Emerging Paradigms in Immunonutrition

Translating Human and Animal Model Studies to Dogs' and Cats' Veterinary Care: Beta-Glucans Application for Skin Disease, Osteoarthritis, and Inflammatory Bowel Disease Management

The inclusion of beta-glucans in dog and cat food is associated with numerous beneficial effects on the health of these animals. In this regard, there is an effort to elucidate the potential of this nutraceutical in chronic patients. Since there is a lack of a review on the topic, this review article aims to compile and discuss the evidence found to date. Atopic dermatitis, inflammatory bowel disease, and osteoarthritis are diseases of significant clinical relevance in dogs and cats. In general, the pathophysiology of these chronic conditions is related to immune-mediated and inflammatory mechanisms. Therefore, the immunomodulation and anti-inflammatory effects of beta-glucans are highlighted throughout this review. The available information seems to indicate that the studies on beta-glucans' impact on allergic processes in dogs indicate a reduction in clinical signs in atopic dermatitis cases. Additionally, while beta-glucans show promise as a safe supplement, particularly for osteoarthritis, further clinical trials are imperative, especially in uncontrolled environments. Beta-glucans emerge as a potential nutraceutical offering immune benefits for inflammatory bowel disease patients, although extensive research is required to define its optimal origin, molecular weight, dosage, and specific applications across animals suffering from this disease.

Supplementation of Diets With Bovine Colostrum Influences Immune and Gut Function in Kittens

In its early life a kitten faces many significant events including separation from its mother, re-homing and vaccination. The kitten is also slowly adapting to their post-weaning diet. Recent advances in companion animal nutrition have indicated that functional ingredients such as colostrum can help support the immune system and gastrointestinal health. Here we report for the first time the effect of feeding a diet containing 0.1% spray dried bovine colostrum (BC) to growing kittens on gut-associated lymphoid (GALT) tissue responses, systemic immune responses, and on intestinal microbiota stability. BC supplementation induced increased faecal IgA expression, and a faster and stronger antibody response to a rabies vaccine booster, indicative of better localised and systemic immune function, respectively. BC supplementation also helped to maintain kittens' intestinal microbiota stability in the face of a mildly challenging life event. These results show that BC supplementation can help strengthen the immune system and enhance the gut microbiota stability of growing kittens.

Supplementation of Diets With Spirulina Influences Immune and Gut Function in Dogs

Spirulina refers to two species of blue green algae (Arthrospira platensis, and A. maxima) consumed by humans as food for centuries. While, Spirulina has been shown to have immune enhancing properties in several animal and human studies, there are no systematic studies in dogs. The aim of this study was to evaluate the immunomodulatory effect of dietary supplementation with Spirulina in dogs. The study was conducted in two phases: Pre-test (8 wks.) and Test (42 wks.). Thirty adult dogs (mean 2.9 yrs.) were randomized into two groups and fed a nutritionally complete diet in the “Pre-test” phase. At the end of “Pre-test” phase all dogs received a rabies vaccine, and dogs in “test group” were switched to diet supplemented with dried Arthrospira platensis (Spirulina). Response to rabies vaccine was evaluated by Rapid Fluorescent Focus Inhibition Test (RFFIT). Gut immune response was assessed by measuring fecal IgA. Gut microbiota was evaluated by Temporal Temperature Gel Electrophoresis (TTGE) methodology. Repeated measures ANOVA was used to test for differences between groups and statistical significance considered to be p < 0.05. Dogs fed diets supplemented with Spirulina demonstrated enhanced immune status by showing significantly higher vaccine response and higher levels of fecal IgA as compared to the control group. Supplementing diets with Spirulina also resulted in significantly increased gut microbiota stability in the test group. In conclusion, diets supplemented with Spirulina significantly enhanced immune response and gut health in dogs.

Profile of gamma-delta (γδ) T lymphocytes in the peripheral blood of crossbreed dogs during stages of life and implication in aging

Background

Data on gamma-delta (γδ) T lymphocytes in the peripheral blood of dogs are scant, related only to healthy pure breed dogs and limited to a restricted age range. The aim of the study was to investigate the modulation of the γδ T lymphocyte (TCRγδ+) subpopulation in peripheral blood of crossbreed healthy dogs according to five identified stages of life: Puppy, Junior, Adult, Mature, Senior and to determine its implication in aging.

