RESUMEN
The hepatitis C virus (HCV)-specific CD4+ T-cell response against nonstructural proteins is strongly associated with successful viral clearance during acute hepatitis C. To further develop these observations into peptide-based vaccines and clinical immunomonitoring tools like HLA class II tetramers, a detailed characterization of immunodominant CD4+ T-cell epitopes is required. We studied peripheral blood mononuclear cells from 20 patients with acute hepatitis C using 83 overlapping 20-mer peptides covering the NS3 helicase and NS4. Eight peptides were recognized by > or = 40% of patients, and specific CD4+ T-cell clones were obtained for seven of these and three additional, subdominant epitopes. Mapping of minimal stimulatory sequences defined epitopes of 8 to 13 amino acids in length, but optimal T-cell stimulation was observed with 10- to 15-mers. While some epitopes were presented by different HLA molecules, others were presented by only a single HLA class II molecule, which has implications for patient selection in clinical trials of peptide-based immunotherapies. In conclusion, using two different approaches we identified and characterized a set of CD4+ T-cell epitopes in the HCV NS3-NS4 region which are immunodominant in patients achieving transient or persistent viral control. This information allows the construction of a valuable panel of HCV-specific HLA class II tetramers for further study of CD4+ T-cell responses in chronic hepatitis C. The finding of immunodominant epitopes with very constrained HLA restriction has implications for patient selection in clinical trials of peptide-based immunotherapies.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Hepacivirus/inmunología , Epítopos Inmunodominantes , Proteínas no Estructurales Virales/inmunología , Adolescente , Adulto , Alelos , Secuencia de Aminoácidos , Presentación de Antígeno , Femenino , Antígenos HLA/genética , Antígenos HLA/fisiología , Hepatitis C/inmunología , Humanos , Leucocitos Mononucleares/inmunología , Activación de Linfocitos , Masculino , Persona de Mediana Edad , Datos de Secuencia MolecularRESUMEN
The surgical management of patients with CD can be complex and fraught with complications. Thorough preoperative evaluation by a multidisciplinary management team should delineate the indications for surgery and allow formulation of an operative strategy. Although surgery is not a cure for CD, approximately three quarters of patients require an operation. Until better postoperative maintenance strategies are developed, many CD patients eventually require a reoperation.
Asunto(s)
Enfermedad de Crohn/cirugía , Enfermedad de Crohn/complicaciones , Humanos , Cuidados PreoperatoriosAsunto(s)
Inflamación/etiología , Intestino Delgado/trasplante , Músculo Liso/patología , Trasplante Homólogo/patología , Quimiocina CCL2/genética , Ciclooxigenasa 2 , Humanos , Interleucina-6/genética , Isoenzimas/genética , Proteínas de la Membrana , Monitoreo Intraoperatorio , Prostaglandina-Endoperóxido Sintasas/genética , Reperfusión , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de TiempoRESUMEN
BACKGROUND AND AIMS: Dysfunction of the immune system with inappropriate responses of lymphocytes to various antigens has been implicated in the development of Crohn's disease. Therefore, the functional and phenotypic characteristics of intestinal intraepithelial lymphocytes (IEL) in comparison to peripheral blood lymphocytes (PBL) were analyzed in patients with and without Crohn's disease. PATIENTS AND METHODS: Six patients with Crohn's disease and six control patients were studied. Isolated IEL and PBL were tested for cytolytic activity against the human adenocarcinoma cells DLD-1 and the human leukemia cells K562 in a 51Cr-release assay. Two-color flow cytometry was performed for phenotype analysis of isolated lymphocytes. RESULTS: IEL from patients with Crohn's disease showed significantly increased cytolytic activity against epithelial-derived target cells when compared with IEL from control patients. In contrast, no functional changes were detectable among PBL from patients with Crohn's disease. IEL from patients with Crohn's disease contained a significantly higher percentage of CD8+ lymphocytes when compared with IEL from control patients, whereas no phenotypic changes were observed among PBL. CONCLUSIONS: In Crohn's disease, the functional and phenotypic changes of T cells are limited to lymphocytes of the intestinal mucosa. Furthermore, it is conceivable that the increased cytolytic activity of IEL contributes to the tissue damage in this disease.
