Hyposalivation, xerostomia and oral health status of HIV-infected subjects in Thailand before HAART era

J Oral Pathol Med (2010) 39 : 28–34
Background:  The aims of this study were to determine hyposalivation, xerostomia, and oral health status of HIV-subjects in Thailand before highly active antiretroviral therapy era.
Methods:  Oral examination and measurement of saliva flow rate of both unstimulated and wax-stimulated whole saliva were performed in 135 subjects (56 HIV-subjects, mean age: 34.5 years, and 79 non-HIV controls, mean age: 29.5 years). Presence of oral candidiasis, cervical root caries, and number of existing teeth were recorded. Microbiological investigation of oral Candida was conducted using oral rinse technique. Risk factors associated with hyposalivation and xerostomia were analysed.
Results:  The unstimulated flow rates in HIV-subjects and non-HIV controls were 0.19 and 0.33 ml/min ( P  = 0.0024). For stimulated flow rates, the corresponding figures were 1.45 and 1.62 ml/min ( P  = 0.31). The unstimulated flow rate was significantly higher in the asymptomatic HIV-subjects: 0.17 ml/min, when compared with the symptomatic/AIDS group 0.11 ml/min ( P  = 0.003). No significant difference between the groups could be found with respect to stimulated flow rate. Hyposalivation was significantly associated with the colony forming unit of Candida . Smoking and alcohol consumption were significantly associated with hyposalivation, but not xerostomia. The following factors were significantly associated with both hyposalivation and xerostomia; sex, stage of HIV infection, risk group of HIV infection, systemic disease, and medication use.
Conclusions:  Salivary flow rate of HIV-subjects in Thailand was affected by HIV infection. The rate was significantly decreased with advanced stage of the disease. Various factors including medication use were associated with hyposalivation and xerostomia among the subjects.     

Whole stimulated salivary flow in patients with chronic hepatitis C virus infection

BACKGROUND: Salivary gland disorders have been included among the extra-hepatic manifestations related to HCV infection. METHODS: The whole stimulated salivary flow rate (spitting technique) was studied in 74 HCV infected patients to evaluate salivary gland dysfunction. RESULTS: The salivary flow of the patients with chronic HCV infection was similar to that of the healthy controls. The association between subjective xerostomia salivary flow was seen to be very weak. No significant associations were found between salivary flow and age, sex, risk factor of acquired infection, ALT, AST, GGT, ALP values, time lapsed since the diagnosis or HCV-RNA detection in saliva. CONCLUSIONS: Although the functional repercussion of hepatitis C related lymphocytic sialoadenitis remains unclear, we did not find a significant reduction in the whole stimulated salivary flow in HCV infected patients.     

Activation of innate immune responses through Toll-like receptor 3 causes a rapid loss of salivary gland function

Background:  Recent studies have demonstrated the expression of Toll-like receptor 3 (TLR3) in salivary glands and epithelial cell lines derived from Sjögren's syndrome (SS) patients. As viral infections are considered to be a trigger for SS, in this study we investigated whether in vivo engagement of TLR3 affects salivary gland function.
Methods:  Female New Zealand Black/WF1 mice were repeatedly injected with polyinosinic:polycytidylic acid [poly(I:C)]. TLR3 expression within submandibular glands was studied using immunohistochemistry. RNA levels of inflammatory cytokines in the submandibular glands were determined by real time polymerase chain reaction. Pilocarpine induced saliva volume was used as an index of glandular function.
Results:  Immunohistochemical analysis of submandibular glands showed TLR3 expression in epithelium of serous and mucous acini, granular convoluted tubules, and ducts. Poly(I:C) treatment rapidly up-regulated the mRNA levels of type I interferon (IFN) and inflammatory cytokines in the submandibular glands. One week after treatment, the saliva volumes in poly(I:C) treated mice were significantly reduced in comparison with the phosphate-buffered saline (PBS) treated mice. Hematoxylin and eosin staining showed that salivary gland histology was normal and lymphocytic foci were not detected. Glandular function recovered after poly(I:C) treatment was stopped.
Conclusions:  Our results demonstrate that engagement of TLR3 within the salivary glands results in a rapid loss of glandular function. This phenomenon is associated with the production of type I IFN and inflammatory cytokines in the salivary glands. Restoration of glandular function suggests that for viral etiology of SS, a chronic infection of salivary glands might be necessary.     

