Relationship between hyposalivation and oxidative stress in aging mice

Extracellular matrix turnover in salivary gland disorders and regenerative therapies: Obstacles and opportunities

Salivary gland (SG) extracellular matrix (ECM) has a major influence on tissue development, homeostasis, and tissue regeneration after injury. During aging, disease, and physical insult, normal remodeling of the SG microenvironment (i.e. ECM) becomes dysregulated, leading to alterations in matrix composition which disrupt tissue architecture/structure, alter cell activity, and negatively impact gland function. Matrix metalloproteinases (MMPs) are a large and diverse family of metalloendopeptidases which play a major role in matrix degradation and are intimately involved in regulating development and cell function; dysregulation of these enzymes leads to the production of a fibrotic matrix. In the SG this altered fibrotic ECM (or cell microenvironment) negatively impacts normal cell function and the effectiveness of gene and stem cell therapies which serve as a foundation for many SG regenerative therapies. For this reason, prospective regenerative strategies should prioritize the maintenance and/or restoration of a healthy SG ECM. Mesenchymal stem cells (MSCs) have great potential for mitigating damage to the SG microenvironment by ameliorating inflammation, reducing fibrosis, and repairing the damaged milieu of extracellular regulatory cues, including the matrix. This review addresses our current understanding of the impact of aging and disease on the SG microenvironment and suggests critical deficiencies and opportunities in ECM-targeted therapeutic interventions.

TGF-β1 Triggers Salivary Hypofunction via Attenuating Protein Secretion and AQP5 Expression in Human Submandibular Gland Cells

Aging-related salivary gland degeneration usually causes poor oral health. Periductal fibrosis frequently occurs in the submandibular gland of the elderly. Transforming growth factor β1 (TGF-β1) is the primary driving factor for fibrosis, which exhibits an increase in the fibrotic submandibular gland tissue. This study aimed to investigate the effects of TGF-β1 on the human submandibular gland (HSG) cell secretory function and its influences on aquaporin 5 (AQP5) expressions and distribution. We found that TGF-β1 reduces the protein secretion amount of HSG and leads to the abundance alteration of 151 secretory proteins. Data are available via ProteomeXchange with the identifier PXD043185. The majority of HSG secretory proteins (84.11%) could be matched to the human saliva proteome. Meanwhile, TGF-β1 enhances the expression of COL4A2, COL5A1, COL7A1, COL1A1, COL2A1, and α-SMA, hinting that TGF-β1 possesses the potential to drive HSG fibrosis-related events. Besides, TGF-β1 also attenuates the AQP5 expression and its membrane distribution in HSGs. The percentage for TGF-β1-induced AQP5 reduction (52.28%) is much greater than that of the TGF-β1-induced secretory protein concentration reduction (16.53%). Taken together, we concluded that TGF-β1 triggers salivary hypofunction via attenuating protein secretion and AQP5 expression in HSGs, which may be associated with TGF-β1-driven fibrosis events in HSGs.

Peroxisomes Are Highly Abundant and Heterogeneous in Human Parotid Glands

The parotid gland is one of the major salivary glands producing a serous secretion, and it plays an essential role in the digestive and immune systems. Knowledge of peroxisomes in the human parotid gland is minimal; furthermore, the peroxisomal compartment and its enzyme composition in the different cell types of the human parotid gland have never been subjected to a detailed investigation. Therefore, we performed a comprehensive analysis of peroxisomes in the human parotid gland's striated duct and acinar cells. We combined biochemical techniques with various light and electron microscopy techniques to determine the localization of parotid secretory proteins and different peroxisomal marker proteins in parotid gland tissue. Moreover, we analyzed the mRNA of numerous gene encoding proteins localized in peroxisomes using real-time quantitative PCR. The results confirm the presence of peroxisomes in all striated duct and acinar cells of the human parotid gland. Immunofluorescence analyses for various peroxisomal proteins showed a higher abundance and more intense staining in striated duct cells compared to acinar cells. Moreover, human parotid glands comprise high quantities of catalase and other antioxidative enzymes in discrete subcellular regions, suggesting their role in protection against oxidative stress. This study provides the first thorough description of parotid peroxisomes in different parotid cell types of healthy human tissue.

Effect of Sustained Systemic Administration of Ginger (Z officinale) Rhizome Extracts on Salivary Flow in Mice

OBJECTIVE

This study aimed to evaluate the effect of methanol (70% v/v), ethanol (80% v/v), dimethyl sulfoxide (DMSO; 100% v/v) extracts of ginger rhizome (GR), and 6-shogaol on the pilocarpine-stimulated salivary flow rate in C57BL/6 mice.

