Rheumatoid Arthritis: Porola P

Porola P, Laine M, Virkki L, Poduval P, Konttinen YT. · Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland. · Ann N Y Acad Sci. · Pubmed #17894007 No free full text.

Abstract: Sjögren's syndrome is an autoimmune disease affecting the exocrine glands, most typically salivary and lacrimal glands. In Sjögren's syndrome, the acinar cells of these glands are damaged and destroyed, leading to diminished secretion of saliva and tear fluid. Accordingly, the current American-European criteria of Sjögren's syndrome include xerostomia (dry mouth) and keratoconjunctivitis sicca (dry eyes). In addition to these sicca symptoms and signs, the diagnostic criteria require autoimmune features in the form of Sjögren's syndrome SS-A and/or SS-B autoantibodies and lymphocyte infiltrates in labial salivary glands. Majority of patients with Sjögren's syndrome are women and the diagnosis is usually done when they are 40-50 years old. The cause of Sjögren's syndrome is unknown, but taking into account the female dominance and the late onset, our hypothesis is that sex steroids play a key role in the etiology of Sjögren's syndrome. More specifically, we believe that the driving factor behind Sjögren's syndrome could be lack of androgens. It has been shown that patients with Sjögren's syndrome have low concentrations of circulating dehydroepiandrosterone sulfate (DHEA-S) compared to age-matched healthy controls. Our hypothesis is that patients with Sjögren's syndrome suffer from an insufficient local androgen effect in the exocrine target tissues of the disease because of low systemic levels and/or ineffective local intracrine handling of DHEA-S prohormone. To further clarify the role of sex steroids and the eventual deficiency of androgens, salivary glands are studied using protein markers regulated by androgens or estrogens.

Konttinen YT, Porola P, Konttinen L, Laine M, Poduval P. · Department of Medicine, FIN-00029 HUS, Finland. · Autoimmun Rev. · Pubmed #17110311 No free full text.

Abstract: Sjögren's syndrome (SS) is characterized by keratoconjunctivitis sicca and xerostomia, which occur in an autoimmune lacrimal and salivary gland disease characterized by lymphocyte infiltrates of exocrine glands and/or Sjögren's syndrome autoantibody production. It has been reported that aquaporin-5 distribution is abnormal in SS, perhaps as a result of paracrine effect of TNF-alpha. Also the neurogenic regulation of the salivary gland is impaired in SS. Apart from functional changes, the syndrome is also characterized by structural abnormalities of the secretory acinar apparatus. The acinar basement membrane is abnormal as it lacks laminin alpha1 chain, which may impair its capability to induce the progenitor cells to differentiate to acinar cells. CRISP-3 and TMPRSS-2 can be used as androgen markers and LIV-1 and Cyr61 as estrogen markers to study the sexual dimorphism of the salivary glands. Patients with SS seem to have low concentrations of dehydroepiandrosterone, which may predispose women and the exocrine glands to this syndrome.

Poduval P, Sillat T, Virtanen I, Porola P, Konttinen YT. · University of Helsinki, Helsinki, Finland. · Arthritis Rheum. · Pubmed #19333954 No free full text.

Abstract: OBJECTIVE: Sjögren's syndrome (SS) is characterized by atrophy and malfunction of the acinar cells. The aim of this study was to investigate whether type IV collagen alpha-chain composition of acinar cell compartments could be abnormal in diseased glands. METHODS: Messenger RNA (mRNA) from human submandibular gland (HSG) cells, cultured with or without growth factor-depleted Matrigel, was analyzed using quantitative reverse transcription-polymerase chain reaction (RT-PCR). Labial salivary glands were analyzed using quantitative RT-PCR and immunohistochemistry. RESULTS: HSG cells of both the ductal and acinar phenotypes synthesized all alpha-chain mRNA, in particular those of the alpha1 and alpha2 chains. Labial salivary glands (LSGs) contained alpha1/2 chains but also contained mRNA of all the other alpha-chains, although the mRNA copy numbers for the alpha3 and alpha4 chains were low, and the corresponding proteins were absent. Type IV collagen alpha1/2-chains were observed in all tubuloalveolar basement membranes. In healthy glands, alpha5 and alpha6 chains were continuous around ducts but discontinuous around acini. In SS glands, these chains were absent or patchy around the ducts and absent around the acini. CONCLUSION: Ductal and acinar epithelial cells are able to locally produce mRNA for all 6 different alpha-chains. Type IV collagen alpha1/2-chains seem to form the backbone in the tubuloalveolar basement membrane in salivary glands. Type IV collagen alpha3 and alpha4 chain mRNA were found in cultured salivary epithelial cells and LSG explants but were not translated to the corresponding alpha-chains in LSGs. Both alpha5 and alpha6 mRNA were observed in salivary epithelial cells and glands. In healthy glands, immunolabeling always disclosed corresponding alpha-chains around ducts, but their synthesis and/or degradation seemed to be locally regulated around acinar cells.

Laine M, Virtanen I, Porola P, Rotar Z, Rozman B, Poduval P, Konttinen YT. · Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland. · Clin Exp Rheumatol. · Pubmed #19032812 No free full text.