A rigorous method of recruitment was used to minimize the influence of internal or external pressure on the immune response. Twenty-three intact female and twenty-four intact male dogs were enrolled. Blood samples were collected and immunophenotyping of peripheral blood T lymphocytes and γδ T cell subpopulations was performed.

Results

The percentage of γδ T cells in peripheral blood lymphocytes was comparable with the value of 2.5% published by Faldyna and co-workers (2001), despite the percentage reported was investigated in less arranged age range groups and coming from four different dog pure breeds, whereas our data were recorded on wider age range groups and coming from crossbreed dogs. Therefore, the γδ T cell percentage (2.5%) is consistent and points out that such value is breed-independent. Statistical analysis highlighted differences in both percentage and absolute γδ T cells according to the stage of life. γδ T cells decreased significantly in the peripheral blood of elder dogs (Senior group) in comparison with previous stages of life (Puppy, Junior, and Adult groups). Differences in γδ T cells are significant and they are reported, for the first time, related to dog aging.

Conclusions

The study confirms dogs to be among the animals with a low TCRγδ+ cell profile. A decrease of the TCRγδ+ subpopulation percentage was observed in elder dogs. TCRγδ+ cells of group S were different from those of groups P, J, and A. The differences are reported for the first time in dog aging. Identifying the stage of life when the decrease of γδ T lymphocytes starts can be useful for providing a rationale for drafting a wellness plan trial to support thymus immune functions and mitigate its functional exhaustion.

NUTRITION AND HEALTH: COMPANION ANIMAL APPLICATIONS: Functional nutrition in livestock and companion animals to modulate the immune response

Advances in the understanding of how the immune system functions in response to diet have altered the way we think about feeding livestock and companion animals on both the short (weeks/months) and long-term (years) timelines; however, depth of research in each of these species varies. Work dedicated to understanding how immune function can be altered with diet has revealed additional functions of required nutrients such as vitamins D and E, omega-3 polyunsaturated fatty acids (PUFA), and minerals such as zinc, while feed additives such as phytogenics and probiotics add an additional layer of immunomodulating potential to modern diets. For certain nutrients such as vitamin D or omega-3 PUFA, inclusion above currently recommended levels may optimize immune function and reduce inflammation, while for others such as zinc, additional pharmacological supplementation above requirements may inhibit immune function. Also to consider is the potential to over-immunomodulate, where important functions such as clearance of microbial infections may be reduced when supplementation reduces the inflammatory action of the immune system. Continued work in the area of nutritional immunology will further enhance our understanding of the power of nutrition and diet to improve health in both livestock and companion animals. This review collects examples from several species to highlight the work completed to understand how nutrition can be used to alter immune function, intended or not.

Social conditions and immune response in human immunodeficiency virus-seropositive pregnant women: a cross-sectional study in Brazil

INTRODUCTION

The functioning of the immune system during pregnancy is altered in both human immunodeficiency virus (HIV)-infected and uninfected women. Unfavorable socioeconomic conditions have been indicative of higher morbidity and mortality and worsening of the immune system. The aim of this study was to correlate social status with levels of interleukin (IL)-10 (non-inflammatory) and interferon-gamma (IFN-γ; inflammatory) cytokines.

METHODS

A cross-sectional study was conducted with three groups of women: 33 pregnant HIV-infected (G1); 40 non-pregnant, HIV-infected (G2); and 35 pregnant, HIV-uninfected. To measure the social status, a compound indicator called the social status index (SSI), was established using sociodemographic variables (i.e., education level, housing conditions, per capita income, and habitation and sanitary conditions).

RESULTS

The HIV-infected women had a higher proportion of unfavorable SSI (73% and 75% of G1 and G2, respectively). There were significantly lower IL-10 levels in the G1 group with both unfavorable and favorable SSI than in the other groups. No significant difference in IFN-γ levels was observed among groups. However, the G1 group had higher IFN-γ values among both favorable and unfavorable SSI groups.

