Nutrition and cellular immunity

Animal Welfare Assessment Protocol for Does, Bucks, and Kit Rabbits Reared for Production

Rabbits are the third species in terms of number of animals reared for meat production in the world. However, in comparison to other species, very few studies have focused on their welfare. The aim of the present study is to implement an animal welfare-assessment protocol developed through a multidimensional approach and containing a number of animal-based measures for bucks, does, and kit rabbits. Thirty Spanish farms with conventional cages in the first year of integration in an animal welfare certification scheme were visited during 2019 and audited by the same auditor. The protocol is divided into four principles and 11 criteria. The Good Feeding principle includes eight parameters (one animal-based), Good Housing includes 15 parameters (six animal-based), Good Health includes 26 parameters (16 animal-based), and Appropriate Behavior contains nine parameters (four animal-based). In general, the main problems found were the absence of platforms, low space allowance and low height of the cage, inappropriate systems for performing emergency killing, insufficient protection of does from other adjacent does when housed individually, and absence of enrichment material. To a minor degree, but also found in an important number of farms, was a lack of temperature data records, high replacement rates of does, and lack of mortality-rate data records. However, in general, most of the farms obtained a good overall score, the maximum found being 73 out of 100 points. Nevertheless, none of the farms reached an excellent score, and four farms were scored below the 55 points required in the animal welfare certification scheme. The Good Feeding principle obtained the highest score, reaching excellent in all farms, and Appropriate Behavior the lowest one, with values ranging from 21 to 41 points out of 100. The results probably show how, for years, rabbit producers have been very focused on feeding needs and very little attention has been paid to behavioral needs.

Fidelity in Animal Modeling: Prerequisite for a Mechanistic Research Front Relevant to the Inflammatory Incompetence of Acute Pediatric Malnutrition

Inflammatory incompetence is characteristic of acute pediatric protein-energy malnutrition, but its underlying mechanisms remain obscure. Perhaps substantially because the research front lacks the driving force of a scholarly unifying hypothesis, it is adrift and research activity is declining. A body of animal-based research points to a unifying paradigm, the Tolerance Model, with some potential to offer coherence and a mechanistic impetus to the field. However, reasonable skepticism prevails regarding the relevance of animal models of acute pediatric malnutrition; consequently, the fundamental contributions of the animal-based component of this research front are largely overlooked. Design-related modifications to improve the relevance of animal modeling in this research front include, most notably, prioritizing essential features of pediatric malnutrition pathology rather than dietary minutiae specific to infants and children, selecting windows of experimental animal development that correspond to targeted stages of pediatric immunological ontogeny, and controlling for ontogeny-related confounders. In addition, important opportunities are presented by newer tools including the immunologically humanized mouse and outbred stocks exhibiting a magnitude of genetic heterogeneity comparable to that of human populations. Sound animal modeling is within our grasp to stimulate and support a mechanistic research front relevant to the immunological problems that accompany acute pediatric malnutrition.

T-helper 1 versus T-helper 2 lymphocyte immunodysregulation is the central factor in genesis of Burkitt lymphoma: hypothesis

BACKGROUND

The HIV epidemic has challenged our previous understanding of endemic Burkitt's lymphoma. Despite the strong association of Burkitt's lymphoma and HIV infection in the Developed world, and against previous postulations that the cancer is due to immunosupression among African children, the HIV epidemic in the Malaria belt has not been associated with a corresponding increase in incidence of childhood Burkitt's lymphoma. Even outside the context of HIV infection, there is substantial evidence for a strong but skewed immune response towards a TH2 response in genesis of Burkitt lymphoma.

PRESENTATION OF THE HYPOTHESIS

Rather than a global and/or profound immunosupression, the final common pathway in genesis of Burkitt's lymphoma is the dysregulation of the immune response towards a TH2 response dominated by B-lymphocytes, and the concomitant suppression of the TH1 cell-mediated immune surveillance, driven by various viral/parasitic/bacterial infections.

