Microbial products from probiotic bacteria inhibit Salmonella enteritidis 857-induced IL-8 synthesis in Caco-2 cells.

Oral administration of Lactobacillus spp. as probiotics is gaining importance in the treatment of intestinal inflammations. However, their mechanism of action is unknown. We investigated whether nonspecific binding Lactobacillus casei Shirota (LcS) and mannose-specific Lactobacillus plantarum 299v (Lp) and their spent culture supernatant (SCS) affect Salmonella enteritidis 857 (Se) growth, IL-8 and Hsp70 syntheses. In one set of experiments human enterocyte-like Caco-2 cells were infected with LcS, Lp or Se at 1-500 bacteria per cell for 1 h. In another set, cells were exposed to Se (0-200 per cell, 1 h) after exposure to lactobacilli (LB) (500 per cell, 30 min) or by co-incubation of Se and LB (1 h). The third set of experiments involved exposure of cells for 1 h to SCS or Se (100 per cell) pretreated (1 h) in SCS. The effect of LB SCS on Se growth was evaluated by agar plate diffusion test. IL-8 and Hsp70 were assessed over 2-24 h using ELISA and Western blotting, respectively. Neither LcS nor Lp affected the Se growth and IL-8 production. In addition, they did not induce Hsp70 expression by Caco-2 cells. Instead, their SCS inhibited the Se growth and IL-8 production and induced the expression of Hsp70 by both crypt- and villus-like cells. The beneficial effect of Lactobacillus spp. to the intestinal inflammations might be associated with a decrease in IL-8 levels. This effect could be mediated, at least in part, via a secreted antimicrobial product(s) either directly against the pathogens or indirectly through the synthesis of Hsp70.

Anti-inflammatory properties of probiotic bacteria on Salmonella-induced IL-8 synthesis in enterocyte-like Caco-2 cells.

Invasion of the gut by pathogenic Salmonella leads to production of IL-8 that initiates inflammatory reactions to combat the bacterium. However, its persistent production causes tissue damage and interventions that suppress IL-8 production prevent tissue damage. We hypothesised that probiotics could mediate their benefits via inhibition of IL-8 synthesis. Caco-2 cells were infected with probiotic Bifidobacterium infantis W52, Lactobacillus casei W56, Lactococcus lactis W58, Lactobacillus acidophilus W70, Bifidobacterium bifidum W23, or Lactobacillus salivarius W24 or pathogenic Salmonella enterica serovar Enteritidis 857 at 0, 0.2, 1, 2, 10, 20, 100 or 200 bacterial cells/Caco-2 cell for 1 hour. Cells were also exposed to a combination of one probiotic bacterium (200 bacterial cells/Caco-2 cell) and the graded numbers of Salmonella as either co-incubation (1 hour) or pre-incubation of the probiotic bacterium (1 hour) followed by Salmonella (1 hour). The cells recovered for 2 or 24 hours. IL-8 and Hsp70 were determined by ELISA and Western blot respectively. Both probiotics and Salmonella induced a dose- and time-dependent synthesis of IL-8 but probiotics induced far lower IL-8 levels than Salmonella. The Salmonella-induced IL-8 was significantly suppressed by B. infantis W52, L. casei W56 and L. lactis W58 at low numbers of Salmonella (0.2 to 20 bacterial cells/Caco-2 cell) and within 2 hours of recovery. The observed probiotic-mediated reduction in IL-8 secretion was transient, and lost after a few hours. In addition, these three probiotics induced a significant increase in Hsp70 expression while L. acidophilus W70, B. bifidum W23 and L. salivarius W24 induced a weak Hsp70 expression and could not suppress the Salmonella-induced IL-8 synthesis. We conclude that suppression of Salmonella-induced IL-8 synthesis by Caco-2 cells is exhibited by probiotics that induce expression of Hsp70, suggesting that the protective role of probiotics could be mediated, at least in part, via Hsp70 expression. This suppression is limited to a low number of infecting pathogenic Salmonella.

Interference of Salmonella enteritidis and Lactobacillus spp. with IL-8 levels and transepithelial electrical resistance of enterocyte-like Caco-2 cells.

