Carcinoembryonic antigen family of adhesion molecules in the cotton top tamarin (Saguinus oedipus).

Humans and the cotton top tamarin, a model for colitis and colorectal cancer, share carcinoembryonic antigen (CEA) moieties. We quantified CEA in colonic washings and extracts in both, and CEA bands were confirmed by Western blot. We compared CEA-family expression in tissues and serum in the tamarin with that of the common marmoset, which develops colitis but not cancer. CEA levels are higher in tamarin washings compared with humans, and higher than in marmosets extracts (P<0.005). CEA molecular species appear to be specific, and human CEA-family member epitopes are also found in these primates. The higher CEA levels in the tamarin may reflect the overall higher cancer prevalence.

Gastrointestinal tract antigenic profile of cotton-top tamarin, Saguinus oedipus, is similar to that of humans with inflammatory bowel disease.

As an animal model for human inflammatory bowel disease and colorectal cancer, the cotton-top tamarin remains controversial. Demonstration of antigenic similarity to the human would enhance its validity. Using colonic extracts and washings, we compared binding of seven monoclonal antibodies reactive with bowel and cancer antigens in both tamarins and humans with inflammatory bowel disease. Additionally, telomerase activity was tested for. Expression of a mucin antigen specific to human cancer was increased in tamarin colonic washings as well as aminoproteoglycans and EGFR in tamarin extracts, as compared to those of humans with inflammatory bowel disease (P < 0.005). An adenoma-associated antigen and k-ras p21 protein were negative in the tamarin. A trend to greater telomerase activity exists in tamarins. The antigenic similarity validates this model for human inflammatory bowel disease and colorectal cancer. A trend to increased telomerase activity in tamarins is consistent with the greater predisposition to cancer in these animals.

Oral efficacy of a leukotriene B4 receptor antagonist in colitic cotton-top tamarins.

Leukotriene B4 (LTB4) is a potent neutrophil activator and chemotaxin that is present in increased concentrations in the colonic tissue and rectal dialysates of acute ulcerative colitis patients. Cotton-top tamarins (CTTs) with confirmed active colitis were treated with the second generation LTB4 receptor antagonist, SC-53228 ((+)-(S)-7-[3-(2-cyclopropyl-methyl)-3-methoxy-4-[(methylamino) carbonyl]phenoxy]propoxy]-3,4-dihydro-8-propyl-2H-1-benzopyran-2- propanoic acid), 20 mg/kg bodyweight by gavage, twice daily for 56 days. End points were body weights, stool consistency, colonic endoscopy, assay of inflammatory mediators, and haematology and clinical chemistry tests. LTB4 and prostaglandin E (PGE) values were measured in rectal dialysates at pretreatment, 28 day and 56 day time points. LTB4 concentrations were reduced from pretreatment mean (SEM) values of 37.3 (0.8) ng/ml to 3.7 (0.8) ng/ml (p < 0.001) and 2.3 (0.5) ng/ml (p < 0.01) at days 28 and 56, respectively. On the other hand, mucosal protective PGE values remained constant or slightly increased during SC-53228 treatment (pre: 6.9 (2.2) ng/ml; day 28: 6.7 (1.4) ng/ml; day 56: 9.9 (1.6) ng/ml). Furthermore, assessment of a panel of 35 clinical chemistry and haematology parameters throughout the treatment showed there were no significant untoward effects of drug treatment. Six CCTs finished the eight week treatment and five of six gained weight (ranging from 27-121 grams each) while one CTT lost weight (50 g). Stool condition improved in five of six animals while one of six remained unchanged. All CCTs showed dramatic improvement histologically, with no or only minimally active colitis after treatment. The histological changes plus significant weight gains and improvement of stool condition (quality of life parameters) after eight weeks of SC-53228 treatment were remarkable. Furthermore, in follow up biopsies seven months after treatment ceased, three of six CTTs had no active colitis. This is the first time afflicted CTTs have not had recurring colitic exacerbations after a treatment regimen was stopped. It is concluded that in colitic CTTs, SC-53228 has shown both an immediate and a long acting anticolitic activity. It is also concluded that reduced LTB4 concentrations during treatment inhibited neutrophil infiltration of the colonic tissue and this, coupled with the maintenance of mucosal protective prostaglandins, contributed to the dramatic anticolitic efficacy. The treatment was safe over eight weeks. A compound such as SC-53228 may be useful in the medical treatment of human inflammatory bowel disease.

