Does autonomic nervous impairment have a role in pathophysiology of Sjögren's syndrome

Variability of salivary metabolite levels in patients with Sjögren's syndrome

PURPOSE

To investigate inter- and intra-individual variation in the levels and outputs (concentration multiplied by salivary flow rate) of salivary metabolites in patients with primary Sjögren's syndrome (pSS).

METHODS

A total of 56 samples of stimulated saliva were collected from 14 female pSS patients during four laboratory visits within 20 weeks and analyzed using proton nuclear magnetic resonance spectroscopy. Single saliva samples from each of 15 controls were also analyzed.

RESULTS

Among 21 quantified metabolites, choline was significantly elevated in the pSS patients at each time point (P ≤ 0.015), taurine at the last three time points (P ≤ 0.013), alanine at the last two time points (P ≤ 0.007) and glycine at the last time point (P = 0.005). Inter-individual variation in metabolite concentrations was generally larger among the patients than among the controls, and significantly large variations were observed for glycine (P ≤ 0.007, all time points), choline (P ≤ 0.033, three last time points) and alanine (P = 0.028, baseline). Metabolite output analysis showed that choline had the lowest intra-patient variation.

CONCLUSION

In spite of considerable intra- and inter-individual variation, levels and outputs of specific metabolites in patients with pSS differ from those in controls, and may be potentially applicable as new biological markers for monitoring of the response to treatment.

Systemic Immunomodulatory Therapy in Severe Dry Eye Secondary to Inflammation

PURPOSE

To report four patients with unusually severe acute keratitis sicca secondary to lacrimal tissue and ocular surface inflammation who eventually required systemic immunosuppressive therapy.

METHODS

Observational case series of four patients with extremely severe acute dry eye syndrome who were profoundly disabled by pain and photophobia (to the extent of staying in dark rooms) despite aggressive conventional therapy. Clinical data including visual acuities, other treatments administered for dry eye, systemic medical conditions, Schirmer and rose bengal staining results, degree of conjunctival injection, and medications were recorded. All four patients were treated with systemic immunomodulatory therapy.

RESULTS

All four patients were female with a mean age at presentation of 40 years (range 22-58 years), and all had systemic autoimmune diseases: systemic lupus erythematosus (SLE) and Sjogren's syndrome (n = 2), Sjogren's syndrome (n = 1), rheumatoid arthritis (RA) and psoriasis (n = 1). Schirmer test values at onset ranged from 0 to 2 mm. All patients had failed aggressive lubrication, topical cyclosporine, lid care, and punctual plugs. In two patients, serum tears and hyphrecation punctal occlusion were tried without success. Various systemic immunosuppressive agents were used to control inflammation of the lacrimal glands: methotrexate and cyclosporine A (patient 1), cyclosporine A (patient 2), prednisone (patient 3), and methotrexate and infliximab (patient 4). Treatment with systemic immunomodulatory agents resulted in resolution of the acute inflammatory assault on the lacrimal glands and control of signs and symptoms of keratoconjunctivitis sicca in all four patients, and visual acuities improved in all of them. Post-treatment Schirmer values ranged from 7 to 10 mm.

CONCLUSION

Systemic immunosuppressive agents may be required in the treatment of recalcitrant primary and secondary Sjogren's syndrome caused by systemic autoimmune conditions. We show that systemic immunomodulatory therapy leads to significantly improved tear production and resolution of the keratoconjunctivitis in these rare but severe cases.

Effect of inflammation on lacrimal gland function

The lacrimal gland is the main contributor to the aqueous layer of the tear film. It secretes proteins, electrolytes and water, which helps to nourish and protect the ocular surface. Lacrimal gland secretion is primarily under neural control, which is achieved through a neural reflex arc. Stimuli to the ocular surface activate afferent sensory nerves in the cornea and conjunctiva. This in turn activates efferent parasympathetic and sympathetic nerves in the lacrimal gland to stimulate secretion. Sex steroid hormones are also important regulators of lacrimal gland functions. A decrease or lack of lacrimal gland secretion is the leading cause of aqueous tear deficient dry eye syndrome (DES). It has been suggested that DES is an inflammatory disorder that affects the ocular surface and the lacrimal gland. In several pathological instances, the lacrimal gland can become a target of the immune system and show signs of inflammation. This can result from autoimmune diseases (Sjögren's syndrome), organ transplantation (graft versus host disease), or simply as a result of aging. The hallmarks of lacrimal gland inflammation are the presence of focal lymphocytic infiltrates and increased production of proinflammatory cytokines. The mechanisms leading to lacrimal gland dysfunction are still poorly understood. Apoptosis, production of autoantibodies, hormonal imbalance, alterations in signaling molecules, neural dysfunction, and increased levels of proinflammatory cytokines have been proposed as possible mediators of lacrimal gland insufficiency in disease states.

