The Significance of Matrix Metalloproteinases in Oral Diseases.

Matrix metalloproteinases (MMPs) belong to a family of structurally related zinc-dependent proteolytic enzymes that are known to play a key role in the catabolic turnover of extracellular matrix (ECM) components. Research studies to date have indicated that MMPs regulate the activity of several non-ECM bioactive substrates, including growth factors, cytokines, chemokines and cell receptors, which determine the tissue microenvironment. Disruption of the balance between the concentration of active matalloproteinases and their inhibitors (TIMPs) may lead to pathological changes associated with uncontrolled ECM turnover, tissue remodeling, inflammatory response, cell growth and migration. This brief review presents some information on MMPs' role in inflammatory, metabolic and cancer abnormalities related to the salivary glands, as well as MMP-related aspects that lead to the formation of human dentinal caries lesions. In oral diseases, the most relevant biological fluid commonly used for diagnosing periodontal diseases is saliva. In diseased patients with significantly higher levels of MMPs in their saliva than healthy people, most extracellular matrix components undergo digestion to lower molecular weight forms. Conventional treatment successfully reduces the levels of MMPs inhibits the progressive breakdown of gingival and periodontal ligament collagens. Beside inflammatory abnormalities like Sjögren's syndrome (SS), a large group of disorders is comprised of cancers, most of them involving the parotid gland.

Matrix metalloproteinases and their inhibitors in non-neoplastic otorhinolaryngological disease.

Matrix metalloproteinases (MMPs) are a family of zinc and calcium-dependent endopeptidases that play a key role in extracellular matrix (ECM) degradation. MMPs are known to be important in normal remodelling processes. Overexpression and activation of MMPs or an imbalance of active MMPs and tissue inhibitors of metalloproteinases (TIMPs) has been linked with a number of specific disease states associated with the breakdown and remodelling of the extracellular matrix. MMPs and TIMPs play a role in the development and progression of conditions such as acute and chronic otitis media, nasal polyposis and Sjogren's disease of salivary glands. Their role in allergic rhinitis has not been proven although they do appear to have a role in asthma, a condition closely linked to rhinitis. The use of a broad spectrum MMP inhibitor has been shown to alter the outcome of acute otitis media and otitis media with effusion. Therapeutic strategies with anti-MMP molecules are currently being developed and may play a role in modulating the course of non-neoplastic otorhinolaryngological disease in the future.

Inhibition of calcium-calmodulin kinase restores nitric oxide production and signaling in submandibular glands of a mouse model of salivary dysfunction.

Nitric oxide is an intracellular and diffusible messenger of neurotransmitters involved in salivary secretion, as well as an inflammatory mediator in salivary gland diseases. It is synthesized by three different isoforms of nitric oxide synthase (NOS), each subject to a fine transcriptional, post-transcriptional and/or post-translational regulation. Our purpose was to study the possible mechanisms leading to NOS downregulation in submandibular glands of normal mice and in the nonobese diabetic (NOD) mouse model of salivary dysfunction with lower NOS activity. NOS activity and cGMP accumulation were determined by radioassays in submandibular glands of both mice in the presence of the protein kinase inhibitors KN-93 and bisindolylmaleimide. NOS I mRNA and protein expression and localization were assessed by RT-PCR, Western blot and immunohistochemistry. A downregulatory effect of calcium-calmodulin kinase II (CaMK II) on NOS activity in submandibular glands of both NOD and BALB/c mice was observed. Our results are consistent with a physiological regulation of NOS activity by this kinase but not by PKC in normal BALB/c mice. They are also supportive of a role for CaMK II in the lack of detectable NOS activity in submandibular glands of NOD mice. KN-93 also restored cGMP accumulation in NOD submandibular glands. The downregulation of NOS in NOD mice seems to be mainly mediated by this kinase rather than the result of a lower expression or different cellular localization of the enzyme. It was not related to different substrate or cofactors availability either.