CONCLUSIONS

Higher rates of unfavorable conditions, including lower education levels, IL-10 levels, and a trend for higher IFN-γ levels, were identified among HIV-infected women, pregnant and non-pregnant. These factors may interfere in health care and lead to poor outcomes during pregnancy. Therefore, we suggest that health policies could be created to specifically address these factors in this population.

A role for whey-derived lactoferrin and immunoglobulins in the attenuation of obesity-related inflammation and disease

Obesity is a strong predictive factor in the development of chronic disease and has now superseded undernutrition as a major public health issue. Chronic inflammation is one mechanism thought to link excess body weight with disease. Increasingly, the gut and its extensive population of commensal microflora are recognized as playing an important role in the development of obesity-related chronic inflammation. Obesity and a high fat diet are associated with altered commensal microbial communities and increased intestinal permeability which contributes to systemic inflammation as a result of the translocation of lipopolysaccharide into the circulation and metabolic endotoxemia. Various milk proteins are showing promise in the prevention and treatment of obesity and chronic low-grade inflammation via reductions in visceral fat, neutralization of bacteria at the mucosa and reduced intestinal permeability. In this review, we focus on evidence supporting the potential antiobesogenic and anti-inflammatory effects of bovine whey-derived lactoferrin and immunoglobulins.

Effects of free amino acids on cytokine secretion and proliferative activity of feline T cells in an in vitro study using the cell line MYA-1

In vitro studies might be an interesting screening method for targeted in vivo studies in the field of immunonutrition and help to reduce and refine animal studies. As the role of amino acids for immune function of cats has not been evaluated in detail so far, the present study aimed at investigating the effects of eight different amino acids (arginine, leucine, isoleucine, valine, glutamine, lysine, threonine and tryptophan) in six concentrations each (0, 0.25, 0.5, 1, 2 and 8x the cat blood level) on cytokine secretion and proliferative activity of feline T cells (MYA-1) in vitro. The results demonstrated that high doses of arginine increased IL-4, IL-10 and TNF-α secretion of T cells, while increasing concentrations of lysine increased IL-10 secretion and proliferative activity of the T cells. High doses of leucine enhanced GM-CSF and IL-10 secretion, while concentrations of threonine in the cell culture media greater than blood concentration also increased GM-CSF and additionally TNF-α secretion of the cells. The effects of glutamine and isoleucine on T cell function were only small. In conclusion, the present in vitro study could evaluate the immunomodulating potential of specific amino acids for feline T cell function. High doses of arginine, lysine, leucine and threonine had a significant impact on cytokine secretion and proliferative activity of the T cells. Targeted in vivo studies should investigate the clinical relevance of dietary supplementation of those amino acids in healthy and diseased cats as a next step.

Modeling-Enabled Systems Nutritional Immunology

This review highlights the fundamental role of nutrition in the maintenance of health, the immune response, and disease prevention. Emerging global mechanistic insights in the field of nutritional immunology cannot be gained through reductionist methods alone or by analyzing a single nutrient at a time. We propose to investigate nutritional immunology as a massively interacting system of interconnected multistage and multiscale networks that encompass hidden mechanisms by which nutrition, microbiome, metabolism, genetic predisposition, and the immune system interact to delineate health and disease. The review sets an unconventional path to apply complex science methodologies to nutritional immunology research, discovery, and development through “use cases” centered around the impact of nutrition on the gut microbiome and immune responses. Our systems nutritional immunology analyses, which include modeling and informatics methodologies in combination with pre-clinical and clinical studies, have the potential to discover emerging systems-wide properties at the interface of the immune system, nutrition, microbiome, and metabolism.

Alcohol extract of Schinu sterebinthifolius raddi (anacardiaceae) as a local antimicrobial agent in severe autogenously fecal peritonitis in rats

PURPOSE

To develop an alcoholic extract of the inner bark of the Schinus terebinthifolius raddi and to test its impact on autogenously fecal peritonitis in Wistar rats.

