Sarcopenia of the longitudinal tongue muscles in rats.

The tongue is a muscular hydrostat, with lingual movements occurring during breathing, chewing, swallowing, vocalization, vomiting, coughing and grooming/sexual activities. In the elderly, reduced lingual dysfunction and weakness contribute to increased risks of obstructive sleep apnea and aspiration pneumonia. In Fischer 344 (F344) rats, a validated model of aging, hypoglossal motor neuron death is apparent, although there is no information regarding tongue strength. The intrinsic tongue muscles, the superior and inferior longitudinal, transversalis and verticalis exist in an interdigitated state. Recently, we established a method to measure the specific force of individual intrinsic tongue muscle, accounting for the tissue bulk that is not in the direction of uniaxial force. In the longitudinal muscles of 6- (n = 10), 18- (n = 9) and 24-month-old (n = 12) female and male F344 rats, we assessed specific force, fatigability, fiber type dependent cross-sectional area (CSA) and overall CSA. Muscle force and fatigue was assessed ex vivo using platinum plate simulation electrodes. Tongue muscles were frozen in melting isopentane, and transverse sections cut at 10 µm. Muscle fiber type was classified based on immunoreactivity to myosin heavy chain (MyHC) isoform antibodies. In H&E stained muscle, CSA and uniaxial muscle contributions to total tongue bulk was assessed. We observed a robust ∼30% loss of longitudinal specific force, with reductions in overall longitudinal muscle fiber CSA and specific atrophy of type IIx/IIb fibers. It will be important to investigate the mechanistic underpinnings of hypoglossal motor neuron death and tongue muscle weakness to eventually provide therapies for age-associated lingual dysfunctions.

Impact of Fall Risk and Direct Oral Anticoagulant Treatment on Quality-Adjusted Life-Years in Older Adults with Atrial Fibrillation: A Markov Decision Analysis.

BACKGROUND AND OBJECTIVE: The decision to initiate anticoagulation in older adults with atrial fibrillation is complicated by the benefit of ischemic stroke prevention vs the risk of falls resulting in major bleeds. The objective of this study was to assess the impact of different treatments including direct oral anticoagulants on quality-adjusted life-years (QALYs) in patients aged 75 years and older with atrial fibrillation in the context of falls. METHODS: A Markov decision process was constructed for older patients with atrial fibrillation taking no anti-thrombotic, aspirin, warfarin, rivaroxaban, and apixaban. Input probabilities for clinical events were estimated from the available literature. One-way and two-way sensitivity analyses were performed by measuring the impact of varying input probabilities of clinical events on QALY outcomes. RESULTS: The base-case scenario estimated that older adults treated with no anti-thrombotic, aspirin, warfarin, rivaroxaban, and apixaban had QALYs of 8.03, 8.69, 10.38, 11.02, and 11.56, respectively. The sensitivity analysis estimated that an older adult would need to fall over 45 (rivaroxaban) and 458 (apixaban) times per year for the QALY of a direct oral anticoagulant to be lower than that of aspirin. CONCLUSIONS: Older adults with atrial fibrillation benefit from stroke protection of anticoagulants, especially direct oral anticoagulants, even if they are at high risk of falls. Clinicians should not consider fall risk as a deciding factor for withholding anticoagulation in this population of patients.