1437
The structural changes in intra - acinar artery manifested mainly by an increase in number of muscular artery resulting from muscularization of precursor cells ( pericytes and intermediate cells ) located within partially muscular and nonmuscular arterial wall to smooth muscle cell , and by the medial wall thickened due to hypertrophy and hyperplasia of smooth muscle cells as well as accumulation of a large amount of collagen , especially the type 1 collagen .
 collagen, type 1 collagen
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 collagen, type 1 collagen