Submandibular Gland Pathogenesis Following SARS-CoV-2 Infection and Implications for Xerostomia.

Although SARS-CoV-2 induces mucin hypersecretion in the respiratory tract, hyposalivation/xerostomia has been reported by COVID-19 patients. We evaluate the submandibular gland (SMGs) pathogenesis in SARS-CoV-2-infected K18-hACE2 mice, focusing on the impact of infection on the mucin production and structural integrity of acini, ductal system, myoepithelial cells (MECs) and telocytes. The spike protein, the nucleocapsid protein, hACE2, actin, EGF, TNF-α and IL-1ß were detected by immunofluorescence, and the Egfr and Muc5b expression was evaluated. In the infected animals, significant acinar hypertrophy was observed in contrast to ductal atrophy. Nucleocapsid proteins and/or viral particles were detected in the SMG cells, mainly in the nuclear membrane-derived vesicles, confirming the nuclear role in the viral formation. The acinar cells showed intense TNF-α and IL-1ß immunoexpression, and the EGF-EGFR signaling increased, together with Muc5b upregulation. This finding explains mucin hypersecretion and acinar hypertrophy, which compress the ducts. Dying MECs and actin reduction were also observed, indicating failure of contraction and acinar support, favoring acinar hypertrophy. Viral assembly was found in the dying telocytes, pointing to these intercommunicating cells as viral transmitters in SMGs. Therefore, EGF-EGFR-induced mucin hypersecretion was triggered by SARS-CoV-2 in acinar cells, likely mediated by cytokines. The damage to telocytes and MECs may have favored the acinar hypertrophy, leading to ductal obstruction, explaining xerostomia in COVID-19 patients. Thus, acinar cells, telocytes and MECs may be viral targets, which favor replication and cell-to-cell viral transmission in the SMG, corroborating the high viral load in saliva of infected individuals.

Oral manifestations of Covid-19-A literature review.

Initially, it was reported that coronavirus 2019 disease (Covid-19) affects respiratory, gastrointestinal and neurological systems, but the oral, olfactory and integumentary systems are also involved. This review discusses various oral manifestations of Covid-19 reported in the literature along with possible underlying mechanisms. The reported manifestations include taste impairment, oral mucosal changes (petechiae, ulcers, plaque-like lesions, reactivation of herpes simplex virus 1(HSV1), geographical tongue and desquamative gingivitis) and dry mouth. The prominent location for mucosal lesions are tongue, palate and labial mucosa. The exact pathogenesis of these oral symptoms is not known. Angiotensin-converting enzyme 2 (ACE2) cell receptors are expressed in abundance on oral mucosa allowing severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) to infect them. Gustatory impairment along with olfactory changes is now listed as a symptom of Covid-19 by the World Health Organization, but further research is needed to confirm a link between reported additional oral symptoms and Covid-19. Dental professionals may encounter individuals with Covid-19 and be called upon to identify various oral manifestations of this disease.

Covid-19 and oral diseases: Crosstalk, synergy or association?

The coronavirus disease 2019 (Covid-19) is a viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that clinically affects multiple organs of the human body. Cells in the oral cavity express viral entry receptor angiotensin-converting enzyme 2 that allows viral replication and may cause tissue inflammation and destruction. Recent studies have reported that Covid-19 patients present oral manifestations with multiple clinical aspects. In this review, we aim to summarise main signs and symptoms of Covid-19 in the oral cavity, its possible association with oral diseases, and the plausible underlying mechanisms of hyperinflammation reflecting crosstalk between Covid-19 and oral diseases. Ulcers, blisters, necrotising gingivitis, opportunistic coinfections, salivary gland alterations, white and erythematous plaques and gustatory dysfunction were the most reported clinical oral manifestations in patients with Covid-19. In general, the lesions appear concomitant with the loss of smell and taste. Multiple reports show evidences of necrotic/ulcerative gingiva, oral blisters and hypergrowth of opportunistic oral pathogens. SARS-CoV-2 exhibits tropism for endothelial cells and Covid-19-mediated endotheliitis can not only promote inflammation in oral tissues but can also facilitate virus spread. In addition, elevated levels of proinflammatory mediators in patients with Covid-19 and oral infectious disease can impair tissue homeostasis and cause delayed disease resolution. This suggests potential crosstalk of immune-mediated pathways underlying pathogenesis. Interestingly, few reports suggest recurrent herpetic lesions and higher bacterial growth in Covid-19 subjects, indicating SARS-CoV-2 and oral virus/bacteria interaction. Larger cohort studies comparing SARS-CoV-2 negative and positive subjects will reveal oral manifestation of the virus on oral health and its role in exacerbating oral infection.