Multiple components contribute to ability of saliva to inhibit influenza viruses

Introduction:  Saliva is a potentially important barrier against respiratory viral infection but its mechanism of action is not well studied.
Methods:  We tested the antiviral activities of whole saliva, specific salivary gland secretions, and purified salivary proteins against strains of influenza A virus (IAV) in vitro .
Results:  Whole saliva or parotid or submandibular/sublingual secretions from healthy donors inhibited IAV based on hemagglutination inhibition and neutralization assays. This differs from human immunodeficiency virus (HIV), for which only submandibular/sublingual secretions are reported to be inhibitory. Among purified salivary proteins, MUC5B, scavenger receptor cysteine-rich glycoprotein 340 (salivary gp-340), histatins, and human neutrophil defensins (HNPs) inhibited IAV at the concentrations present in whole saliva. In contrast, some abundant salivary proteins (acidic proline-rich proteins and amylase) had no activity, nor did several other less abundant salivary proteins with known activity against HIV (e.g. thrombospondin or serum leukocyte protease inhibitor). Whole saliva and MUC5B did not inhibit neuraminidase activity of IAV and viral neutralizing and aggregating activity of MUC5B was potentiated by the neuraminidase inhibitor oseltamivir. Hence, MUC5B inhibits IAV by presenting a sialic acid ligand for the viral hemagglutinin. The mechanism of action of histatins requires further study.
Conclusions:  These findings indicate that saliva represents an important initial barrier to IAV infection and underline the complexity of host defense activity of oral secretions. Of interest, antiviral activity of saliva against IAV and HIV differs in terms of specific glandular secretions and proteins that are inhibitory.     

Relationship of cytomegalovirus to salivary gland dysfunction in HIV-infected patients

In a previous retrospective study of HIV-infected patients we detected a relationship between xerostomia and the presence of cytomegalovirus in saliva. This prospective study compares 13 patients with HIV and a complaint of xerostomia and low salivary flow rates with a control group of 7 patients with HIV without xerostomia and normal salivary flow rates. Both groups were evaluated for the presence of cytomegalovirus in saliva, peripheral blood mononuclear cells, and labial minor salivary glands. Viral cultures, polymerase chain reaction, and histopathologic examination were used to detect cytomegalovirus. Xerostomia and low salivary flow rates were associated with the presence of CMV in saliva. The virus was detected in 10 of 13 xerostomia patients and 2 of 7 controls (p = 0.05, Fisher's exact test). Cytomegalovirus was detected in the saliva of patients who did not also have it in their blood suggesting a local source of virus replication such as the salivary glands. The minor salivary glands were not a major site of cytomegalovirus. Culture was more sensitive then polymerase chain reaction in detecting salivary cytomegalovirus as a result of the presence of inhibitors to the reaction in saliva. These results suggest a link between cytomegalovirus in saliva and salivary gland dysfunction in HIV-infected patients.     

Transient TWEAK overexpression leads to a general salivary epithelial cell proliferation

Objectives:  Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) is a multifunctional cytokine that has pro-apoptotic, pro-angiogenic and pro-inflammatory effects. In liver, TWEAK leads to proliferation of progenitor oval cells, but not of mature hepatocytes. This study evaluated the hypothesis that TWEAK overexpression in salivary glands would lead to the proliferation of a salivary progenitor cell.
Methods:  A recombinant, serotype 5 adenoviral vector encoding human TWEAK, AdhTWEAK, was constructed, initially tested in vitro , and then administered to male Balb/c mice via cannulation of Wharton's duct. TWEAK expression in vivo was monitored as protein secreted into saliva and serum by enzyme-linked immunosorbent assays. Salivary cell proliferation was monitored by proliferating cell nuclear antigen staining and apoptosis was monitored using TUNEL staining.
Results:  AdhTWEAK administration led to a dose-dependent, transient TWEAK protein expression, detected primarily in saliva. Salivary epithelial cell proliferation was generalized, peaking on ∼days 2 and 3. TWEAK expression had no detectable effect on apoptosis of salivary epithelial cells.
Conclusion:  Transient overexpression of TWEAK in murine salivary glands leads to a general proliferation of epithelial cells vs a selective stimulation of a salivary progenitor cell.     

