Protein kinetics in stable heart failure patients

Area of Science:

• Physiology
• Metabolism
• Cardiovascular Science

Background:

• Aging naturally decreases protein turnover.
• The impact of congestive heart failure (CHF) on protein metabolism in older adults is not well understood.
• This study investigates how CHF affects protein synthesis and turnover in aging individuals.

Purpose of the Study:

• To compare whole-body protein turnover between older adults with stable CHF and age-matched controls.
• To determine if liver and skeletal muscle protein metabolism are affected by CHF.

Main Methods:

• Whole-body protein synthesis rate measured using U-(15)N-labeled algal protein hydrolysate in 10 CHF patients and 10 controls.
• Skeletal muscle fractional synthesis rate assessed via [U-(13)C]alanine in vastus lateralis muscle biopsies.
• Hepatic protein synthesis rates (fibrinogen, complement C-3, ceruloplasmin, transferrin, VLDL apolipoprotein B-100) measured using (2)H(5)-labeled l-phenylalanine tracer.

Main Results:

• Whole-body protein synthesis rate was significantly reduced in CHF patients compared to controls.
• Skeletal muscle fractional synthesis rate and very low-density lipoprotein apolipoprotein B-100 synthesis were also depressed in CHF patients.
• CHF patients exhibited hyperinsulinemia, suggesting altered metabolic signaling.

Conclusions:

• Protein turnover is significantly depressed in patients with congestive heart failure.
• Both skeletal muscle and liver protein metabolism are negatively impacted by CHF.
• The observed protein metabolism changes in CHF are comparable to those seen with bed rest, suggesting inactivity as a contributing factor.