IPL Journal ClubKaria Coleman Jr.

KN 501November 1, 2013

Endurance Exercise Activates Matrix Metalloproteinases in Human Skeletal Muscle

• Eric Rullman, Jessica Norrbom, Anna Stromberg, Dick Wagsaer, Helene Rundqvist, Tara Haas, and Thomas Gustafsson

• Journal of Applied Physiology January 2009

Endurance Exercise Activates Matrix Metalloproteinases in Human Skeletal Muscle

• Background / Introduction• Methods• Results• Supplementary data (circulation)• Summary / Conclusion

Background

Skeletal Muscle• Most changes in function and

structure involves ECM remodeling

• Physiological / Pathological• Physical exercise several

factors that could affect MMP expression– local ischemia– increases in muscle stretching– shear stress, wall tension of

blood vessels

MMP’s• Remodels / Degrades ECM

proteins• Physiological / Pathological• the vast majority of genes

upregulated in response to exercise training are related to ECM

Background

Matrix Metalloproteinases• MMP-2• MMP-9• MMP-14• TIMP-1

Targets• ECM

– Elastins– Fibronectin– Laminin– Collagens (I-XIV)

• Basement Membrane (Collagen IV)

Background

• MMP-2 / GA • MMP-9 / GB

• Hypothesis?

Method• 10 - healthy male subjects• Age 24 (20 –27) yr, • Height 181 (173–190) cm, • Weight 75 (63–90) kg, • VO2max was 51 (43– 64) mlkg-1 min-1. • Welltrained subjects (VO2max 65 mlkg-1 min-1) were

excluded maximize the subjects’ training responses.

Study Design• Endurance Exercise in the supine position performed

with the dynamic constant-load knee-extension exercise for 45 min at 60 revolutions/min.

• 45 min of one-legged exercise with a 20% restriction in blood flow at their highest tolerable workload.

• Then, 45 mins exercise with the opposite leg without blood flow restriction at same workload as first leg

– 4x / week for 5 weeks

Study Design• Muscle biopsies were obtained • Biopsy from vastus lateralis of both legs:

– pre and 2 h after the first exercise bout– after 10 days of training– after 5 wk of training

Testing• Immunohistochemistry• RNA Extraction and Reverse Transcription

– mRNA expression– MMP2, MMP9, MMP14, & TIMP1

• Laser Capture Microdissection– mRNA express and activity within multiple cell types– 3 subjects only– mRNA for MMP2 only– Pre and 10 days only

• Protein Extraction and Zymography– Enzyme activity– Pro-MMP9, active MMP9, & MMP2 only– All time points

Results Zymography

Results mRNA MMP9 vs. Housekeeping

Results MMP2

Results

Result MMP14 & TIMP1

Results Immunohistochemistry MMP9

Results Immunohistochemistry MMP2

Summary• Avg workload (4 bouts) 5 training wk • Wk1 - 1,975• Wk2 - 2,461• Wk3 - 2,803• Wk4 - 3,157 • Wk5 - 3,350 W

Summary

MMP2• No change after single

bout of exercise (R or UR)• Maintained elevated

expression and activity from Day 10 to Wk 5

• Enzymatic activity scattered (in ECM and ICM of muscle, but more intense adjacent to capillaries)

MMP9• Significant change in (Pro and

Activated MMP9) expression and activity after single bout of exercise (R & UR)

• Maintained elevated transcription after Day 10, however not significant because of high variance

• Enzymatic activity only found in ECM around muscle and capillaries, not within

Summary

MMP14• Expression and activity

followed the same trend as MMP2

TIMP1• Transcription increased at

every data collection point, however, not significant until after Day 10

MMP-9 and Circulation

• Circulating MMP-9 during exercise in humans– E. Rullman, K. Olsson, D. Wagsater, T. Gustafsson

Study Design

Subjects• Ten healthy male subjects• Age: 25 (18–37) years• Height: 180 (170–190)

cm• Weight: 77 (58–82) kg• (VO2max) 3.7 (3.1–4.3) L

min-1.

Exercise and Method• Exercise perrformed on

an electrodynamically loaded cycle ergometer

• 60 min of cycle exercise• Graded increases in

intensity• Femoral blood draws at

27mins, 57mins, and 120mins after end of Ex.

Results

MMP9• No significant difference in

Femoral Artery and ipsilateral Femoral Vein before exercise

• Significant increase in both Femoral Artery and Femoral Vein 27mins after exercise

• no evidence of neutrophil degranulation to coorelate with MMP9 turnover associated with Collagen IV degradation

Type IV Collagen• No significant difference

in Femoral Artery and ipsilateral Femoral Vein before exercise

• Significant increase in both Femoral Artery and Femoral Vein 27mins and 57mins after exercise

Questions

• Eric Rullman, Jessica Norrbom, Anna Stromberg, Dick Wagsater, Helene Rundqvist, Tara Haas, and Thomas Gustafsson

• Endurance exercise activates matrix metalloproteinases in human skeletal muscle. J Appl Physiol 106: 804–812, 2009.

• E. Rullman, K. Olsson, D. Wagsater, T. Gustafsson

• Circulating MMP-9 during exercise in humans. Eur J Appl Physiol (2013) 113:1249–1255