Non-controlled, open-label clinical trial to assess the effectiveness of a dietetic food on pruritus and dermatologic scoring in atopic dogs

Oxidative Stress in Canine Diseases: A Comprehensive Review

Oxidative stress (OS), defined as a disruption in redox balance favoring oxidants, has emerged as a major contributor to numerous diseases in human and veterinary medicine. While several reviews have explored the implication of OS in human pathology, an exhaustive review of the canine species is lacking. This comprehensive review aims to summarize the existing literature on the role of OS in canine diseases, highlighting its potentially detrimental effect on various organs and systems. Some inconsistencies among studies exist, likely due to varying biomarkers and sample types. However, there is substantial evidence supporting the involvement of OS in the development or progression of numerous canine disorders, such as cardiovascular, oncologic, endocrine, gastrointestinal, hematologic, renal, neurologic, infectious, and parasitic diseases, among others. Additionally, this review discusses the efficacy of antioxidant and pro-oxidant therapeutic agents for these conditions. Dietary interventions to counteract OS in dogs have gained significant attention in recent years, although further research on the topic is needed. This review aims to serve as a foundational resource for future investigations in this promising field.

Iron deficiency in dogs suffering from atopic dermatitis

BACKGROUND

Iron-deficiency is associated with increased morbidity and mortality in non-communicable diseases. However, iron parameters are rarely assessed in dogs. Here, we aimed to assess and correlate iron parameters in dogs suffering from Canine Atopic Dermatitis (CAD) compared to non-atopic, healthy dogs.

RESULTS

For this retrospective study, blood values and sera of 34 dogs with confirmed CAD were compared with 94 healthy non-atopic dogs. In our cohort, dogs with CAD had significantly lower mean corpuscular volume (MCV, ) mean corpuscular hemoglobin (MCH) but higher white blood cell counts due to increased levels of circulating neutrophils and monocytes. CAD patients also had elevated total protein and c-reactive protein (CRP), but lower albumin levels compared to our healthy control dogs, indicated low-grade inflammation in the CAD cohort. Spearman correlations associated negatively clinical symptom (CADESI-4/PVAS) with MCV; ceruloplasmin and hepcidin, but positively with serum iron. Only in the CAD-cohort, MCV, CRP and albumin-levels negatively affected serum iron-levels and were positively associated with ceruloplasmin. Linear regression analysis revealed that serum iron-levels in CAD subjects, were positively dependent on hematocrit (packed cell volume, PCV) and albumin, and negatively dependent with white blood cells and neutrophils numbers. In contrast, in the healthy cohort, hepcidin was the sole factor associated with serum iron.

CONCLUSIONS

A decreased iron status was associated with a higher symptom burden. Iron homeostasis differed markedly in healthy and atopic dermatitis dogs. CAD patients had depleted iron-stores and presented themselves with subclinical inflammation.

A Randomized Controlled Trial to Evaluate the Impact of a Novel Probiotic and Nutraceutical Supplement on Pruritic Dermatitis and the Gut Microbiota in Privately Owned Dogs

Pruritic dermatitis (PD) is a common presentation of canine allergic skin diseases, with diversity in severity and treatment response due to complex etiopathogenesis. Evidence suggests the gut microbiota (GM) may contribute to the development of canine allergies. A 10-week double-blind randomized controlled trial evaluated a novel probiotic and nutraceutical blend (PNB) on clinical signs of skin allergy, health measures, and the GM of privately owned self-reported pruritic dogs. A total of 105 dogs were enrolled, with 62 included in pruritus and health analysis and 50 in microbiome analysis. The PNB supported greater improvement of owner-assessed clinical signs of PD at week 2 than the placebo (PBO). More dogs that received the PNB shifted to normal pruritus (digital PVAS10-N: <2) by week 4, compared to week 7 for the PBO. While a placebo effect was identified, clinical differences were supported by changes in the GM. The PNB enriched three probiotic bacteria and reduced abundances of species associated with negative effects. The PBO group demonstrated increased abundances of pathogenic species and reduced abundances of several beneficial species. This trial supports the potential of the PNB as a supplemental intervention in the treatment of PD; however, further investigation is warranted, with stricter diagnostic criteria, disease biomarkers and direct veterinary examination.

