Jesper L Andersen

Publications (2)7.73 Total impact

• Article: Aging is associated with diminished muscle re-growth and myogenic precursor cell expansion in the early recovery phase after immobility-induced atrophy in human skeletal muscle.

  Charlotte Suetta, Ulrik Frandsen, Abigail L Mackey, Line Jensen, Lars G Hvid, Monika L Beyer, Stine J Petersson, Henrik D Schrøder, Jesper L Andersen, Per Aagaard, Peter Schjerling, Michael Kjaer
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  ABSTRACT: Recovery of skeletal muscle mass from immobilisation-induced atrophy is faster in young than older individuals, yet the cellular mechanisms remain unknown. We examined the cellular and molecular regulation of muscle recovery in young and old human subjects subsequent to 2 weeks of immobility-induced muscle atrophy. Re-training consisted of 4 weeks of supervised resistive exercise in 9 older (OM: 67.3yrs, range 61-74) and 11 young (YM: 24.4yrs, range 21-30) males. Measures of myofiber area (MFA), Pax7-positive satellite cells (SC) associated with type I and type II muscle fibres, as well as gene expression analysis of key growth and transcription factors associated with local skeletal muscle milieu were performed after 2 weeks immobility (Imm) and following 3 days (+3d) and 4 weeks (+4wks) of re-training. OM demonstrated no detectable gains in MFA (VL muscle) and no increases in number of Pax7-positive SCs following 4 wks re-training, whereas YM increased their MFA (p<0.05), number of Pax7-positive cells, and had more Pax7-positive cells per type II fibre than OM at +3d and +4wks (p<0.05). No age-related differences were observed in mRNA expression of IGF-1Ea, MGF, MyoD1 and HGF with re-training, whereas myostatin expression levels were more down-regulated in YM compared to OM at +3d (p<0.05). In conclusion, the diminished muscle re-growth after immobilisation in elderly humans was associated with lesser response in satellite cell proliferation in combination with an age-specific regulation of myostatin. In contrast, expression of local growth factors did not seem to explain the age related difference in muscle mass recovery.
  The Journal of Physiology 06/2013; · 4.72 Impact Factor
• Source

  Available from: Gedske Daugaard

  Article: Progressive resistance training and cancer testis (PROTRACT) - efficacy of resistance training on muscle function, morphology and inflammatory profile in testicular cancer patients undergoing chemotherapy: design of a randomized controlled trial.

  Jesper F Christensen, Jesper L Andersen, Lis Adamsen, Birgitte Lindegaard, Abigail L Mackey, Rie H Nielsen, Mikael Rørth, Gedske Daugaard
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  ABSTRACT: Standard treatment for patients with disseminated germ cell tumors is combination chemotherapy with bleomycin, etoposide and cisplatin (BEP). This treatment is highly effective, but the majority of patients experience severe adverse effects during treatment and are at risk of developing considerable long-term morbidity, including second malignant neoplasms, cardiovascular disease, and pulmonary toxicity. One neglected side effect is the significant muscular fatigue mentioned by many patients with testicular cancer both during and after treatment. Very limited information exists concerning the patho-physiological effects of antineoplastic agents on skeletal muscle. The primary aim of this study is to investigate the effects of BEP-treatment on the skeletal musculature in testicular cancer patients, and to examine whether the expected treatment-induced muscular deterioration can be attenuated or even reversed by high intensity progressive resistance training (HIPRT). The PROTRACT study is a randomized controlled trial in 30 testicular cancer patients undergoing three cycles of BEP chemotherapy. Participants will be randomized to either a 9-week HIPRT program (STR) initiated at the onset of treatment, or to standard care (UNT). 15 healthy matched control subjects (CON) will complete the same HIPRT program. All participants will take part in 3 assessment rounds (baseline, 9 wks, 21 wks) including muscle biopsies, maximum muscle strength tests, whole body DXA scan and blood samples. Primary outcome: mean fiber area and fiber type composition measured by histochemical analyses, satellite cells and levels of protein and mRNA expression of intracellular mediators of protein turnover. Secondary outcomes: maximum muscle strength and muscle power measured by maximum voluntary contraction and leg-extensor-power tests, body composition assessed by DXA scan, and systemic inflammation analyzed by circulating inflammatory markers, lipid and glucose metabolism in blood samples. Health related Quality of Life (QoL) will be assessed by validated questionnaires (EORTC QLQ-C30, SF-36). This study investigates the muscular effects of antineoplastic agents in testicular cancer patients, and furthermore evaluates whether HIPRT has a positive influence on side effects related to chemotherapy. A more extensive knowledge of the interaction between cytotoxic-induced physiological impairment and exercise-induced improvement is imperative for the future development of optimal rehabilitation programs for cancer patients. Current Controlled Trials ISRCTN32132990.
  BMC Cancer 08/2011; 11:326. · 3.01 Impact Factor