[Study of free-radical processes and antioxidant defense parameters during hirudotherapy of patients with diseases of salivary glands]. / Izuchenie pokazatelei svobodnoradikal'nykh protsessov i antioksidantnoi zashchity u lits s zabolevaniiami sliunnykh zhelez, poluchaiushchikh girudoterapiiu.

Hirudotherapy was used in the treatment of 39 patients (10 male and 29 female) aged 28-58 years with chronic sialadenitis and sialadenosis. Control group consisted of 15 normal subjects without diseases of salivary glands. Lipid peroxidation (LPO) and antioxidant defense (AOD) parameters were under study. Hirudotherapy led to improvement of the clinical status in the majority of patients with sialadenosis; the content of superoxide dismutase (SOD) normalized and ceruloplasmin (CP) level increased. The status of patients with sialadenitis also improved; catalase and glutathione peroxidase levels normalized and SOD and CP levels increased. The best therapeutic effect was attained in patients with sialadenitis. No appreciable improvement was observed in patients with chronic parenchymatous parotitis in the presence of Sjogren's syndrome.

Increased matrix metalloproteinase-2 activity induced by TGF-beta 1 in duct cells of human salivary gland is associated with the development of cyst formation in vivo.

Proteolytic enzyme activity has been shown to be important for cyst formation. In this study, we constructed a cyst-like structure in vivo and analyzed molecular mechanisms involved in the development of the lesion. When SV40-immortalized duct cells of normal human salivary gland (NS-SV-DC) were treated with TGF-beta 1 at a concentration of 1 ng/ml or 5 ng/ml followed by co-inoculation with Matrigel into the backs of nude mice, they formed large cysts containing fluid when 5 ng/ml of TGF-beta 1 was used. Analysis of the fluid demonstrated high MMP activity. Immunohistochemical staining exhibited strong reactivity with anti-MMP-2 antibody in TGF-beta 1 (5 ng/ml)-treated NS-SV-DC. Northern blot analysis indicated that the expression of TGF-beta 1 and MMP-2 mRNAs in cells was greatly enhanced by treatment with 5 ng/ml TGF-beta 1. These findings suggest that the in vivo cyst formation by TGF-beta 1-treated cells is associated with continuous induction of MMP-2 activity.

Proteolytic enzymes in salivary extravasation mucoceles.

We examined the content of type IV collagenases and plasminogen activators (PAs) in luminal fluid of four extravasation mucoceles by means of gelatin or casein zymography. Immunohistochemical staining for type IV collagenases and PAs was performed to identify the possible source of these enzymes. The luminal fluid examined by gelatin zymography showed a high level of type IV collagenases compared with saliva from Wharton's duct. PAs were detected in only one of the cases by casein zymography, and none was detected in the saliva. By immunohistochemical staining, type IV collagenases and PAs were detected in duct and myoepithelial cells of the adjacent salivary gland and in macrophages and fibroblasts of the cyst wall. The results suggest that proteolytic enzymes are involved in the pathogenesis of mucoceles.

Immunohistochemical localization of amylase in sialoadenitis and salivary gland tumors.

Immunohistochemical demonstration of alpha-amylase has been made in sialoadenitis-involved tissue and salivary gland tumors, as well as in normal salivary glands. Immunoreactive alpha-amylase with trypsin pretreatment was confined to irregularly staining serous acinar cells in the parotid and submandibular glands, and to demilunes in sublingual glands. In obstructive adenitis, staining was irregular from high to negative in acini in early or intermediate stages. Dilated ductal segments contained cells positive for alpha-amylase in the early stage following obstruction. Pleomorphic adenomas were usually negative for alpha-amylase but in rare cases tumor epithelia stained variably positive; i.e., staining occurred throughout the cytoplasm or at the periphery or apical part of the tumor cells. Luminal cavities of tubular and duct-like structures contained alpha-amylase-positive material. Epithelia in Warthin's tumor were also negative in general; however, scattered single or grouped tumor cells containing alpha-amylase were found. Mucoepidermoid tumors were also negative, though slightly positive cells were found intermingled among the negative squamous and mucous tumor cells. Cystic lesions in mucoepidermoid tumor were sometimes positive in the wall cells together with material secreted into the lumen.

