As a function of our growing population of older adults, it is estimated that 3.48 million total knee arthroplasty (TKA) surgeries will be performed annually in the US by 2030 (Kurtz et al., 2007). Two-thirds of all TKAs are performed on older women (Kurtz et al., 2011) and despite the near universal success of this surgery in mitigating chronic knee pain, TKA is not as successful at restoring physical function in women (Parsley et al., 2010). This phenomenon, termed the “never catch up syndrome” (Lavernia et al., 2009), is primarily due to quadriceps weakness; women produce ~50% less force than men 2 years post-TKA (Silva et al., 2003). Atrophy is the number one contributor to long-term quadriceps weakness, explaining 77% of the strength deficit 1-3 years post-TKA (Meier et al., 2009). Muscle atrophy following TKA occurs in both the operative and non-operative lower extremity (Ratchford et al., 2012) and early quadriceps weakness in the non-operative leg is associated with poorer functional outcomes 1-2 years post-TKA (Zeni & Snyder-Mackler, 2010). For older women, muscle atrophy may become a permanent clinical barrier as their ability to increase muscle mass is significantly compromised (Ivey et al., 2000; Roth et al., 2001; and Bamman et al., 2003). Thus, preventing muscle loss and preserving strength are critically important and clinically meaningful as early functional mobility will translate into improved long-term functional outcomes and quality of life for older women following TKA.
The general objectives of our lab are to use molecular methods to test experimental approaches that preserve and restore skeletal muscle volume following TKA and to devise clinically meaningful intervention strategies to facilitate the return of skeletal muscle and physical function. From muscle biopsy samples we use a combination of molecular and cellular methodologies to: 1) measure alterations in transcriptional profiles (mRNA), 2) isolate proteins to quantify relative expression levels and phosphorylation status (cell signaling), and 3) visualize muscle cross-sections using immunohistochemistry and electron microscopic methods to determine muscle fiber type, proportions, area, colocalization of signaling proteins and transcription factors (spacial overlap within the nuclear or cytoplasmic fractions of muscle cells) and capillarization.
Lab Address: 722 E. 11th Street. Eugene, OR. 97401