Xerostomia, gustatory and olfactory dysfunctions in patients with COVID-19.

BACKGROUND: The novel Coronavirus Disease-19 (COVID-19) continues to have profound effect on global health. Our aim was to evaluate the prevalence and characterize specific symptoms associated with COVID-19. METHODS: This retrospective study included 326 patients with confirmed SARS-CoV-2 infection evaluated at the Emergency Department of the Umberto I Polyclinic Hospital, Rome, Italy between March 6th and April 30th, 2020. In order to assess xerostomia, olfactory and gustatory dysfunctions secondary to COVID-19, a telephone-based a modified survey obtained from the National Health and Nutrition Examination Survey (NHANES) 2013-2014 for taste and smell disorders and the Fox Questionnaire for dry mouth were administered to 111 patients (34%) after discharge between June 4th and June 12th. RESULTS: Taste dysfunction was the most common reported symptom (59.5%; n = 66), followed by xerostomia (45.9%; n = 51) and olfactory dysfunctions (41.4%; n = 46). The most severe symptom was olfactory dysfunction with a median severity score of 8.5 (range: 5-10). Overall 74.5% (n = 38) of patients with xerostomia, 78.8% (n = 52) of patients with gustatory dysfunctions and 71.1% (n = 33) of patients with olfactory dysfunctions reported that all symptoms appeared before COVID-19 diagnosis. Overall, the majority of patients reported one symptom only (45.9%, n = 51), 37 (33.3%) reported the association of two symptoms, and 23 (20.7%) patients reported the association of three symptoms at the same time. CONCLUSION: Xerostomia, gustatory and olfactory dysfunctions may present as a prodromal or as the sole manifestation of COVID-19. Awareness is fundamental to identify COVID-19 patients at an early stage of the disease and limit the spread of the virus.

Sicca complex among Egyptian patients with chronic hepatitis C virus infection.

The objective of this study was to assess the prevalence of sicca complex (SC) in patients with chronic hepatitis C virus (HCV) infection and its association with clinical and laboratory features of liver disease. Subjective and objective criteria of xerophthalmia and xerostomia were investigated in 120 HCV Egyptian patients. The lacrimal gland function was assessed by: tear film break-up time and lid parallel conjunctival folds test (LIPCOF), dacroscintigraphy (DSG) for lacrimal drainage and that of salivary glands by sialoscintigraphy. Sixty six of 120 patients (55%) had SC; all (100%) were proved to have xerostomia by sialoscintigraphy and xerophthalmia detected by ophthalmologic tests. Using dacroscintigraphy all SC patients (100%) were positive for lacrimal drainage abnormalities. Only 10.1% were symptomatic for SC. None of our patients had anti-Ro or anti-La antibodies. The presence of SC was associated with older age (r = 0.28, p = 0.00), female gender (p = 0.001), cirrhosis (r = 0.34, p = 0.00), thrombocytopenia (r = -0.72, p = 0.00), and rheumatologic manifestation (p = 0.000), but not with viral load (r = 0.19, p = 0.06). DSG showed significant statistical correlation with ophthalmologic tests (r = 0.87, p = 0.00). High prevalence of SC in HCV Egyptian patients was detected. LIPCOF and DSG are objective and noninvasive methods for early diagnosis of xerophthalmia and assessment of the nasolacrimal drainage, respectively. Hindrance of lacrimal drainage proved by DSG was frequently encountered in HCV patients with SC (100%) and strongly correlated with xerophthalmia.

Xerostomia, hyposalivation and sialadenitis in patients with chronic hepatitis C are not associated with the detection of HCV RNA in saliva or salivary glands.

