Lymphatic lacunae of the human eye conjunctiva embedded within a stroma containing CD34⁺ telocytes

Abstract

An accurate identification of telocytes (TCs) was limited because of the heterogeneity of cell types expressing the markers attributed to TCs. Some endothelial lineage cells also could fit within the pattern of TCs. Such endothelial cells could line conjunctival lacunae previously assessed by laser confocal microscopy. We have been suggested that an accurate distinction of TCs from endothelial cells in the human eye conjunctiva could be achieved by use of CD31, CD34 and D2‐40 (podoplanin); and that the conjunctival lacunae are in fact lymphatic. We aimed as testing the hypothesis by an immunohistochemical study on human eye conjunctiva biopsy samples. Samples of human eye conjunctiva from 30 patients were evaluated immunohistochemically by use of the primary antibodies: CD34, D2‐40 and CD31. D2‐40 was equally expressed within epithelia and laminae propria. Basal epithelial cells were D2‐40 positive. Within the stromal compartment, the lymphatic marker D2‐40 labelled several lymphatic vessels. CD31 labelled both vascular and lymphatic endothelial cells within the lamina propria. When capillary lymphatics were tangentially cut, they gave the false appearance of telocytes. Blood endothelial cells expressed CD34, whereas lymphatic endothelial cells did not. Stromal CD34‐expressing cells/telocytes were found building a consistent pan‐stromal network which was equally CD31‐negative and D2‐40‐negative. The conjunctival lymphatic lacunae seem to represent a peculiar anatomic feature of eye conjunctiva. They are embedded within a CD34‐expressing stromal network of TCs. The negative expression of CD31 and D2‐40 should be tested when discriminating CD34‐expressing TCs.

Telocytes in the Female Reproductive System: Up-to-Date Knowledge, Challenges and Possible Clinical Applications

“…Without overstating, it can be said that TCs have been described in almost every organ one can think of. Except of the FRS, TCs have been discovered in the intestine [18], lungs [19], skeletal muscle [20], skin [21], ureter [22], heart [23], testes [24], prostate [25], eye [26], and even in remarkable locations such as a cow s teat [27]. TCs in the FRS are quite alike to TCs in other organs, but there are several morphological and functional characteristics that make them distinct.…”

Telocytes/CD34+ Stromal Cells in Pathologically Affected White Adipose Tissue

“…However, no review has focused on studying the current state of telocyte behaviour in adipose tissue affected by pathologic processes. Telocytes express CD34, among other markers, and therefore correspond to the CD34+ stromal cells observed in light microscopy [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. This immunohistochemical expression of telocytes, which allows us to consider them as telocytes/CD34+stromal cells (TCs/CD34+SCs), facilitates the correlation with previous descriptions or original observations of CD34+ resident/native stromal/interstitial cells in pathologic adipose tissue.…”

Stromal Hücrelerin Tarihçesi: İnterstisyel Cajal Hücrelerinden Telositlere - İnsan Telositlerine ve Olası İşlevlerine Kısa Bir Bakış

“…It has been reported that a stromal network of TCs surrounds the conjunctival lymphatic lacunae in the human eye and that stromal CD34-expressing cells/TCs are constructing a consistent pan-stromal network (46). The stroma of the human sclera contains a progenitor cell niche that is accomodating TC-like cells (47).…”