Caco-2 cells (exhibiting characteristics of mature villus enterocytes) were used to determine bacteria (Salmonella enteritidis causing human gastroenteritis)-intestinal cell interactions. The interference of bacteria with the transepithelial electrical resistance (TEER) of filter-grown Caco-2 cells and the production of IL-8 after exposure of the cells to S. enteritidis 857 and/or Lactobacillus strains (L. gasseri LF221 and L. rhamnosus BGT10) was evaluated. The strain 857 decreased TEER of filter-grown Caco-2 cells; in contrast, lactobacilli had a little or no effect. The effect of S. enteritidis on the TEER decreased if Caco-2 cells were pre-incubated with lactobacilli. This strain induced high levels of IL-8 (which can lead to cell damage). Compared to the IL-8 synthesis after exposure of Caco-2 cells to S. enteritidis 857, simultaneous exposure of Caco-2 cells to S. enteritidis and lactobacilli inhibited the IL-8 synthesis after short recovery periods.

Anti-inflammatory properties of heat shock protein 70 and butyrate on Salmonella-induced interleukin-8 secretion in enterocyte-like Caco-2 cells.

Intestinal epithelial cells secrete the chemokine interleukin (IL)-8 in the course of inflammation. Because heat shock proteins (Hsps) and butyrate confer protection to enterocytes, we investigated whether they modulate Salmonella enterica serovar Enteritidis (S. serovar Enteritidis)-induced secretion of IL-8 in enterocyte-like Caco-2 cells. Caco-2 cells incubated with or without butyrate (0-20 m M, 48 h) were infected with S. serovar Enteritidis after (1 h at 42 degrees C, 6 h at 37 degrees C) or without prior heat shock (37 degrees C). Levels of Hsp70 production and IL-8 secretion were analysed using immunostaining of Western blots and enzyme-linked immunosorbent assay (ELISA), respectively. The cells secreted IL-8 in response to S. serovar Enteritidis and produced Hsp70 after heat shock or incubation with butyrate. The IL-8 secretion was inhibited by heat shock and butyrate concentrations as low as 0.2 m M for crypt-like and 1 m M for villous-like cells. In a dose-dependent manner, higher butyrate concentrations enhanced IL-8 secretion to maximal levels followed by a gradual but stable decline. This decline was associated with increasing production of Hsp70 and was more vivid in crypt-like cells. In addition, the higher concentrations abolished the heat shock inhibitory effect. Instead, they promoted the IL-8 production in heat-shocked cells even in the absence of S. serovar Enteritidis. We conclude that heat shock and low concentrations of butyrate inhibit IL-8 production by Caco-2 cells exposed to S. serovar Enteritidis. Higher butyrate concentrations stimulate the chemokine production and override the inhibitory effect of the heat shock. The IL-8 down-regulation could in part be mediated via production of Hsp70.

Evaluation of 99mTc-MAMA-chrysamine G as an in vivo probe for amyloidosis.

To date, systemic amyloidosis is diagnosed histologically using Congo red staining or in vivo using iodine-123 labelled serum amyloid P component (123I-SAP) scintigraphy. We developed 99mTc-MAMA-CG, a 99mTc-labelled derivative of the lipophilic Congo red analogue chrysamine G (CG), as a possible alternative to 123I-SAP. In vivo 99mTc-MAMA-CG scintigraphy, performed in chickens with spontaneous joint amyloidosis, resulted as soon as 10 min after injection in scintigraphic images showing uptake of activity in amyloid-loaded organs (liver, joints). One of these chickens was studied also with 123I-SAP resulting in scintigraphic images revealing 123I-SAP binding to amyloid deposits in the liver. However, up to 11 h after injection no radioactivity was visible in the amyloid positive joints. In vitro autoradiography, performed on sections of chicken joints with Enterococcus faecalis induced amyloid arthropathy (chjAA), demonstrated the failure of 99mTc-MAMA-CG to bind significantly to amyloid deposits in the presence of 10 microM Congo red The specificity of 99mTc-MAMA-CG localisation was also established by the absence of 99mTc-MAMA-CG binding in non-amyloidotic organs in vitro and in vivo. 99mTc-MAMA-CG did not show any sign of acute toxicity. These findings establish the usefulness of 99mTc-MAMA-CG as a non-invasive in vivo diagnostic probe in chickens with amyloid arthropathy and suggest that it may also be applicable to human amyloidosis.

