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Histopathology of melanosis coli and determination of its associated genes by comparative analysis of expression microarrays.

Li XΑ, Zhou Y, Zhou SΧ, Liu HR, Xu JM, Gao L, Yu XJ, Li XH - Mol Med Rep (2015)

Bottom Line: The results demonstrated that the pigment deposits in MC consisted of lipofuscin.Western blotting and immunofluorescence assays indicated that the expression of CYP3A4 in the normal tissue was higher than in the MC tissue.The results of the present study provided a comprehensive description of the histopathological characteristics and pathogenesis of MC and for the first time, to the best of our knowledge, demonstrated that the cytochrome P450‑associated genes were significantly downregulated in melanosis coli.

View Article: PubMed Central - PubMed

Affiliation: The Gastroenterology Tumor and Microenvironment Laboratory, Department of Gastroenterology, The First Affiliated Hospital of Chengdu Medical College, Chengdu Medical College, Chengdu, Sichuan 610041, P.R. China.

ABSTRACT
Melanosis coli (MC) refers to the condition characterized by abnormal brown or black pigmentation deposits on the colonic mucosa. However, the histopathological findings and genes associated with the pathogenesis of melanosis coli remain to be fully elucidated. The present study aimed to examine the histopathological features and differentially expressed genes of MC. This involved performing hematoxylin and eosin staining, specific staining and immunohistochemistry on tissues sections, which were isolated from patients diagnosed with MC. DNA expression microarray analysis, western blotting and immunofluorescence assays were performed to analyze the differentially expressed genes of melanosis coli. The results demonstrated that the pigment deposits in MC consisted of lipofuscin. A TUNEL assay revealed that a substantial number of apoptotic cells were present within the macrophages and superficial lamina propria of the colonic epithelium. Expression microarray analysis revealed that the significantly downregulated genes were CYP3A4, CYP3A7, UGT2B11 and UGT2B15 in melanosis coli. Western blotting and immunofluorescence assays indicated that the expression of CYP3A4 in the normal tissue was higher than in the MC tissue. The results of the present study provided a comprehensive description of the histopathological characteristics and pathogenesis of MC and for the first time, to the best of our knowledge, demonstrated that the cytochrome P450‑associated genes were significantly downregulated in melanosis coli. This novel information can be used to assist in further investigations of melanosis coli.

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Pigmentation characteristics of melanosis coli. (A) Representative endoscopic images of the three characterized severities. Severe, black-brownish pigmentation of the mucosa of the entire colon. Moderate, diffusely brownish pigmentation. Mild, edematous, snake-skin appearance and pigmentation of the mucosa. (B) Hematoxylin and eosin staining revealing typical pigments in granule-laden macrophages in the lamina propria.
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f1-mmr-12-04-5807: Pigmentation characteristics of melanosis coli. (A) Representative endoscopic images of the three characterized severities. Severe, black-brownish pigmentation of the mucosa of the entire colon. Moderate, diffusely brownish pigmentation. Mild, edematous, snake-skin appearance and pigmentation of the mucosa. (B) Hematoxylin and eosin staining revealing typical pigments in granule-laden macrophages in the lamina propria.

Mentions: Examining the characteristics of MC revealed colonoscopy characteristics in three representative cases. Severe MC, in which a marked black-brownish pigmentation was apparent in the mucosa of the whole colon; moderate MC, in which diffuse and brown pigmentation was observed throughout the colon; and mild MC, in which the mucosa had a diffusely brownish, snake-skin appearance (Fig. 1A). H&E staining revealed that the yellow-brown granular pigment was confined to the tunica propria of the mucosa of large mononuclear histiocytes (Fig. 1B). Of the 26 patients who underwent endoscopy, 10 (38.46%) had neoplasia and 10 (34.62%) had adenocarcinoma. It total, 76.92% of the patients with MC had a history of long-term laxative use (Table I). This suggested that the use of laxatives was associated with MC.