Asunto(s)
Enfermedad de Crohn/inmunología , Mucosa Intestinal/inmunología , Linfocitos T Citotóxicos/inmunología , Estudios de Casos y Controles , Citotoxicidad Inmunológica , Citometría de Flujo , Humanos , Mucosa Intestinal/citología , Células Asesinas Naturales/inmunología , Fenotipo , Células Tumorales CultivadasRESUMEN
CD8+ T lymphocytes play a major role in antiviral immune defense. Their significance for acute hepatitis C is unclear. Our aim was to correlate the CD8+ T cell response with the outcome of infection. Eighteen patients with acute hepatitis C and 19 normal donors were studied. Hepatitis C virus (HCV)-specific CD8+ T cells were identified in the enzyme-linked immunospot assay by their interferon-gamma (IFN-gamma) production after specific stimulation. The highest numbers of IFN-gamma-producing HCV-specific CD8+ T cells were found in patients with acute hepatitis C and a self-limited course of disease during the first 6 months after onset of disease, but these numbers dropped thereafter to undetectable levels. The differences in responsiveness between patients with self-limited disease versus patients with a chronic course were statistically significant (P<.001). Our data show that the number of IFN-gamma-producing HCV-specific CD8+ T cells during the first 6 months after onset of disease is associated with eradication of the HCV infection.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/virología , Hepacivirus/inmunología , Hepatitis C/inmunología , Enfermedad Aguda , Adolescente , Adulto , Anciano , Linfocitos T CD4-Positivos/inmunología , Células Cultivadas , Femenino , Hepatitis C Crónica/inmunología , Antígenos de Histocompatibilidad Clase I/sangre , Humanos , Interferón gamma/biosíntesis , Activación de Linfocitos , Masculino , Persona de Mediana Edad , Recurrencia , Valores de Referencia , Proteínas Virales/biosíntesisRESUMEN
BACKGROUND & AIMS: We have shown that intestinal manipulation leads to a significant inhibition of circular muscle contraction. We hypothesized that the inflammatory mediator inducible nitric oxide (NO) plays a role in surgically induced ileus. METHODS: Rats and inducible NO synthase (iNOS) knockout and wild-type mice underwent a simple intestinal manipulation. Reverse-transcription polymerase chain reaction and immunohistochemistry were used to detect and localize iNOS expression. Nitrite and NO production were measured in muscularis cultures. Spontaneous and bethanechol-stimulated jejunal circular muscle contractions were measured in an organ bath. RESULTS: Intestinal manipulation resulted in significant iNOS messenger RNA induction in mucosa and muscularis. Immunohistochemistry localized iNOS in phagocytes within the muscularis. Nitrite and NO production increased 59.8-fold 24 hours after manipulation. L-n(6)-(1-iminoethyl) lysine (L-NIL) inhibited this response. In control rats, selective iNOS inhibition did not increase spontaneous muscle activity, but after manipulation L-NIL significantly improved spontaneous activity. iNOS knockout mice showed a significant 81% decrease in neutrophil infiltration into the muscularis after intestinal manipulation compared with wild-types. Contractile activity was normal in knockout mice after intestinal manipulation. CONCLUSIONS: These results show that leukocyte-derived inducible NO inhibits gastrointestinal motility after manipulation and plays an essential role in the initiation of intestinal inflammation.
