[Physiological and pathological effects of nitric oxide and nitric oxide synthase in oral cavity].

Nitric oxide (NO) is a short-lived free radical which is not only involved in regulating many physiological processes of the body, but also closely related to many diseases. Nitric oxide synthase (NOS) is the key enzyme for NO production. NOS exists as three distinct isoforms, the endothelial NOS (eNOS), neuronal NOS (nNOS) and inducible NOS (iNOS). It has been found that nNOS and eNOS were expressed in normal pulp tissues, periodontal tissues and salivary glands, and the NO produced from nNOS and eNOS was involved in their physiological functions. NO and iNOS are involved in the occurrence and development of pulpitis, periodontitis, salivary gland disease and oral cancer. This review focuses on the physiological and pathological effects of NO and different subtypes of NOS in oral cavity.

Treatment-refractory ALK-positive inflammatory myofibroblastic tumour of the oral cavity.

We present a challenging case of a previously healthy 23-year-old man who developed an inflammatory myofibroblastic tumour of the hard palate, harbouring a rearrangement of the anaplastic lymphoma kinase (ALK) locus. Despite surgical intervention, radiotherapy and ALK-inhibition therapy, the tumour recurred locally and metastasised to regional lymph nodes, and the patient passed away roughly 9 months after diagnosis from local progression. The rapid progression of this patient's disease and its resistance to treatment demonstrate the potentially aggressive clinical course of inflammatory myofibroblastic tumours. ALK-inhibition therapy was unsuccessful in this ALK-positive tumour, highlighting the need for further investigation of markers predictive of disease progression and treatment response.

Síndrome de boca ardiente: revisión y puesta al día / Burning mouth syndrome: a review and update

El síndrome de boca ardiente (SBA) es un cuadro clínico que padecen mayoritariamente mujeres de edad media o avanzada. Se caracteriza por una sensación muy molesta de ardor o escozor sobre la lengua o en otras zonas de la mucosa bucal. Puede estar acompañado de xerostomía y de disgeusia. Se suele presentar de forma espontánea y tiene un perfil clínico muy característico. Las molestias son continuas, pero aumentan hacia la tarde-noche. Aunque clásicamente se había atribuido a múltiples factores, en los últimos años hay evidencia para relacionarlo con una disfunción neuropática de tipo periférico (fibras C sensitivas o trigeminales) o de tipo central (sistema dopaminérgico nigroestriado). En el diagnóstico hay que descartar lesiones objetivables en la mucosa oral o alteraciones en la analítica sanguínea que puedan ser causa de ardor bucal. El manejo de los pacientes se basa en evitar focos irritativos orales y soporte psicológico. Para el tratamiento farmacológico del ardor en el SBA primario de causa periférica, se puede administrar clonacepam de uso tópico, y pacientes con SBA de tipo central parecen mejorar con el uso de antidepresivos del tipo de la duloxetina, anticonvulsionantes como la gabapentina, o la amisulprida (AU)

Burning mouth syndrome (BMS) is mainly found in middle aged or elderly women and is characterized by intense burning or itching sensation of the tongue or other regions of the oral mucosa. It can be accompanied by xerostomia and dysgeusia. The syndrome generally manifests spontaneously, and the discomfort is typically of a continuous nature but increases in intensity during the evening and at night. Although BMS classically has been attributed to a range of factors, in recent years evidence has been obtained relating it peripheral (sensory C and/or trigeminal nerve fibers) or central neuropathic disturbances (involving the nigrostriatal dopaminergic system). The differential diagnosis requires the exclusion of oral mucosal lesions or blood test alterations that can produce burning mouth sensation. Patient management is based on the avoidance of causes of oral irritation and the provision of psychological support. Drug treatment for burning sensation in primary BMS of peripheral origin can consist of topical clonazepam, while central type BMS appears to improve with the use of antidepressants such as duloxetine, antiseizure drugs such as gabapentin, or amisulpride (AU)

Secreted aspartic protease cleavage of Candida albicans Msb2 activates Cek1 MAPK signaling affecting biofilm formation and oropharyngeal candidiasis.