A putative CEA moiety is shared by the cotton-top tamarin (Saguinus oedipus) and humans.

CEA-like molecules immunologically distinct from those in humans have been described in non-human primates. These primates do not share the human predilection for colitis and subsequent development of colorectal cancer. CEA expression has not been fully evaluated in a lower-order primate, the cotton-top tamarin (Saguinus oedipus), an animal model for colitis and colorectal cancer. We found increased levels of CEA in both colonic washings and tissues of these animals using a commercially available kit, CEA AIA-PACK (Tosoh Medics, Foster City, CA). In contrast, we observed that other CEA kits failed to detect CEA in tamarins. To elucidate the nature of the CEA-like protein detected, we used the two component monoclonal antibodies used in the CEA AIA-PACK kit, and identified the reactive molecules by Western blotting. A band of approximately M(r) 50,000 was found to be common to samples from both humans and the tamarins. Minimal binding was observed with NCA antibody. We conclude that a CEA-like molecule shared by humans and tamarins may play a role in the pathogenesis of colitis and cancer in both species.

Genetic epidemiology of colon cancer in the cotton-top tamarin (Saguinus oedipus).

Colon cancer is known to be heritable in humans, but the opportunity to investigate the genetic epidemiology of cancer in nonhuman primates has been limited by the size of available populations. The cotton-top tamarin (Saguinus oedipus) colony at the Oak Ridge Associated Universities (ORAU) Marmoset Research Center is a large population with a high rate of spontaneous colon cancer that has been monitored over several years, thus allowing investigation of the genetic basis for colon cancer in this colony. The presence of colon cancer at death was scored in 392 necropsies at the colony. Genealogical and demographic data for these animals were obtained from colony records. The heritability of the liability to colon cancer was estimated using maximum-likelihood-based pedigree analyses after evaluating the effects of gender, origin (wild-born or laboratory-born), and age at death on cancer experience. Cancer rates were not significantly different between males and females or between wild- and laboratory-born animals. Differences in age at death were also statistically insignificant for both laboratory- and wild-born animals. The heritability estimate for the liability to contract colon cancer is 17% for the ORAU cotton-top tamarins. This heritability estimate is not significantly different from zero, indicating no evidence for heritable variation in cancer experience in this population. If genetic factors affect cotton-top tamarin colon cancer, they are fixed or nearly fixed in this population.

Anti-colitic efficacy of SC-41930 in colitic cotton-top tamarins.

To evaluate anti-colitic efficacy, eight cotton-top tamarins (CTTs) with histologically confirmed persistent active colitis were given the anti-inflammatory agent SC-41930 (10 mg/kg BW by gavage BID) for eight weeks. Colonic endoscopy and biopsy observations, CBCs and clinical chemistries, and stool consistency were evaluated pre-, mid-, and posttreatment. Colitic activity was graded histologically from A1 (mild) to A5 (severe); results varied among the seven animals that completed the study: five improved, one worsened, and one was unchanged. Serum enzyme levels were significantly reduced with treatment. Stool condition remained puddly throughout treatment and body weights did not vary from pretreatment levels. However, SC-41930 produced histological evidence (reduced numbers of polymorphonuclear cells) of anti-colitic efficacy over an eight-week treatment period in CTTs with persistent active colitis. These results support the use of the CTT colitis model to evaluate efficacy of therapeutic agents and provide useful predictive information to aid in the medical management of human IBD.

Inflammatory mediator changes in cotton-top tamarins (CTT) after SC-41930 anti-colitic therapy.