TESTING THE HYPOTHESIS

Case control studies comparing TH2 and TH1 immune responses in Burkitt lymphoma of different etiological types (sporadic, HIV-related, endemic and post-transplant) to demonstrate significant dominance of TH2 immune response in presence of poor CMI response as a common factor. Immunological profiling to evaluate differences between immune states that are associated (such as recurrent Malaria infection) and those that are not associated (such as severe protein-energy malnutrition) with Burkitt lymphoma. Prospective cohorts profiling chronology of immunological events leading to Burkitt lymphoma in children with EBV infection.

IMPLICATIONS OF THE HYPOTHESIS

The dysregulation of the immune response may be the missing link in our understanding of Burkitt lymphomagenesis. This will provide possibilities for determination of risk and for control of development of malignancy in individuals/populations exposed to the relevant infections.

Sarcopenia is predictive of nosocomial infection in care of the elderly

Protein-energy malnutrition and nosocomial infection (NI) are frequent in elderly patients, and a causal link between the two has often been suggested. The aim of the present study was to identify the nutritional parameters predictive of NI in elderly patients. We assessed on admission 101 patients (sixty-six women, thirty-five men, aged over 65 years) admitted to an acute care of the elderly department. Sarcopenia was detected by dual-energy X-ray absorptiometry, with appendicular skeletal muscle mass expressed with respect to body area. Weight, BMI, albuminaemia, serum transthyretin and C-reactive protein values were also determined on admission, and known risk factors, such as functional dependence and invasive biomedical material, were also evaluated. After up to 3 weeks of hospitalisation, patients were classified according to whether they had developed an NI. After 3 weeks of hospitalisation, we found that twenty-nine patients had suffered an NI, occurring after a mean of 16.1 d. Patients who were sarcopenic on admission had a significantly higher risk of contracting an NI (relative risk 2.1, 95 % CI 1.1, 3.8). None of the other morphometric or biological parameters differed significantly between the two groups of patients on admission. Patients who experienced an NI were also more likely, on admission, to have a medical device (P=0.02 to P=0.001 depending on the device), to have swallowing problems (P=0.002) or to have restricted autonomy (P<0.01). Sarcopenia on admission to an acute care of the elderly unit, as measured by X-ray absorptiometry, was therefore associated with a doubled risk of NI during the first 3 weeks of hospitalisation.

Histopathology of the thymus

The thymus is a primary lymphoid organ that manifests dynamic physiological changes as animals age in addition to being exquisitely sensitive to stress and toxic insult. It is typically the first lymphoid tissue to respond to immunotoxic xenobiotics, with the first change being loss of cortical lymphocytes by apoptosis. This is followed by removal of the apoptotic cellular debris and, in the absence of recovery, may lead to loss of the cortico-medullary demarcation and organ atrophy. Nonneoplastic proliferative changes include focal lymphoid hyperplasia and proliferation of medullary epithelial cells, often with formation of ribbons, cords, or tubules. Thymomas are relatively rare tumors that exhibit a wide spectrum of morphologic types but do not metastasize. Thymic lymphomas are common in some mouse strains and can become leukemic with hematogenous spread throughout the body.

Restraint stress alters lung gene expression in an experimental influenza A viral infection

In the present study the global effect of restraint stress on gene expression in the murine lung during an experimental influenza A/PR8 viral infection was examined. Gene expression profiling using high density oligonucleotide microarrays revealed that the expression of 95 genes was altered on day 3 post infection (p.i.), while 48 genes were altered on day 7 p.i. Restraint stress reduced and delayed the expression of specific cytokines, cell adhesion molecules and cell surface receptors indicating alterations in cell migration to the site of infection. Furthermore, mapping of the candidate genes to known pathways revealed that genes associated with host defense and immune responses, including chemotaxis and chemokine function, antigen presentation and processing, MHC class II receptor function and inflammation were the major pathways affected by restraint stress.

