Bryan Kim

Transcriptional profiling of human cavernosal endothelial cells reveals distinctive cell adhesion phenotype and role for claudin 11 in vascular barrier function

To determine specific molecular features of endothelial cells (ECs) relevant to the physiological process of penile erection we compared gene expression of human EC derived from corpus cavernosum of men with and without erectile dysfunction (HCCEC) to coronary artery (HCAEC) and umbilical vein (HUVEC) using Affymetrix GeneChip microarrays and GeneSifter software. Genes differentially expressed across samples were partitioned around medoids to identify genes with highest expression in HCCEC. A total of 190 genes/transcripts were highly expressed only in HCCEC. Gene Ontology classification indicated cavernosal enrichment in genes related to cell adhesion, extracellular matrix, pattern specification and organogenesis. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed high expression of genes relating to ECM-receptor interaction, focal adhesions, and cytokine-cytokine receptor interaction. Real-time PCR confirmed expression differences in cadherins 2 and 11, claudin 11 (CLDN11), desmoplakin, and versican. CLDN11, a component of tight junctions not previously described in ECs, was highly expressed only in HCCEC and its knockdown by siRNA significantly reduced transendothelial electrical resistance in HCCEC. Overall, cavernosal ECs exhibited a transcriptional profile encoding matrix and adhesion proteins that regulate structural and functional characteristics of blood vessels. Contribution of the tight junction protein CLDN11 to barrier function in endothelial cells is novel and may reflect hemodynamic requirements of the corpus cavernosum.

Histological study of graft failure in AlphaCor transplantation

To report clinical and histopathologic findings in a case of a failed AlphaCor artificial cornea explanted due to corneal stromal melting. We describe the case of a 77-year-old man who received multiple penetrating keratoplasties (PKPs) and subsequent placement of an AlphaCor artificial cornea. Examination showed total corneal infiltration as well as an AlphaCor that was partially dehisced from the host cornea. After explantation, the implant and adjacent host tissue underwent hematoxylin and eosin staining and high-resolution scanning electron microscopy (HR-SEM). Histopathologic analysis of the specimens revealed infiltration of the skirt pores by reactive corneal fibroblasts. Although the AlphaCor implant is an established method of treating multiple failed PKPs, in this case, HR-SEM imaging strongly suggests that the strength of the interface between the implant and corneal tissue is highly dependent on collagen deposition between the pores found in the implant skirt. Collagen deposition then increases the mechanical strength of the cornea–skirt interface.

Microkeratome-assisted lamellar keratoplasty using frozen tissue for management of a post-LASIK corneal stromal scar.

A 56-year-old man developed severe P aeruginosa infectious keratitis 2 years after uncomplicated LASIK surgery. On presentation, visual acuity in the affected eye was light perception. A hypopyon and stromal infiltration of the flap interface (160-lm depth) were noted (Fig. 1a). The infectious keratitis resolved after aggressive treatment. However, a dense and paracentral corneal scar at the level of the LASIK flap interface resulted in irregular astigmatism along the visual axis (Fig. 1b) and uncorrected visual acuity (UCVA) of 0.1. An LKP was performed to remove the corneal scar at the LASIK flap interface. Preoperative pachymetry was 520 lm in the affected eye and 590 lm in the other eye. A Hansatome microkeratome (Bausch & Lomb, Rochester, NY, USA) was used to create a 180-lm flap. The superior hinge was cut, and the old LASIK flap, including the corneal scar from the previous infection, was removed. A 180-lm donor flap from a thawed globe was created by means of an identical microkeratome arrangement. The donor flap was transferred and sutured to the recipient stromal bed, with the superior hinges matched. One week after LKP, the transplanted LASIK flap was completely epithelialized. Three weeks after LKP, selective suture removal was commenced. Cataract had developed and was removed with IOL implantation 4 months after LKP. Best spectacle-corrected visual acuity (BSCVA) after the cataract surgery and suture removal was 0.5 with -2.50 ? 4.50 9 57 (Fig. 2a, b). Six months after LKP, the residual corneal astigmatism was corrected with standard LASIK by lifting the transplanted lamellar flap (Fig. 2c). One week after LASIK, the flap was well positioned without epithelial ingrowth or flap striae. The UCVA was 0.5 with -1.50 sphere (Fig. 2d). The BSCVA was 1.0 with a contact lens. The patient, however, was intolerant of contact lens wearing.