunohistochemical quantitative study of the peritubular lamina propria after induction of testicular atrophy induced by epinephrine.

Changes in the testicular peritubular lamina propria in rats treated for 1-11 weeks with intra-scrotal injections of epinephrine were studied by quantitative immunohistochemical methods. In control testes, BrdU-labelled nuclei (proliferating cells) were observed only in spermatogonia and some primary spermatocytes, whereas testes from epinephrine-treated rats showed BrdU labelling in some of the spermatogonia and in peritubular cells. Immunostaining for transforming growth factor beta 1 (TGF-beta 1) was present in germ cells, Sertoli cells and Leydig cells; vimentin immunostaining was found mainly in Sertoli cells; desmin immunostaining was found in the peritubular cells, and immunostaining for type IV collagen, laminin and fibronectin was found in the extracellular matrix of the lamina propria. The volume densities of seminiferous tubules (including seminiferous epithelium, lamina propria and tubular lumen) that immunostained for TGF-beta 1, vimentin, laminin, desmin or fibronectin were calculated. All of these parameters increased significantly in testes from epinephrine-treated animals during the course of the experiment, except for desmin immunostaining which showed no significant change in volume density. Since total seminiferous tubule volume decreased markedly in the testes of treated rats during the experiment, the transformation of relative values for immunostaining into absolute volumes per testis revealed a significant increase in TGF-beta 1 immunostaining, no significant change in vimentin immunostaining, and a significant decrease in desmin immunostaining during the time of the study. The absolute volume occupied by laminin and fibronectin immunostaining decreased from the 3rd to the 8th weeks of treatment, and increased from the 8th to the 11th weeks. These changes, associated with germ cell depletion and tubular fibrosis, suggest that tubular ischaemic atrophy caused by epinephrine alters the peritubular myoid cells, which change immunophenotype and increase their secretion of the extracellular matrix components producing tubular fibrosis. The mechanism of this alteration may involve direct effects on the peritubular cells or the changes may be secondary to germ cell and/or Sertoli cell lesions.

[Somatostatin and growth hormone in post-colectomy intestinal hyperplasia in rats]. / Somatostatina y hormona de crecimiento en la hiperplasia intestinal post-colectomía en la rata.

AIM: Somatostatin exerts significant effects on gastrointestinal function that may include mucosal growth regulation, probably through its action on growth hormone release. The aim of this work was to correlate somatostatin and growth hormone plasma levels and the hyperproliferative status of intestinal mucosa after colectomy. EXPERIMENTAL DESIGN: Adult Wistar rats were divided into two groups: control sham operated (n = 8) and large bowel resection (n = 8). Seven days post-colectomy, the animals were killed. Ileal mucosal samples were assayed for proliferative status (morphometry, and proliferating cell nuclear antigen labeling) and blood samples for plasmatic somatostatin and growth hormone measurement. RESULTS: A hyperproliferative status was observed with significant increases in villous length and crypt proliferating cell nuclear antigen labeling. Plasma somatostatin showed a 95% significant decrease while growth hormone levels increased significantly. CONCLUSION: The intestinal adaptation seen after colectomy is associated with lower somatostatin and higher growth hormone plasma level, possibly by regulating the intestinal adaptative process.

Testicular alterations in rats due to gestational and early lactational administration of lead.

A solution of lead acetate (300 mg/L) was administered via drinking water to pregnant Wistar rats from day 1 of pregnancy to delivery (Pb-treated day 0 group) or throughout gestation and early lactation (from day 1 to day 5 postnatal) (Pb-treated day 5 group). When the pups were born, four dams and their offspring in each group (control day 0, Pb-treated day 0, control day 5, and Pb-treated day 5) were sacrificed on day 0 (day 0 groups) or on day 5 (day 5 groups). Relative testicular weight and gross testicular structure were not altered by the treatment. The seminiferous tubule diameter and the number of prospermatogonia were reduced by the treatment. Determination of the n-ploidy stage of prospermatogonia indicates that these cells have more proliferative activity in Pb-treated rats than in control rats. On the other hand, the total DNA, RNA, and protein content of the testes in treated rats was significantly reduced, but the DNA: RNA ratio remained unaltered.

[Administration of growth hormone enhances the intestinal adaptive response after resection of small intestine in rats]. / La administración de hormona de crecimiento incrementa la respuesta adaptativa intestinal posterior a una resección de intestino delgado en la rata.

The aim of this study was to assess the proliferative effect of growth hormone (GH) on the remnant intestinal mucosa after small bowel resection in the rat. Three groups (n = 8/group) of adult Wistar rats were established as follows: 1) control, 2) 90% small bowel resection (SBR) and 3) 90% small bowel resection + GH 1 mg/kg-day (SBR+GH) during 7 days. Ileal samples were taken prior to resection (basal), and at sacrifice, for assessment of intestinal mucosal growth by means of morphometric (crypt and villous length) and proliferative (proliferating cell nuclear antigen, PCNA) techniques. GH administered to resected rats (SBR+GH) significantly increased the number of proliferating cells and crypt and villous length when compared to resected non-treated animals (SBR). In conclusion, in the rat, GH markedly increases the trophic action of intestinal mucosa in hyperproliferative states like massive bowel resection, enhancing remnant bowel morphologic and proliferative adaptation.