Perception of external stimuli and generation of an appropriate response are crucial for host colonization by pathogens. In pathogenic fungi, mitogen activated protein kinase (MAPK) pathways regulate dimorphism, biofilm/mat formation, and virulence. Signaling mucins, characterized by a heavily glycosylated extracellular domain, a transmembrane domain, and a small cytoplasmic domain, are known to regulate various signaling pathways. In Candida albicans, the mucin Msb2 regulates the Cek1 MAPK pathway. We show here that Msb2 is localized to the yeast cell wall and is further enriched on hyphal surfaces. A msb2Δ/Δ strain formed normal hyphae but had biofilm defects. Cek1 (but not Mkc1) phosphorylation was absent in the msb2Δ/Δ mutant. The extracellular domain of Msb2 was shed in cells exposed to elevated temperature and carbon source limitation, concomitant with germination and Cek1 phosphorylation. Msb2 shedding occurred differentially in cells grown planktonically or on solid surfaces in the presence of cell wall and osmotic stressors. We further show that Msb2 shedding and Cek1 phosphorylation were inhibited by addition of Pepstatin A (PA), a selective inhibitor of aspartic proteases (Saps). Analysis of combinations of Sap protease mutants identified a sap8Δ/Δ mutant with reduced MAPK signaling along with defects in biofilm formation, thereby suggesting that Sap8 potentially serves as a major regulator of Msb2 processing. We further show that loss of either Msb2 (msb2Δ/Δ) or Sap8 (sap8Δ/Δ) resulted in higher C. albicans surface ß-glucan exposure and msb2Δ/Δ showed attenuated virulence in a murine model of oral candidiasis. Thus, Sap-mediated proteolytic cleavage of Msb2 is required for activation of the Cek1 MAPK pathway in response to environmental cues including those that induce germination. Inhibition of Msb2 processing at the level of Saps may provide a means of attenuating MAPK signaling and reducing C. albicans virulence.

The heme oxygenase system and oral diseases.

Oral Diseases (2011) 17, 252-257 Heme oxygenase (HO) system catabolizes heme into three products: carbon monoxide (CO), biliverdin/bilirubin and free iron, which consists of three forms identified to date: the oxidative stress-inducible protein HO-1 and the constitutive isozymes HO-2 and HO-3. HO has been involved in many physiological and pathophysiological processes, ranging from Alzheimer's disease to cancer. The interest in HO system by scientists and clinicians involved with the oral and maxillofacial region is fairly recent, and few papers currently cited on HO relate to diseases in this anatomical area. This review will focus on the current understanding of the physiological significance of HO-1 induction and its possible roles in the oral diseases studied to date. The implications for possible therapeutic manipulation of HO are also discussed.

Tissue inhibitors of metalloproteinases (TIMPs): their biological functions and involvement in oral disease.

Several families of enzymes are responsible for the degradation of extracellular matrix (ECM) proteins during the remodeling of tissues. An important family of such enzymes is that of the matrix metalloproteinases (MMPs). To control MMP-mediated ECM breakdown, tissue inhibitors of metalloproteinases (TIMPs) are able to inhibit MMP activity. A disturbed balance of MMPs and TIMPs is found in various pathologic conditions, such as cancer, rheumatoid arthritis, and periodontitis. The role of MMPs in pathology has been extensively described in the literature. The main focus of this review lies in the biological functions of TIMPs and their occurrence in disease, especially in the head and neck area. Their biological functions and their role in diseases like oral cancers and periodontitis, and in the development of cleft palate, will be discussed. Finally, the diagnostic and therapeutical opportunities of TIMPs will be evaluated.

Apoptosis in normal and diseased oral tissues.

Apoptotic cell death plays an important role in maintenance of the normal physiological state and in the pathogenesis of diseases in the body. Over the last three decades the molecular mechanisms of apoptosis have been unravelled leading to development of novel therapeutic approaches. This paper aims to present current knowledge of the role of apoptosis in normal oral tissues and in the development of oral diseases.

Cyclooxygenase-2 is a possible target of treatment approach in conjunction with photodynamic therapy for various disorders in skin and oral cavity.