Immunohistochemical investigation of the brain of aged dogs. I. Detection of neurofibrillary tangles and of 4-hydroxynonenal protein, an oxidative damage product, in senile plaques.

In the aging dog brain lesions develop spontaneously. They share some morphological characteristics with those of Alzheimer 's disease in man. Diffuse and primitive plaques are well known, whereas neuritic plaques rarely develop. Neurofibrillary tangles have not been seen in the canine. The aim of the present investigation was to study major age-related changes of the dog's brain using paraffin sections with respect to cross-immunoreactivity of tau, A beta protein and other immunoreactive components including hydroxynonenal protein, which is a marker for oxidative damage. The occurrence of neurofibrillary tangles and of the protein tau therein was studied in serial brain sections of two dogs with the Gallyas stain and by immunohistochemistry with three different antibodies against tau. Senile plaques were stained with a monoclonal anti-A beta (residues 8-17), polyclonal anti-apolipoprotein E and a monoclonal antibody against 4-hydroxynonenal (HNE). Amyloid deposits and controls were screened by Congo red staining viewed in fluorescent light, followed by polarized light for green birefringence. With the Gallyas stain and one of the antisera against tau, neurofibrillary tangles were revealed in a similar dispersed pattern, whereas the other antitau antisera gave negative results. With the anti-HNE a positive reaction was found in cerebral amyloid deposits and in vascular wall areas where amyloid deposition was confirmed by Congo-red staining, and in perivascular cells and in some neurons. These results indicate that the canine with his tangles and plaques which show oxidative changes, forms a spontaneous modelfor understanding the early changes and their interrelationships in Alzheimer's disease.

Leukocyte responses in two breeds of layer chicken that differ in susceptibility to induced amyloid arthropathy.

Amyloid arthropathy in chicken can be induced by intravenous inoculation of an arthropathic and amyloidogenic Enterococcus faecalis in susceptible breeds. The commercial brown layer hybrids (BL) are more susceptible to the disease compared to their white counterparts (WL). The precursor of amyloid-A protein, which is serum amyloid-A (SAA), is identical in WL and BL. To investigate the factors involved in the breed-restricted susceptibility to amyloid arthropathy, we studied the type of leukocyte response and inflammatory reactions in E. faecalis-induced disease. In the BL, a significant dose dependent peripheral leukocytosis mainly by heterophils, and plasma cell infiltration in arthritic joints was found. In contrast, secondary lymphoid nodular aggregates in the synovial membrane were prominent in the WL. The aggregates consisted mainly of CD8+ T cells. The high number of circulating leukocyte and prolific plasma cell responses in the BL predict extensive humoral and acute phase reactions. This is in agreement with literature data on suppressed T-cell function in casein-induced amyloid-susceptible mice strains. The difference in leukocyte response and type of inflammation between WL and BL, when arthropathic and amyloidogenic bacteria induce infection, in conjunction with susceptibility to amyloid arthropathy, is discussed in view of the murine T-helper responses.

Casein related amyloid, characterization of a new and unique amyloid protein isolated from bovine corpora amylacea.

Amyloid bodies can be found in mammary secretory tissue of various species. These corpora amylacea (CA) have a lamellated structure, contain amyloid fibrils and are predominantly located in the alveolar lumina. The nature of the amyloid was not known, but CA were suggested to originate either from milk casein or mammary alveolar epithelial keratin. In the present report, bovine CA were analyzed histochemically. Furthermore, CA were isolated, analyzed and the amyloid was purified and characterized by amino acid sequencing. CA amyloid appeared to be potassium permanganate sensitive and tryptophan positive, and in this respect different from most other amyloid types except for AA and beta-2 microglobulin amyloid. Gel filtration of purified amyloid fibrils showed a HMW peak and a major 4 kD peak. N-terminal amino acid sequencing showed the amyloid to consist of tryptic-like peptides with an unusually high content of amino acids with bulky side chains. The amyloid protein was identified as derived from alpha-S2-casein. The fragments are of varying length (32, 33 and 45 amino acids), but all start at position 81 of alpha-S2-casein. We have identified a new and unique amyloid protein, and we propose to designate it as A alpha-S2C according to the guidelines for amyloid nomenclature.

