Serum leptin and ghrelin levels in response to methylprednisolone injection in healthy dogs

Serum adipokine concentrations in dogs with naturally occurring pituitary-dependent hyperadrenocorticism

BACKGROUND

An excess of intra-abdominal fat is observed frequently in dogs with hyperadrenocorticism (HAC). Adipokine dysregulation is a possible cause of complications related to visceral obesity, but little information is available on adipokine in dogs with naturally occurring HAC.

OBJECTIVES

To examine the differences in the circulating adipokines concentrations in overweight dogs with and without pituitary-dependent HAC (PDH).

ANIMALS

Thirty healthy dogs and 15 client-owned dogs with PDH.

METHODS

Case-controlled observational study, which enrolled 15 overweight dogs diagnosed with PDH and 30 otherwise healthy dogs of similar body condition score. Nine of 15 dogs with PDH were treated with low-dose trilostane twice daily and reassessed after treatment.

RESULTS

The serum leptin (P < .0001) and insulin (P < .0001) concentrations were significantly higher in the PDH group (leptin, 22.8 ± 8.8 [mean ± SD]; insulin, 9.1 ± 6.1) than the healthy group (leptin, 4.9 ± 3.7; insulin, 1.9 ± 0.9). However, there were no significant differences in the adiponectin, resistin, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-10, and IL-18 levels between the 2 groups. In the PDH group, the serum cortisol concentrations had a linear association with the leptin concentrations, and there were significant decreases in the leptin (P = .0039) and insulin (P = .0039) levels after trilostane treatment. However, the leptin and insulin levels remained higher after trilostane treatment than in healthy control dogs with similar body condition score.

CONCLUSIONS AND CLINICAL IMPORTANCE

Hypercortisolemia in dogs with PDH might upregulate the circulating leptin levels. However, a large population-based study will be necessary to determine whether the upregulation of leptin is involved directly with the complications caused by HAC.

Influence of different storage conditions and anticoagulants on the measurement of total and acylated ghrelin in dogs: a preliminary study

The objective of this study was to evaluate and compare different sample treatments and storage conditions in order to determine optimal conditions for total and acylated canine ghrelin measurement using ELISA assays. Under the conditions assessed in this study, total ghrelin concentration was stable when stored at room temperature or under cooled conditions (4°C) for approximately six hours regardless of the type of anticoagulant used. When samples were stored at under -20°C, three freeze/thaw cycles during storage did not alter total ghrelin concentration if serum or plasma treated with EDTA or with EDTA-aprotinin is used. When samples were stored at under -80°C, no significant differences were observed after three freeze/thaw cycles in total ghrelin concentrations in serum or plasma treated with EDTA, EDTA-aprotinin or heparin. While acylated ghrelin showed to be very instable, its analysis should be performed within an hour of sample collection or stored at -80°C preferably in serum in order to acquire accurate data. Addition of HCl did not improve total or acylated ghrelin stability. Furthermore, acidification of plasma samples decreased the stability of total ghrelin and impeded determination of acylated ghrelin with the ELISA used in this study.

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

The aim of the study was to determine the magnitude of diurnal variability of serum adiponectin in healthy beagle dogs, and the possible roles of feeding and glucocorticoids on adiponectin concentrations. For this, adiponectin was measured at 8:00, 10:00, 12:00, 16:00, 20:00, 24:00 and at 4:00 h in 4 beagle dogs that were fasted on the day of the experiment and in 4 dogs that were fed as usual at 9:00 h. Diurnal variability in serum adiponectin concentrations was negligible in both the fed and the fasted dogs. To study the possible effect of glucocorticoids on adiponectin, beagle dogs (n = 14) were assigned to one of three experimental groups. Dogs of the control group were injected with 0.1 ml/kg 0.9% NaCl subcutaneously, while dogs of Groups 1 and 2 were injected with 1 mg/kg and 5 mg/kg of methylprednisolone, respectively, and adiponectin was measured at 8:00, 10:00, 12:00, 16:00 and 20:00 h. Average serum adiponectin levels were not significantly different before and after methylprednisolone exposure at different time-points in the two treated groups. In conclusion, no evidence of postprandial changes in adiponectin level or effects of single-dose glucocorticoid administration on adiponectin were observed in the present study.

Ghrelin, appetite and critical illness

PURPOSE OF REVIEW

Recovery and rehabilitation after critical illness is a vital part of intensive care management. The role of feeding and nutritional intervention is the subject of many recent studies. The gastric hormone ghrelin has effects on appetite and food intake and on immunomodulatory functions. Here we review the interactions between critical illness, appetite regulation, nutrition and ghrelin.

RECENT FINDINGS

Critical illness results in significant loss of lean body mass; strategies to prevent this have so far proven unsuccessful. Ghrelin has been shown to reduce catabolic protein loss in animal models of critical illness and improve body composition in chronic cachectic illnesses in humans.

SUMMARY

Enhancing recovery from critical illness will improve both short-term and long-term outcomes. Ghrelin may offer an important means of improving appetite, muscle mass and rehabilitation in the period after critical illness, although studies are needed to see whether this potential is realized.

