Kadar leptin pada orang obes dengan dan tanpa resistensi insulin

SIMLIATY, Prof. dr. H. A. H. Asdie, SpPD-KEMD

2008 | Tesis | S2 Ilmu Penyakit Dalam

Latar Belakang: Obesitas berhubungan dengan terjadinya diabetes melitus tipe 2 yang ditandai dengan resistensi insulin. Jaringan adiposa yang sebelumnya dikenal hanya sebagai tempat penyimpanan energi berupa trigliserida, diketahui mensekresi adipokin. Leptin, suatu protein 16-k-Da diekspresikan terbanyak di jaringan adiposa putih dan pada manusia kadarnya berkorelasi erat dengan presentasi lemak tubuh. Beberapa penelitian terdahulu menunjukkan adanya hubungan antara leptin dengan insulin atau resistensi insulin dimana terjadi disregulasi aksis adipoinsular pada orang obes sehingga terjadi hiperinsulinemia kronik yang merupakan patogenesis terjadinya diabetes. Tujuan Penelitian: Mengetahui perbedaan kadar leptin pada orang obes dengan dan tanpa resistensi insulin. Metode dan Cara Penelitian: Penelitian dilakukan secara potong lintang pada pasien obes di klinik general check-up dan klinik endokrinologi RSUP Dr. Sardjito Yogyakarta. Dilakukan pemeriksaan kadar leptin plasma pada 56 pasien obes dengan indeks masa tubuh ≥25 kg/m2. Resistensi insulin dinilai dengan perhitungan homeostasis model assessment insulin resistance (HOMA IR) yang didapat dari kadar insulin puasa dan kadar gula darah. Pengukuran kadar leptin menggunakan Quantikine Human Leptin Immunoassay. Perbedaan antara kedua kelompok dianalisa dengan uji t tidak berpasangan dan Mann Whitney U-test. Hasil Penelitian: Terdapat 56 subyek obes, 24 (42,9%) subyek dengan resistensi insulin dan 32 (57,1%) tanpa resistensi insulin. Kadar leptin kesan lebih tinggi pada pria obes dengan resistensi insulin daripada tanpa resistensi insulin tetapi secara statistik perbedaan tersebut tidak bermakna [ 9,34(2,71-35,13) dan 8,26(2,08-69,14), P=0,95]. Kadar leptin pada wanita obes dengan resistensi insulin kesan lebih rendah daripada tanpa resistensi insulin tetapi tidak bermakna secara statistik [ 16,52(3,68-62,20) dan 29,26(3,82-104,96), P=0,69]. Simpulan: Kadar leptin tidak berbeda bermakna antara subyek obes dengan resistensi insulin dan obes tanpa resistensi insulin.

Backgorund: The association of obesity with type 2 diabetes has been recognized and the major basis for this link is the ability of obesity to engender insulin resistance. The traditional view of adipose tissue as a passive reservoir for energy storage is no longer valid. Adipose tissue is now known to express and secrete adipokines. Leptin is a 16-kDa protein produced primarily in white adipose tissue. Circulating leptin concentration in humans correlates closely with the percentage of body fat. Recent studies suggest a complex interrelationship between leptin and insulin or insulin resistance. Dysregulation of the adipoinsular axis in obese individuals may result in chronic hyperinsulinemia and may contribute to the pathogenesis of diabetes. Objective: To evaluate plasma leptin levels in obese subjects with and without insulin resistance. Methods: This was a cross sectional study including obese outpatients, recruited from general check-up and endocrinology clinic, Sardjito General Hospital Yogyakarta. We examined plasma levels of leptin in 56 obese subjects with body mass index (BMI) ≥25 kg/m2. Insulin resistance was assessed using the homeostasis model assessment insulin resistance (HOMA IR) derived from fasting insulin and glucose levels. Quantikine Human Leptin Immunoassay was used to measure plasma leptin levels. Differences between groups were compared by Student’s unpaired t-test and Mann Whitney U-test. Results: There were 56 obese subjects, 24 (42,9%) with insulin resistance and 32 (57,1%) without insulin resistance. Leptin levels seemed higher in obese men with insulin resistance than without insulin resistance [ 9,34(2,71-35,13) vs. 8,26(2,08-69,14), P=0,95] and lower in obese women with insulin resistance [16,52(3,68-62,20) vs. 29,26(3,82-104,96)], P=0,69 although they’re not statistically significant. Conclusions: Leptin levels were not significantly different between obese subjects with and without insulin resistance.

Kata Kunci : Leptin, Obes, Resistensi insulin, insulin resistance.