Leptin System in Obese Dog Skin: A Pilot Study

Abstract

Obesity predisposes to several health problems including skin diseases. However, information on the relationship between obesity and skin disorders in pets is very scarce. Leptin (LEP) is mainly produced by adipose tissue and has a prominent role in skin biology. This study evaluated the LEP system in the skin of obese dogs compared to normal-weight animals. The investigation was carried out on 10 obese (Obese group) and 10 normal-weight (Normal-weight group) dogs through Real-time PCR and immunohistochemistry. Cells of skin associated immune system were also evaluated. No differences were evidenced between the two groups as well as skin inflammation. LEP differences were no significant, while LEPR transcript appeared 10-fold higher in obesedogs than in normal-weight ones. Immunostaining for both molecules was observed in several skin structures such as the epidermis, hair follicles, and glands. No differences appeared in the skin associated immune system composition. This study is a preliminary report showing that LEP system changes in obese dog skin. The increased LEPR expression observed in the obese group suggests that the receptor plays a modulating role in the system control. However, the exact role of LEPin the skin under obesity conditions needs further elucidation.

Effects of Obesity on Adiponectin System Skin Expression in Dogs: A Comparative Study

“…To our knowledge, this is the first description of a downregulation of ADIPOQ and ADIPOR2 in the skin of obese dogs; thus, showing a possible role of adiponectin in this serious health problem. This study expands the knowledge on the role of adipokines in the skin, starting from previous evaluations in dogs [ 39 ], with respect to obesity [ 14 ].…”

“…Twenty mixed breed, medium-sized dogs were recruited; the animals were the same as in a previously published paper, to which we refer to [ 14 ]. All animals were healthy as verified by clinical, hematological, and biochemical examination, and devoid of pre-existing pathological conditions.…”

“…For histochemical procedures, biopsies were quickly fixed in 10% neutral buffered formalin solution in phosphate buffered saline (PBS 0.1 M, pH 7.4) and processed until they were embedded in paraffin wax [ 12 ]. Sections with a thickness of 5-µm were mounted onto poly-L-lysine coated glass slides and stained with hematoxylin–eosin and Giemsa, to exclude the presence of skin lesions and to evaluate the number of mast cells respectively [ 14 ]. Mast cells were blindly evaluated, counting their numbers on five contiguous high-power fields (magnification 400× with a field number of the ocular of 22) for each section.…”

“…Total RNA was extracted from the skin biopsies of 10 dogs from each experimental group, as previously described [ 14 ]. Five µg of total RNA was reverse transcribed in 20 µL of iScript cDNA using random hexamer according to the protocol provided by the manufacturer (Bio-Rad Laboratories, Milan, Italy).…”

“…Adipokine levels may vary in the obese according to adipose tissue accumulation. In addition to adipose tissue, several peripheral tissues secrete adipokines [ 8 , 9 , 10 , 11 , 12 , 13 ], where they perform local actions that can be affected by obesity [ 14 ]. Adiponectin (ADIPOQ) is the most abundant gene product in adipose tissue and accounts for 0.01% of total plasma protein [ 15 ].…”