Familial amyloidosis in cats: Siamese and Abyssinian AA proteins differ in primary sequence and pattern of deposition.

Familial AA amyloidosis is a hereditary trait in Abyssinian cats, with the kidney as the main target organ. The amino acid sequence of the amyloid A protein of the Abyssinian cat has been described earlier. Recently, familial amyloidosis has been found in Siamese cats, with the liver as the main target organ. In the present paper, we describe the complete amino amid sequence of the major constituent protein, of two Siamese cats. Siamese hepatic protein AA showed homology with, but was different from all feline SAA and AA sequences hitherto reported. Two substitutions (46Q-R and 52A-V) from the Abyssinian protein sequence were identified, one of which (46Q-R) is a non-homologous substitution not found in mammalian SAA, but is present in two bird AA amyloid proteins. This shows the presence of an unique amyloidogenic SAA isotype in Siamese cats. Both the Siamese and the Abyssinian sequence are amyloidogenic, thus making identification of amyloidogenic residues difficult. Apart from the apparent inherent amyloidogenicity of SAA, it can not be excluded that certain amino acid substitutions could enhance its amyloidogenicity but also could contribute to tissue predilection in amyloidosis.

Polyarthritis and periostitis induced by Escherichia coli. Lipopolysaccharide injection in young male hamsters.

OBJECTIVE: To describe the clinicopathological manifestations of lipopolysaccharide (LPS) induced arthritis in the hamster and to compare its time of onset, duration, and severity with other forms of experimentally induced arthritis. METHODS: A preparation containing 30 microg LPS from Escherichia coli was injected subcutaneously for 5 to 21 days into young male hamsters (Mesocricetus auratus). Arthritis was quantified by measuring soft tissue swelling of affected joints with calipers. After decalcification, paraffin sections were cut and stained with hematoxylin and eosin, Giemsa, and azan. Acute phase reactant apolipoprotein serum amyloid A (apoSAA) levels were determined by ELISA. RESULTS: Symmetrical polyarthritis developed within 3 days and persisted for 14-21 days, provided the hamsters received daily LPS injections. Most prominent were lesions in the carpal-metacarpal joints of the front legs and in the tarsal-metatarsal joints of the hind legs. Animals in whom LPS injections were discontinued after 4 or 7 days recovered completely. Histological findings of exudative synovitis, periarticular soft tissue swelling, and juxtaarticular periostitis were associated with a sharp rise in serum titers of apoSAA. CONCLUSION: The unusually rapid onset of arthritis and periostitis in this experimental animal model suggests that its systemic manifestations were not mediated by a classical immune response, and may represent an "innate" response of targeted cells within the synovial membrane and periosteum to bacterial cell wall endotoxins.

The role of various agents in chicken amyloid arthropathy.

The results of an inventory of field cases of amyloid arthropathy in chickens and of routine post-mortem recordings over a two years period are described. Studies were also performed to evaluate the amyloidogenic potential of arthrotropic bacterial species (Staphylococcus aureus, Escherichia coli and Salmonella enteritidis) isolated from chickens as well as several Enterococcus faecalis isolates compared to the amyloidogenic E. faecalis isolate (previously isolated from amyloidotic joints). As chicken anemia virus was also isolated from amyloidotic joints of field cases, it was also screened for its amyloidogenic potential. In another experiment, Mycoplasma synoviae, inactivated E. faecalis isolate 6085.94, Freund's adjuvant and an arthrotropic reovirus field isolate were also screened for amyloidogenicity by intra-articular injection. These studies showed that the ability to elicit extensive amyloid arthropathy is reserved primarily to E. faecalis, but that this property is not common to every E. faecalis isolate. Intra-articular application of complete Freund's adjuvant led to the formation of extensive joint amyloid deposits. Of the other micro-organisms studied, S. aureus, S. enteritidis and E. coli were also able to cause joint amyloidosis, but in very small amounts. Inactivated E. faecalis, chicken anemia virus and reovirus did not cause amyloid arthropathy after intra-articular inoculation. This study is consistent with results of the analyses of previous field cases and of the induction of amyloid arthropathy in chickens, suggesting a considerable role for E. faecalis in this clinical-pathological entity. Finally, strain typing by analysis of chromosomal DNA restriction endonuclease digests by pulsed-field gel electrophoresis (PFGE) of amyloidogenic, non-amyloidogenic, amyloid-associated and other E. faecalis isolates from various origins showed that all amyloidogenic and amyloid-associated E. faecalis isolates had similar restriction digests, suggesting clonal spread.