Histopathology of melanosis coli and determination of its associated genes by comparative analysis of expression microarrays.

Li XΑ, Zhou Y, Zhou SΧ, Liu HR, Xu JM, Gao L, Yu XJ, Li XH - Mol Med Rep (2015)

Pigmentation characteristics of melanosis coli. (A) Representative endoscopic images of the three characterized severities. Severe, black-brownish pigmentation of the mucosa of the entire colon. Moderate, diffusely brownish pigmentation. Mild, edematous, snake-skin appearance and pigmentation of the mucosa. (B) Hematoxylin and eosin staining revealing typical pigments in granule-laden macrophages in the lamina propria.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581826&req=5

f1-mmr-12-04-5807: Pigmentation characteristics of melanosis coli. (A) Representative endoscopic images of the three characterized severities. Severe, black-brownish pigmentation of the mucosa of the entire colon. Moderate, diffusely brownish pigmentation. Mild, edematous, snake-skin appearance and pigmentation of the mucosa. (B) Hematoxylin and eosin staining revealing typical pigments in granule-laden macrophages in the lamina propria.
Mentions: Examining the characteristics of MC revealed colonoscopy characteristics in three representative cases. Severe MC, in which a marked black-brownish pigmentation was apparent in the mucosa of the whole colon; moderate MC, in which diffuse and brown pigmentation was observed throughout the colon; and mild MC, in which the mucosa had a diffusely brownish, snake-skin appearance (Fig. 1A). H&E staining revealed that the yellow-brown granular pigment was confined to the tunica propria of the mucosa of large mononuclear histiocytes (Fig. 1B). Of the 26 patients who underwent endoscopy, 10 (38.46%) had neoplasia and 10 (34.62%) had adenocarcinoma. It total, 76.92% of the patients with MC had a history of long-term laxative use (Table I). This suggested that the use of laxatives was associated with MC.

Bottom Line: The results demonstrated that the pigment deposits in MC consisted of lipofuscin.Western blotting and immunofluorescence assays indicated that the expression of CYP3A4 in the normal tissue was higher than in the MC tissue.The results of the present study provided a comprehensive description of the histopathological characteristics and pathogenesis of MC and for the first time, to the best of our knowledge, demonstrated that the cytochrome P450‑associated genes were significantly downregulated in melanosis coli.

View Article: PubMed Central - PubMed

Affiliation: The Gastroenterology Tumor and Microenvironment Laboratory, Department of Gastroenterology, The First Affiliated Hospital of Chengdu Medical College, Chengdu Medical College, Chengdu, Sichuan 610041, P.R. China.

ABSTRACT
Melanosis coli (MC) refers to the condition characterized by abnormal brown or black pigmentation deposits on the colonic mucosa. However, the histopathological findings and genes associated with the pathogenesis of melanosis coli remain to be fully elucidated. The present study aimed to examine the histopathological features and differentially expressed genes of MC. This involved performing hematoxylin and eosin staining, specific staining and immunohistochemistry on tissues sections, which were isolated from patients diagnosed with MC. DNA expression microarray analysis, western blotting and immunofluorescence assays were performed to analyze the differentially expressed genes of melanosis coli. The results demonstrated that the pigment deposits in MC consisted of lipofuscin. A TUNEL assay revealed that a substantial number of apoptotic cells were present within the macrophages and superficial lamina propria of the colonic epithelium. Expression microarray analysis revealed that the significantly downregulated genes were CYP3A4, CYP3A7, UGT2B11 and UGT2B15 in melanosis coli. Western blotting and immunofluorescence assays indicated that the expression of CYP3A4 in the normal tissue was higher than in the MC tissue. The results of the present study provided a comprehensive description of the histopathological characteristics and pathogenesis of MC and for the first time, to the best of our knowledge, demonstrated that the cytochrome P450‑associated genes were significantly downregulated in melanosis coli. This novel information can be used to assist in further investigations of melanosis coli.

Show MeSH
Related in: MedlinePlus