Use of the CTT model provides insight into the inflammatory mediator contribution in the pathogenesis of idiopathic colitis. To evaluate anti-colitic efficacy, the leukotriene B4 receptor antagonist and anti-inflammatory agent, SC-41930, was administered (10 mg/kg BW by gavage BID) for 8 weeks to CTTs with histologically confirmed persistent and defined active colitis. The inflammatory mediators LTB4, PGE2, TXB2, and PAF were assayed in colonic dialysate that was collected after 1 1/2 h from four CTTs pre-, mid-, and post-treatment, frozen at -70 degrees C, and analyzed by RIA after HPLC purification. LTB4 levels were lower at mid- and post-treatment and had little inter-animal variation post-treatment. PGE2 and PAF levels were elevated during SC-41930 treatment, but there was a trend towards lower thromboxane B2 levels. Reduced LTB4 (PMN degranulation and chemotaxis) and increased PGE2 (mucosal-protective effect) may, in part, explain the observed efficacy of SC-41930 in active tamarin colitis.

Mr 40,000 human colonic epithelial protein expression in colonic mucosa and presence of circulating anti-Mr 40,000 antibodies in cotton top tamarins with spontaneous colitis.

Saguinus oedipus, Callithrix jacchus, and Saguinus fuscicollis are three species of New World monkeys which develop a form of colitis that is similar to human ulcerative colitis. Only S oedipus, however, develop colon cancer. We examined intestinal tissues from these animals for the presence of an antigen cross reacting to the Mr 40,000 human colonic epithelial protein that acts as an autoantigen in ulcerative colitis. Using an anti-Mr 40,000 monoclonal antibody (7E12H12, IgM isotype), by an immunoperoxidase assay we showed that all colon specimens from S oedipus reacted with 7E12H12; however, the colonic tissue from C jacchus and S fuscicollis did not. In immunotransblot analysis eluted IgG antibody bound to human ulcerative colitis colon (CCA-IgG) reacted with Mr 40,000 protein(s) present in the extracts of colon from S oedipus animals and humans. Small intestinal tissue reacted neither with 7E12H12 nor with CCA-IgG. In S oedipus, the Mr 40,000 protein was localised exclusively to colonic epithelial cells. Preincubation of seven S oedipus colon specimens with eight of 10 sera from animals with acute or chronic colitis and 0 of four sera from animals without colitis almost completely inhibited the binding of 7E12H12 to the colonic epithelium. Four of these 10 sera inhibited the binding of 7E12H12 to the autologous colon. These results show the presence of circulating autoantibodies in S oedipus with colitis against an epitope(s) on Mr 40,000 protein shared by human and S oedipus colon.

Inflammatory mediators in cotton-top tamarins (CTT) with acute and chronic colitis.

Spontaneous colitis in CTT's presents cytological characteristics similar to chronic ulcerative colitis in humans, e.g. inflammatory cell infiltrate and crypt abscesses. To better characterize CTT colitis as a potential model for human inflammatory bowel disease (IBD), inflammatory mediators identified in colonic tissue of human IBD patients and/or experimental colitis models were assayed. Inflammatory mediator changes in plasma and colon from tamarins with acute (n = 10) and chronic (n = 10) colitis (by mucosal biopsy) were assayed by RIAs. Similar inflammatory mediators were found in the CTT's with acute colitis. In the plasma, PAF and PGE2 levels were lower in acute colitis CTT's, no LTB4 was detected, and histamine levels were not different from chronic colitic animals. In the colon, myeloperoxidase and interleukin-1 beta were significantly higher in acute colitis, PGE2 and LTB4 were higher but not significantly, and PAF was not different from chronic CTT's. These data suggest that a combination of events are occurring in the pathogenesis of tamarin colitis that involves some of the same mediators that are found in the human disease and in other experimental models. The importance of these findings to human IBD remains for further investigation; however, the spontaneous primate model offers an exciting approximation of the disease development and merits further investigation for understanding the pathogenesis of human IBD as well as to aid in development of targeted therapeutics.

Analysis of T lymphocyte subsets in tamarins with colitis and colon cancer.

The cotton-top tamarin, Saguinus oedipus, serves as an animal model for the study of human colon cancer. This New World monkey has a high incidence of colitis and colon cancer that develops spontaneously. Evidence suggests that these diseases may be the result of a virally induced immunodeficiency. We have shown that T4+/T8+ cell ratios are significantly altered in tamarins with acute colitis and colon cancers. The T4+/T8+ ratios were 1.50 +/- 0.09, 0.70 +/- 0.05, and 0.48 +/- 0.05 for negative controls, acute colitis, and cancer positive tamarins, respectively. Statistical analysis showed a significant difference (p less than or equal to .0005) between negative controls vs. acute colitis and cancer positive groups.

