Ultrastructural Observations On The Parotitis Autoimmunica In The Nzb/Nzw Hybrid 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.

Understanding mechanisms of hypertension in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder that predominately affects women of reproductive age. Hypertension is an important cardiovascular risk factor that is prevalent in this patient population. Despite the high incidence of hypertension in women with SLE, the pathophysiological mechanisms underlying the development of hypertension remain poorly understood. This review will focus on disease-related factors, including inflammation, autoantibodies, and sex hormones that may contribute to hypertension in patients with SLE. In addition, we will highlight studies performed by our laboratory using the female NZBWF1 (F1 hybrid of New Zealand Black and New Zealand White strains) mouse model, a spontaneous model of SLE that mimics human disease and develops hypertension and renal injury. Specifically, using female NZBWF1 mice, we have demonstrated that multiple factors contribute to the pathogenesis of hypertension, including the inflammatory cytokine, tumor necrosis factor (TNF)-α, oxidative stress, as well as B-cell hyperactivity and autoantibody production.

The pathophysiology of hypertension in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disorder that predominantly affects women during their reproductive years. Although SLE can affect any organ system, the kidneys are prominently involved in the form of immune complex glomerulonephritis. In addition, in women with SLE, risk for the development of cardiovascular disease is dramatically increased. Hypertension is a major risk factor for cardiovascular disease and is highly prevalent in women with SLE. Nevertheless, there has been little exploration of the pathophysiological mechanisms that promote SLE hypertension. This review discusses the role of several mechanisms, with an emphasis on the kidney, in SLE hypertension. These mechanisms include the renin-angiotensin system, endothelin, oxidative stress, sex steroids, metabolic changes, peroxisome proliferator-activated receptor-gamma, and, perhaps most importantly, chronic inflammation and cytokines. Growing evidence suggests a link between chronic inflammation and hypertension. Therefore, elucidation of mechanisms that promote SLE hypertension may be of significant value not only for patients with SLE, but also for a better understanding of the basis for essential hypertension.

Lacrimal and salivary gland inflammation in the C3H/Ipr autoimmune strain mouse: a potential mode for Sjögren's syndrome

Sjögren's syndrome is an autoimmune inflammatory disease that affects the lacrimal and salivary glands. To identify a potential animal model for study of Sjögren's syndrome, an evaluation was made of lacrimal and salivary glands in the C3H/Ipr autoimmune strain mouse at ages before (2 months) and after (5 months) systemic autoimmune disease onset at 3 to 4 months. Quantitative and qualitative analyses of C3H/Ipr lacrimal and salivary (parotid, submandibular, and sublingual) gland histopathology were performed using age-matched C3H/HeJ nonautoimmune mice to control for inflammation of nonautoimmune origin. No lacrimal or salivary gland inflammation was seen in either of the strains at 2 months of age and measures of systemic autoimmune disease were negative. At 5 months of age, the nonautoimmune C3H/HeJ controls showed a slight increase in lacrimal gland inflammation, but this was not significantly different from the 2 month old controls. A significant increase in lacrimal gland inflammation was found in the 5 month old C3H/Ipr autoimmune mice in a histologic pattern similar to that of Sjögren's syndrome in human beings. Furthermore, the degree of inflammation was positively correlated with serum immune complexes and spleen weight. Sporadic inflammation of the submandibular gland was seen in both autoimmune and control mice, but this was neither statistically significant nor correlated with measures of autoimmunity. No significant inflammation was seen in the parotid or sublingual glands.

Sialographic images of pathological changes in the mouse parotid gland

In order to correlate pathological changes of mouse parotid glands with their sialographic images, we conducted studies on mice with known pathological changes: mice with Stensen's duct ligated, NZB mice with a systemic auto-immune disease, and aged mice. The sialographic images were found to be specific for the pathological changes: The glands after ligation of Stensen's duct were characterized by dilated, large excretory ducts with a reduced system of peripheral ducts; the glands of NZB mice showed lobular leakage of the contrast medium from small excretory ducts; and the glands of aged mice showed a great reduction in the ductal system. It is concluded that sialography yields useful information on the pathological changes of the ductal systems in the mouse parotid gland.

Experimental autoallergic sialadenitis in mice. Histopathological and ultrastructural studies

Experimental autoallergic sialadenitis was induced in SL/Ni mice by one or two injections of syngeneic submandibular gland homogenate emulsified with adjuvant. Light microscopically, there were marked lymphoid cell infiltration in the submandibular glands with high incidence and proliferation of duct epithelia. Furthermore complete alteration of whole glandular lobules in some cases was observed. Ultrastructurally, small and medium sized lymphocytes and plasma cells constituted a major portion of the infiltrating cells, and lymphocytes were frequently observed inside the basal lamina of ductal and acinar regions, especially observed in the small ductal region. In the aggregates of infiltrating cells, the cell remnants of salivary gland epithelia were scattered. Furthermore some of the epithelial cell remnants in aggregates of infiltrating cells could be recognized as epithelial masses which were composed of proliferated duct epithelial cells, though no typical structure of epimyoepithelial islands seen in Sjögren's syndrome was found. Antisalivary duct antibody was detected in only one case.

The autoimmune submandibular sialoadenitis of the NZB/NZW hybrid mice. A light and electron microscopical investigation

An electron microscopic study of the submandibular salivary gland lesion occurring in the NZB/NZW F1 hybrid mice was performed, and the findings were discussed and correlated to the autoimmune salivary gland disease observed in patients with Sjögren's syndrome. Within the submandibular salivary gland of this mouse strain focal infiltrates of mononuclear inflammatory cells were observed. Lymphoid cells were observed inside the basal lamina of acini and ducts, leading to destruction of these glandular units. The typical duct cell proliferation found in the autoimmune sialoadenitis of Sjögren's syndrome with the formation of the typical epimyoepithelial islands was not found in the submandibular glands of NZB/NZW mice.