METHODS

The inner bark of the Schinus terebinthifolius raddi was kept for seven days in 70% ethanol alcohol. The total elimination of the solvent was performed in a rotary evaporator under reduced pressure at 55-60°C. Four milliliter of this extract was injected, after 24 h, into the abdominal cavity of six out of eight survival rats that underwent autogenously fecal peritonitis with five milliliter of 10% filtered fecal suspension. They were clinically followed up for 45 days when they were euthanized. The necropsy findings (inventory) of the abdominal and thorax cavities were inspected and the main findings were recorded and photographed. The investigation was approved by the Ethics Committee.

RESULTS

Two out of six survival rats that were critically ill after 24 h died within the 12 h after the extract injection into the abdominal cavity. Four rats that were also critically ill recovered and gradually became healthy, eating well, regaining weight and moving normally in the cage. At 45 days post severe peritonitis the necropsy findings revealed few signs of residual infection on the abdominal and thorax cavities. There were no bowel adhesions.

CONCLUSION

The impact of alcoholic extract of the inner bark of the Schinus terebinthifolius raddi was considered very positive and promising as natural local antiseptic against very severe peritonitis in Wistar rats.

The impact of weight loss on circulating cytokines in Beagle dogs

Chronic low-grade inflammation in obesity is characterized by an increased production of pro-inflammatory and chemotactic cytokines that are contributing to insulin resistance and related co-morbidities. Cytokines act in networks and exhibit pleiotropic effects so we investigated the circulating levels of a wide array of cytokines (pro and anti-inflammatory, chemotactic and growth factors) in a canine model of weight loss. The dogs served as their own control in order to study the impact of weight loss independent of potential confounding factors, such as history of excess weight or gender. While low-grade inflammation had been previously investigated in obese dogs by measuring changes in adipokines, acute phase proteins and key pro-inflammatory cytokines, to the best of our knowledge this is the first study to evaluate how weight loss impacts a wide array of circulating cytokines. Eighteen overweight Beagle dogs were recruited (six spayed females and 12 neutered males), and none of them were grossly obese according to the body condition score (BCS). All the dogs reached an ideal weight by the end of the program. Parameters were assessed before (baseline), at mid-point (month 3) and at end-point (month 6). Plasma GM-CSF, IL-2, Il-4, IL-6, IL-7, IL-8, IL-10, IL-15, IL-18, IFNγ, IP-10, TNFα, monocyte chemotactic protein 1 (MCP-1), keratinocyte chemokine (KC) were measured with canine multiplex immunoassays. Fat mass was assessed by dual energy X-ray absorption (DEXA). Several cytokines decreased throughout the weight loss program (p<0.01) and were correlated with the percentage of fat measured by DEXA (p<0.05): chemotactic (MCP-1), growth factors (GM-CSF, IL-7 and IL-2), and pro-inflammatory (KC and IL-18). We could not show trends for several cytokines, possibly because their level may be lower than the assay sensitivity: anti-inflammatory (IL-4 and IL-10), and pro-inflammatory (IL-6 and TNFα). In conclusion, while our findings for several pro-inflammatory and chemotactic cytokines are in accordance with human and rodent studies, we may have identified additional cytokines, such as growth factors, related to obesity-induced low-grade inflammation. Considering the weight loss was enabled by an adjusted diet, the role of this association of cytokines in insulin resistance and related co-morbidities needs to be clarified. Our results could help better understand the cytokine biology in dogs, and as such are relevant for further elucidating the relationship between immune function and metabolism/nutrition.

Amino acid supplementation and impact on immune function in the context of exercise

Moderate and chronic bouts of exercise may lead to positive metabolic, molecular, and morphological adaptations, improving health. Although exercise training stimulates the production of reactive oxygen species (ROS), their overall intracellular concentration may not reach damaging levels due to enhancement of antioxidant responses. However, inadequate exercise training (i.e., single bout of high-intensity or excessive exercise) may result in oxidative stress, muscle fatigue and muscle injury. Moreover, during the recovery period, impaired immunity has been reported, for example; excessive-inflammation and compensatory immunosuppression. Nutritional supplements, sometimes referred to as immuno-nutrients, may be required to reduce immunosuppression and excessive inflammation. Herein, we discuss the action and the possible targets of key immuno-nutrients such as L-glutamine, L-arginine, branched chain amino acids (BCAA) and whey protein.