Maintenance of cotton-top tamarins fed an experimental pelleted diet versus a highly diverse sweetened diet.

The future study of colon disease in captive callitrichid colonies may require manipulation of diets. The limited knowledge of the nutritional requirements for these species and the varied diets and supplementations fed to these animals in various colonies suggest the importance of testing the palatability and acceptability of diets for these primates. Individually housed cotton-top tamarins (Saguinus oedipus) were given either the regular Oak Ridge Associated Universities (ORAU) diet (monkey chow slurry, canned diet and supplements), a similar slurry using an experimental natural ingredient diet plus supplements, or the experimental diet without supplements. Neither dry food consumption, body weight, fecal output, nor the histological evaluation of the colons were affected by these diets. Daily intake of protein and calories were higher than previously reported estimates for the species. These results demonstrate that a natural ingredient non-sweetened pelleted diet is palatable for cotton-top tamarins for a period of 3.5 months, however, further testing over longer time periods is necessary. The nonnutritional (e.g. psychological) advantages of providing a highly diverse diet to primates housed in a relatively monotonous environment should be considered before adopting such a diet for an entire colony.

Colon cancer cells in peripheral blood of cancerous tamarins.

Diagnosing colon cancer in its early stages would lower the mortality rate. The cotton-top tamarin, Saguinus oedipus, serves as a model for the study of human colon cancer. This New World monkey has a high incidence of colitis and colon cancer. The mouse anti-human monoclonal antibody BR55.2, with specificity for human colon adenocarcinoma, was biotinylated. Peripheral blood mononuclear cells (PBMC) from animals with colon cancer were fluorescently stained with the biotinylated BR55.2. These results showed the cross-reactivity of mouse anti-human colon cancer monoclonal antibody to the PBMC of cancerous tamarins. Antibodies from either cancerous or chronic colitis tamarins were also biotinylated. Fluorescently labeled cells were detected when PBMC from cancerous tamarins were incubated with biotinylated antibodies from cancerous tamarins. Cytofluorographic analysis also showed a significant 4.5-fold difference in the percentage of fluorescently labeled PBMC between cancerous and chronic colitis tamarins when stained with biotinylated antibodies from cancerous tamarins. DNA flow cytometry analysis showed that PBMC from cancerous tamarins have a higher percentage of aneuploid cells than PBMC from chronic colitis tamarins.

Effect of various biological factors on spontaneous marmoset and tamarin colitis. A retrospective histopathologic study.

Histological sections of colons from 69 tamarins (46 Saguinus oedipus and 23 Saguinus fuscicollis illigeri) and 27 marmosets (Callithrix jacchus) that died between 1979 and 1984 were examined for colitis. Evaluated biological factors were species, age at death, source of animals, manner of death, presence of colon cancer, and time after importation. Most normal colons were found in young animals (dead at less than 1 years of age). Nearly all (approximately 96%) animals had colitis; 70-80% of most groups were graded as chronic colitis. Usually, one grade adequately described the condition of the entire colon. The strongest observed correlation of factors (P less than 0.05) was between acute colitis and colon cancer in S. oedipus. A higher percentage of S. oedipus had acute colitis than did the other two species. When colitis incidence data were adjusted for S. oedipus with colon cancer, there were no observed species differences between colons of colony-born and imported animals nor between those that died naturally and those that were euthanized. In an additional group of 18 S. oedipus that were imported in 1975, acute colitis was found in 60% of those dying immediately after importation (less than 1 year of colony age) and those that survived greater than 3 years. At this time, no causative agent has been identified in marmoset colitis.

Visualization and biopsy of the colon in tamarins and marmosets by endoscopy.