BACKGROUND: Anti-cancer effects of cyclooxygenase (COX)-2 inhibitors have been reported, but not fully investigated in skin and oral diseases. 5-aminolaevulinic acid (ALA)-based photodynamic therapy (PDT) for treating those patients with skin and oral lesions is a highly sophisticated procedure, but the incidence of disease recurrence after treatment is rather significant. OBJECTIVE: To confirm that COX-2 could be a molecular target in adjunctive therapy to ALA-based PDT, we investigated (i) COX-2 expression in various skin and oral diseases, and (ii) the inhibitory effects on cellular growth of COX-2 selective inhibitor (nimesulide), ALA-based PDT and their combination on human oral squamous cell carcinoma (SCC) cell lines. METHODS: A total of 129 biopsy samples from the skin and oral mucosal lesions were tested immunohistochemically for COX-2 expression. Then the in vitro effects of nimesulide, ALA-based PDT, and their combination were determined on two SCC cell lines, HSC-2 and HSC-4. Three different methods (MTT assay, double-staining for annexin V and propidium iodide, caspase-3/CPP32 fluorometric protease assay) were applied for evaluation of their inhibitory effects on these two cell lines. RESULTS: Among the skin diseases, a considerable number of COX-2 high expressers were found in actinic keratosis (15 of 25, 60%), Bowen's disease (13 of 17, 76%) and extramammary Paget's disease (15 of 15, 100%). In contrast, only one of 33 (3%) basal cell carcinoma tumours was a COX-2 high expresser. Among the oral mucosal biopsies, the proportion of COX-2 high expressers increased gradually from hyperplasia (one of six, 17%) through mild dysplasia (five of eight, 63%) and moderate dysplasia (20 of 23, 87%) to severe dysplasia (two of two, 100%). Nimesulide had an inhibitory effect in vitro on HSC-2 (proven to be a COX-2 high expresser), but not on HSC-4 (a COX-2 non-expresser). While ALA-based PDT showed an inhibitory effect on both HSC-2 and HSC-4, most importantly the combination of nimesulide and ALA-based PDT demonstrated a significant synergistic effect on the cellular growth inhibition of only HSC-2, but not of HSC-4. CONCLUSIONS: Our study strongly suggests that COX-2 can be one of the molecular targets in treating various skin and oral diseases. The results from our in vitro experiments also prompt us to develop a new protocol with a combination of COX-2 selective inhibitor and ALA-based PDT for more effective treatment of those diseases.

In vitro secreted aspartyl proteinase activity of Candida albicans isolated from oral diseases and healthy oral cavities.

The in vitro secreted aspartyl proteinase (SAP) activity of Candida albicans isolated from a variety of oral conditions, including healthy oral cavities, was determined. SAP activity (units/10(6) cells/ml, +/-SD) was 0.28 +/- 0.33 for pseudomembranous candidosis isolates (n = 18), 0.35 +/- 0.46 for chronic erythematous candidosis isolates (n = 21) and 0.30 +/- 0.32 for chronic hyperplastic candidosis isolates (n = 50). SAP activity of 0.19 +/- 0.22 was recorded for isolates from squamous cell carcinoma (n = 18), 0.26 +/- 0.37 for burning mouth syndrome isolates (n = 29), 0.25 +/- 0.38 for isolates from xerostomia (n = 15) and 0.39 +/- 0.50 for isolates from lichen planus (n = 13). The SAP activity of isolates from oral disease states was significantly (P < 0.05) higher than that recorded for 28 isolates from healthy mouths (activity of 0.04 +/- 0.03). However, there was no significant difference in the SAP activity between the three forms of clinical oral candidosis (P > 0.05). SAP activity was inhibited in control samples containing the SAP inhibitor, pepstatin A. These results indicate that C. albicans strains associated with oral disease have inherently higher SAP activity.

Cysteine peptidases of mammals: their biological roles and potential effects in the oral cavity and other tissues in health and disease.