METHODS

Three extracts of ginger (Zingiber officinale) rhizome prepared by maceration using the respective solvents and 6-shogoal were reconstituted in normal saline with 0.2% DMSO. Thirty C57BL/6 15-week-old mice were divided into 5 groups: Group 1, saline; Group 2, 70% methanol extract; Group 3, 80% ethanol extract; Group 4, 100% DMSO extract; and Group 5, 6-shogaol. The baseline pilocarpine-stimulated salivary flow rate was measured at the age of 15 weeks (15th week), and treatment solutions were administered by intraperitoneal injection from the 16th to 18th week. The stimulated salivary flow rate during treatment weeks was recorded for each group, and its difference with baseline was analysed using paired-sample t test. The change in salivary flow rate between the treatment groups and the control group was analysed using one-way analysis of variance.

RESULTS

Groups 2, 3, 4, and 5 showed a significant increase in salivary flow rate when compared to baseline (P < .05). The increase in salivary flow rate in all 4 treatment groups was significant when compared to the control group (P < .05). Group 4 produced the highest increase in salivary flow rate; however, the differences amongst the treatment groups did not reach statistical significance (P > .05).

CONCLUSIONS

All GR extracts (70% methanol, 80% ethanol, 100% DMSO) and 6-shogaol were equally effective in increasing the pilocarpine-stimulated salivary flow rate in C57BL/6 mice when administered systemically as a sustained dose for 3 weeks.

Potential effects of mung bean protein and a mung bean protein-polyphenol complex on oxidative stress levels and intestinal microflora in aging mice

This study investigated the effects of mung bean protein (MPI) and a MPI-polyphenol complex on oxidative stress levels and intestinal microflora in a D-galactose-induced aging mouse model. MPI and MPI-polyphenol complex intervention significantly increased activity of superoxide dismutase (SOD) and catalase and other antioxidant enzymes, improved the abundance and diversity of intestinal flora, and decreased the Firmicutes to Bacteroidetes ratio. Among them, the complex was more conducive to the improvement of the activity of antioxidant enzymes. The addition of MPI and the MPI-polyphenol complex can help the proliferation of Bacteroidetes, Bifidobacterium and Roseburia in the intestinal tract of aging mice, and inhibit the growth of Firmicutes and Ruminococcus, and the proliferation effect of the complex on Bifidobacterium was better than that of MPI. MPI significantly upregulated five pathways related to lipid and energy metabolism. Roseburia and Muribaculaceae were negatively correlated with malondialdehyde levels and positively correlated with SOD and other antioxidant enzyme indices. Our findings showed that MPI and MPI-polyphenol complexes can delay aging in mice by reducing oxidative damage and regulating intestinal flora. We also found a strong relationship between the abundance of intestinal flora and the levels of oxidative stress-related enzymes. This study provides theoretical support for the health and anti-aging benefits of mung bean food products.

Aging-associated stem/progenitor cell dysfunction in the salivary glands of mice

Although stem cell aging leads to a decline in tissue homeostasis and regenerative capacity, it remains unclear whether salivary gland stem cell function changes during this process. However, the salivary glands are gradually replaced by connective tissue during aging. Here, we show a decline in the stem cell ability of CD133-positive stem/progenitor cells in the salivary glands of aged mice. The CD133-positive cells were isolated from young, adult, and aged mice. The number of CD133-positive cells was significantly decreased in aged mice. They also showed a lower sphere formation capacity compared to young and adult mice. RNA sequencing revealed that CD133-positive cells in aged mice exhibited lower gene expression of several aging-related genes, including FoxO3a, than those in young and adult mice. Salivary gland cells infected with a recombinant lentivirus encoding the FoxO3a gene showed a reduction in oxidative stress induced by hydrogen peroxide compared with those infected with a control virus. Thus, FoxO3a may inhibit stem cell aging via oxidative stress.

The KEAP1-NRF2 System in Healthy Aging and Longevity

Aging is inevitable, but the inherently and genetically programmed aging process is markedly influenced by environmental factors. All organisms are constantly exposed to various stresses, either exogenous or endogenous, throughout their lives, and the quality and quantity of the stresses generate diverse impacts on the organismal aging process. In the current oxygenic atmosphere on earth, oxidative stress caused by reactive oxygen species is one of the most common and critical environmental factors for life. The Kelch-like ECH-associated protein 1-NFE2-related factor 2 (KEAP1-NRF2) system is a critical defense mechanism of cells and organisms in response to redox perturbations. In the presence of oxidative and electrophilic insults, the thiol moieties of cysteine in KEAP1 are modified, and consequently NRF2 activates its target genes for detoxification and cytoprotection. A number of studies have clarified the contributions of the KEAP1-NRF2 system to the prevention and attenuation of physiological aging and aging-related diseases. Accumulating knowledge to control stress-induced damage may provide a clue for extending healthspan and treating aging-related diseases. In this review, we focus on the relationships between oxidative stress and aging-related alterations in the sensory, glandular, muscular, and central nervous systems and the roles of the KEAP1-NRF2 system in aging processes.