Parasympathetic nervous system dysfunction in primary Sjögren's syndrome

In the past sicca syndromes were attributed to destruction of glandular tissue. It is now thought that cytokines, autoantibodies, and parasympathetic nervous system dysfunction all have an important role in the xerostomia and xerophthalmia in Sjögren's syndrome.

Autoantibodies in primary Sjögren's syndrome: new insights into mechanisms of autoantibody diversification and disease pathogenesis

Characterisation of autoantibodies and their target autoantigens in primary Sjögren's syndrome (SS) is an important entry point for studying this common systemic autoimmune disease. Diversification of anti-Ro/La responses is believed to occur by a process of determinant spreading following initiation of an autoimmune response to one component, possibly 52-kD Ro (Ro52). Recent evidence supports the ER-resident chaperone Grp78 as a potential candidate in the initiation of an autoimmune response against Ro52, by binding to a Grp78 binding motif in the COOH-terminal region of Ro52. The subsequent diversification of the anti-Ro/La response is influenced by distinct HLA class II alleles. Anti-salivary duct autoantibodies have been revisited and shown to be mimicked by cross-reactive isoantibodies to AB blood group antigens. Identification of autoantibodies that act as antagonists at M3-muscarinic receptors represents an important advance. As well as contributing to the sicca symptoms, the functional effects of these autoantibodies may explain associated features of autonomic dysfunction in patients with SS. Anti-M3 receptor autoantibodies occur in both primary and secondary SS and allow Sjögren's syndrome to be viewed as a disorder of anti-receptor autoimmunity.

The oral side of Sjögren syndrome. Diagnosis and treatment. A review

Sjögren syndrome (SS) is an inflammatory disease of the exocrine glands. Although not always present, signs and symptoms of dry eyes and xerostomia are characteristic features of SS. Oral dryness is one of the most important data of patients with SS. Several sets of criteria have been published; however, there is no definitive agreement concerning which is the most useful. In addition to its various clinical manifestations, lack of understanding of the causes of SS delays prompt diagnosis. Histologically, the salivary gland shows a characteristic lymphocytic infiltrate, which is implicated in the destruction of gland cells. Saliva performs an important role in maintaining and protecting oral health. Deficient quality and quantity of saliva have a detrimental consequence for dental and oral health. In some patients, appropriate information regarding dry mouth care is not offered because most professionals either neglect or ignore adequate attention to oral health. Therefore, lack of treatment is frequent. Medical and dental studies that focus on the oral aspects of diagnosis, consequences, and treatment of SS are commented on. Diagnostic methods used for the oral component are also reviewed. The role of the oral tests developed to diagnose SS is assessed, especially tests used by the majority of criteria. Impairment of salivary secretion increases the risk of developing oral diseases; the therapeutic modalities designed to ameliorate these damages by increasing salivary output or by substitution of saliva are reviewed. We discuss published prevention techniques to diminish dental, periodontal, and soft tissue infections.

Magnetic resonance imaging and magnetic resonance sialography of parotid glands in primary Sjogren's syndrome

OBJECTIVE

To look for structural parotid gland changes on magnetic resonance (MR) imaging and MR sialography of primary Sjögren's syndrome (SS) patients and healthy control subjects and to compare these methods with each other.

METHODS

MR imaging and MR sialography of both parotid glands were performed on 26 patients and 7 healthy controls. Bilateral surface coils were used to obtain high spatial resolution.

RESULTS

Twenty-two of the 26 patients had abnormalities on MR imaging. Twenty-one had a nodular or dendritic parenchymal pattern, 5 had cavities, and 6 had duct dilatations. On MR sialography, 25 of the 26 patients had abnormalities of the ducts, and 16 of them also had cavities. One patient and all 7 controls had normal results with both methods. The structural appearance of the parotid glands on MR images had marginal linear association with the duct system changes but no correlation with the cavitary changes seen on MR sialography. Furthermore, duct system abnormalities did not correlate with cavitary changes. Both parenchymal and sialographic abnormalities were associated with the presence of Ro/SSA antibodies but not with age of the patient, disease duration, salivary flow rate, or the presence of hypergammaglobulinemia or extraglandular manifestations.

CONCLUSION

MR imaging and MR sialography are noninvasive methods that provide definitive information of morphologic changes in parotid glands and can be used as diagnostic indicators of primary SS. Because these methods give information on different aspects of glandular pathology, both should be performed when evaluating parotid glands of SS patients. MR sialography is more sensitive, but conventional MR imaging gives complementary information on the progressive pathologic changes of glandular parenchyma.