Expression of the pro-apoptotic gene gadd153/chop is elevated in liver with aging and sensitizes cells to oxidant injury

Aging is generally accompanied by reduced tolerance to oxidative stress and altered responsiveness to proliferative signals. We have shown that hepatocytes derived from aged rats (24-26 months) exhibit greater sensitivity to H(2)O(2) treatment and reduced proliferation following epidermal growth factor (EGF) treatment than cells of young adult rats (5-6 months). Here we examined the effects of aging and calorie restriction (CR) on expression of the oxidative stress-inducible and pro-apoptotic gene gadd153 (chop) in these hepatocytes, and we investigated its influence on sensitivity to oxidants. We show that aging was associated with elevated expression of gadd153, both basally and in response to H(2)O(2) treatment. CR, which attenuates age-associated declines in stress tolerance, prevented the age-related increase in gadd153 expression. EGF treatment also resulted in gadd153 induction in old cells. This effect was absent in young cells and in old cells of CR rats. gadd153 induction by EGF was reactive oxygen species-dependent and correlated with heightened sensitivity to subsequent H(2)O(2) treatment, suggesting that elevated Gadd153 contributes to the greater sensitivity of EGF-pretreated old cells to oxidative stress. Additional support for this hypothesis was provided by experiments with Rat1 fibroblasts in which conditional expression of Gadd153 conferred increased sensitivity to H(2)O(2). We propose a model whereby the diminished ability of old hepatocytes to overcome an EGF-triggered reactive oxygen species load leads to induction of the proapoptotic gene gadd153, which, in turn, sensitizes the cells to oxidant injury. Our findings point to gadd153 expression levels as an important factor in liver aging.

Acute-phase response and immunological markers in morbid obese patients and patients following adjustable gastric banding

OBJECTIVE

We measured markers of acute-phase response and immunological markers in morbid obese patients and in formerly morbid obese patients after a massive weight loss following adjustable gastric banding (GB).

SUBJECTS

A total of 49 morbid obese female patients with a body mass index (BMI) above 40 kg/m(2) were investigated during a study period of 6 months. Of these, 24 patients received a gastric banding (GB) and lost a minimum of 20 kg in 1 y (GB group) and 25 patients maintained their weight (obese group). In sum, 13 normal weight subjects (BMI<24 kg/m(2)) were taken for controls.

METHOD

Plasma concentration of the acute-phase proteins, C-reactive protein (CRP), orosomucoid, complement factors C3 and C4 and white blood cell count, lymphocyte subsets and serum immunoglobulins were analyzed.

RESULTS

Acute-phase proteins were significantly lower in GB compared to morbid obese patients and remained significantly elevated in GB compared to controls. In addition, leukocytes, polymorphonuclear leukocytes and lymphocytes were significantly lower after GB and reached levels comparable to controls (except PMN). No difference in CD3 counts was observed in the three groups. CD4 increased and CD8 decreased in obese and GB patients when compared to controls whereas no statistical difference was found between obese and GB patients.

CONCLUSION

Our results confirm the positive effect of GB followed by a massive weight loss without apparent malnutrition. Subclinical chronical inflammation in morbid obese patients leads to irregularities in leukocyte and lymphocyte subsets. These alterations can be positively influenced by GB.

Immunomodulation of experimental colitis via caloric restriction: role of Nk1.1+ T cells

Inflammatory bowel diseases are immune-mediated disorders. Dietary restriction and NK1.1+ liver-associated lymphocytes (LAL) are considered to be involved in immunomodulation of autoimmune diseases. Our aim was to evaluate the effect of caloric restriction on experimental colitis and to determine NK1.1+ LAL function in immunoregulation. Experimental colitis was induced in C57 black mice by intracolonic instillation of trinitrobenzene sulfonic acid. Caloric restriction to 60% of the daily requirement was started 2 weeks prior to, or simultaneously with, colitis induction and continued throughout the study. Control mice were fed ad libitum. Colitis was assessed by standard clinical and macroscopic scores. To determine the mechanism involved in immunomodulation, liver lymphocytes were isolated and analyzed for NK1.1+ T-cell markers by FACS. T-cell function was evaluated by T-cell proliferation. Serum cytokines were measured by ELISA. Dietary restriction to 60% markedly ameliorated experimental colitis in both groups. These mice gained weight and showed improved macroscopic parameters of colitis. NK1.1+ LAL numbers increased fourfold and NKT cytotoxicity twofold in caloric-restricted mice. The antigen-specific T-cell proliferation index decreased (from 4.45 in controls to 1.15), and IFN-gamma and IL-12 serum levels decreased (from 290 to 200 pg and from 122 to 53 pg, respectively) in caloric-restricted mice. Our conclusion was that dietary restriction induced immunomodulation of experimental colitis and ameliorated the disease. This effect was mediated via an increase in NK1.1+ T lymphocytes, which may play a critical role in keeping the T-cell balance in immunoregulation.

