A comparative histopathological evaluation of sacs from boys and girls with inguinal hernia

Association and haplotype analyses of positional candidate genes in five genomic regions linked to scrotal hernia in commercial pig lines

Scrotal hernia in pigs is a complex trait likely affected by genetic and environmental factors. A large-scale association analysis of positional and functional candidate genes was conducted in four previously identified genomic regions linked to hernia susceptibility on Sus scrofa chromosomes 2 and 12, as well as the fifth region around 67 cM on chromosome 2, respectively. In total, 151 out of 416 SNPs discovered were genotyped successfully. Using a family-based analysis we found that four regions surrounding ELF5, KIF18A, COL23A1 on chromosome 2, and NPTX1 on chromosome 12, respectively, may contain the genetic variants important for the development of the scrotal hernia in pigs. These findings were replicated in another case-control dataset. The SNPs around the ELF5 region were in high linkage disequilibrium with each other, and a haplotype containing SNPs from ELF5 and CAT was highly significantly associated with hernia development. Extensive re-sequencing work focused on the KIF18A gene did not detect any further SNPs with extensive association signals. These genes may be involved in the estrogen receptor signaling pathway (KIF18A and NPTX1), the epithelial-mesenchymal transition (ELF5) and the collagen metabolism pathway (COL23A1), which are associated with the important molecular characteristics of hernia pathophysiology. Further investigation on the molecular mechanisms of these genes may provide more molecular clues on hernia development in pigs.

Evaluation of Extracellular Matrix Protein Composition in Sacs Associated with Undescended Testis, Hydrocele, Inguinal Hernia, and Peritoneum

OBJECTIVES

To investigate and compare the distribution and intensity of staining of extracellular matrix proteins--laminin, fibronectin, and types 1 and 4 collagen--in various congenital inguinoscrotal abnormalities and the peritoneum through immunohistochemical staining.

METHODS

The sacs associated with undescended testis (n = 28), hydrocele (n = 29), inguinal hernia (n = 31), and parietal peritoneum (n = 28) were stained with antibodies for laminin, fibronectin, and types 1 and 4 collagen. The peritoneum served as the control group. Appropriate tissue sections of each group of samples were identified and compared with regard to the intensity and distribution of staining.

RESULTS

The expression of laminin was significantly greater in the sacs associated with undescended testes and inguinal hernia than in the peritoneum. The expression pattern of fibronectin did not differ in the sacs of the different inguinoscrotal abnormalities compared with peritoneum. Type 1 collagen was strongly expressed in the sacs obtained from the hydroceles compared with the other groups and the peritoneum. Expression of type 4 collagen was significantly increased in the sacs associated with hydrocele and inguinal hernia compared with the peritoneum.

CONCLUSIONS

The distribution and expression of laminin and types 1 and 4 collagen showed variability in the sacs associated with undescended testis, hydrocele, and inguinal hernia and the peritoneum. The tensile forces that the sacs associated with childhood inguinoscrotal abnormalities are exposed to per se could account for some of the differences seen between the inguinoscrotal tissues and anterior peritoneum. These differences in the extracellular matrix proteins could also reflect congenital properties of various childhood inguinoscrotal abnormalities.