Sjögren''s syndrome: the diagnostic potential of early oral manifestations preceding hyposalivation/xerostomia

Sjögren's syndrome (SS) is a systemic autoimmune exocrinopathy that affects mainly the salivary and lacrimal glands, leading to progressive reduction in saliva and tear flow. Although the underlying immuno‐mediated glandular destruction is thought to develop slowly over several years, a long delay from the start of the symptoms to final diagnosis has been frequently reported. A limited knowledge concerning SS natural history is among the major causes of the actual diagnostic delay. Although very few studies have been focused on the analysis of SS early clinical onset, a series of oral features preceding xerostomia/hyposalivation development in patients eventually diagnosed as having SS have been reported. Sialochemistry alterations, salivary gland swelling, early dental loss and sialorrhea have been observed before the onset of typical signs and symptoms (namely xerostomia and/or hyposalivation), which usually lead to SS clinical presentation and diagnosis. Here we suggest, after evaluating available data, that the traditional ‘untouchable’ association between SS and xerostomia/hyposalivation might probably be reconsidered, and that astute clinicians should not underestimate the possible presence or development of SS in patients without xerostomia/hyposalivation and presenting these atypical early oral features.     

非肥胖型糖尿病小鼠自发性涎腺炎的发生与发展

目的 观察雌性非肥胖型糖尿病（NOD）小鼠自发性涎腺炎的发生发展过程。方法 选择5、10、15、20周龄雌性NOD小鼠各6只。测定刺激全唾液流率（STFR）、施墨试验、唾液总蛋白、常规HE切片及电镜超微结构观察涎腺组织的改变。以BALB／c小鼠作对照。结果 10、15、20周NOD小鼠STFR、唾液总蛋白均明显低于对照组（P〈0．05），相应的下颌下腺分泌颗粒减少。10周雌性NOD小鼠涎腺炎发病率为4／6，15、20周均为6／6。淋巴细胞浸润主要见于下颌下腺，舌下腺极少，腮腺未见。10周时NOD小鼠已有淋巴细胞浸润灶形成。15周显著增多而且面积增加。STFR与淋巴细胞浸润灶数呈负相关。结论 雌性NOD小鼠5～10周淋巴细胞开始浸润下颌下腺，刺激唾液和蛋白分泌降低。不同腺体受累情况不同。     

Hyposalivation and Xerostomia in Dentate Older Adults

BackgroundOlder adults are susceptible to reduced saliva production related to certain medications, radiation and chronic conditions. Many of these people have many physical and oral health problems and limited access to dental care. The use of effective screening tools for xerostomia and hyposalivation would be helpful in identifying those at risk. The authors conducted a study to investigate the association between three measures of oral dryness: hyposalivation (low unstimulated salivary flow), self-reported xerostomia and clinically assessed dry mouth.MethodsThe authors included a convenience sample of 252 nondemented and dentate West Virginia participants 70 years and older who were part of a larger study on oral health and cognition among older adults. Participants completed a self-reported xerostomia index, provided an unstipulated salivary sample and underwent an oral assessment for the study.ResultsTwenty-eight participants (11.1 percent) had hyposalivation, eight of whom reported having xerostomia (sensitivity = 28.6 percent). Of the 43 participants who reported having xerostomia, only eight had hyposalivation (positive predictive value = 18.6 percent). Hyposalivation and self-reported xerostomia were not significantly related. Clinically assessed dry mouth correlated modestly, but significantly, with hyposalivation and self-reported xerostomia.ConclusionsObtaining routine unstimulated salivary flow rates in addition to self-reported information and oral evaluations may increase early detection of oral dryness, which would assist in implementing early interventions to improve patients' quality of life.Clinical ImplicationsVisually inspecting oral tissues for dryness and asking a patient if his or her mouth is dry are insufficient measures for clinicians to use to determine if the patient has hyposalivation. The authors recommend that clinicians determine the patient's unstimulated salivary flow rate.     