Asunto(s)
Intestino Delgado/fisiología , Intestino Delgado/cirugía , Óxido Nítrico Sintasa/metabolismo , Animales , Betanecol/farmacología , Inhibidores Enzimáticos/farmacología , Técnicas In Vitro , Intestino Delgado/fisiopatología , Lisina/análogos & derivados , Lisina/farmacología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Contracción Muscular/efectos de los fármacos , Contracción Muscular/fisiología , Músculo Liso/fisiología , Músculo Liso/fisiopatología , Músculo Liso/cirugía , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa/deficiencia , Óxido Nítrico Sintasa/genética , Óxido Nítrico Sintasa de Tipo II , Nitritos/metabolismo , Fagocitos/enzimología , Ratas , Ratas Endogámicas ACIRESUMEN
BACKGROUND & AIMS: The prospective comparison of patients with acute hepatitis C virus (HCV) who spontaneously clear the virus with those who cannot achieve viral elimination and progress to chronic hepatitis offers the unique opportunity to analyze natural mechanisms of viral elimination. METHODS: We studied the HCV-specific CD4(+) T-cell response in 38 patients with acute HCV and correlated the clinical course with the antiviral immune response. The individual HCV-specific T-cell response was assessed in a proliferation assay ((3)H-thymidine uptake) and an enzyme-linked immunospot assay. RESULTS: Patients were classified according to their clinical course and pattern of CD4(+) T-cell responses in 3 categories: first, patients mounting a strong and sustained antiviral CD4(+)/Th1(+) T-cell response who cleared the virus (HCV RNA-negative; n = 20); second, patients who were unable to mount an HCV-specific CD4(+) T-cell response and developed chronic disease (n = 12); and third, patients who initially displayed a strong CD4(+) T-cell response and eliminated the virus (HCV PCR-negative) but subsequently lost this specific T-cell response (n = 6). The loss of the HCV-specific CD4(+) T-cell response was promptly followed by HCV recurrence. CONCLUSIONS: The results indicate that a virus-specific CD4(+)/Th1(+) T-cell response that eliminates the virus during the acute phase of disease has to be maintained permanently to achieve long-term control of the virus. The induction and/or maintenance of virus-specific CD4(+) T cells could represent a promising therapeutic approach in HCV infection.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Hepacivirus/inmunología , Hepatitis C/inmunología , Hepatitis C/virología , Enfermedad Aguda , Adulto , Anciano , Linfocitos T CD4-Positivos/patología , División Celular/fisiología , Femenino , Hepacivirus/genética , Hepatitis C/patología , Hepatitis C Crónica/inmunología , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , ARN Viral/análisis , Recurrencia , Valores de ReferenciaRESUMEN
BACKGROUND: Surgical manipulation of the intestine results in the massive movement of leukocytes into the intestinal muscularis at 24 hours. This is associated with muscle inhibition. The aim of this study was to temporally associate leukocyte extravasation with ileus after surgical manipulation. METHODS: Rats underwent a simple manipulation of the small bowel and were killed at various times (0, 0.25, 0.5, 1, 3, 6, 12, and 24 hours) postoperatively. Jejunal circular-muscle contractile activity was assessed in a standard organ bath. Both extravasating and resident leukocytes were immunohistochemically stained in muscularis whole mounts. RESULTS: Contractile activity was significantly reduced immediately after surgery, but rapidly returned to control levels at 3 hours. After recovery, muscle function decreased at 12 and 24 hours (41% and 81%, respectively). The resident muscularis macrophage network demonstrated cellular activation 1 hour postoperatively. The number of leukocytes increased over time (neutrophils, 67.5-fold; monocytes, 98.2-fold; and mast cells, 47-fold at 24 hours). CONCLUSIONS: The functional results demonstrate a biphasic response in the suppression of muscle activity after surgical manipulation. Regression analysis (r2 = 0.998) of the temporal development of leukocyte infiltration and the protracted phase of muscle inhibition provides evidence for a correlation between cellular inflammation and postoperative dysmotility.
Asunto(s)
Intestino Delgado/cirugía , Músculo Liso/patología , Músculo Liso/fisiopatología , Complicaciones Posoperatorias/etiología , Animales , Tránsito Gastrointestinal , Histocitoquímica , Humanos , Intestino Delgado/patología , Intestino Delgado/fisiopatología , Leucocitos/patología , Masculino , Contracción Muscular , Peroxidasa/metabolismo , Complicaciones Posoperatorias/patología , Complicaciones Posoperatorias/fisiopatología , Ratas , Ratas Endogámicas ACI , Factores de TiempoRESUMEN
Cytokines that are secreted as a response to viral antigen not only have direct antiviral properties but also crucially influence immune reactions determining the outcome of infection. As an advantageous alternative to the study of cytokines present in the supernatants of antigen-specific T cell clones and lines, we have used ELISPOT assays to determine the number of interferon-gamma (IFN-gamma)- and IL4-producing cells generated by peripheral blood mononuclear cells from patients with acute hepatitis B (AHB) and chronic hepatitis B (CHB) infection in response to HBcAg in a short-term culture (48 h). In response to HBcAg IFN-gamma was predominantly produced. In contrast to the results obtained in acute hepatitis B, the typical lymphokine pattern in CHB was characterized by a weak or absent antigen-specific IFN-gamma production. A predominance of IL-4-producing cells was not observed in either AHB or CHB. A significant number of IFN-gamma-producing cells was usually detectable during phases of viral elimination and the quality of the lymphokine response seemed to be epitope independent. Comparison of the results obtained in proliferation assays and ELISPOT assays clearly shows that lymphokine production upon stimulation with viral protein is totally independent of T cell proliferation and more sensitively reflects antiviral reactivity.
