Fish oil supplementation increases concentration of adiponectin in healthy dogs

Analysis of insulin resistance using the non-linear homeostatic model assessment index in overweight canines

Background and Aim:

Diabetes mellitus is a carbohydrate metabolism disorder produced mainly by a deficit in insulin production or insulin resistance. The homeostatic model assessment (HOMA) is a broad method for estimating insulin resistance and β-cell function. This study aimed to evaluate the stages of insulin resistance using non-linear HOMA index analysis in normoglycemic normal weight and obese canines.

Materials and Methods:

Insulin resistance was evaluated using the mathematical HOMA non-linear model in canines with different body and glycemic conditions. Forty canines were studied, including 20 normoglycemic normal weight canines and 20 normoglycemic obese canines. Chi-square statistical test was applied, in which the body condition and HOMA non-linear index were evaluated. The Spearman correlation test was conducted to evaluate the glycemic and insulin variables in both types of canines.

Results:

The Spearman correlation presented a correlation between increased blood glucose levels and insulin in obese canines, with a correlation of 0.79, while no significant changes in insulin were found in normal weight canines with different blood glucose levels, with a correlation of −0.11. The analysis of the non-linear HOMA index showed significant differences between non-linear HOMA insulin resistance in normal weight and obese canines, with a Chi-square statistic of 16.9424 and p = 0.000039. Canine with increased HOMA 2 showed higher levels of insulin with increasing blood glucose compared to those with normal HOMA 2.

Conclusion:

The HOMA 2 is a marker for evaluating increased insulin resistance in obese dogs and can be used to determine patients at risk for glycemic alterations.

Dietary Fatty Acids Differentially Regulate Secretion of Adiponectin and Interleukin-6 in Primary Canine Adipose Tissue Culture

The aim of this study was to determine the effect of n3 polyunsaturated fatty acids (PUFA) on canine adipose tissue secretion of adiponectin, interleukin-6 (IL6), and tumor necrosis factor-α (TNFα). Subcutaneous and omental visceral adipose tissue samples were collected from 16 healthy intact female dogs. Concentrations of adiponectin were measured in mature adipocyte cultures, and concentrations of IL6 and TNFα were measured in undifferentiated stromovascular cell (SVC) cultures following treatment with eicosapentaenic acid (EPA, 20:5n-3), arachidonic acid (ARA, 20:4n-6), or palmitic acid (PAM, 16:0) at 25, 50, or 100 μM. Secretion of adiponectin from mature adipocytes was higher (p < 0.001) following EPA treatment at 50 μM compared to control in subcutaneous tissue, and higher following EPA treatment compared to PAM treatment at 25 μM in both subcutaneous (p < 0.001) and visceral tissues (p = 0.010). Secretion of IL6 from SVC derived from subcutaneous tissue was lower following EPA treatment and higher following PAM treatment compared to control both at 50 μM (p = 0.001 and p = 0.041, respectively) and 100 μM (p = 0.013 and p < 0.001, respectively). These findings of stimulation of adiponectin secretion and inhibition of IL6 secretion by EPA, and stimulation of IL6 secretion by PAM, are consistent with findings of increased circulating concentrations of adiponectin and decreased circulating concentration of IL6 in dogs supplemented with dietary fish oil, and show that the effect of fish oil on circulating concentrations of adiponectin and IL6 is, at least partially, the result of local effects of EPA and PAM on adipose tissue.

The associations between serum adiponectin, leptin, C-reactive protein, insulin, and serum long-chain omega-3 fatty acids in Labrador Retrievers

