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Resistance vessel remodeling and reparative angiogenesis in the microcirculatory bed of long-term denervated skeletal muscles
Resistance vessel remodeling and reparative angiogenesis in the microcirculatory bed of long-term denervated skeletal muscles
- Source :
- Microvascular research. 63(1)
- Publication Year :
- 2001
-
Abstract
- In denervated skeletal muscles, atrophy of muscle fibers and interstitial fibrosis are associated with alterations within the vascular bed. Our study has placed particular emphasis on changes occurring in resistance vessels and the microcirculatory bed of rat hindlimb skeletal muscles that had been denervated for 25 months. We found that the tunica media of the majority of long-term denervated resistance vessels undergoes deterioration. In small intramuscular arteries and arterioles, atrophic vascular smooth muscle cells (vSMCs) enclosed in a thick basal lamina are separated by expanded extracellular space. The remodeling and sclerotic changes in the arterial wall occasionally result in deformation of the lumen. It was also found that the microcirculatory bed undergoes significant alterations. In 25-month denervated extensor digitorum longus muscle, the capillary-to-fiber ratio is only 0.13 +/- 0.01 and the mean number of capillaries per fascicle decreases almost ninefold compared to contralateral control muscle. Ultrastructural findings demonstrate that 24.67 +/- 0.48% of capillaries examined in the chronically denervated fascicles show structural features typical for capillary regeneration. In addition, long cytoplasmic extensions of pericytes might develop a layer completely encircling the capillary endothelium. In pre- and postcapillary segments of the microcirculatory bed, some perivascular cells possess a phenotype that is intermediate between that of pericytes and atrophic vSMCs. RT-PCR and/or Western blot analyses showed that molecules participating in angiogenesis are detected in 25-month denervated skeletal muscle. We hypothesize that despite the fact that the microcirculatory bed of chronically denervated muscle undergoes significant reduction it still sustains the capacity for reparative capillary growth.
- Subjects :
- Vascular Endothelial Growth Factor A
Cytoplasm
Vascular smooth muscle
Time Factors
Blotting, Western
Neovascularization, Physiologic
Endothelial Growth Factors
Biology
Biochemistry
Microcirculation
Extensor digitorum longus muscle
Proto-Oncogene Proteins
Microcirculatory Bed
medicine
Animals
Receptors, Growth Factor
Muscle, Skeletal
Lymphokines
Vascular Endothelial Growth Factor Receptor-1
Reverse Transcriptase Polymerase Chain Reaction
Vascular Endothelial Growth Factors
Skeletal muscle
Receptor Protein-Tyrosine Kinases
Muscle, Smooth
Cell Biology
Anatomy
Hypoxia-Inducible Factor 1, alpha Subunit
Immunohistochemistry
Sciatic Nerve
Capillaries
Rats
Microscopy, Electron
medicine.anatomical_structure
Phenotype
Receptors, Vascular Endothelial Growth Factor
Microscopy, Fluorescence
Circulatory system
RNA
Basal lamina
Cardiology and Cardiovascular Medicine
Blood vessel
Transcription Factors
Subjects
Details
- ISSN :
- 00262862
- Volume :
- 63
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Microvascular research
- Accession number :
- edsair.doi.dedup.....be62ef329b21e22096b08c33967e6056