Immunotoxicity risks associated with land-treatment of petrochemical wastes revealed using an in situ rodent model

Land-treatment of petrochemical wastes is a widely used method to dispose of hazardous and non-hazardous waste by biodegradation. However, no comprehensive assessment of the impact of such disposal techniques on terrestrial ecosystems has been conducted. Despite the presence of suspected immunotoxicants in the soil, wild rodents frequently reside on these waste sites after closure or abandonment. We explored the seasonal sensitivity of the immune system of the hispid cotton rat (Sigmodon hispidus) to in situ exposures on sites land-treated with petrochemical wastes. Animals were monitored on five contaminated land-treatment sites and five ecologically matched-reference sites in Oklahoma, USA, over two seasons (summer and winter). Most hematological parameters were not adversely affected by land-treatment; however, platelet counts were 26% greater in cotton rats from land-treatment sites compared to reference sites in winter. Significant treatment-related differences were observed in total serum protein concentrations, organ mass and organ cellularity, but these differences were not consistent across the five land-treatment units. Lymphoproliferative responses of cotton rat splenocytes stimulated in vitro were elevated for a T-cell mitogen and depressed for a B-cell mitogen in animals from land-treatment compared to reference sites. The ability of splenocytes to proliferate in response to interleukin-2 receptor-binding was not influenced by treatment. Total yields of peritoneal cells, yield of peritoneal macrophages, and yield of peritoneal lymphocytes were influenced to varying degrees by land-treatment. Functionally, in vitro metabolic activity of peritoneal macrophages was 114% greater in cotton rats from land-treatment sites compared to reference sites during summer. These results indicate that petrochemical wastes applied to soils on these five land-treatment sites had variable immunomodulatory effects in resident cotton rats. Immune alterations for some assays were indicative of enhancement on some land-treatment sites while suppressive on other land-treatment sites, which could have been a function of type and concentration of immunotoxicants present on each site and highlights the uniqueness of each land-treatment site.

Zinc intervention on macrophages and lymphocytes response

Normal zinc levels are essential for the development and maintenance of immune functions; Zn deficiency is detrimental to the embryo and offspring of experimental animals, especially concerning immune development. It is known that Zn supplementation improves immune responses. To further explore the relation between Zn administration and the metal in vitro effects, we studied zinc (500 mg/l) supplementation impact on lymphocytes and macrophages and zinc in vitro effects, in BALB/c mice supplemented from gestation to lactation. Results show a significant increase in proliferation (assessed by 3H incorporation) in lymphocytes exposed to Zn (0.1 mM) in vitro, in 3-wk-old mice; this effect is annulled when the supplementation period is lengthened, indicating saturation of the mechanisms involved in zinc induced stimulation. Macrophages functional capacity assessed by erythrophagocytosis was also improved by Zn supplementation and furthermore by the in vitro exposure to the metal, in mice 3 wk old, this was also depressed by Zn accumulation due to the supplementation period extension (9 weeks). Results show an improvement in the immune parameters analysed due to zinc supplementation and to zinc in vitro exposure. Results also suggest the accumulation of zinc as a result of prolonged supplementation periods, suppresses the cells response to zinc in vitro.