Cysteine peptidases (CPs) are phylogenetically ubiquitous enzymes that can be classified into clans of evolutionarily independent proteins based on the structural organization of the active site. In mammals, two of the major clans represented in the genome are: the CA clan, whose members share a structure and evolutionary history with papain; and the CD clan, which includes the legumains and caspases. This review focuses on the properties of these enzymes, with an emphasis on their potential roles in the oral cavity. The human genome encodes at least (but possibly no more than) 11 distinct enzymes, called cathepsins, that are members of the papain family C1A. Ten of these are present in rodents, which also carry additional genes encoding other cathepsins and cathepsin-like proteins. Human cathepsins are best known from the ubiquitously expressed lysosomal cathepsins B, H, and L, and dipeptidyl peptidase I (DPP I), which until recently were considered to mediate primarily "housekeeping" functions in the cell. However, mutations in DPP I have now been shown to underlie Papillon-Lefevre syndrome and pre-pubertal periodontitis. Other cathepsins are involved in tissue-specific functions such as bone remodeling, but relatively little is known about the functions of several recently discovered enzymes. Collectively, CPs participate in multiple host systems that are active in health and in disease. They are involved in tissue remodeling and turnover of the extracellular matrix, immune system function, and modulation and alteration of cell function. Intracellularly, CPs function in diverse processes including normal protein turnover, antigen and proprotein processing, and apoptosis. Extracellularly, they can contribute directly to the degradation of foreign proteins and the extracellular matrix. However, CPs can also participate in proteolytic cascades that amplify the degradative capacity, potentially leading to pathological damage, and facilitating the penetration of tissues by cancer cells. We know relatively little regarding the role of human CPs in the oral cavity in health or disease. Most studies to date have focused on the potential use of the lysosomal enzymes as markers for periodontal disease activity. Human saliva contains high levels of cystatins, which are potent CP inhibitors. Although these proteins are presumed to serve a protective function, their in vivo targets are unknown, and it remains to be discovered whether they serve to control any human CP activity.

Does expression of inducible nitric oxide synthase correlate with severity of oral epithelial dysplasia?

The small molecule nitric oxide (NO) has generated an exponential amount of research since its discovery as a biological messenger in 1987. It has a vast number of actions, many of which are poorly understood. It has been studied in a variety of human cancers and has been implicated both in tumour promotion and inhibition. Although NO is produced by three distinct isoforms of the enzyme nitric oxide synthase (NOS), most cancer research is directed towards the calcium-independent form, iNOS which following induction, produces much higher quantities of NO than the other two. In this study the expression of iNOS is assessed by immunohistochemistry in 26 cases of oral epithelial dysplasia ranging in severity from mild to severe. iNOS staining was found in all 26 cases of dysplasia with the degree of staining correlating to the severity of dysplasia (p < 0.001). There was no iNOS staining seen in adjacent normal epithelium. The possible role of iNOS in the complex transformation from dysplasia to invasive oral cancer and the clinical applications are discussed.

[Study and detection of telomerase activity in oral squamous cell carcinomas and precancerous lesions].

OBJECTIVE: To find out the expression of telomerase activity in oral squamous cell carcinomas (SCC) and oral precancerous lesions. METHODS: Telomerase activity was examined by telomerase PCR ELISA assay and telomere repeat amplification protocol (TRAP) electrophoresis. 60 fresh oral specimens were selected, including 20 oral SCC, 30 oral precancerous lesions (10 oral leukoplakia, LK, 20 oral lichen planus, LP) and 10 normal mucosa (NM). RESULTS: Telomerase activity detected in SCC (0.128) was highest among all of the tissues(LK: 0.054, LP: 0.0094, NM: 0.0014). Statistical difference was notable between SCC and LK, LP, NM (P < 0.01). A little difference was detected between LK, LP and NM. No difference was found between LK, and LP (P > 0.05). CONCLUSION: Telomerase may play an important role during oncogenesis of oral precancerous lesions, and may be a good molecular biomarker for observing the cancerization ability of precancerous lesion and estimating its prognosis.

Protein N-glycosylation: molecular genetics and functional significance.