The potential role of leptin and adiponectin in obesity: a comparative review

Leptin and adiponectin are adipokines produced by the white adipose tissue. The adipokines have been shown to be valuable quantitative markers of adiposity in dogs. Leptin positively correlates with body condition score (BCS) in dogs, regardless of age, sex and breed, and is influenced by feeding state, pharmacological treatment and thyroid gland activity. Conversely, adiponectin negatively correlates with body fat mass and is therefore more abundant in lean animals. The implication of leptin and adiponectin in the pathogenesis of metabolic syndrome is well established in humans, but currently lacking in dogs. Additional studies are necessary to demonstrate their potential usefulness for monitoring the progression of obesity-related diseases and response to treatment. To date, measurement of canine leptin and adiponectin has been used in experimental studies only, whereas bodyweight and BCS are considered the first-approach parameters for the routine assessment of body fat content in obese dogs.

Effect of preoperative single-dose corticosteroid administration on postoperative morbidity following esophagectomy

BACKGROUND

Eight clinical trials involving the administration of preoperative i.v. methylprednisolone have been undertaken in order to decrease the considerable inflammatory response to esophageal resection, in an effort to decrease the supposedly associated morbidity and mortality

METHOD

A meta-analysis was performed for eight clinical end-points. Due to quality problems in seven of the eight included studies, a Bayesian meta-analysis using a skeptical prior derived from the results of the classical analysis was also performed.

RESULTS

The end-points including any organ dysfunction (OR = 0.30), respiratory complication (OR = 0.41), sepsis (OR = 0.37), liver dysfunction (OR = 18), cardiovascular dysfunction (OR = 0.28), and surgical anastomotic leak (OR = 0.42) were significantly decreased by methylprednisolone pretreatment. Following the Bayesian analysis, despite the use of skeptical priors, there is a 95% probability to obtain a relative risk reduction of at least 23% to 54%, depending of the end-point, by methylprednisolone pretreatment.

CONCLUSION

We are in the presence of a potential benefit that cannot be accepted at face value due to the quality problems of the included studies. But in the presence of a remaining potential benefit after a Bayesian analysis starting from a skeptical prior, the best option would be the planning of a large multicenter prospective randomized study.

Strength training combined with plyometric jumps in adults: sex differences in fat-bone axis adaptations

Leptin and osteocalcin play a role in the regulation of the fat-bone axis and may be altered by exercise. To determine whether osteocalcin reduces fat mass in humans fed ad libitum and if there is a sex dimorphism in the serum osteocalcin and leptin responses to strength training, we studied 43 male (age 23.9 2.4 yr, mean +/- SD) and 23 female physical education students (age 23.2 +/- 2.7 yr). Subjects were randomly assigned to two groups: training (TG) and control (CG). TG followed a strength combined with plyometric jumps training program during 9 wk, whereas the CG did not train. Physical fitness, body composition (dual-energy X-ray absorptiometry), and serum concentrations of hormones were determined pre- and posttraining. In the whole group of subjects (pretraining), the serum concentration of osteocalcin was positively correlated (r = 0.29-0.42, P < 0.05) with whole body and regional bone mineral content, lean mass, dynamic strength, and serum-free testosterone concentration (r = 0.32). However, osteocalcin was negatively correlated with leptin concentration (r = -0.37), fat mass (r = -0.31), and the percent body fat (r = -0.44). Both sexes experienced similar relative improvements in performance, lean mass (+4-5%), and whole body (+0.78%) and lumbar spine bone mineral content (+1.2-2%) with training. Serum osteocalcin concentration was increased after training by 45 and 27% in men and women, respectively (P < 0.05). Fat mass was not altered by training. Vastus lateralis type II MHC composition at the start of the training program predicted 25% of the osteocalcin increase after training. Serum leptin concentration was reduced with training in women. In summary, while the relative effects of strength training plus plyometric jumps in performance, muscle hypertrophy, and osteogenesis are similar in men and women, serum leptin concentration is reduced only in women. The osteocalcin response to strength training is, in part, modulated by the muscle phenotype (MHC isoform composition). Despite the increase in osteocalcin, fat mass was not reduced.

Endotoxin increases plasma leptin and ghrelin levels in dogs

OBJECTIVE

Evaluations of plasma leptin and ghrelin levels and their relations with circulating levels of proinflammatory mediators, stress hormones, and biochemical markers of hepatorenal injury during experimental endotoxemia in dogs.

SETTING

Uludag University.

DESIGN

Placebo-controlled animal study.

ANIMALS

Adult mongrel dogs (n = 16).

INTERVENTIONS

Intravenous injection of endotoxin (1 mg/kg) and blood sample withdrawal before and at 0.5-48 hrs posttreatment.

MEASUREMENTS AND MAIN RESULTS

Mean baseline plasma leptin and ghrelin levels were 2.4 +/- 0.1 ng/mL and 867 +/- 58 pg/mL, respectively. Plasma leptin and ghrelin increased significantly by 16% (p < .05) and 72% (p < .001) at 0.5 hr, and they remained elevated by 33-41% (p < .001) and 59-74% (p < .001) at 48 hrs after administration of endotoxin, respectively. There was positive correlation (r = .844; p < .001) between plasma leptin and ghrelin levels in endotoxin-treated dogs. Endotoxemia was associated with several-fold elevations in circulating levels of stress hormones, proinflammatory mediators, and hepatorenal injury markers. Plasma leptin and ghrelin levels in endotoxin-treated dogs were correlated with serum nitric oxide (r = .955 and r = .890; p < .001), procalcitonin (r = .825 and r = .716; p < .001), cortisol (r = .823 and r = .786; p < .001), and hepatorenal injury markers (r = .580 to .745 and r = .393 to .574; p < .05 to .01).

CONCLUSIONS

Circulating leptin and ghrelin levels increase during endotoxemia, and these increases are associated with elevated levels of proinflammatory mediators, stress hormones, and serum biochemical markers for hepatorenal dysfunction.