Micronutrients and host resistance to viral infection

Previous work in our laboratory demonstrated that a virus could undergo rapid mutation in a host deficient in Se, leading to a normally avirulent virus acquiring virulence due to genome changes. Once these mutations occur, even a host with adequate Se-nutriture is susceptible to the newly virulent virus. What influence does the deficiency in Se have on the immune response of the host? Infection with myocarditic strains of coxsackievirus induces an inflammatory response in the cardiac tissue. It is this immune response that induces the heart damage, rather than direct viral effects on the heart tissue. Chemokines are chemo-attractant molecules that are secreted during an infection in order to attract immune cells to the site of the injury, and have been found to be important for the development of coxsackievirus-induced myocarditis. We found that a deficiency in Se influences the expression of mRNA for the chemokine monocyte chemo-attractant protein-1, which may have implications for the development of myocarditis in the Se-deficient host. Expression of mRNA for interferon-gamma was also greatly decreased in the Se-deficient animal. Thus, a deficiency in Se can have profound effects on the host as well as on the virus itself. How the alteration of the immune response of the Se-deficient animal affects the development of the virulent genotype remains to be answered.

Reduced immune function and malnutrition in the elderly

An important observation in elderly subjects is their susceptibility to infection associated with a decline in host immune function. Nutrition is also an important factor that influences host defense against infection. We, therefore, evaluated the relationship between nutritional status in 155 healthy subjects ranging in age from 20 to 99 years and various immunological parameters, including the phagocytic and bactericidal activities of neutrophils and monocytes, superoxide production and chemotaxis of neutrophils, lymphocyte subsets, blastoid transformation and serum immunoglobulins. Aging was associated with increased phagocytic activity of neutrophils but not bactericidal activity, superoxide production or chemotaxis of neutrophils. Aging was also associated with a significant decrease in the number of lymphocytes as well as a decline in mature T cells and helper/inducer T cells but with increased numbers of activated T cells, suppressor T cells and natural killer cells. In addition, blastoid transformation in response to phytohemagglutinin (PHA) and concanavalin A (Con A) was significantly reduced in aged subjects. A poor nutritional status was noted in individuals 60 years of age or older. The nutritional status did not influence neutrophil function but correlated significantly with the number of lymphocytes and degree of blastoid formation with PHA and Con A stimulation. Our results suggest that the cell-mediated immunity in elderly subjects is reduced as a result of malnutrition, and that improvement of the nutritional status may enhance the immune function, likely contributing to their successful aging.

Immunonutrition: the pediatric experience

The health benefits of specific nutrients in the diet are reviewed as they pertain to the pediatric population and its unique needs. Secretory immunoglobulins, lysozyme, interferon, and growth factors, among others, are known to confer immunological advantages to breast milk. Inhibition of bacterial pathogens, as well as permissive growth of a protective colonic ecoflora occur as a result of various cellular and biochemical mechanisms at play. The immunomodulatory properties of minerals such as iron, zinc, and selenium, are presented and the newly recognized protective role of vitamin A and its importance in developing countries and in conditions of compromised nutrition are discussed. The review also covers the role of arginine, glutamine, and nucleotides in adaptive responses of the developing gut and in pathologic states such as necrotizing enterocolitis, short bowel syndrome, and inflammatory bowel disease. Probiotics (specific microbial feeds with potential benefits to the host), and prebiotics (dietary components such as complex carbohydrates able to change the colonic microenvironment fostering colonization with non-enteropathogens) are areas of current interest because they offer alternatives for the management of the growing problem of multiple antibiotic resistance and overwhelming infections in the hospitalized patient.

Altered macrophage intracellular signaling induced by protein-calorie malnutrition

Protein-calorie malnutrition (PCM) contributes to increased morbidity and mortality through impairment of host defense mechanisms and reduced macrophage function. The present study examined alterations in macrophage intracellular signaling associated with the impairment in host defense capabilities. Mice were randomized to either control (regular diet) or protein-free diets (PCM) and pair-fed for 1 week. Following endotoxin stimulation, peritoneal macrophages from PCM mice produce significantly less TNF-alpha and IL-6 product and had significantly less cell-associated IL-6 when compared to macrophages from control mice. Similarly, macrophages from PCM mice had a significant reduction in mRNA levels for both TNF-alpha and IL-6. Other macrophage intracellular signaling mechanisms, such as calcium flux and tyrosine kinase phosphorylation were also altered by PCM. The etiology of PCM-induced defects in macrophage function and intracellular signaling remain unknown but may be related to the neuroendocrine response to PCM.