Light microscopic, immunohistochemical, and electron microscopic features of amyloid arthropathy in chickens.

Amyloid arthropathy has been recently recognized as a spontaneous syndrome in chickens. Predominantly, femorotibial and tarsometatarsal joints were affected, showing (peri) articular orange amyloid deposits. Immunohistochemical evaluation revealed the amyloid to be of the reactive type. Induction of amyloid arthropathy in chickens was carried out using a single intravenous injection of Enterococcus faecalis cultures. In the naturally occurring and the induced cases, amyloid deposits were found in the hypertrophic synovial villi and in the articular cartilage, particularly in the superficial layer and in the nutritional blood vessel walls. Highly sulfated glycosaminoglycans (GAGs) were found in the amyloid deposits. Ultrastructurally, bundles of amyloid fibrils were seen in invaginations of synoviocytes and chondrocytes. Immunogold electron microscopy failed to reveal signs of intracellular amyloid formation. The predilection site for amyloid deposition in the major leg joints of the chickens with reactive amyloid could be explained by the arthritic condition caused by Enterococcus faecalis bacteriaemia. The polyarthritis triggers hepatic acute phase protein synthesis and increases the vascular serum amyloid A (SAA) supply to the joint. Inflammatory and degenerative changes in the articular cartilage and adjoining tissues result in an increase of highly sulphated GAGs, which are considered to enhance deposition of SAA as amyloid.

Generalized AA-amyloidosis in Siamese and Oriental cats.

During a 7 year period (1987-1994), 194 Siamese cats including a colour variant designated Oriental cat, were presented for post-mortem examination. Twelve of these animals (6.2%) were diagnosed with amyloidosis. Major gross pathological findings included enlarged pale livers with haemorrhages, pale and swollen spleens, and dilated intestines. Deposits of amyloid were found in these tissues. The amyloid was found to cross-react with anti dog AA-antiserum when examined with peroxidase antiperoxidase (PAP) staining (four cases). Amyloid fibrils were purified by the water extraction method and its major constituting protein (AA) was isolated by gel filtration. Amino acid sequence analysis of this protein from a Siamese cat and an Abyssinian cat revealed a significant difference between these breeds. In the Siamese protein AA two amino acid substitutions (46 R for Q and 52 V for A) were encountered. This finding indicates the existence of a new feline amyloid A protein occurring in the Siamese breed which differs from presently known (apoS)AA-proteins. Additionally, the pedigree analysis of affected cats suggests a familial trait.

Characterisation of the acute phase response of heifers to a prolonged low dose infusion of lipopolysaccharide.

The effect of a prolonged low dose infusion of bacterial lipopolysaccharide (LPS) on acute phase-like reactions was examined in heifers. LPS (2 micrograms kg-1 dissolved in 100 ml water), or saline was infused (at 1 ml min-1) intravenously for 100 minutes and blood samples were taken at various times before, during and after the infusion. The serum concentrations of tumour necrosis factor-alpha (TNF alpha), interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and serum amyloid A (SAA) and the rectal temperature increased in response to the LPS infusion. Serum TNF alpha increased before the increases in IL-1 beta and IL-6 and remained high from 20 minutes after the onset of the infusion until the end of the sampling period (six hours). The LPS-induced increases in serum IL-1 beta and IL-6 were biphasic. Plasma cortisol and lactate concentrations also increased, and plasma glucose and beta-hydroxybutyrate concentrations decreased in response to the LPS infusion. The similarity of these reactions to changes observed in response to bacterial infections shows that the prolonged infusion of low doses of LPS is a good model for studying the acute phase response to Gram-negative bacterial infection in heifers.

