Clinical Research Directory

The Efficacy of Aerobic Exercise Training on ANS and Endothelial Function in Compensated Cirrhosis

The goal of this randomized controlled trial is to investigate whether a 16-week structured aerobic exercise program combined with nutritional consultation can improve autonomic and endothelial function in patients with compensated cirrhosis. Study Design: This assessor-blinded, parallel-group randomized controlled trial will be conducted at King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Fifty adults with compensated (Child-Pugh class A) cirrhosis will be recruited during routine hepatology clinic visits. Eligible participants are aged 45-75 years, have a sedentary lifestyle (\<150 minutes of moderate or \<75 minutes of vigorous physical activity per week), and have abstained from alcohol for at least six months. Exclusion criteria include active or recently treated hepatocellular carcinoma (within three months), severe portal hypertension complications (untreated large varices, prior variceal bleeding, or severe gastropathy), transjugular intrahepatic portosystemic shunt (TIPS), unstable cardiac disease, orthopedic limitations, morbid obesity (BMI \>35 kg/m²), or current use of alpha- or beta-blockers that affect autonomic function. Intervention: Participants will be randomly assigned to either the intervention or control group. Both groups will receive nutritional consultation and individualized dietary guidance at baseline, week 8, and week 16. Nutritional goals are set at 35 kcal/kg/day and 1.2 g/kg/day of protein intake. If targets are unmet, the dietitian will provide individualized recommendations to support adequate intake. The intervention group will participate in a 16-week aerobic exercise program consisting of brisk walking at moderate intensity (50-70% of maximal heart rate), totaling 150 minutes per week. The program includes two phases: * Phase 1 (Weeks 1-4): Combined hospital-based (1 session per week) and home-based exercise under physical therapist supervision, with gradual intensity titration. * Phase 2 (Weeks 5-16): Fully home-based exercise following prescribed intensity and frequency, with weekly follow-up via telephone or messaging to monitor adherence, safety, and exercise log completion. The control group will maintain their usual physical activity levels while receiving the same schedule of nutritional consultations and weekly follow-up for monitoring compliance and adverse events. Outcomes: Primary outcomes include changes in autonomic and endothelial function after 16 weeks. * Autonomic function will be assessed using the Ewing autonomic battery test (HR response to standing, deep breathing, and Valsalva maneuver; BP response to posture and sustained handgrip) and heart rate variability (HRV) indices (SDNN, RMSSD, LF/HF ratio). * Endothelial function will be evaluated using flow-mediated dilation (FMD) of the brachial artery, analyzed via Cardiovascular Suite™ software to assess nitric oxide-dependent vasodilation. Secondary outcomes include: 1. Splanchnic hemodynamics: Changes in celiac and superior mesenteric artery (SMA) blood flow measured via mesenteric Doppler ultrasound (Vivid IQ, GE Healthcare). Time-averaged mean velocity (TAMV), vessel diameter, and blood flow will be recorded at baseline and post-intervention. 2. Sarcopenia-related measures: Muscle mass (DEXA, BIA), muscle strength (handgrip dynamometry), and physical performance (6-minute walk test). 3. Laboratory outcomes: Serum ammonia, liver function tests, fasting glucose, albumin, renal function, and coagulation profile. 4. Correlative analyses: Associations between (a) muscle mass and serum ammonia, and (b) muscle mass and autonomic parameters (e.g., HRV indices).

Comparing Approaches to Assess Nitric Oxide-dependent Cutaneous Vasodilation

The increase in skin blood flow in response to rapid local heating of the skin (i.e., cutaneous vasodilation) is commonly used to assess nitric oxide (NO)-dependent dilation and overall microvascular function. Historically, rapid local heating to 42°C was considered the standard approach for these assessments. More recently, many investigators have adopted rapid local to 39°C instead, based on its larger dependency on NO and therefore improved ability to quantify NO-dependent dilation without the use of pharmacological techniques. However, to date, only one direct methodological comparison between these protocols has been performed. In this study, the investigators use the blood vessels in the skin as a representative vascular bed for examining mechanisms of microvascular dysfunction in humans. Using a minimally invasive technique (intradermal microdialysis for the local delivery of pharmaceutical agents) they examine the blood vessels in a nickel-sized area of the skin in young adults ages 18 - 30 years old. Local heating of the skin at the microdialysis sites is used to explore differences in mechanisms governing microvascular control. As a compliment to these measurements, the investigators also have participants fill out a variety of surveys to assess things such as sleep quality, physical activity, daily stressors, etc.