Leptin and immune function: integrating the evidence

Salivary leptin levels in normal weight and overweight individuals and their correlation with orthodontic tooth movement

OBJECTIVES

To assess and compare the concentration of leptin in saliva between normal weight and overweight individuals and to evaluate the rate of orthodontic tooth movement.

MATERIALS AND METHODS

Thirty female subjects were divided into two groups: I (normal weight) and II (overweight group) based on their body mass index. All subjects underwent fixed appliance therapy requiring upper first premolar extraction and distal movement of the canine. Distal force was applied to the maxillary right canine using active lacebacks. Salivary samples were collected just before force application (T₀), 1 hour (T₁), and 1 month (T₂) after force application. The rate of tooth movement was evaluated over 3 months and was measured on study models.

RESULTS

At all three time intervals, mean leptin concentration was greater in overweight individuals than normal weight individuals. In both groups at T₁, the mean leptin concentration was found to increase significantly compared with the baseline value (T₀), but at T₂, the leptin concentration declined to values lesser than the baseline values (T₀).

CONCLUSIONS

Overweight individuals had greater salivary leptin concentration. There was a positive correlation between salivary leptin concentration and rate of tooth movement in both normal and overweight individuals. The rate of tooth movement is decreased in overweight individuals as compared with normal weight individuals.

Serum leptin levels, skin leptin and leptin receptor expression in psoriasis

BACKGROUND

Recent studies support the relation of psoriasis with obesity and cardiovascular disease. Leptin, a peptide hormone secreted predominantly from adipose tissue, is involved in the regulation of energy intake and expenditure. Recently, it has been shown to have several immunological effects including induction of proinflammatory cytokine production.

OBJECTIVES

To investigate the possible role of leptin in psoriasis pathogenesis.

METHODS

Forty-three patients with psoriasis, 10 diseased and 10 healthy controls with normal body mass index were included. Serum fasting leptin levels of the study group were examined by enzyme-linked immunosorbent assay. Tissue leptin and leptin receptor expression of both patients and controls were investigated by immunohistochemistry.

RESULTS

Serum leptin levels, tissue leptin and leptin receptor expression were significantly higher in patients with severe psoriasis than patients with mild-moderate psoriasis and controls (P < 0.05). Serum leptin levels showed a positive correlation with Psoriasis Area and Severity Index and involved body surface area in patients with psoriasis. In addition, serum leptin levels, tissue leptin and leptin receptor expression showed a positive correlation with disease duration in patients with psoriasis (P < 0.01, r = 0.979; P < 0.01, r = 0.691; P < 0.01, r = 0.428, respectively).

CONCLUSIONS

We assume that leptin might serve as a marker of severity in psoriasis and also may be a pathogenetic cofactor contributing to chronicity of the disease. Consequently, its role in obesity and cardiovascular disease in patients with psoriasis deserves to be studied. In addition, drugs targeting the proinflammatory effects of leptin may be a new adjuvant therapeutic approach in psoriasis.

Levels of serum interleukin (IL)-6, IL-1beta, tumour necrosis factor-alpha and leptin and their correlation in depression

OBJECTIVE

To investigate the relationship between leptin and cytokines in depressed patients.

METHODS

Thirty-three unmedicated patients (24 female, nine male) with depressive disorder and 23 healthy controls (16 female, seven male) were assessed for serum levels of interleukin (IL)-6, IL-1beta, tumour necrosis factor-alpha (TNF-alpha) and leptin.

RESULTS

Levels of IL-6 and TNF-alpha in depressed patients were higher than in normal controls. There were significantly lower leptin levels in depressed patients than in normal controls. There were also significant differences in the leptin levels, being higher in female than in male patients, and in female than in male controls.

CONCLUSIONS

IL-6 and TNF-alpha cytokines and leptin are important in the psychoimmunology of depressed patients. There were gender differences in leptin levels in depression.