Chicken joint amyloid protein is of the AA-type. I. Characterization of the amyloid protein.

Amyloid fibrils were extracted from deposits in joint tissue of heavy breed layers with spontaneous amyloid arthropathy and characterized as being of the AA-type. Amino acid sequencing revealed a pattern quite similar to duck AA. Acute phase sera of chicken experimentally injected with Enterococcus faecalis showed a SAA-protein like band cross reacting with anti-chicken AA in immunoblot.

Lung, ileum and heart are predilection sites for AApoAII amyloid deposition in CD-1 Swiss mice used for toxicity studies. Pulmonary amyloid indicates AApoAII.

Amyloid deposits represent frequent histological findings in SPF strains of mice mainly used for toxicological studies. Usually, these are deposits of reactive amyloid (AA-amyloid) derived from the acute phase protein serum amyloid A (SAA). The SAA is an apoprotein of high density lipoprotein (apoSAA). Senescence-accelerated amyloid (ASsam) occurs in a special strain of mice. This type of amyloid is derived from apolipoprotein-AII and, therefore, is called AApoAII. Recently, C57B1/Ka control mice not treated for long duration with immunosuppressive agents, were found to have developed AApoAII-amyloidosis with a predilection for the deposits in the ileum (HogenEsch et al. 1993). In the present study, SPF CD-1 Swiss outbred mice, used for chronic toxicity experiments, were investigated. Amyloidosis was diagnosed by haematoxylin and eosin staining. The tissue localization of amyloid was recorded and confirmed by Congo red staining. The chemical type of amyloid was investigated by peroxidase antiperoxidase (PAP)-immunostaining using anti-murine AA and anti-murine AApoAII antibodies. Those animals which died during the study and the mice killed at end of the experiment, aged 18 months, from treated as well as non-treated control groups, showed AApoAII-amyloid deposits with similar prevalence. The AApoAII amyloid had organ predilection for gut, heart and lung tissue. A group of animals was euthanazed intercurrently at a young age, since they suffered from spontaneous dermatitis associated with Staphylococcus aureus infection. Sixty-eight percent had reactive amyloid deposits found primarily in spleen, liver, kidney and gut. From these findings and literature data on various other mouse strains, it is concluded that in mice used for toxicity studies, AA and AApoAII types of amyloidosis may be expected. The deposition patterns of these types of amyloid are slightly different. AA-amyloid has a predilection for spleen, liver, gut and kidney, and is often associated with inflammatory lesions of the skin, whereas masses of amyloid in lung, heart and ileum suggest AApoAII. Pulmonary amyloid appears to represent the most reliable deposition criterion for discriminating between both types of amyloidosis.

First evidence for the existence of multiple isoforms of bovine serum amyloid-A (apoSAA).

Bovine serum amyloid-A (SAA) was purified from acute-phase high density lipoprotein (HDL) by affinity chromatography and subsequent gel filtration chromatography. The identity of the isolated protein was checked by Western blotting following SDS-urea-PAGE using antisera raised against the purified protein fraction (SAA) and Amyloid A (AA). The antiserum raised against the purified SAA stained Congo red positive regions in the kidney of an AA-amyloidotic cow and reacted on Western blot with an AA-related protein of approximately 14 kDa. Moreover, it immunostained two to three bands, of approximately 14 kDa, present in serum from diseased cows, proportionally to the serum SAA concentration as measured by ELISA. Isoelectric focusing of the purified bovine SAA fraction revealed three major (pI 5.5, 6.0, 6.4) and three minor (pI 4.8, 5.0, 7.3) isoforms and two-dimensional SDS-urea-PAGE confirmed the identity of the major isoforms. Isoelectric focusing of SAA isolated from sera, obtained from cows affected with different diseases, showed a variable ratio of the isoforms. In SAA isolated from serum obtained from a cow suffering from spontaneous AA-amyloidosis only one isoform (pI 4.8) was detectable. It is concluded that the results give first evidence for the existence of multiple isoforms of bovine SAA, occurring in different plasma concentration ratios during different diseases.