Endoscopic visualization and biopsy have been performed under anesthesia in more than 65 tamarins and marmosets to study the pathogenesis of colitis and cancer of the colon. This procedure allows examination of the large bowel from the anus to the cecum and has been repeated at 2-6 month intervals with few complications. However, care must be exercised not to perforate the colon. Successful use of this technique will permit study of the pathogenesis of colonic diseases throughout the life of the animal and should provide cause-effect information about colitis and colon cancer in tamarins that may apply to the human diseases.

Glycoconjugates in the colons of New World monkeys with spontaneous colitis. Association between inflammation and neoplasia.

A spontaneously occurring experimental model of chronic colitis has been described in three closely related species of New World monkeys. One species, Saguinus oedipus oedipus, has the additional feature of developing adenocarcinoma of the colon in this setting. Pathological and lectin histochemistry studies were undertaken in 50 such colonic specimens to determine if pathological or histochemical features were associated with the concomitant development of cancer. Chronic inflammation was found in all of the colons examined, and 14% had features of acute inflammation, which was significantly associated with those animals that developed cancer. An oncofetal glycoconjugate structure has been defined in human colons by the ability to bind peanut lectin. A similar glycoconjugate, probably a mucin, was expressed in the colons of 65% of these animals. A marked degree of expression of the mucin was significantly associated with those animals that developed cancer. A highly significant association was found between the presence of acute inflammation and the expression of the mucin. These studies demonstrate similarities in glycoconjugate expression between the human colon and the New World monkey model of spontaneous colitis. A form of mucin is expressed in these animals that is highly associated with both the presence of acute inflammation and the development of cancer elsewhere in the colon. In addition, an association between acute inflammatory activity and neoplasia was found, suggesting a potential etiologic linkage between the two.

Effects of chronic topical application of 12-O-tetradecanoylphorbol-13-acetate on the skin and internal organs of SENCAR mice.

Repetitive topical applications of 2 micrograms 12-O-tetradecanoylphorbol-13-acetate (TPA) twice weekly for 37 to 52 weeks induced a sustained epidermal hyperplasia, hyperplasia of hair follicles, and increased dermal cellularity in SENCAR mice. In addition, after 52 weeks of protracted promoter treatment most animals developed generalized amyloidosis involving liver and spleen, as well as interstitial nephritis. Severe pyelonephritis and papillary necrosis were also frequently seen. Reactive lymphoid hyperplasia was also a frequent finding. Chronic administration of TPA is not an innocuous treatment affecting only the interfollicular epidermis. The general effect of the promoter on the animals was a marked decrease in their longevity, probably through impairment of the immune system.

Patterns of cell proliferation during recovery from oxygen injury. Species differences.

Do rats, mice, hamsters, and marmosets respond differently to acute lung injury? Animals of each species were exposed to 100% oxygen for 48 h, then osmotic pumps, which released 3H-thymidine for a 1-wk period, were implanted. The labeling index (LI) (cells labeled/total cells counted) was increased in all 4 species. Repair in rats was manifested by a high LI, dominated by endothelial cell proliferation. Mice and hamsters had a lower LI, which was dominated by type II pneumocyte proliferation in mice, whereas in hamsters, macrophages and pneumocytes proliferated. The pattern of cell proliferation in marmosets most resembled that seen in mice.

Histology of colon cancer in Saguinus oedipus oedipus.

Diagnosis of colon cancer in tamarins often requires histologic (microscopic) inspection of the entire colon before minute primary sites can be located in the flat colonic mucosa. In other cases the cancer is easily recognized grossly because infiltration produces local desmoplastic reactions. The cancer does not have a preceding benign polypoid stage. The carcinoma is most typically poorly differentiated. The PAS stain, however, demonstrates that some of the malignant cells always produce mucin. With other special stains and electron microscopy, undifferentiated stem cells, mitochondria-rich absorptive cells, and cells rich in argentaffin granules are demonstrated. Most commonly the carcinomatous cells are distributed in structureless masses, but occasionally they form tubular structures that resemble glands. Preneoplastic epithelial changes in the crypts are disguised by epithelial hyperplastic (reparative) changes without hyperchromatic nuclear changes. Nuclear pleomorphism and enlarged nuclear/cytoplasmic ratios are commonplace in nonmalignant as well as malignant cells. All colon cancers found in this species arise in association with a pre-existing, chronic ulcerating colitis.