Time-resolved hypothalamic open flow micro-perfusion reveals normal leptin transport across the blood–brain barrier in leptin resistant mice

Objective The inability of leptin to suppress food intake in diet-induced obesity, sometimes referred to as leptin resistance, is associated with several distinct pathological hallmarks. One prevailing theory is that impaired transport of leptin across the blood–brain barrier (BBB) represents a molecular mechanism that triggers this phenomenon. Recent evidence, however, has challenged this notion, suggesting that leptin BBB transport is acquired during leptin resistance. Methods To resolve this debate, we utilized a novel cerebral Open Flow Microperfusion (cOFM) method to examine leptin BBB transport in male C57BL/6J mice, fed a chow diet or high fat diet (HFD) for 20 days. Results Basal plasma leptin levels were 3.8-fold higher in HFD-fed mice (p
Highlights • Cerebral Open Flow Microperfusion can be utilized to assess hypothalamic leptin levels. • Twenty days of high-fat diet feeding causes functional resistance to exogenous leptin. • Transport of leptin across the BBB is not impaired by HFD-induced leptin resistance.