Increased apoptosis of CD45RO- T cells with aging

Increasing susceptibility to infectious and autoimmune phenomena have long been recognized to accompany advancing age in otherwise healthy individuals. Recently animal models of aging have suggested that age-associated immune dysfunction may correlate with defects in T cell apoptosis. We have examined activation-induced apoptosis defects in human peripheral T cells from young individuals (mean age = 31 +/- 3 years old) compared to aged individuals (mean age = 67 +/- 8 years old). Following in vitro activation of T cells with PHA and IL-2, apoptosis was measured in T cell subsets using 7-amino actinomycin D (7-AAD) staining and analysis via three colour flow cytometry. There was no significant difference in apoptosis of the total CD3+ T cell population at early and late time points. Interestingly, increased apoptosis in the CD3+ CD45RO- T cell population of older adults was observed by culture day 6. While the total number of CD3+ CD45RO- cells was not different between young (< 33 years) and old (> 65 years) individuals, 32% of these cells did not undergo apoptosis in younger individuals while only 10% of these cells avoided this fate in older individuals. These results suggest that accumulation of CD45RO+ T cells may occur in aged subjects due in part to preferential elimination of CD45RO- cells with activation. Furthermore, as new or continued immune response requires differentiation of CD45RO+ T cells to CD45RO+ T cells after activation, increased apoptosis instead of survival in aged individuals could lead to observed T cell immune deficiency.

New environmental agents associated with lupus-like disorders

An increasing number of environmental agents are being investigated as possible risk factors in the etiology of certain connective tissue disorders. Exposure to a variety of therapeutic agents, foods and dietary supplements, occupational and other toxic exposures, and infectious agents has been associated with the onset of lupus-like disorders. The mechanisms by which these agents might induce lupus remain unknown but may involve alteration of cellular components or activation of the immune system. Individual host susceptibility factors, including pre-existing organ dysfunction and particular metabolic enzyme or immunogenetic phenotypes, may also be important risk factors for development of environmentally-associated lupus-like disorders. Awareness of the many environmental agents implicated with lupus and related disorders, and dissection of their pathogenetic mechanisms through appropriate case-controlled investigations, may identify additional toxic agents and may lead to a better understanding of the idiopathic lupus syndromes.

Histopathology of the immune system as a tool to assess immunotoxicity

Immunotoxicology studies the undesired effects of interactions between xenobiotics and the immune system, mainly in toxicity experiments in rodents. The histopathology of the lymphoid organs is a cornerstone in such studies. In this review we describe practical aspects of sampling lymphoid organs and subsequent tissue processing and application of conventional and advanced histologic techniques. Thereafter, some aspects of proper reading and interpretation of histopathology is discussed, in relation to modifying factors such as age, sex, strain of animals, housing conditions, and nutritional status. These factors can substantially confound the outcome and interpretation of experiments, due to the highly dynamic characteristics of the immune system. Immunotoxicity tests are normally performed in a tiered approach. We describe the screening tier in the rat species that has been developed in the National Institute of Public Health and Environmental Protection, Bilthoven, The Netherlands, and illustrate the value of histopathology by an example of immunotoxicity testing of pesticides. Subsequently, the tiered approach in the mouse species followed by the National Toxicology Program in the USA, is described. In the evaluation of chemicals with suspected immunotoxic potential using this approach, histopathology proved to be less sensitive in 'flagging' immunotoxicity. This may be related to the lower doses that are applied in this toxicity design, because at higher doses histopathology is a sensitive indicator of toxicity. A global description of pathologic alterations after toxic insult is given, followed by representative examples taken from immunosuppressive drugs--the cytostatic agent 5-fluorouracil, and drugs interfering with cytokine expression, namely, Cyclosporin A, FK-506, and Rapamycin.