Protein N-glycosylation is a metabolic process that has been highly conserved in evolution. In all eukaryotes, N-glycosylation is obligatory for viability. It functions by modifying appropriate asparagine residues of proteins with oligosaccharide structures, thus influencing their properties and bioactivities. N-glycoprotein biosynthesis involves a multitude of enzymes, glycosyltransferases, and glycosidases, encoded by distinct genes. The majority of these enzymes are transmembrane proteins that function in the endoplasmic reticulum and Golgi apparatus in an ordered and well-orchestrated manner. The complexity of N-glycosylation is augmented by the fact that different asparagine residues within the same polypeptide may be modified with different oligosaccharide structures, and various proteins are distinguished from one another by the characteristics of their carbohydrate moieties. Furthermore, biological consequences of derivatization of proteins with N-glycans range from subtle to significant. In the past, all these features of N-glycosylation have posed a formidable challenge to an elucidation of the physiological role for this modification. Recent advances in molecular genetics, combined with the availability of diverse in vivo experimental systems ranging from yeast to transgenic mice, have expedited the identification, isolation, and characterization of N-glycosylation genes. As a result, rather unexpected information regarding relationships between N-glycosylation and other cellular functions--including secretion, cytoskeletal organization, proliferation, and apoptosis--has emerged. Concurrently, increased understanding of molecular details of N-glycosylation has facilitated the alignment between N-glycosylation deficiencies and human diseases, and has highlighted the possibility of using N-glycan expression on cells as potential determinants of disease and its progression. Recent studies suggest correlations between N-glycosylation capacities of cells and drug sensitivities, as well as susceptibility to infection. Therefore, knowledge of the regulatory features of N-glycosylation may prove useful in the design of novel therapeutics. While facing the demanding task of defining properties, functions, and regulation of the numerous, as yet uncharacterized, N-glycosylation genes, glycobiologists of the 21st century offer exciting possibilities for new approaches to disease diagnosis, prevention, and cure.

Overexpression of c-Src in areas of hyperproliferation in head and neck cancer, premalignant lesions and benign mucosal disorders.

To examine which proteins are responsible for the elevated protein tyrosine kinase (PTK) activity in human head and neck squamous cell carcinoma (HNSCC) and adjacent histologically normal epithelium, paraffin embedded sections of these tissues were stained for PTK c-Src. Using double labeling techniques and antibodies against both the proliferation marker Ki-67 and PTK c-Src, we have shown that c-Src is overexpressed in areas of hyperproliferation in HNSCC, dysplastic epithelium, benign papillomas and inflamed normal tissue. Our data indicate that c-Src is (one of) the protein(s) responsible for the increased PTK activity in HNSCC. We could not demonstrate that c-Src expression is responsible for the increased PTK activity in normal epithelium adjacent to tumour tissue. We assume that c-Src plays a role in the increased proliferation seen in (pre)malignant and benign epithelial lesions as well as in reactive inflammatory epithelial hyperplasia.

Detection of telomerase activity in oral lesions.

Telomerase is a ribonucleoprotein complex intimately associated with cell immortalization and neoplastic transformation. In almost all types of cancer this enzyme is reactivated and stabilizes telomere length. It may be necessary for continuous cell proliferation. In this study we used a non-radioactive polymerase chain reaction assay to analyze telomerase activity in various tissue specimens taken from the oral cavity. Four of 4 (100%) squamous cell carcinoma cell lines, 28 of 29 (96%) malignant tumors, 10 of 28 (36%) benign lesions, and none of the 14 (0%) oral control tissues possessed telomerase activity. Moreover, 4 of 15 (27%) oral rinses and 3 of 3 (100%) samples of ascites and pleural effusion taken from patients with oral malignancy were telomerase positive. These findings indicate that the evaluation of telomerase activity in tissue and body fluid specimens may provide information useful in the diagnosis of oral malignancy.

The functional balance of metalloproteinases and inhibitors in tissue degradation: relevance to oral pathologies.

Members of the family of matrix metalloproteinases (MMPs) are key enzymes in normal and pathological tissue remodelling. They function at neutral pH and can digest synergistically all the macromolecules of the extracellular matrix. Biochemical and cloning studies indicate that there are three major groups: the specific collagenases cleave interstitial collagens; the gelatinases degrade other types of collagen and act synergistically with collagenases by degrading denatured collagens (gelatins); and the stromelysins which have broader specificity and can degrade basement membrane collagens as well as proteoglycans and matrix glycoproteins. Others in the family, but not in the major groups, are matrilysin, metallo-elastase, and several recently cloned membrane-bound metalloproteinases. Naturally occurring inhibitors, TIMPs (tissue inhibitors of metalloproteinases), are important controlling factors in the actions of MMPs, and tissue destruction in disease processes often correlates with an imbalance of MMPs over TIMPs. The relevance of recent molecular research to periodontal diseases is discussed.