Abstract: OBJECTIVE:To analyze the epithelial cell-basement membrane attachment, in particular in the secretory end pieces (responsible for secretion of saliva) and in Sjögren's syndrome (SS) characterized by acinar cell failure.METHOD:Immunohistochemistry with laminin receptor chain-specific monoclonal antibodies to integrin (Int) subunits, Lutheran blood group antigen and alpha-dystroglycan.RESULTS:Only acinar cells contained Int alpha1 and alpha2 subunits. This staining was interrupted but strong in controls, but very weak in SS. Both acinar and ductal cells contained Int alpha3, alpha6, b1 and b4 and Lutheran blood group antigen and ductal cells also contained alpha-dystroglycan. These staining patterns were similar in SS and controls. CONCLUSIONS:Binding of the acinar and ductal cells to the basement membrane laminins seems to be mediated by Int alpha3b1, alpha6b1 and alpha6b4 integrin-receptors and Lutheran blood group antigen and alpha-dystroglycan non-integrin receptors. This structure-supporting system is intact in SS, compatible with the maintenance of the tubuloalveolar architecture of the SS glands. The irregular staining pattern of the acinus-specific Int alpha1b1 and alpha2b1 was compatible with a regulated signaling role, which was apparently impaired in SS. Indeed, their laminin counterparts (Lm -1/111 and -2/211) are also aberrant in SS revealing this as the central cell-matrix defect in the syndrome.

Porola P, Virkki L, Przybyla BD, Laine M, Patterson TA, Pihakari A, Konttinen YT. · Institute of Clinical Medicine, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland. · J Rheumatol. · Pubmed #18843777 No free full text.

Abstract: OBJECTIVE: .We hypothesized that in addition to dehydroepiandrosterone (DHEA) depletion, Sjögren's syndrome (SS) is characterized by local androgen deficiency in salivary glands and defects in local processing of DHEA. METHODS: Sex steroid levels in serum and saliva were measured using enzyme immunoassays. Androgen effects on salivary gland cells were analyzed using the cysteine-rich secretory protein-3 (CRISP-3) androgen biomarker. RESULTS: Serum and salivary concentrations of androgens were low in SS. Substrate to end-product ratios and correlations suggest that in SS salivary glands DHEA is effectively converted to testosterone, but that there are defects in converting testosterone further to dihydrotestosterone (DHT). In healthy controls no such phenomenon was seen, but testosterone is effectively converted to DHT. Salivary glands contained type I 5-alpha-reductase, and its inhibition with dutasteride completely blocked the upregulating effect of DHEA, but not of DHT, on CRISP-3 in human salivary gland acinar cells. CONCLUSION: DHEA and DHT upregulate CRISP-3, which is reportedly low in SS. The effect of DHEA on CRISP-3 is indirect and is inhibited by dutasteride, showing that there is intracrine processing of DHEA in salivary glands. In healthy glands, but not in SS, DHEA is effectively taken up and converted to DHT. Sex steroid concentrations in saliva in part reflect glandular uptake of DHEA-sulfate and local intracrine DHEA metabolism, which seem to be defective in SS. Our study demonstrates a prominent androgen deficiency and a defect in intracrine production of active androgens in SS salivary glands, also suggesting that salivary DHT cannot be maintained at a normal level in this female-dominant autoimmune exocrinopathy.

Laine M, Porola P, Udby L, Kjeldsen L, Cowland JB, Borregaard N, Hietanen J, Ståhle M, Pihakari A, Konttinen YT. · Helsinki University Central Hospital, and University of Helsinki, FIN-00029 HUS, Helsinki, Finland. · Arthritis Rheum. · Pubmed #17665393 links to  free full text

Abstract: OBJECTIVE: Sjögren's syndrome (SS), an autoimmune disease of exocrine glands, typically starts at the time of adrenopause. We undertook this study to test the hypothesis that SS is characterized by an insufficient androgen effect at the target tissue level. METHODS: We searched for androgen response elements (AREs) in the cysteine-rich secretory protein 3 (crisp-3) gene. Dehydroepiandrosterone (DHEA) responsiveness was experimentally studied using quantitative reverse transcriptase-polymerase chain reaction and immunofluorescence staining of human submandibular gland-derived acinar cells and labial salivary gland explants with or without DHEA. Finally, glandular and salivary CRISP-3 in healthy controls and SS patients was analyzed using immunohistochemistry, in situ hybridization, and enzyme-linked immunosorbent assay. Serum DHEA sulfate (DHEAS) and salivary DHEA levels were measured using a radioimmunometric method. RESULTS: Literature analysis and a search for AREs in gene banks suggested androgen dependency of human CRISP-3, and this was verified by studies of human submandibular gland acinar cells cultured with or without DHEA, in which DHEA increased CRISP-3 messenger RNA (mRNA) levels (P = 0.018). This finding was confirmed by the results of DHEA stimulation of labial salivary gland explants. Glandular CRISP-3 mRNA and protein labeling was weak and diffuse, coupled with low secretion in saliva (mean +/- SEM 21.1 +/- 2.7 mug CRISP-3/15 minutes in SS patients versus 97.6 +/- 12.0 mug CRISP-3/15 minutes in healthy controls; P < 0.0001). Compared with healthy controls, SS patients had low serum levels of DHEAS (P = 0.008) and also low salivary levels of DHEA (mean +/- SEM 224 +/- 33 pmoles versus 419 +/- 98 pmoles; P = 0.005). CONCLUSION: CRISP-3 pathology was seen in acini remote from lymphocyte foci and is apparently not secondary to local inflammation, but may represent some systemic effect in SS. Indeed, androgen deprivation in the salivary glands of SS patients is evidenced both by low salivary levels of DHEA and by low levels of DHEA-regulated CRISP-3. This may explain some of the characteristic features of SS.