Myoid cell proliferation in rat seminiferous tubules after ischaemic testicular atrophy induced by epinephrine. Morphometric and immunohistochemical (bromo-deoxyuridine and PCNA) studies.

The proliferation of peritubular myoid cells in the testes of rats treated for 1-11 weeks with intra-scrotal injections of epinephrine was investigated using immunohistochemistry and quantitative histology. The percentage of peritubular cells that were immunopositive for proliferating cell nuclear antigen (PCNA) or that were labelled with 5'-bromodeoxyuridine (BrdU) in the S-phase of the cell cycle, were calculated in control and treated rats after 1,3,5,8 and 11 weeks of treatment. In addition, the change in the number of peritubular cells per testis was calculated using two different stereological methods. The possible correlation between the changes observed using the two proliferation indices (PCNA immunoreaction and labelling of BrdU) in peritubular myoid cells was evaluated by regression analysis. The results of the study indicate that both proliferation indices increased in peritubular cells between the third and the eighth weeks of treatment, and that this increase was correlated with an increase in the number of these cells. From weeks 8-11 of treatment, both proliferation indices decreased and the same occurred with the number of peritubular cells. We hypothesize that proliferation of the peritubular cells occurs in order to increase their secretion of extracellular matrix components leading to enlargement of the lamina propria of the seminiferous tubule.

[Early or late orchidopexy? An evaluation of germ cell proliferation by PCNA immune expression]. / Orquidopexia precoz o tardía? Valoración de la proliferación de las células germinales mediante inmunoexpresión de PCNA.

A immunocytochemical study for detection of proliferating cell nuclear antigen (PCNA) in order to quantify the number of PCNA-positive spermatogonia, and cytophotometric determination of spermatogonial DNA were performed in cryptorchid and control testes. The number of PCNA-positive spermatogonia, and the average DNA content of spermatogonia in the cryptorchid testes were altered from first years of age. These precocious spermatogonial alterations suggest that the early surgical testicular descent doesn't prevent lesions of germ cells.

[Intestinal trophic effect of neurotensin after colectomy]. / Efecto trófico intestinal de la neurotensina tras colectomía.

Neurotensin is a trophic peptide for the intestinal mucosa. Intestinal resection is a well known adaptive process of mucosal growth. Our aim was to determine the effect of exogenous neurotensin administration on intestinal mucosal growth after colectomy in the rat. Two groups: colon resection (n = 15) and colon resection plus neurotensin (n = 15, 600 micrograms/kg/day, 13 days post-surgery) were studied. Intestinal growth was assessed by means of the proliferating cell nuclear antigen (PCNA) technique on the intestinal crypt. Our results showed that neurotensin increased (p < 0.0001) epithelial cell growth when compared to non treated animals. Body weight loss was found in the non treated group but not in neurotensin treated animals. In conclusion, neurotensin increases cell growth in rats with colectomy, and maintains body weight. Neurotensin may have beneficial effects in colectomized patients.

[Importance of the colon in intestinal adaptation. Study with the proliferating cell nuclear antigen]. / Importancia del colon en la adaptación intestinal. Estudio mediante el antígeno nuclear de proliferación celular.

Proliferating cell nuclear antigen (PCNA) is an auxiliary protein to DNA polymerase delta necessary for tissue cellular proliferation. The colon releases several peptides or hormones which are probably related to intestinal proliferation. Colonic resection determines adaptive changes in the remnant bowel. In the present study, proliferative changes after colectomy were studied by means of the murine monoclonal PC10 antibody. A control group (n = 10 rats) and a 75% proximal colon resection group (n = 10 rats) were studied. 14 days after resection, jejunal, ileal and colon samples were taken and assayed for PCNA. Relationship between immunostained nuclei and the total number of nuclei was determined. The three intestinal segments showed statistically significant increases (p < 0.001) in the number of immunostained nuclei. PCNA proliferative index was greater in the remnant large bowel.

Cytophotometric DNA quantification in human spermatogonia of cryptorchid testes.

The DNA content of spermatogonia was studied by cytophotometric quantification in the testes of cryptorchid children and adults, as well as in age-matched control males. In most cases, the average DNA content of spermatogonia was significantly increased in the cryptorchid testes of children with uni- or bilateral cryptorchidism, as well as in the contralateral scrotal testes of children with unilateral cryptorchidism. In the group of adult men the average DNA content of spermatogonia in the testes was even more increased than in children. There were not significant differences between 4 and 14 years of age, between unilateral and bilateral cryptorchidism, or between cryptorchid testes and contralateral normally descended testes. The DNA content of spermatogonia in the surgically descended testes of 3 children who were re-biopsied 3-4 years after orchidopexy was similar before and after orchidopexy. These findings suggest that the spermatogonia of many cryptorchid males bear a congenital lesion.