Obesity has been associated with an increased inflammatory response and insulin resistance due to adipose tissue–derived adipokines and increases in C-reactive protein (CRP). Dogs appear to be similar to other species with the exception of adiponectin, which might not be affected by obesity status. Serum long-chain polyunsaturated fatty acid concentrations have been positively and negatively associated with serum adipokines. The aim of the study was to examine the relationship between leptin, CRP, adiponectin, and insulin to body condition score (BCS) and to the long-chain omega-3 fatty acids in serum lipoproteins, including alpha-linolenic acid, eicosapentaenoic acid (EPA), docosapentanenoic acid (DPA), and docosahexaenoic acid (DHA) as a reflection of dietary omega-3 status in the Labrador Retriever. Seventy-seven Labrador Retrievers were evaluated for BCS, percent fasting serum lipoprotein fatty acid concentrations, as well as serum leptin, adiponectin, insulin, and CRP. A multivariable general linear regression model was constructed to examine the association between the dependent variables leptin, CRP, adiponectin, and insulin and the predictor variables of BCS, age, and sex, as well as concentrations of alpha-linolenic acid, EPA, DHA, and DPA. Adiponectin concentration was positively associated with age (P<0.0008), EPA (P=0.027) and negatively associated with DHA (P=0.008). Leptin concentration was positively associated with an increased DHA (P=0.009), BCS (P<0.0001), age (P=0.02), and decreased DPA (P=0.06). Insulin concentration was only associated with BCS (P<0.0001), and no meaningful associations were found for CRP. Longer chain omega-3 fatty acids may play a role in regulating adiponectin concentrations in dogs. However, because insulin concentrations were associated only with BCSs, further examination of the role of adiponectin in canine obesity is warranted. EPA and DPA may reduce the overall inflammatory state in dogs as these omega-3 fatty acids reflect increased adiponectin (increased EPA and decreased DHA) and decreased leptin (decreased DHA and increased DPA).

Effects of administration of omega-3 fatty acids with or without vitamin E supplementation on adiponectin gene expression in PBMCs and serum adiponectin and adipocyte fatty acid-binding protein levels in male patients with CAD

OBJECTIVE

Adiponectin is a unique anti-atherogenic adipocytokine. Regulation of adiponectin secretion is dysfunctional in cardiovascular diseases. The current trial study assessed the effects of omega-3 fatty acids with or without vitamin E on adiponectin gene expression in peripheral blood mononuclear cells and serum adiponectin and adipocyte fatty acid-binding protein (A-FABP; also called ap2 and FABP4) levels in patients with coronary artery disease (CAD).

METHODS

This randomized, double-blind, placebo-controlled trial included 67 male patients with CAD. First of the four group of participants received 4 g/day omega-3 fatty acids plus 400 IU/day vitamin E (OE), second group 4 g/day omega-3 fatty acids plus vitamin E placebo (OP), or both omega-3 fatty acid and vitamin E placebos (PP) for 8 weeks. Adiponectin gene expression and serum adiponectin and FABP4 levels were evaluated.

RESULTS

The combination of omega-3 fatty acids and vitamin E in patients with CAD affected their serum adiponectin and FABP4 levels and the adiponectin/FABP4 ratio significantly. In the OP group, serum adiponectin levels did not change significantly. Consumption of omega-3 fatty acids with and without vitamin E had no significant effect on adiponectin gene expression.

CONCLUSION

Omega-3 fatty acids with or without vitamin E improve adiponectin levels in patients, without any significant changes in adiponectin gene expression. This nutritional intervention may prevent complications in patients with CAD because of increased adiponectin levels.

Increased serum concentrations of adiponectin in canine hypothyroidism

Serum concentrations of adiponectin were compared between sex-matched hypothyroid (n = 18) and euthyroid (n = 18) client-owned dogs with comparable ages and body condition scores (BCS). Concentrations of adiponectin (mean; 95% confidence interval) were significantly (P < 0.01) higher in hypothyroid (17.2 µg/mL; 12.1-20.5 µg/mL) than healthy (8.0 µg/mL; 5.6-11.4 µg/mL) dogs following adjustment for potential confounders (BCS, age and sex). Serum concentrations of adiponectin were significantly negatively associated with concentrations of total thyroxine (P <0.05) and positively correlated with concentrations of cholesterol (r = 0.6, P <0.01) in hypothyroid dogs. In conclusion, this study demonstrated increased serum concentrations of adiponectin in dogs with hypothyroidism. Suggestive of the presence of resistance to adiponectin that could have contributed to development of hyperlipidemia and insulin resistance in these dogs or alternatively, could be a consequence of these metabolic alterations.