Obesity blunts cephalic-phase microvascular responses to food

Area of Science:

• Physiology
• Metabolic Health
• Vascular Biology

Background:

• Neurally mediated anticipatory responses, or cephalic-phase responses, and microcirculatory regulation are key to metabolic homeostasis.
• Altered cephalic-phase responses are implicated in obesity and its metabolic sequelae.
• In vivo microcirculatory assessment during cephalic-phase responses in obesity is understudied.

Purpose of the Study:

• To investigate the in vivo microcirculatory response during cephalic-phase stimulation in individuals with obesity.
• To compare microvascular function between individuals with obesity and healthy controls during cephalic-phase responses.
• To assess capillary recruitment and microhemodynamics in response to cephalic-phase stimulation.

Main Methods:

• Randomized controlled trial comparing individuals with obesity (n=27) and healthy subjects (n=17).
• Patients with obesity were randomized into cephalic-phase response stimulation (CP group, n=13) and control (n=14) groups.
• Skin microcirculation assessed using dorsal finger and dynamic nailfold videocapillaroscopy to measure functional capillary density (FCD) and red blood cell velocity (RBCV) during post-occlusive reactive hyperemia (PORH).

Main Results:

• Patients with obesity, regardless of stimulation, failed to demonstrate increased FCD during PORH, indicating a lack of capillary recruitment (p=0.221 and p=0.307).
• Healthy subjects showed a significant increase in FCD during PORH (p=0.004), demonstrating effective capillary recruitment.
• Microhemodynamic variables (RBCV, RBCVmax, TRBCVmax) changed in both CP groups (healthy and obese).

Conclusions:

• This study provides the first in vivo evidence of absent capillary recruitment during cephalic-phase responses in individuals with obesity.
• The findings suggest a microvascular impairment contributing to metabolic dysregulation in obesity.
• Further research into microvascular dysfunction in obesity is warranted.