Serum adiponectin concentration in dogs - absence of diurnal variation and lack of effect of feeding and methylprednisolone administration

Impact of low-carbohydrate diet on serum levels of leptin and adiponectin levels: a systematic review and meta-analysis in adult

Background

Various studies have evaluated the effects of low-carbohydrate diet (LCD) on serum concentrations of adipokines. Although the association between LCD and serum levels of leptin and adiponectin has been studied extensively, the results were not consistent.

Objective

The purpose of this study was to systematically evaluate the effect of LCD on serum levels of leptin and adiponectin.

Design

Electronic databases were retrieved in PubMed, Embase, Scopus and Web of Science to search relevant publications. Pooled standard mean difference (SMD) with 95% confidence interval (CI) was calculated by the random-effect model. Cochrane Q test and I² statistic were used to test heterogeneity. Subgroup analysis and meta-regression were applied to assess possible sources of heterogeneity.

Results

A total of thirty-five articles were included in final analysis. Meta-analysis results revealed no statistical association between LCD and adiponectin concentration (WMD: 0.32 ng/ml, 95% CI: - 0.02, 0.66, p=0.062). Subgroup analysis showed that LCD increased adiponectin concentration in subjects under 45 years old and in studies with long term duration intervention. Also, did not observe a significant effect from the LCD on serum concentration of leptin (WMD: - 0.77 ng/ml, 95% CI: -3.15, 1.61, P=0.409). Subgroup analysis did not show any new information. The results of this study did not support the evidence for the positive effects of LCD on serum leptin and adiponectin levels.

Influence of macronutrient composition of commercial diets on circulating leptin and adiponectin concentrations in overweight dogs

Leptin and adiponectin play important roles in obesity‐related inflammation and comorbidities. Previous research suggests that alterations in dietary macronutrient composition can modify circulating leptin and adiponectin concentrations in people, but limited research on this subject has been performed in dogs. This study investigated the effects of commercial high protein (HP), high fat (HF) and high carbohydrate medium protein (HCMP) diets on baseline (T₋₁) concentrations, post‐prandial peak concentrations and total release in a ten‐hour time span of leptin and adiponectin in dogs, when compared to a maintenance high carbohydrate low protein (HCLP) diet. Thirty‐six overweight dogs were fed the HCLP diet in a one‐week control period, after which the animals were assigned to one of three groups. In three four‐week periods, each group was fed all test diets in a different sequence. At the last day of each period, blood was sampled at one hour before feeding (T₋₁) and at three (T₃), six (T₆) and nine (T₉) hours after feeding. Feeding caused peak leptin concentrations at T₆ and T₉ (p < .001). No significant post‐prandial change in adiponectin concentrations was found (p = .056). The HP diet resulted in lower leptin peak concentrations (p = .004) and AUC_T−1–T9 (p = .01), but none of the diets influenced baseline leptin concentrations (p = .273). Baseline adiponectin concentrations were lower for the HF diet (p = .018) and HCMP (p < .001), and the HP, HF and HCMP AUC_T−1–T9 (p < .001) were lower compared with the HCLP diet. Female dogs had lower adiponectin baseline concentrations (p = .041) and AUC_T−1–T9 (p = .023) than male dogs. In conclusion, the HP diet was associated with the lowest post‐prandial peak leptin concentration and the least decrease in adiponectin release, suggesting that a HP diet may improve immune‐metabolic health and post‐prandial satiety in overweight dogs.

Serum and salivary adiponectin dynamics in septic and non-septic systemic inflammation in a canine model

Adiponectin is a 30 kDa protein hormone that has anti-atherogenic properties, being an insulin-sensitizing and anti-inflammatory molecule. Salivary adiponectin concentrations correlate positively with serum, thus, saliva was indicated as appropriate biofluid for its measurement in different clinical situations. However, inflammation was indicated as main confounding factor when evaluating the usefulness and the reliability of determination of salivary adiponectin. The aim of the present report was to evaluate the dynamics of salivary and serum adiponectin in systemic non-septic and septic inflammation using a dogs as a model. Forty bitches were enrolled. Seventeen dogs were healthy (group I, non-septic) and 23 bitches were diagnosed with pyometra (group II, septic). Ovariohysterectomy was performed for all animals. Saliva and blood samples were collected before (D0) and 3 (D3) and 10 (D10) days after ovariohysterectomy. At D0, Group I showed higher serum and salivary adiponectin than group II, although statistical significance was only detected in salivary adiponectin between the two groups at D0 (P = 0.001). In serum, adiponectin was higher on D0 than on D3 and tended to reach pre-surgery values on D10 in both groups. Salivary adiponectin showed similar behaviour to serum in Group I, while in group II salivary adiponectin concentrations were lowest on D0 and tended to increase on D3 and D10. The data obtained in present study describe for the first time the comparative behavior of salivary adiponectin in non-septic and septic inflammation. Salivary, and not serum, adiponectin seemed to mimic better the inflammatory and general health status.

Effect of physiological determinants and cardiac disease on plasma adiponectin concentrations in dogs

Background

In humans, a high concentration of adiponectin is associated with a favorable cardiovascular risk profile whereas, in patients with heart failure (HF), a high concentration of adiponectin is associated with a less favorable prognosis.

Hypothesis/Objectives

To evaluate the physiological determinants of plasma adiponectin concentration in dogs and the influence of heart disease, myxomatous mitral valve disease (MMVD), and dilated cardiomyopathy (DCM).

Animals

One hundred and fourteen client‐owned dogs and 9 Beagles from the research colony of the Clinical Veterinary Unit of the University of Liège.

Methods

We prospectively measured circulating adiponectin concentration in healthy control dogs (n = 77), dogs with MMVD (n = 22) and dogs with DCM (n = 15) of various degrees of severity. Diagnosis was confirmed by Doppler echocardiography. Plasma adiponectin concentration was measured by a canine‐specific sandwich ELISA kit.

Results

An analysis of covariance showed an association between adiponectin concentration and age, neuter status, and heart disease. No association between adiponectin concentration and class of HF, sex, body condition score, body weight, circadian rhythm, or feeding was found. Plasma adiponectin concentration was negatively correlated with age (P = .001). Adiponectin was lower in neutered (P = .008) compared to intact dogs. Circulating adiponectin concentration was increased in dogs with DCM compared to healthy dogs (P = .018) and to dogs with MMVD (P = .014).

Conclusions and Clinical Importance

Age and neutering negatively influence circulating adiponectin concentration. Plasma adiponectin concentration increased in dogs with DCM. Additional research is required to investigate if this hormone is implicated in the pathophysiology of DCM and associated with clinical outcome.