Non-controlled, open-label trial to assess clinical and immunological parameters in atopic dogs feeding monoprotein grain free diet versus a standard grain diet

Canine atopic dermatitis (cAD) is a common inflammatory skin disease that is treated with medicines or allergen-specific immunotherapy. An improvement diet can help treatment of cAD. The purpose of this study was compare two diets on clinical and immunological parameters in atopic dogs without food hypersensitivity. Diet A, a commercial based on rice, was offered to 22 atopic dogs during 30 days and Diet B (grain free, rich in salmon) was given to 8 atopic dogs. Clinical scores were assessed by CADESI-4 and PVAS at the beginning (T0) and at the end of the study (T30). CD4+ and CD8+ were measured in PBMCs, and serum cytokines (TNF-α, IL-10, IL-31 and IL-34) were determined. Both diets decreased CADESI-4 score and Diet A decreased PVAS score (p < 0.05). There were no statistical significant differences between diets at T30 for CD4+ and CD8+. A decrease in the IL-31 concentrations and increase in IL-10 levels (p < 0.05) was observed with Diet A at T30. There were no differences between any of the two diets when the other results at T0 and T30 were compared for any of the parameters analysed. In conclusion, the results indicate that dietary intervention had not influence on cellular component of the immune system, but a positive effect was observed on IL-31, IL-10 serum levels for Diet A. Further studies are needed to enrich dietary components of the food for atopic dogs without food hypersensibility to help improvement the management of the cAD.

Evidence-base for the beneficial effect of nutraceuticals in canine dermatological immune-mediated inflammatory diseases - A literature review

BACKGROUND

Immune-mediated inflammatory diseases (IMIDs) are associated with an abnormal immune response, resulting in a disturbed homeostasis and chronic inflammation. Most canine dermatological IMIDs (cDIMIDs), such as allergies, autoimmune and immune-mediated diseases, require long-term treatment with immunosuppressive drugs with potential adverse effects. In general, nutraceuticals are thought to be safe. As a result, there is a tendency for the more frequent use of nutraceuticals in veterinary medicine.

OBJECTIVES

The aim of this review was to present evidence-based proof for the use of various nutraceuticals in the treatment of cDIMIDs and, where possible, to provide conclusions to guide their use in veterinary dermatological practice.

METHODS

A comprehensive literature search on common cDIMIDs and nutraceuticals was performed. Only peer-reviewed articles published in English and related to the study topic were included. A total of 64 eligible publications were classified in five categories based on study design and substantively assessed on additional criteria such as standardisation of diets and number of included animals. For final appraisal, classification of major, minor or no evidence was used whereby efficacy was based on clinical outcome measurements.

CONCLUSIONS

Minor evidence for the beneficial use of several nutraceuticals, including essential fatty acids, niacinamide and probiotics, was found for treatment of specific cDIMIDs. These nutraceuticals may improve clinical signs or reduce the required dose of concurrent medication (e.g. drug-sparing effect) in some dogs. Some nutraceuticals also may be used for long-term maintenance therapy. Despite some promising findings, major evidence for the use of nutraceuticals in cDIMIDs is lacking, warranting further research.