The relation between xerostomia and hyposalivation in subjects with rheumatoid arthritis or fibromyalgia

Aim of this study was to evaluate the relation between xerostomia and hyposalivation in 100 subjects with either rheumatoid arthritis or fibromyalgia, and further, to evaluate the predictive value of xerostomia on hyposalivation. Unstimulated and chewing stimulated whole saliva was collected in the morning with the subjects in a strict fasting condition and then about 2 hours later, after intake of a standardised breakfast. All participants filled in a questionnaire, mainly dealing with xerostomia. Forty subjects demonstrated a pathological fasting unstimulated whole saliva secretion rate, the corresponding number for fasting stimulated secretion being 39. For unstimulated, but not for stimulated saliva, the fasting secretion rate was significantly lower than the non-fasting. Xerostomia was reported by 74 subjects, this group having significantly lower both unstimulated and stimulated secretion rates than the non-xerostomic group. On the individual level, the predictive value of xerostomia on hyposalivation showed high sensitivity but unsatisfactory specificity. In conclusion, this study underlines the importance of applying strictly standardised procedures when collecting saliva, and that fasting unstimulated whole saliva is the diagnostic salivary secretion of choice. Finally, xerostomia was found to predict hyposalivation on a group, but not on an individual level.     

Effect of HAART on salivary gland function in the Women's Interagency HIV Study (WIHS)

Objective:  To determine the impact of highly active antiretroviral therapy (HAART) on salivary gland function in human immunodeficiency virus (HIV) positive women from the Women's Interagency HIV Study (WIHS).
Design:  Longitudinal cohort study.
Subjects and methods:  A total of 668 HIV positive women from the WIHS cohort with an initial and at least one follow-up oral sub-study visit contributed 5358 visits. Salivary gland function was assessed based on a dry mouth questionnaire, whole unstimulated and stimulated salivary flow rates, salivary gland enlargement or tenderness and lack of saliva on palpation of the major salivary glands.
Main outcome measures:  Changes in unstimulated and stimulated flow rates at any given visit from that of the immediate prior visit (continuous variables). The development of self-reported dry mouth (present/absent), enlargement or tenderness of salivary glands (present/absent), and absence of secretion on palpation of the salivary glands were binary outcomes (yes/no).
Results:  Protease Inhibitor (PI) based HAART was a significant risk factor for developing decreased unstimulated ( P  =   0.01) and stimulated ( P  =   0.0004) salivary flow rates as well as salivary gland enlargement ( P  =   0.006) as compared with non-PI based HAART.
Conclusions:  PI-based HAART therapy is a significant risk factor for developing reduced salivary flow rates and salivary gland enlargement in HIV positive patients.     

Medication-induced hyposalivation: etiology, diagnosis, and treatment

Polypharmacy in the nation's growing geriatric population will require increasingly complex pharmacologic management of multiple disease states. This brief review describes normal salivary function, potential causes of salivary dysfunction, oral health concerns associated with hyposalivation, diagnostic tests, and options for patient care. Medications can reduce salivary flow, creating the condition known as xerostomia. A major complication of xerostomia is the promotion of dental caries. Asking several standardized questions regarding symptoms may help confirm salivary gland hypofunction. The general approach to patients with hyposalivation and xerostomia is directed at palliative treatment for the relief of symptoms and prevention of oral complications.     

Effects of Toll-like receptor 4 on Porphyromonas gingivalis-induced bone loss in mice