OBJECTIVE: Salivary gland disorders in patients with chronic hepatitis C (CHC) have been considered oral extrahepatic manifestations, reinforcing the hepatitis C virus (HCV) as a sialotropic virus. Hence, the authors investigated the prevalence of HCV RNA in saliva and salivary glands and its possible association with xerostomia, hyposalivation and sialadenitis in patients with CHC. PATIENTS AND METHODS: In 65 patients with confirmed CHC, the HCV RNA was investigated by nested RT-PCR in saliva samples and minor salivary glands. Xerostomia, hyposalivation, clinical and histopathological evidence of sialadenitis were also evaluated. Univariate and multivariate analyses were employed to verify associations. RESULTS: HCV RNA was detected in the saliva of 26/65 (40.0%) patients and in 12/65 (18.5%) salivary glands. Xerostomia was reported by 23/65 (35.4%) patients, and hyposalivation was diagnosed in 13/65 (20.0%) patients. Sialadenitis was confirmed by histopathological features in 31/65 (47.7%) patients. Twelve (38.7%) of the 31 patients with sialadenitis presented HCV RNA in saliva and 2/31 (6.5%) in salivary glands. No associations were found between xerostomia, hyposalivation or sialadenitis and the detection of HCV RNA in saliva or in salivary glands. CONCLUSIONS: Although xerostomia, hyposalivation and sialadenitis are frequent findings in CHC patients, our study did not confirm the association between the detection of HCV RNA in saliva or salivary glands with these salivary gland disorders. However, an indirect role of HCV by immune-mediated virus mechanisms in the pathogenesis of salivary gland disorders in this group of patients cannot be ruled out.

Detection of HCV RNA in saliva does not correlate with salivary flow or xerostomia in patients with chronic hepatitis C.

OBJECTIVE: The objective of this study was to investigate the prevalence of hepatitis C virus (HCV) RNA in saliva and its possible association with xerostomia and hyposalivation in patients with chronic hepatitis C. STUDY DESIGN: One hundred and thirty-six patients with confirmed diagnosis of chronic hepatitis C were prospectively analyzed before HCV treatment. The prevalence of xerostomia and hyposalivation was clinically evaluated. HCV RNA was investigated in saliva samples by qualitative PCR test. Univariate and multivariate analyses were used to verify associations. RESULTS: Xerostomia was reported by 48 (35.3%) patients, whereas hyposalivation was observed in 26 (19.1%). HCV RNA was positive in the saliva of 53 (39.0%) patients. An association among HCV RNA-positive saliva with xerostomia or hyposalivation was not observed. CONCLUSION: Our results demonstrate that the detection of HCV in saliva does not correlate with salivary flow or xerostomia in patients with chronic hepatitis C.

A mouse model linking viral hepatitis and salivary gland dysfunction.

OBJECTIVE: Viral hepatitis is known to cause xerostomia in humans, but this has not been reported in an animal model. We report a severe, acute, highly reproducible saliva deficiency occurring in BALB/c mice as a result of experimental viral hepatitis. MATERIALS AND METHODS: BALB/c mice, splenectomized or carrying genetic mutations to detect immunological contributions to the saliva deficiency syndrome, were infected intraperitoneally with a non-lethal dose of murine cytomegalovirus. Pilocarpine-stimulated saliva volumes were determined between 0 and 15 days after infection. Salivary gland, liver, spleen, and sera were analyzed for the presence of virus, cytokines, inflammatory infiltrates, and tissue damage. RESULTS: Saliva deficiency was detectable 2 days after cytomegalovirus infection, peaked at 88% below normal by day 7, and resolved partially in all mice by 15 days postinfection as sialoadenitis increased. Neither salivary gland viral titers, sialoadenitis, splenectomy, nor systemic inflammatory markers correlated with hyposalivation severity. Elevated liver enzymes did correlate with hyposalivation, and mice genetically resistant to murine cytomegalovirus-induced hepatitis were significantly protected. CONCLUSIONS: Murine cytomegalovirus-induced salivary gland dysfunction is biphasic, with an acute hepatitis-associated phase and a later sialoadenitis-associated phase. Acute murine cytomegalovirus infection of BALB/c mice may provide a model for investigation of hepatitis-associated xerostomia.

Salivary dysfunction associated with systemic diseases: systematic review and clinical management recommendations.