Asunto(s)
Virus de la Hepatitis B/inmunología , Hepatitis B Crónica/inmunología , Hepatitis B/inmunología , Interferón gamma/biosíntesis , Interleucina-4/biosíntesis , Linfocitos T/inmunología , Enfermedad Aguda , Virus de la Hepatitis B/aislamiento & purificación , Humanos , Inmunoensayo , Interferón gamma/inmunología , Interleucina-4/inmunología , Activación de LinfocitosRESUMEN
BACKGROUND: Currently, therapeutic treatments for irritable bowel syndrome fail to produce significant clinical results. We hypothesized that alosetron, a selective 5-HT3 antagonist, may provide symptomatic relief in irritable bowel syndrome patients through a decrease in the amplitude of gastrointestinal contractions. AIM: To determine the in vitro effect of alosetron on neuromuscular transmission in the canine and human jejunal and colonic muscularis externa. RESULTS: Alosetron diminished electrical field-stimulated (EFS) contractions recorded from muscles of the canine and human small and large intestines. Mechanistically, the diminished EFS response could be explained by the ability of alosetron to decrease the fractional release of 14C-choline radiolabelled acetylcholine evoked by EFS from human jejunal muscle. The inhibition of EFS contractions was not limited to atropine-sensitive events, as non-cholinergic excitatory EFS evoked contractions were also inhibited. Additionally, alosetron at high concentrations (> 30 microM) directly altered bethanechol stimulated contractions. CONCLUSION: Caution must be used in the interpretation of these data because significant alterations in EFS-induced contractions were only observed with large pharmacological concentrations of alosetron, and the response was not selective for cholinergically-mediated excitatory neuromuscular transmission.
Asunto(s)
Carbolinas/farmacología , Intestinos/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Antagonistas de la Serotonina/farmacología , Animales , Colina/metabolismo , Perros , Electrofisiología , Humanos , Técnicas In Vitro , Contracción Muscular/efectos de los fármacosRESUMEN
BACKGROUND & AIMS: Postoperative ileus is a poorly understood and common problem. We previously demonstrated an association between a suppression in jejunal circular muscle activity and a massive extravasation of leukocytes into the muscularis after surgical manipulation of the small bowel. This study was pursued to establish a direct causal link between these events. METHODS: Reverse-transcription polymerase chain reaction and immunohistochemistry were used to detect and localize expression of adhesion molecules: P-selectin, intercellular adhesion molecule 1 (ICAM-1), and lymphocyte function-associated antigen 1 (LFA-1). Leukocyte infiltration and in vitro jejunal circular muscle function were quantified in controls and manipulated animals with and without antibody treatment (1A29, WT.1, and WT.3). RESULTS: Surgical manipulation caused a significant up-regulation within the muscularis of ICAM-1 and P-selectin messenger RNA. ICAM-1 and P-selectin protein expression was increased within the muscularis microvasculature, and ICAM-1 and LFA-1 were expressed on infiltrating cells. Administration of adhesion molecule antibodies prevented the recruitment of monocytes and neutrophils into the muscularis and also averted jejunal circular muscle dysfunction. CONCLUSIONS: The data demonstrate that adhesion molecule antibodies prevent surgically induced suppression of intestinal muscle contractions and therefore suggests that late postoperative ileus is mediated through a leukocytic inflammatory response within the intestinal muscularis externa.