Immunohistochemical observations on carbonic anhydrase I and II in human salivary glands and submandibular obstructive adenitis.

Immunohistochemical identification of carbonic anhydrase I and II (CA-I, CA-II) was made in human major salivary glands and obstructive adenitis in submandibular glands. Normal salivary glands stained the strongest for CA-II in serious acinar cells and were negative in mucous cells. Moderate to strong staining for CA-I and CA-II was found in ductal segments. Submandibular glands with obstructive adenitis exhibited reduced CA-I activity in atrophic acinar cells, but not in ductal elements in the early and intermediate stages of the disorder. In the late stage of the obstructive lesion, CA staining in duct-like structures was moderate; however, almost degenerate ductal cells were negative for CA. During the progression of the degeneration in the obstructive lesion, the CA staining decreased dependent on acinar atrophy. Even after longstanding obstruction of the salivary gland, altered ductal epithelia may retain some of their functions.

Salivary phosphohexoseisomerase activity in health and salivary gland diseases.

The attitude of phosphohexoseisomerase (PHI), a glycolytic enzyme, in parotid and submandibular saliva of healthy human control subjects of different sex and age was studied flow rate dependent. The results obtained from this group were compared to the PHI activity measured in the saliva of patients suffering from salivary gland diseases. Significantly elevated salivary PHI levels were found in chronic sialadenitis, while in sialadenosis, parotid gland infarction and parotid cysts the enzyme activity was within the normal range. Single patients suffering from parotid gland tumors showed elevated PHI values. A possible role of salivary PHI activity for the differential diagnosis of salivary gland diseases is discussed.

[Phosphohexose isomerase activity in parotid and submandibular saliva as a parameter in the diagnosis of chronic sialadenitis]. / Phosphohexoseisomerase-Aktivität im Parotis- und Submandibularisspeichel als Parameter in der Diagnostik chronischer Sialadenitiden.

The phosphohexose isomerase (PHI) activity was measured in parotid and submandibular saliva of patients suffering from chronic sialadenitis and of healthy control persons. In control persons the mean PHI value determined in parotid saliva (10.93 +/- 1.17 U/l) was significantly lower compared to that measured in submandibular saliva (38.18 +/- 4.44 U/l). In chronic sialadenitis the salivary PHI activity was significantly increased and reached values up to 5440 U/l in parotid secretion and values up to 1620 U/l in submandibular secretion. The possible role of salivary PHI activity as a parameter for the diagnosis of chronic sialadenitis is discussed.

Elevated serum amylase activity in the absence of clinical pancreatic or salivary gland disease: possible role of acute hypoxemia.

Elevated serum amylase activity, in the absence of clinically apparent pancreatic or salivary gland disease, has been observed in many seemingly unrelated conditions. In a search for common etiological factors to account for hyperamylasemia in these conditions, a retrospective analysis was performed. Eighty-four episodes of hyperamylasemia (greater than 300 I.U./l. Phadebas method) occurring in 75 patients over a one-year period ending in June, 1975 were assigned to one of two groups. Group 1 consisted of 56 (67%) episodes of hyperamylasemia with clinical pancreatitis. Group 2 consisted of 28 (33%) episodes of hyperamylasemia in the absence of clinical pancreatitis. Hypoxemia (pO2 less than 75 mm. Hg.) was found in 9/15 patients in Group 2 who had arterial blood gases measured. To assess the possible relationship between acute hypoxemia and amylase activity, a prospective study was initiated. Patients with known causes of pancreatitis or renal failure were eliminated. Hyperamylasemia was found in 3/8 hypoxemic patients. This raises the possibility that acute hypoxemia alone or in combination with other factors may raise serum amylase activity, possibly through ischemic injury to the pancreas or salivary glands or other amylase containing tissues.