Association between expression of stratum corneum chymotryptic enzyme and pathological keratinization in human oral mucosa.

Stratum corneum chymotryptic enzyme (SCCE) may function in the degradation of intercellular cohesive structures in the stratum corneum preceding desquamation. Previous results have suggested that SCCE may be specifically expressed in squamous epithelia undergoing terminal differentiation and keratinization. The aim of the present work was to further elucidate the association between SCCE expression and terminal differentiation in squamous epithelia. Using immunohistochemical methods, we have examined the expression of SCCE in two diseases of human oral mucosa, which produce a pathological keratinization of the epithelium at sites which are normally non-keratinized. Affinity-purified polyclonal rabbit antibodies raised against recombinant SCCE and monoclonal antibodies against the differentiation-specific keratins nos. 10 and 13 were used on formaldehyde-fixed and paraffin-embedded biopsies. Whereas there was essentially no expression of SCCE in normal, non-keratinized buccal mucosa, there was a strong expression in suprabasal cells in orthokeratotic and parakeratotic areas of the lesions of oral lichen planus (an inflammatory disease) and benign oral keratosis (a non-inflammatory disease). There was a close association between the expression of SCCE and keratin no. 10, i.e. a keratin which is specifically expressed in cornifying squamous epithelia. The results suggest that SCCE expression may be a true marker of terminal differentiation in squamous epithelia and give further evidence for a role of SCCE in the formation and/or turnover of the stratum corneum.

Significance of glutathione S-transferase-pi as a tumor marker in patients with oral cancer.

BACKGROUND: The authors analyzed the clinical usefulness of glutathione-S-transferase-pi (GST-pi) as a tumor marker in patients with oral cancer. METHODS: GST-pi levels in plasma of 61 patients with oral squamous cell carcinomas, 65 patients with benign oral diseases, and 78 healthy subjects were investigated with the sandwich enzyme-immunoassay (EIA) system. RESULTS: Elevated GST-pi levels in plasma were observed in patients with oral cancer, but patients with benign oral diseases had normal GST-pi levels. More than 70% of patients with Stage III or IV oral cancer and more than 50% of those with Stage I and II disease had elevated levels of GST-pi in plasma. Elevated levels of GST-pi in plasma were also discovered in most patients with tumor recurring after surgery before recurrence was detected clinically. GST-pi also was found to be a useful marker for evaluating the response to chemotherapy, for monitoring postoperative tumor resectability or tumor burden, and for predicting the recurrence of tumor in patients with oral cancer. CONCLUSIONS: GST-pi is considered to be a useful aid for early diagnosis, predicting tumor extent, and determining parameters of treatment efficacy and prognosis for oral cancer.

[Clinical observation of the superoxide dismutase (SOD) and lipid peroxide (LPO) changes in oral-maxillofacial surgical patients].

This article reports examination of superoxide dismutase (SOD) activity in RBC and lipid peroxide (LPO) content in the plasma of the oral-maxillofacial operation patients. The results showed that the LPO content in postoperation ascended remarkably compared with pre-operation (P < 0.001) and that the SOD activity rose also (P < 0.05). It was discovered that the difference of LPO content between the pre-operation and post-operation was closely relative with the difference of SOD activity, the operative time and the operation method (intra- or extra-oral approach). The results demonstrated that the operative damage resulted in the increasing of the reactivity of superoxide radical and LPO and that the rising of SOD activity was probably the compensation of the body.

[Enzyme immobilization on the dental enamel and its probable role in the physiology and pathology of the oral cavity]. / Immobilizatsiia fermentov na émali zubov i ikh veroiatnaia rol' v fiziologii i patologii polosti rta.

Immobilized alkaline phosphatase was detected on the dental enamel surface of man by histochemical analysis for the first time. A heretofore unknown mechanism of the regulation of metabolic processes on the enamel-saliva border is discussed. Experimental findings confirm that irreversible absorption represent the immobilization mechanism. A new mechanism of enamel remineralization is suggested: that due to phosphatase-active proteins.