Asunto(s)
Obstrucción Intestinal/etiología , Intestinos/patología , Leucocitos/fisiología , Músculo Liso/patología , Complicaciones Posoperatorias/etiología , Animales , Inmunohistoquímica , Molécula 1 de Adhesión Intercelular/genética , Molécula 1 de Adhesión Intercelular/fisiología , Antígeno-1 Asociado a Función de Linfocito/análisis , Masculino , Selectina-P/genética , Selectina-P/fisiología , ARN Mensajero/análisis , Ratas , Ratas Endogámicas ACIRESUMEN
BACKGROUND: To evaluate the safety and efficacy of treating low-lying rectal lesions with resection and primary repair using a pull-through technique with rectal stump eversion and external coloanal anastomosis with immediate reintroduction into the pelvis. METHODS: All coloanal anastomoses with the above technique on the Gastrointestinal Surgery Service at the University of Pittsburgh from March 1990 to September 1995 were evaluated. RESULTS: Fifty-two patients underwent coloanal anastomoses with the above technique, and follow-up was available for 96% (50 of 52) of patients. Rectal lesions in the 50 patients included cancer (n = 34), rectal adenomas (n = 13), and other lesions (n = 3). Mean follow-up period was 29.6 +/- 21.8 months (28.5 months for patients with carcinoma). Fecal continence was normal or good in 88% (44 of 50) of patients. Moderate or complete incontinence was present in 12% (6 of 50) of patients. The local recurrence rate of rectal cancer was 0%. Morbidity occurred in 22% (11 of 50) of patients. Survival was 90% (45 of 50 patients). CONCLUSIONS: Coloanal anastomosis with this technique provides effective treatment for low-lying malignant or benign rectal lesions and has an acceptable complication rate.
Asunto(s)
Canal Anal/cirugía , Colon/cirugía , Neoplasias del Recto/cirugía , Anastomosis Quirúrgica/métodos , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud , Enfermedades del Recto/cirugía , Estudios Retrospectivos , Factores de TiempoRESUMEN
OBJECTIVE: To investigate the pathophysiologic mechanisms that lead to ileus after abdominal surgery. SUMMARY BACKGROUND DATA: The common supposition is that more invasive operations are associated with a more extensive ileus. The cellular mechanisms of postsurgical ileus remain elusive, and few studies have addressed the mechanisms. METHODS: Rats were subjected to incremental degrees of surgical manipulation: laparotomy, eventration, "running," and compression of the bowel. On postsurgical days 1 and 7, muscularis infiltrates were characterized immunohistochemically. Circular muscle activity was assessed using mechanical and intracellular recording techniques in vitro. RESULTS: Surgical manipulation caused an increase in resident phagocytes that stained for the activation marker lymphocyte function-associated antigen (LFA-1). Incremental degrees of manipulation also caused a progressive increase in neutrophil infiltration and a decrease in bethanechol-stimulated contractions. Compression also caused an increase in other leukocytes: macrophages, monocytes, dendritic cells, T cells, natural killer cells, and mast cells. CONCLUSION: The data support the hypothesis that the degree of gut paralysis to cholinergic stimulation is directly proportional to the degree of trauma, the activation of resident gut muscularis phagocytes, and the extent of cellular infiltration. Therefore, postsurgical ileus may be a result of an inflammatory response to minimal trauma in which the resident macrophages, activated by physical forces, set an inflammatory response into motion, leading to muscle dysfunction.