Background and Objective:  Toll-like receptor 4 (TLR-4)/myeloid differentiation protein-2 complex ligation by lipopolysaccharide induces production of pro-inflammatory cytokines and co-stimulatory molecules on antigen presenting cells. The aim of this study was to determine the role of the TLR-4 in bone loss-resistant C57BL mice and in bone loss-susceptible BALB/c mice after infection with Porphyromonas gingivalis .
Material and Methods:  The BALB/c and C57BL/10 mice, either normal or TLR-4 deficient, were infected or sham-infected orally four times, at 4 day intervals, with 10⁹ colony forming units of P. gingivalis . At 47 days, defleshed jaws were stained and photographed in a standardized position. We measured the surface area of the root trunk to assess the alveolar bone loss.
Results:  Porphyromonas gingivalis -infected wild-type BALB/c mice lost 13.8% more bone than P. gingivalis -infected wild-type C57BL/10 mice. In contrast, P. gingivalis -infected TLR-4-deficient C57BL/10 mice lost 12.7% more bone than P. gingivalis -infected TLR-4-deficient BALB/c mice. Porphyromonas gingivalis -infected wild-type C57BL/6 and TLR-2 knockout C57BL/6 mice had similar bone levels to sham-infected control mice.
Conclusion:  Toll-like receptor 4 is protective for C57BL/10 but detrimental to BALB/c mice, since its absence allowed C57BL/10 but not BALB/c mice to lose alveolar bone. Toll-like receptor 2 does not contribute to this protection in genetically similar C57BL/6 mice.     

DNA demethylating agent decitabine increases AQP5 expression and restores salivary function

Xerostomia is the symptom of oral dryness resulting most frequently, but not exclusively, from salivary gland hypofunction. Because the prevalence of xerostomia may increase with age, it has multiple oral health consequences in aging populations. In the present study, we demonstrate that the in vivo administration of 5-aza-2'-deoxycytidine (5-Aza-CdR; decitabine), a DNA demethylating agent, to the murine aging model C57BL/6CrSlc mice (24 wks old) increased the volumes of salivary flow compared with those of control mice. Western blot analysis and immunohistochemical staining demonstrated the augmented expression of AQP5 protein in the salivary glands of 5-Aza-CdR-treated mice compared with those of control mice. In addition, AQP5 protein expression levels in 5-Aza-CdR-treated old mice (27 wks old) were much higher than those in untreated and young mice (6 wks old). Global methylation levels in the salivary glands were significantly lower in the 5-Aza-CdR-treated mice than in the untreated mice. Moreover, the induction of demethylation in the AQP5 promoter of 5-Aza-CdR-treated mice was stronger than in the control mice. Analysis of our data therefore suggests that a DNA demethylating agent may be a useful drug for restoring hyposalivation in elderly individuals, thereby leading to the resolution of xerostomia.     

Involvement of E2f1 deficiency in salivary gland hypofunction: A review of studies of E2f1-deficient NOD/SCID mice

BackgroundSaliva is essential for the preservation of oral health, and disorders of salivary physiology are associated with numerous oral problems. Hyposecretion of saliva, and consequent xerostomia, leads to severe dental caries, periodontal disease, and mucosal infections, which reduce a patient׳s quality of life. Sjögren׳s syndrome, the use of drugs with anticholinergic effects, and radiotherapy for the treatment of head and neck cancers are the most common causes of xerostomia. However, the pathophysiological features of xerostomia are not yet clear.HighlightRecently, we established E2f1-deficient non-obese diabetic/severe combined immunodeficiency disease (NOD/SCID) mice. The mutant mice demonstrated a reduction of salivary fluid secretion following stimulation with a cholinergic agonist, and xerostomia behavior under physiological conditions. In this article, we review the pathophysiology of xerostomia in E2f1-deficient NOD/SCID mice and discuss the involvement of the E2f1 deficiency in salivary gland hypofunction.ConclusionIn E2f1-deficient NOD/SCID mice, the number of duct cells increased while the number of acinar cells decreased. The water channel aquaporin 5, a marker of acinar cells, demonstrated diffuse localization, ubiquitination, and decreased expression in E2f1-deficient NOD/SCID mice. These events seem to trigger salivary gland hypofunction in E2f1-deficient NOD/SCID mice, which suggest that E2f1 is a key factor in the development of xerostomia.     

Exosomes from human saliva as a source of microRNA biomarkers

Objective:  The aim of this study was to examine the presence of microRNAs (miRNAs) within exosomes isolated from human saliva and to optimize and test methods for successful downstream applications.
Design:  Exosomes isolated from fresh and frozen glandular and whole human saliva were used as a source of miRNAs. The presence of miRNAs was validated with TaqMan quantitative PCR and miRNA microarrays.
Results:  We successfully isolated exosomes from human saliva from healthy controls and a patient with Sjögren's syndrome. microRNAs extracted from the exosomal fraction were sufficient for quantitative PCR and microarray profiling.
Conclusions:  The isolation of miRNAs from easily and non-invasively obtained salivary exosomes with subsequent characterization of the miRNA expression patterns is promising for the development of future biomarkers of the diagnosis and prognosis of various salivary gland pathologies.     