Nutrition of aging dogs

Aging is a normal process characterized by a variety of physiologic changes. Geriatric dogs are also more likely to be afflicted with certain disease conditions. Both normal and abnormal physiologic changes associated with aging in the dog may be amenable to nutritional intervention. Specific alterations in nutrients or in dietary characteristics can be beneficial; however, these are best done in the context of an individualized nutritional assessment and monitoring paradigm.

Optimizing nutrition therapy to enhance mobility in critically ill patients

Critically ill patients are at high risk of malnutrition and lean body mass loss. Screening for malnutrition and performing detailed assessment of energy needs should be routine for patients admitted to intensive care units. Providing adequate calorie and protein provisions can attenuate muscle loss in many at-risk patients. Enteral nutrition is associated with decreased risks of morbidity and infections and is therefore preferred to parenteral nutrition in hemodynamically stable patients with favorable anatomy. Judicious use of steroids and paralytics in combination with adequate glucose control may decrease the risk of developing critical illness polyneuromyopathy. There is growing evidence for the potential immune-enhancing benefits of many micronutrients and vitamins in the critically ill, but more research is needed to determine which nutrients are most effective in which disease processes and what dosing regimens are safe and effective. Elderly, obese, and very young patients pose unique challenges for nutrition therapy and early mobility programs. Pairing early mobility programs with optimal nutrition therapy can help reduce morbidity, limit muscle loss, and speed recovery in intensive care unit patients.

Supplementation of diets with bovine colostrum influences immune function in dogs

While the need for colostrum in neonates is well established, the systemic effect of feeding bovine colostrum (BC) to adult humans is gaining increasing attention. However, no systematic studies evaluating the immunomodulatory effect of BC in dogs have been reported. The aim of the present study was to evaluate the immunomodulatory effect of dietary supplementation of BC in dogs. The study was conducted in two phases: pre-test (8 weeks) and test (40 weeks), with twenty-four dogs (mean age 2.5 years) randomised into two groups. In the 'pre-test' phase, both groups were fed a nutritionally complete diet. At the end of the 'pre-test' phase, all dogs received a canine distemper virus (CDV) vaccine, and dogs in the 'test group' were switched to a diet supplemented with 0.1% spray-dried BC. Response to the CDV vaccine was evaluated by measuring vaccine-specific plasma IgG levels. Gut-associated lymphoid tissue response was assessed by measuring faecal IgA levels. Gut microbiota were evaluated by the temporal temperature gel electrophoresis methodology. Dogs fed the BC-supplemented diet demonstrated a significantly higher vaccine response and higher levels of faecal IgA when compared with the control group. Supplementing diets with BC also resulted in significantly increased gut microbiota diversity and stability in the test group. In conclusion, diets supplemented with BC significantly influence immune response in dogs.

Probiotics and Immune Response to Exercise

Probiotics are live microorganisms present in several foods and nutritional supplements that may prevent or limit the effects of various illnesses and infections and elicit a range of health benefits in physically active individuals. The primary clinical areas of interest with probiotics include metabolism; gastrointestinal, inflammatory, and functional disorders; the respiratory system; and a range of infections and allergies. The gastrointestinal tract is a key element controlling and regulating adaptation to exercise and physical activity. Gut symptomatology such as nausea, bloating, cramping, pain, diarrhea, and bleeding occurs in some highly active individuals such as athletes, particularly in prolonged exhaustive events. A small number of studies examining probiotic supplementation in highly active individuals indicate modest clinical benefits in terms of reduced frequency, severity, and/or duration of respiratory and gastrointestinal illness. The purported mechanisms of action for probiotics include direct interaction with the gut microbiota, interaction with the gut epithelium and mucosal immune system, and via immune signaling to organs and systems including the liver, brain, and respiratory tract. Future research will identify additional biologically and clinically beneficial strains, validate multicomponent formulations, clarify dose–response issues, and inform the development of guidelines for clinicians, health care practitioners, and the general community.