Asunto(s)
Obstrucción Intestinal/etiología , Yeyuno/cirugía , Músculo Liso/cirugía , Complicaciones Posoperatorias/etiología , Animales , Histocitoquímica , Inmunohistoquímica , Inflamación/etiología , Yeyuno/patología , Masculino , Músculo Liso/patología , Ratas , Ratas Endogámicas ACIAsunto(s)
Motilidad Gastrointestinal , Intestino Delgado/fisiología , Intestino Delgado/trasplante , Fagocitos/fisiología , Animales , Intestino Delgado/irrigación sanguínea , Isquemia , Macrófagos/fisiología , Masculino , Monocitos/fisiología , Contracción Muscular , Músculo Liso/irrigación sanguínea , Músculo Liso/fisiología , Músculo Liso/trasplante , Neutrófilos/fisiología , Ratas , Ratas Endogámicas ACI , Reperfusión , Trasplante Isogénico/fisiologíaRESUMEN
A strong virus-specific CD4+ and CD8+ T lymphocyte response to hepatitis B virus (HBV) has been associated with viral clearance, but little is known about factors determining the individual's ability to mount such a T cell response. Recently a strong association between the HLA class II allele DR13 and a self-limited course of HBV infection has been described. In the present study of 33 patients with acute hepatitis B we show that individuals carrying HLA-DR13 mount a more vigorous CD4+ T cell response to HBV core (5706 ct/min (25th/75th percentile 3239 ct/min; 10,552 ct/min)) than patients without HLA-DR 13 (1365 ct/min (490 ct/min; 5334 ct/min); P = 0.006). However, peptide epitopes aa 50-69, aa 61-85, and aa 81-105 were recognized most frequently by both patient groups. Moreover, among 14 HBV core-specific CD4+ T cell clones from two patients with HLA-DR13, only one T cell clone was HLA-DR13-restricted. Our data suggest that the beneficial effect of the HLA-DR13 alleles on the outcome of HBV infection could be explained by a more vigorous HBV core-specific CD4+ T cell response, which may either be due to more proficient antigen presentation by the HLA-DR13 molecules themselves or a linked polymorphism in a neighbouring immunoregulatory gene.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Antígenos HLA-DR/inmunología , Antígenos del Núcleo de la Hepatitis B/inmunología , Hepatitis B/inmunología , Enfermedad Aguda , Alelos , Células Clonales , Epítopos , Antígenos HLA-DR/análisis , Subtipos Serológicos HLA-DR , Hepatitis B/virología , Prueba de Histocompatibilidad , Humanos , Ictericia/inmunología , Leucocitos Mononucleares/inmunología , Activación de LinfocitosRESUMEN
The basal presence of immunologically potent cells within the intestinal muscularis externa and their functional significance is unclear. Our aim was to investigate the basal distribution of various leukocyte populations within the rat jejunal muscularis. In addition, we sought to immunohistochemically phenotype the muscularis macrophage in jejunal whole-mounts, isolate these cells in primary culture, and investigate their ontogenesis. Macrophages form a regularly distributed network that expresses major histocompatibility complex class II, CD14 receptors, and a low level of CD11/CD18. The macrophages are activated by dissection and are present in fetal animals. Enriched macrophage cultures show a normal resident phenotype and remain present for weeks in dissociated muscularis cultures. The results also demonstrate the presence of neutrophils, monocytes, mast cells, and lymphocytes within the muscularis and suggest that the dense network of muscularis macrophages may be a potent resident trigger for inflammation in response to tissue injury or bacterial translocation.
Asunto(s)
Yeyuno/citología , Leucocitos/citología , Músculo Liso/citología , Animales , Células Cultivadas , Femenino , Macrófagos/citología , Masculino , Fenotipo , Embarazo , Ratas , Ratas Endogámicas ACIRESUMEN
Infiltration of a transplanted organ by host lymphoid cells is the hallmark of acute rejection. However, after intestinal transplantation, physiological lymphocyte migration may lead to host cell infiltration of the graft even in the absence of rejection. It is unclear whether this lymphocyte migration also involves the intraepithelial compartment of the graft or whether infiltration there is indicative of acute rejection. We demonstrate here that host cell infiltration of the intestinal mucosa occurs both during acute rejection of a small bowel allograft and, to a lesser extent, when rejection is prevented by immunosuppression with FK506. The infiltrating host cells consisted of CD3+ T cells with a predominant CD4-CD8+ phenotype resembling intraepithelial lymphocytes (IELs). Functional studies showed that the nonspecific cytolytic activity of IELs was not affected by acute rejection or by immunosuppression with FK506. These findings indicate that host cell infiltration of the intestinal mucosa does not connote an ongoing acute rejection. Furthermore, the decreased mucosal barrier function during acute rejection of intestinal allgrafts is probably not due to impaired cytolytic activity of IELs.
