Telocytes in minor salivary glands of primary Sjögren's syndrome: association with the extent of inflammation and ectopic lymphoid neogenesis

Abstract

It has been recently reported that telocytes, a stromal (interstitial) cell subset involved in the control of local tissue homeostasis, are hampered in the target organs of inflammatory/autoimmune disorders. Since no data concerning telocytes in minor salivary glands (MSGs) are currently available, aim of the study was to evaluate telocyte distribution in MSGs with normal architecture, non-specific chronic sialadenitis (NSCS) and primary Sjögren’s syndrome (pSS)-focal lymphocytic sialadenitis. Twelve patients with pSS and 16 sicca non-pSS subjects were enrolled in the study. MSGs were evaluated by haematoxylin and eosin staining and immunofluorescence for CD3/CD20 and CD21 to assess focus score, Tarpley biopsy score, T/B cell segregation and germinal center (GC)-like structures. Telocytes were identified by immunoperoxidase-based immunohistochemistry for CD34 and CD34/platelet-derived growth factor receptor α double immunofluorescence. Telocytes were numerous in the stromal compartment of normal MSGs, where their long cytoplasmic processes surrounded vessels and encircled both the excretory ducts and the secretory units. In NSCS, despite the presence of a certain degree of inflammation, telocytes were normally represented. Conversely, telocytes were markedly reduced in MSGs from pSS patients compared to normal and NSCS MSGs. Such a decrease was associated with both worsening of glandular inflammation and progression of ectopic lymphoid neogenesis, periductal telocytes being reduced in the presence of smaller inflammatory foci and completely absent in the presence of GC-like structures. Our findings suggest that a loss of MSG telocytes might have important pathophysiological implications in pSS. The specific pro-inflammatory cytokine milieu of pSS MSGs might be one of the causes of telocyte loss.

Telocytes in normal and keratoconic human cornea: an immunohistochemical and transmission electron microscopy study

“…It is commonly believed that TC may play an important role in driving organ development and contributing to the maintenance of local tissue homoeostasis and, hence, TC damage and dysfunction may occur in several disorders 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 52, 53. In this context, we herein demonstrate that the normal morphological features and distribution of TC are severely compromised within the corneal stromal compartment in keratoconic pathology.…”

“…Moreover, this peculiar stromal cell type is being increasingly implicated in a wide range of pathologies with potential applications in regenerative medicine 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36. Telocyte possess unique ultrastructural features consisting of a small cell body and extremely long and thin prolongations, termed telopodes, displaying a moniliform aspect characterized by the alternation of thin segments (called podomers) and small dilated regions (called podoms) accommodating mitochondria, endoplasmic reticulum cisternae and caveolae 11, 12, 37.…”

Telocytes in ileum of the Chinese giant salamander: ultrastructural evidence

“…TCs might also play a role in glandular cells regeneration of ileum as TCs in another digestive gland—liver 13, 14. Moreover, TCs might play important roles in the maintenance of glandular homeostasis 6, 15. Likewise, TCs might contribute to control some physiological responses in the gut, hence their close proximity to nerve fibres 2.…”

Mobilization of lymphatic endothelial precursor cells and lymphatic neovascularization in primary Sjögren's syndrome

“…Focus score and Tarpley biopsy score (0–4 scale) 20 were performed on hematoxylin‐ and eosin‐stained sections. Cellular infiltrate and lymphoid organization were assessed by immunofluorescence staining of serial MSG sections with antibodies against human CD3 (T‐cell marker), CD20 (B‐cell marker) and CD21 (marker of follicular dendritic cells characteristic of germinal centre‐like structures) as described elsewhere 21.…”