Sargassum horneri extract containing polyphenol alleviates DNCB-induced atopic dermatitis in NC/Nga mice through restoring skin barrier function

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by skin barrier dysfunction. Sargassum horneri (S. horneri) is a brown alga that has been widely used in traditional medicine of eastern Asian countries. Recent studies proved that a brown alga S. horneri has anti-inflammatory activity. In this study, we investigated the effect of S. horneri ethanol extract (SHE) against AD in 2,4-dinitrobenzene (DNCB) induced AD in NC/Nga mice. We observed that SHE treatment decreased the epidermal thickness and epidermal hyperplasia that had been worsened through DNCB application. Moreover, SHE significantly inhibited the proliferation of mast cells and decreased the expression of IL-13 on CD4⁺ cells prompted by elevated thymic stromal lymphopoietin (TSLP) expression in DNCB-induced AD in mice. We also demonstrated that SHE directly inhibited the expression of keratinocyte-produced TSLP known to exacerbate skin barrier impairment. Especially, the decrease of filaggrin, an integral component of proper skin barrier function through a function in aggregating keratin filaments, observed in DNCB-induced AD mice was significantly improved when treated with SHE. More importantly, we proved that SHE was able to decrease the serum levels of IgG₁ and IgG₂ₐ, two crucial factors of AD, indicating the protective effect of SHE. Taken together, our findings suggest that SHE may protect NC/Nga mice against DNCB-induced AD via promoting skin barrier function.

Randomized, double-blind, placebo-controlled clinical trial measuring the effect of a dietetic food on dermatologic scoring and pruritus in dogs with atopic dermatitis

Background

Canine atopic dermatitis (AD) is a common condition that often requires multimodal therapy. Including a diet in the multimodal management of AD may reduce medication doses, saving pet owners money and reducing side effects. The objective of this randomized, double-blind, placebo-controlled clinical trial was to determine if a diet fortified in antioxidants, polyphenols, and omega-3 fatty acids can reduce the clinical signs of AD. Forty client-owned dogs with AD were enrolled in the study and assigned to either an enriched diet (diet B) or control diet (diet A) for 60-days. CADESI-4 index scores and owner-reported pruritus scores were measured periodically.

Results

Total CADESI-4 index scores for dogs eating diet B were lower on day 60 compared to baseline (P = 0.003). There was no statistical difference in scores for dogs eating diet A over a 60-day period. Diet B dogs had 25 and 49% reductions in CADESI-4 index scores on days 30 and 60, respectively (P = 0.0007) while diet A had no change over the study period. When comparing the percent change in owner-reported pruritus scores, diet B also performed better than diet A. By day 60, owners feeding diet B to their dogs reported a significant reduction (P < 0.0001) of 46.4% in itching, while those on diet A reported a 26.8% reduction, which was not statistically significant (P = 0.08).

Conclusions

These study results demonstrate feeding a diet enriched with ingredients to improve skin health and reduce inflammation improves the clinical signs of AD in dogs.

A novel therapeutic diet can significantly reduce the medication score and pruritus of dogs with atopic dermatitis during a nine month controlled study

Background

Canine atopic dermatitis (cAD) is a common chronic relapsing pruritic skin disease for which management commonly relies on life‐long use of immunomodulatory drugs. A number of the medications used are associated with adverse effects and the potential for complications during long‐term use.

Hypothesis

The goal of the study was to determine if a complete and balanced diet formulated for therapeutic benefit could contribute towards management of cAD. We hypothesised that the diet would reduce pruritus while also reducing the requirement for medication during the study period.

Animals, materials and methods

Forty privately owned dogs, having undergone a comprehensive diagnosis for cAD, were randomly allocated to two groups, each group being fed one of two diets (test or control) for up to nine months. We assessed pruritus, Canine Atopic Dermatitis Extent and Severity Index‐(4th iteration) and medication score, the latter reflecting the medication required to maintain a satisfactory quality of life for the animal.

Results

Both diets were well‐accepted and ‐tolerated. There was a significant improvement in the pruritus score after three months of feeding the therapeutic diet (P = 0.0001). No such improvement was observed at any time point in the group of dogs given the control diet. There was a reduced drug requirement for dogs receiving the therapeutic diet after three months (P = 0.058), and that decrease was significant at six months (P = 0.021) and nine months (P = 0.018). No improvement was seen at any time point in the control group.