Asunto(s)
Rechazo de Injerto/patología , Mucosa Intestinal/patología , Intestino Delgado/trasplante , Linfocitos/patología , Animales , Citometría de Flujo , Rechazo de Injerto/prevención & control , Inmunosupresores/uso terapéutico , Intestino Delgado/patología , Masculino , Fenotipo , Ratas , Ratas Endogámicas Lew , Ratas Sprague-Dawley , Tacrolimus/uso terapéuticoRESUMEN
BACKGROUND: Intestinal grafts are placed either heterotopically (out of continuity) or orthotopically (in continuity); the latter is believed to be advantageous, as intraluminal nutrients and intestinal secretions might modulate the intestinal immune status and possibly delay rejection. METHODS: This study was designed to delineate the effects of heterotopic versus orthotopic allograft position on the morphology and function of intestinal smooth muscle in our rat model of chronic rejection. Syngeneic orthotopic grafts were evaluated to control for changes due to the transplantation process. RESULTS: Histochemistry of the graft's muscularis externa showed a significant thickening due to hyperplasia and hypertrophy, which was most pronounced in heterotopic grafts (control = 92+/-2.4 microm, syngeneic grafts = 140+/-6.7 microm, orthotopic allografts = 278+/-26.6 microm, heterotopic allografts = 456+/-50 microm). In terms of function, muscle strips from allografts only generated 23% of the total bethanechol-induced contractile force in vitro compared to unoperated controls and syngeneic grafts. The mean resting membrane potential of control and isograft muscle cells was -69 +/- 0.9 mV with a slow-wave amplitude of 20+/-0.5 mV. Chronic rejection hyperpolarized the resting membrane potential of orthotopic allografts (-66 +/- 0.5 mV) and even more so of heterotopic allografts (-58 +/- 3.4 mV). Slow-wave amplitudes were decreased in orthotopic (14+/-0.9 mV) and nearly abolished in heterotopic allografts (2+/-1.2 mV). CONCLUSIONS: Our data indicate that allografts in heterotopic position are most susceptible to the insult of chronic rejection exemplified by increased proliferative and hypertrophic transformation of intestinal smooth muscle and a marked decrease in mechanical and electrical activity.
Asunto(s)
Rechazo de Injerto/patología , Mucosa Intestinal/trasplante , Intestino Delgado/trasplante , Músculo Liso/trasplante , Trasplante Heterotópico/fisiología , Trasplante Homólogo/fisiología , Animales , Betanecol/farmacología , Electrofisiología/métodos , Técnicas In Vitro , Mucosa Intestinal/patología , Mucosa Intestinal/fisiología , Intestino Delgado/patología , Intestino Delgado/fisiología , Yeyuno/fisiología , Masculino , Contracción Muscular/efectos de los fármacos , Músculo Liso/patología , Músculo Liso/fisiología , Ratas , Ratas Endogámicas ACI , Ratas Endogámicas Lew , Trasplante Heterotópico/inmunología , Trasplante Heterotópico/patología , Trasplante Homólogo/inmunología , Trasplante Homólogo/patología , Trasplante Isogénico/inmunología , Trasplante Isogénico/patología , Trasplante Isogénico/fisiologíaRESUMEN
PURPOSE: In 1997, the immunocytologic detection of isolated tumor cells in bone marrow, termed micrometastasis, will be optionally included in the tumor-node-metastasis (TNM) classification indicated M1(i). In the present meta-analyses, 20 studies, which included 2,494 patients, regarding the prognostic influence of a positive bone marrow micrometastases (BMM) status on relapse-free and/or overall survival were analyzed. MATERIALS AND METHODS: The literature search included the Medline and Current Contents bibliographic data bases from August 1980 to June 1997. The statistical evaluation considered the prognostic influence of the prevalence of micrometastatic cells in bone marrow on relapse-free and/or overall survival. The comparable effect estimate and its corresponding 95% confidence interval (CI) were calculated with the Mantel-Haenszel method using the originally published data of the retrieved studies. RESULTS: The presence of epithelial cells in bone marrow was detectable in all carcinoma types, with a median prevalence of approximately 35%. Fourteen of 20 studies found a positive correlation between positive BMM status and reduced relapse-free survival by univariate analysis, but only five of 11 studies confirmed positive BMM status as an independent predictor of short disease-free survival. Regarding overall survival, positive BMM status was identified univariately in five of 12 studies, but multivariately in only two studies, as an independent factor of poor survival. Despite the heterogeneity of the studies, calculation of the relative risk (RR) for reduced relapse-free survival was possible for breast cancer, which resulted in a Mantel-Haenszel RR (RR(MH)) of 1.34 (95% CI, 1.27 to 1.42). CONCLUSION: In conclusion, the results suggest that the prognostic impact of epithelial cells in bone marrow remains to be substantiated by further studies using standardized methodic protocols before its entrance in the TNM classification.