The distribution of relaxin receptors in the anterior segment of primary open-angle glaucoma patients

Purpose:Relaxin is a polypeptide hormone produced by the corpus luteum and the decidua in females and by the prostate in males. It has vasodilatory and antifibrotic effects. In the past, it has been reported that injection of relaxin hormone has caused a reduction in the intraocular pressure although its mechanism has not yet been fully understood and the expression of relaxin receptors has not yet been evident in the human eye. Therefore, the purpose of this current study was to examine the presence of relaxin receptors in the human eye anterior segment.Methods:This is an interventional non-randomized study. Patients with primary open-angle glaucoma who underwent trabeculectomy were recruited. During the surgery, a punch biopsy (including the cornea, sclera, trabecular meshwork, and Schlemm''s canal) was taken and stained with hematoxylin-eosin, and immunohistochemistry staining for relaxin/insulin-like family peptide receptor 1 (RXFP1).Results:A positive staining was noted for RXFP1 in the inner uveal, corneoscleral, and cribriform meshwork and Schlemm''s canal''s endothelium. Negative staining for RXFP1 was noted in the cornea and sclera.Conclusion:RXFP1 is present in the anterior segment drainage system of the human eye. Therefore, this receptor may have an active role in regulating the outflow facility and in the reduction of intraocular pressure.     

Interaction between muscles and fascia in the mystacial pad of whisking rodents

In whisking rodents, the mystacial pad is supplied with vibrissae and contains a collagenous skeleton that is a part of the snout fascia. The collagenous skeleton is composed of three interconnected layers: superficial, deep spongy mesh and subcapsular fibrous mat. We found that the first two layers contain diverse fascial structures, such as sheets of subcutaneous connective tissue, tendons, ligaments and follicular capsules which transmit muscle efforts to vibrissae and are thus involved in whisking. Subcapsular fibrous mat is built of oriented rostro-caudal wavy fibrils. It maintains spatial arrangement of whisker follicles, provides a quick response to deformation and connects entire mystacial pad to the skull. To move vibrissae, the forces of intrinsic muscles are applied directly to the capsules of the vibrissa follicles, whereas the forces of extrinsic muscles are applied to other parts of the collagenous skeleton, which transmit the forces to the capsules. According to the spatial distribution and anchoring sites of the muscles and fascia, extrinsic muscles provide vibrissa protraction or retraction by pulling the superficial layer of the collagenous skeleton rostral or caudal, respectively. Vibrissae can be also retracted when the efforts of extrinsic muscles are applied to the subcapsular fibrous mat. When the muscles relax, fascial structures return the vibrissae to their resting position. The deep spongy layer encompasses vibrissal follicles providing a uniform distribution of stresses and strains during whisking. In the mystacial pad, fascia is a dominant type of tissue that maintains the integrity of the vibrissa motor plant, translates muscular momentum to the vibrissae, and plays a role in vibrissae movements.