Mitochondrial biogenesis and COX activity are impaired in frail old.

<p>(A) PGC-1α, CS, COX subunits- I, II, and IV, and phospho-GSK3β (Ser⁹) protein content, (B) citrate synthase and (C) mitochondrial complex IV activity (nmol.min⁻¹.mg of protein⁻¹) in the <i>vastus lateralis</i> of young, AO, and SO subjects (N = 10/group; ♀  =  ♂). (D) Mitochondrial complex IV activity (nmol.min⁻¹.mg of protein⁻¹) positively correlates (r = 0.77) with maximal isometric torque (N.m). Asterisk denotes significant changes <i>vs.</i> young, dagger denotes significant changes <i>vs.</i> AO, and double dagger denotes significant changes <i>vs.</i> both young and AO (P≤0.05).</p

A sedentary lifestyle exacerbates functional decline and systemic inflammation in the elderly.

<p>(A) Maximal isometric torque (N.m) in young, AO, and SO subjects. Each point represents an individual who underwent strength testing as described in the methods. (B) Walk test and timed stair-climb test in AO and SO subjects as described in the methods. (C) CRP levels (ng.mg of protein⁻¹) in the <i>vastus lateralis</i> of young, AO, and SO subjects (N = 10/group; ♀  =  ♂). Asterisk denotes significant changes <i>vs.</i> young, and dagger denotes significant changes <i>vs.</i> AO (P≤0.05).</p

Reduced Mn-SOD activity is due to tyrosine nitration in frail old.

<p>(A) Mn-SOD was immunoprecipitated (IP) followed by immunoblotting (IB) for Mn-SOD nitrotyrosine content and (B) nNOS protein content in the <i>vastus lateralis</i> of young, AO, and SO subjects (N = 10/group; ♀  =  ♂). Asterisk denotes significant changes <i>vs.</i> young, and dagger denotes significant changes <i>vs.</i> AO (P≤0.05).</p

Study subjects' characteristics.

<p>Values are means ± SD. ^‡♀  =  ♂; ^* significantly different from young and AO (P<0.05); ^†significantly different from young (P<0.05).</p

Mitochondrial Mn-SOD activity is reduced in frail old.

<p>(A) Mn-SOD protein content and (B) total- and Mn- SOD activity (U.mg of protein⁻¹) in the <i>vastus lateralis</i> of young, AO, and SO subjects (N = 10/group; ♀  =  ♂). Asterisk denotes significant changes <i>vs.</i> young, and dagger denotes significant changes <i>vs.</i> AO (P≤0.05).</p