Effect of voluntary exercise and food restriction in response to lipopolysaccharide in hamsters.

We tested the hypothesis that voluntary running and moderate food restriction alter the acute phase response (APR), one index of nonspecific immune function. Hamsters were kept sedentary or permitted to run and were fed ad libitum or had food restricted for 20 days and were then injected intraperitoneally with saline or lipopolysaccharide (LPS). Fever and circulating interleukin-6, serum amyloid A (SAA), serum iron, and cortisol were measured by biotelemetry, B-9 cell growth assay, indirect enzyme-linked immunosorbent assay, colorimetric analysis, and radioimmunoassay, respectively. The febrile temperature; hypoferremia; and elevation of circulating interleukin-6, SAA, and cortisol after LPS injection were not altered by exercise. Because baseline temperatures were elevated in the exercised hamsters, the change in temperature in response to LPS was less than it was in the sedentary hamsters. Food restriction significantly decreased SAA and elevated cortisol after LPS injection and depressed the absolute temperature to which the core temperature rose in response to LPS in one trial but not in another. Because food restriction depressed baseline temperatures, it also affected the change in temperature after LPS injection. The hypoferremic response to LPS was inhibited in hamsters that were both food restricted and permitted to run. We conclude that exercise does not enhance the APR to a low dose of LPS, whereas food restriction and the combination of exercise and food restriction depress some portions of the APR in hamsters.

Effect of exercise and food restriction on selected markers of the acute phase response in hamsters.

Acute aerobic exercise has been shown to elicit physiological changes characteristic of the acute phase response (APR), a nonspecific host defense response. Regular evocation of these changes may prime the immune system to improve resistance to disease. Because food deprivation is associated with an impaired APR, food restriction may prevent these beneficial changes. We tested the hypotheses that voluntary exercise elicits an APR and that food restriction modifies this response in four groups of hamsters: ad libitum-fed sedentary, ad libitum-fed exercised, food-restricted sedentary, and food-restricted exercised. Five variables altered during an APR were examined: core temperature, serum iron, serum interleukin-6, serum amyloid A, and serum glucocorticoids measured by biotelemetry, colorimetric analysis, B-9 cell growth assay, indirect enzyme-linked immunosorbent assay, and radioimmunoassay, respectively. Blood was drawn during the hamsters' inactive period after 19-20 days of access to running wheels. Resting core temperature was elevated by exercise and depressed by food restriction (P < 0.01). Iron was depressed by food restriction (P < 0.01). Cortisol, but not corticosterone, was elevated by food restriction (P < 0.001). There were no significant differences among groups in interleukin-6 (P > 0.49) or serum amyloid A (P > 0.29). We conclude that there is little evidence that voluntary exercise or exercise combined with food restriction causes an APR in hamsters.

Gastrointestinal AAPOAII and systemic AA-amyloidosis in aged C57BL/Ka mice. Amyloid-type dependent effect of long-term immunosuppressive treatment.

The light microscopic and immunohistochemical features of a novel localized senile amyloidosis in the gastrointestinal tract of C57BL/Ka mice are described. Senile gastrointestinal amyloidosis was predominantly found in the lamina propria of the ileum, cecum and stomach and infrequently in other segments of the gastrointestinal tract. The Congo red affinity of the senile amyloid was sensitive to potassium permanganate pretreatment. The amyloid did not react with anti-AA and anti-immunoglobulin antisera, but stained positively for apoAII, a major apolipoprotein of high density lipoproteins. A similar type of amyloid, termed AApoAII, has recently been described in a systemic form of senile amyloidosis in mice. In the present study, we investigated the effect of long-term immunosuppressive treatment on the incidence of systemic AA-amyloidosis and gastrointestinal AApoAII-amyloidosis in aged C57BL/Ka mice. Gastrointestinal amyloidosis occurred in 60% of the control mice, but significantly less in mice of the immunosuppressed groups. In contrast, systemic AA-immunoreactive amyloidosis was only found in mice that were given immunosuppressive treatment. There was no codeposition of AA and AApoAII-amyloid. These findings indicate that immunosuppressive drugs have a profound effect on the incidence as well as the type of amyloidosis in C57BL/Ka mice.