OBJECTIVES: The objective of this study was to identify systemic diseases associated with hyposalivation and xerostomia and develop evidence-based management recommendations for hyposalivation/xerostomia. STUDY DESIGN: Literature searches covered the English language medical literature from 1966 to 2005. An evidence-based review process was applied to management studies published from 2002 to 2005. RESULTS: Several systemic diseases were identified. From studies published 2002 to 2005, 15 were identified as high-quality studies and were used to support management recommendations: pilocarpine and cevimeline are recommended for treating hyposalivation and xerostomia in primary and secondary Sjögren's syndrome (SS). IFN-alpha lozenges may enhance saliva flow in primary SS patients. Anti-TNF-alpha agents, such as infliximab or etanercept, are not recommended to treat hyposalivation in SS. Dehydroepiandrosterone is not recommended to relieve hyposalivation or xerostomia in primary SS. There was not enough evidence to support any recommendations for the use of local stimulants, lubricants, and protectants for hyposalivation/xerostomia. However, professional judgment and patient preferences may support the use of a specific product for an individual patient. CONCLUSIONS: These evidence-based management recommendations should guide the clinician's management decisions for patients with salivary dysfunction related to systemic disease. Future treatment strategies may include new formulations of existing drugs, e.g., local application of pilocarpine. Recent discoveries on gene expression and a better understanding of the etiopathogenesis of SS may open new treatment options in the future.

Histopathological analysis and demonstration of EBV and HIV p-24 antigen but not CMV expression in labial minor salivary glands of HIV patients affected by diffuse infiltrative lymphocytosis syndrome.

BACKGROUND: The diffuse infiltrative lymphocytosis syndrome (DILS) in HIV patients is characterized by the persistence of CD8-circulating lymphocytes and lymphocytic infiltration, predominantly in salivary glands. METHODS: We examined seven HIV-positive patients with bilateral parotid enlargement and sicca symptoms. Minor labial salivary gland biopsies were performed in all patients and submitted for histopathological analysis and immunohistochemistry for CD4, CD8, cytomegalovirus (CMV), LMP-EBV protein, and HIV p-24 protein. RESULTS: In all cases, lymphocytic infiltration of the minor salivary glands, mainly periductal, was found. Acinar atrophy, ductal ectasia, and mild to moderate fibrosis were also observed. We noticed strong immunohistochemical reaction for LMP-EBV and p-24 proteins in ductal cells in all cases, while staining for CMV was consistently negative. The lymphocytes were positive for CD8, but consistently negative for CD4. CONCLUSIONS: A role of Epstein-Barr virus (EBV) and HIV, but not CMV, in the pathogenesis of DILS, is suggested by our immunohistochemical findings.

Oral lesions in HIV/AIDS patients undergoing highly active antiretroviral treatment including protease inhibitors: a new face of oral AIDS?

The objective of this work was to assess the prevalence of human immunodeficiency virus-related oral lesions (HIV-ROL) in HIV-positive/acquired immunodeficiency syndrome (AIDS) patients receiving highly active antiretroviral therapy (HAART) including HIV-protease inhibitors. One hundred fifty-five (154) AIDS patients (69 intravenous drug users [IDU], 53 heterosexuals, 29 males who have sex with males, 1 transfused, and 2 of unknown contagious source) receiving HAART, were examined. We found the following prevalences: HIV-ROL 53.2%; oral candidiasis 34.4%; hairy leucoplakia 26.6%; xerostomia 15.5%; herpes simplex labialis 1.9%; HIV/periodontitis-gingivitis 0.6%. No cases of Kaposi's sarcoma were observed. The highest prevalence of HIV-ROL was found in the IDU group, and in patients with viral load more than 10,000 copies and CD4(+) cell count less than 200. Using our historical controls, this suggests that the prevalence of all oral lesions, particularly oral candidiasis, herpes simplex labiali, Kaposi's sarcoma, and periodontal disease has decreased more than 30% after the institution of HAART.

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.

Relationship of oral disease to the presence of cytomegalovirus DNA in the saliva of AIDS patients.

Cytomegalovirus is an important pathogen in persons infected with human immunodeficiency virus. In this study a thorough oral examination was done and blood and urine cultures for cytomegalovirus were obtained from a group of 31 patients with acquired immunodeficiency syndrome with CD4 lymphocyte counts less than 150 cells/mm3. Whole saliva was also collected for detection of cytomegalovirus deoxyribonucleic acid (DNA) via the polymerase chain reaction. The presence of cytomegalovirus DNA in the saliva specimens was not related to the presence of cytomegalovirus in the urine, which suggests a local source of cytomegalovirus from salivary gland and kidney parenchyma. There was also a strong statistical relationship between salivary cytomegalovirus DNA and xerostomia (p = 0.0004), which suggests that cytomegalovirus may be a cause of salivary gland dysfunction in patients with acquired immunodeficiency syndrome with low CD4 counts.