Conclusion

The results suggest that a novel therapeutic diet can assist in the management of cAD by helping to control pruritus and reducing reliance on medication.

Polyphenols and Fish Oils for Improving Metabolic Health: A Revision of the Recent Evidence for Their Combined Nutraceutical Effects

Polyphenols and omega-3 polyunsaturated fatty acids from fish oils, i.e., eicosapentaenoic and docosahexaenoic acids, are well-recognized nutraceuticals, and their single antioxidant and anti-inflammatory properties have been demonstrated in several studies found in the literature. It has been reported that the combination of these nutraceuticals can lead to three-fold increases in glutathione peroxidase activity, two-fold increases in plasma antioxidant capacity, decreases of 50-100% in lipid peroxidation, protein carbonylation, and urinary 8-isoprotanes, as well as 50-200% attenuation of common inflammation biomarkers, among other effects, as compared to their individual capacities. Therefore, the adequate combination of those bioactive food compounds and their single properties should offer a powerful tool for the design of successfully nutritional interventions for the prevention and palliation of a plethora of human metabolic diseases, frequently diet-induced, whose etiology and progression are characterized by redox homeostasis disturbances and a low-grade of chronic inflammation. However, the certain mechanisms behind their biological activities, in vivo interaction (both between them and other food compounds), and their optimal doses and consumption are not well-known yet. Therefore, we review here the recent evidence accumulated during the last decade about the cooperative action between polyphenols and fish oils against diet-related metabolic alterations, focusing on the mechanisms and pathways described and the effects reported. The final objective is to provide useful information for strategies for personalized nutrition based on these nutraceuticals.

Polyphenols and Cannabidiol Modulate Transcriptional Regulation of Th1/Th2 Inflammatory Genes Related to Canine Atopic Dermatitis

Canine atopic dermatitis (AD) is a multifactorial allergic disease associated with immune and abnormal skin barrier dysfunction and it is one of the primary causes of pruritus. Using a novel in vitro model of AD, here we tried to revert the alteration of transcriptional regulation of AD canine key genes testing a nutraceutical mixture containing flavonoids, stilbene, and cannabinoids, which are already well-known for their applications within dermatology diseases. The nutraceutical mixture induced in inflamed cells a significant downregulation (p < 0.05) of the gene expression of ccl2, ccl17, and tslp in keratinocytes and of ccl2, ccl17, and il31ra in monocytes. Consistent with the observed alterations of tslp, ccl2, ccl17, and il31ra messenger RNA (mRNA) levels, a significant increase (p < 0.05) of DNA methylation at specific CpG sites on the gene regulatory regions was found. These results lay the foundation for the use of these natural bioactives in veterinary medicine and provide a model for deeper understanding of their mechanisms of action, with potential translation to human research.

Palmitoylethanolamide and Related ALIAmides: Prohomeostatic Lipid Compounds for Animal Health and Wellbeing

Virtually every cellular process is affected by diet and this represents the foundation of dietary management to a variety of small animal disorders. Special attention is currently being paid to a family of naturally occurring lipid amides acting through the so-called autacoid local injury antagonism, i.e., the ALIA mechanism. The parent molecule of ALIAmides, palmitoyl ethanolamide (PEA), has being known since the 1950s as a nutritional factor with protective properties. Since then, PEA has been isolated from a variety of plant and animal food sources and its proresolving function in the mammalian body has been increasingly investigated. The discovery of the close interconnection between ALIAmides and the endocannabinoid system has greatly stimulated research efforts in this field. The multitarget and highly redundant mechanisms through which PEA exerts prohomeostatic functions fully breaks with the classical pharmacology view of “one drug, one target, one disease”, opening a new era in the management of animals’ health, i.e., an according-to-nature biomodulation of body responses to different stimuli and injury. The present review focuses on the direct and indirect endocannabinoid receptor agonism by PEA and its analogues and also targets the main findings from experimental and clinical studies on ALIAmides in animal health and wellbeing.