Effect of cevimeline on radiation-induced salivary gland dysfunction and AQP5 in submandibular gland in mice

The aim of this study was to clarify the effects of the muscarinic receptor agonist, cevimeline, on saliva flow and expression of aquaporin5 (AQP5) in submandibular gland after X-ray irradiation. Using a previously established radiation-induced xerostomia model mouse, saliva flow from at 7 days before irradiation to at 28 days after irradiation was investigated in mice that were treated with cevimeline before or after irradiation. Radiation caused a significant decrease in saliva flow compared with nonirradiated salivary glands. Cevimeline post-treatment also caused a significant decrease in saliva flow. In contrast, cevimeline pre-treatment did not significantly decrease saliva flow. Expression of AQP5 fluorescent intensity and mRNA were also analyzed. Irradiation significantly decreased expression of AQP5 in submandibular gland. However, pre-treatment with cevimeline prevented this decrease in AQP5 expression. These data suggest that pretreatment with cevimeline prevents radiation-induced xerostomia and radiation-induced decrease in expression of AQP5 in submandibular gland.     

Effects of Diabetes on Salivary Gland Protein Expression of Tetrahydrobiopterin and Nitric Oxide Synthesis and Function

Background: Xerostomia is defined as dry mouth resulting from a change in the amount or composition of saliva and is often a major oral health complication associated with diabetes mellitus (DM). Studies have shown that xerostomia is more common in females at the onset of DM. Evidence suggests that nitric oxide (NO) plays a critical role in healthy salivary gland function. However, the specific mechanisms by which NO regulates salivary gland function at the onset of DM have yet to be determined. This study has two aims: 1) to determine whether protein expression or dimerization of NO synthase enzymes (neuronal [nNOS] and endothelial [eNOS]) are altered in the onset of diabetic xerostomia; and 2) to determine whether the changes in nNOS/eNOS protein expression or dimerization are correlated with changes in NO cofactor tetrahydrobiopterin (BH₄) biosynthetic enzymes (guanosine triphosphate cyclohydrolase‐1 and dihydrofolate reductase). Methods: Functional and Western blot studies were performed in streptozotocin‐induced and control Sprague‐Dawley female rats with DM (type 1 [t1DM]) using standardized protocols. Confirmation of xerostomia was determined by increased water intake and decreased salivary flow rate. Results: The results showed that in female rats with DM, salivary hypofunction is correlated with decreased submandibular and parotid gland sizes. The results also show a decrease in NOS and BH₄ biosynthetic enzyme in submandibular glands. Conclusions: These results indicate that a decrease in submandibular NO‐BH₄ protein expression may provide insight pertaining to mechanisms for the development of hyposalivation in DM‐induced xerostomia. Furthermore, understanding the role of the NO‐BH₄ pathway may give insight into possible treatment options for the patient with DM experiencing xerostomia.     

Expression of two drug-metabolizing cytochrome P450-enzymes in human salivary glands

Objective:  The oral cavity is constantly lubricated by saliva and even small amounts of xenobiotics and / or their metabolites in the saliva may affect the oral mucosa. Our aim was therefore to clarify if xenobiotic metabolizing enzymes CYP1A2 and CYP3A4 are expressed in salivary glands.
Methods:  Formalin-fixed paraffin-embedded specimens from parotid (10), submandibular (7) and labial (10) salivary glands were examined immunohistochemically and by in situ hybridization for expression of CYP1A2 and CYP3A4 protein and mRNA.
Results:  CYP1A2 and CYP3A4 protein and mRNA were detected in ductal and seromucous / serous acinar cells in all gland types although to a varying degree and intensity. Mucous acinar cells were positive to a lesser extent.
Conclusion:  The results indicate a xenobiotic metabolizing capability of salivary glands. This may have implications for development of oral mucosal disease as a result of mucosal exposure to metabolites originating from internal sources (blood) as well as from saliva.