Relationship between sialoadenitis and periductal laminin expression in the submandibular salivary gland of NZBxNZWF(1) mice

The NZB/W F1 mouse model for Sjögren's syndrome: A historical perspective and lessons learned

Sjögren's syndrome (SS) is a chronic rheumatic autoimmune disorder affecting multiple organ systems. The clinical findings in SS patients show considerable heterogeneity and overlap with other autoimmune diseases. In addition, the autoimmune response in SS initiates several years before the appearance of clinical symptoms. Thus, understanding the pathogenic mechanisms involved in the disease process have been a challenge. Several animal model systems of SS-like disease have been developed to overcome these issues. The New Zealand Black (NZB) x New Zealand White (NZW) F1 (NZB/W F1) mouse represents the first spontaneous mouse model of SS. In this review, we provide a historical perspective and detailed description of this mouse model focusing on exocrine gland histopathology, autoantibody populations, and glandular dysfunction. Considering that NZB/W F1 mice also develop a systemic lupus erythematosus (SLE)-like disease, this mouse model mimics the clinical presentation of polyautoimmunity seen in a sizable subset of SS patients. It is plausible that such patients will require distinct therapeutic interventions necessary to treat both SLE and SS. Therefore, the NZB/W F1 mouse is a powerful tool to decipher pathogenic mechanisms involved in SS related polyautoimmunity and develop appropriate therapeutic strategies.

Dysfunction of lacrimal and salivary glands in Sjögren's syndrome: nonimmunologic injury in preinflammatory phase and mouse model

Sjögren's syndrome (SjS) is a chronic autoimmune disorder characterized by dry eyes and dry mouth due to dacryoadenitis and sialoadenitis with SS-A/Ro and/or SS-B/La autoantibodies in genetically predisposed individuals. Destruction of lacrimal and salivary glands by autoimmune reactions may lead to clinical manifestation. However, the mechanisms behind the decreased volume of secretions in tears and saliva are complex and are not fully understood. Exocrine gland dysfunction may precede autoimmunity (acquired immunity) or represent a process independent from inflammation in the pathogenesis of SjS. The preceded functional and morphologic changes of those tissues by nonimmunologic injury before the development of inflammation at the sites of target organs have been implicated. This paper focuses on the several factors and components relating to glandular dysfunction and morphologic changes by nonimmunologic injury during the preinflammatory phase in mouse model, including the factors which link between innate immunity and adaptive immunity.

Genes and Sjögren's syndrome

The evidence for a strong genetic component conferring susceptibility to primary Sjögren's syndrome (SS) is mounting. Several associations with SS have been reported and provide evidence that the HLA region harbors important susceptibility loci and that multiple genes outside the HLA region play a role. Genetic discovery lags behind success observed in related autoimmune diseases. Identifying genetic factors that cause SS will allow more precise definition of pathogenic mechanisms leading to the overall SS phenotype and clinically heterogeneous subsets of patients. Critical opportunities are certain to follow for translation into improved diagnosis and therapies for SS and its spectrum diseases.

Systemic treatment of anti-CD4CD25 T cell monoclonal antibody exacerbates sialoadenitis in submandibular glands during the early life in lupus-prone female NZB x NZWF mice

BACKGROUND

The maintenance mechanisms of peripheral tolerance by CD4(+)CD25(+) T cells before the development of sialoadenitis in secondary Sjögren's syndrome (sSS) are not well understood. The aim of the present study is to examine the effect of reduction of CD4(+)CD25(+) T cells on the development of sialoadenitis during the early life in female NZB x NZWF(1) (B/WF(1)) mice, a model for human sSS.

METHODS

Female B/WF(1) mice at 3 days after birth were treated with either anti-mouse CD4(+)CD25(+) T cells rat IgG(1) monoclonal antibody (mAb) or Rat IgG(1)(control). At 25 weeks of age, autoantibodies against nucleus and cytoplasm of ductal epithelial and myoepithelial cells, and histpathology of submandibular glands were examined in the mAb-treated and control groups. Also the development of anti-Ro/SS-A antibodies was examined until 25 weeks of age in both groups.

RESULTS

The mAb-treated group showed severe lesions with the development of autoantibodies compared to the control group.

CONCLUSIONS

The present results suggest that peripheral CD4(+)CD25(+) T cells may, at least in part, contribute to down-regulate the development of sialoadenitis in submandibular glands of lupus-prone female B/WF(1) mice during their early life.

Ultrastructure of myoepithelial cells as a target cell in sialoadenitis of submandibular glands of lupus-prone female NZBxNZWF1 mice

The changes of myoepithelial cells of sialoadenitis in submandibular glands in lupus-prone female NZB x NZWF1 (B/WF1) mice, a model for human secondary Sjögren's syndrome (sSS), were examined ultrastructurally. Inflammatory foci consisting of mainly lymphoid cells (lymphocytes and plasma cells) in the interlobular interstitium began to develop from 18 weeks of ages, and those were found within acini from the age of 25 weeks. These were paralleled with the production of anti-double-stranded deoxyribonucleic acid and anti-Ro/SS-A antibodies with age. Infiltrated lymphoid cells consisted of CD4+ T cells and Ig+ (or IgG2a+) cells. Electron microscopy revealed destruction of myoepithelial cells with lysis of basement membranes contacted with either lymphocytes or plasma cells. These led to the destruction (degeneration and necrosis) of the epithelium in striated and intercalated ducts and acinar epithelium. Further destruction of those cells occurred by the invasion of lymphocytes into the epithelial layers. Small numbers of apoptotic myoepithelium and duct epithelium from the age of 25 to 36 weeks and an increase of those cells in survived mice at 44 weeks of age were observed. The present study suggests that the myoepithelium may be one of the target cells and that the destruction of myoepithelial cells by infiltrated lymphoid cells may precede the destruction of acinar ducts and epithelium in sialoadenitis in sSS.

Usefulness of mouse models to study the pathogenesis of Sjögren's syndrome

Sjögren's syndrome (SS) is an autoimmune disorder characterized by ocular and oral dryness as well as systemic manifestations. The immunopathogenesis of SS is complex with different intricate factors. Because of the delay in the appearance of symptoms and due to ethical issues it is very difficult to study the wide array of factors intervening in the pathogenesis of SS in human patients. To circumvent this problem, different animal models have been elaborated for studying the different subsets of the aspects of the physiopathology of this disease. In this review, we focus on the mouse models that have been established to deepen our insight into the immunopathogenesis of SS.

Newer MR imaging techniques for head and neck

Dynamic and functional imaging techniques are being developed to improve the evaluation of various pathologic processes of the head and neck region. These techniques include dynamic contrast-enhanced MR imaging for evaluating soft tissue masses and cervical lymph nodes, the use of ultrasmall superparamagnetic iron oxide contrast agent, and functional techniques such as in vivo and in vitro MR spectroscopy of head and neck cancer and lymph nodes and apparent diffusion coefficient mapping of parotid glands. These techniques can help to differentiate nonmalignant tissue from malignant tumors and lymph nodes and can aid in differentiating residual malignancies from postradiation changes. From methodological development, they are making the critical transition to preclinical and clinical validating methods and eventually to widespread clinical tools.