Advanced Glycation End Products Increase Salivary Gland Hypofunction in d-Galactose-Induced Aging Rats and Its Prevention by Physical Exercise

A declined salivary gland function is commonly observed in elderly people. Advanced glycation end products (AGEs) are believed to contribute to the pathogenesis of aging. Although physical exercise is shown to increase various organ functions in human and experimental models, it is not known whether it has a similar effect in the salivary glands. In the present study, we evaluated the AGEs burden in the salivary gland in the aging process and the protective effect of physical exercise on age-related salivary hypofunction. To accelerate the aging process, rats were peritoneally injected with D-galactose for 6 weeks. Young control rats and d-galactose-induced aging rats in the old group were not exercised. The rats in the physical exercise group ran on a treadmill (12 m/min, 60 min/day, 3 days/week for 6 weeks). The results showed that the salivary flow rate and total protein levels in the saliva of the d-galactose-induced aging rats were reduced compared to those of the young control rats. Circulating AGEs in serum and secreted AGEs in saliva increased with d-galactose-induced aging. AGEs also accumulated in the salivary glands of these aging rats. The salivary gland of aging rats showed increased reactive oxygen species (ROS) generation, loss of acinar cells, and apoptosis compared to young control mice. However, physical exercise suppressed all of these age-related salivary changes. Overall, physical exercise could provide a beneficial option for age-related salivary hypofunction.

Effects of age and gender on the redox homeostasis of morbidly obese people

Obesity is a chronic disease of complex etiology. Recent evidence suggests that obesity is caused by inflammation of adipose tissue leading to metabolic disorders, cardiovascular disease and cancer. This is the first study to evaluated the effects of age and gender on redox homeostasis, glutathione metabolism, and oxidative damage to plasma/serum lipids and proteins in morbidly obese patients. The study included 120 (60 men and 60 women) morbidly obese patients with class 3 obesity (BMI > 40 kg/m2), classified into three groups depending on age: 20-39 years (n = 20), 40-59 years (n = 20) and 60 years or older (n = 20). The number of patients was calculated a priori based on our previous experiment. We observed a reduction in serum activity of antioxidant enzymes (↓SOD) and plasma concentration of non-enzymatic antioxidants (↓GSH) in obese patients compared to the lean controls, which further decreased with age. Redox status (↑TAC, ↑TOS and ↓OSI) in morbidly obese men and women was shifted towards oxidation. Moreover, lipid (↑MDA and ↑LOOH) and protein (↑AOPP, ↑AGE and ↑Amadori products) damage products of oxidation and nitrosylation/nitration (↑total NO, ↑S-nitrosothiols, ↑peroxynitrite and ↑nitrotyrosine) were elevated in both genders of morbidly obese patients and were higher in the elderly. Interestingly, the concentrations of oxidative and nitrosative stress markers were generally higher in obese men compared to obese women at the same age. Summarizing, we showed that the total antioxidant/oxidant potential of obese patients is significantly increased and shifted towards oxidation. Obese patients have increased lipid and protein oxidation, glycation and nitration as compared to the lean controls. Disturbances in redox homeostasis increase with age in obese patients. Oxidative and nitrosative stress are more intense in men than in women at the same age.

Peroxisomes in the mouse parotid glands: An in-depth morphological and molecular analysis

BACKGROUND

The parotid gland is a major salivary gland that has important roles in the digestive and immune system. Peroxisomes are ubiquitous, single-membrane-bound organelles that are present in all eukaryotic cells. Peroxisomes help mediate lipid and reactive oxygen species metabolism, as well as polyunsaturated fatty acid, cholesterol and plasmalogen synthesis. Much of the knowledge on peroxisomes has derived from metabolic organs, however no detailed knowledge is available on peroxisomes in the parotid glands. We thus aimed to comprehensively delineate the localization and characterization of peroxisomal proteins in the murine parotid gland.

METHODS

We characterized peroxisomes in the acinar and striated duct cells of the murine parotid gland by fluorescence and electron microscopy, as well as protein and mRNA expression analyses for important peroxisomal genes and proteins.

RESULTS

We found that peroxisomes are present in all cell types of the mouse parotid gland, however, exhibit notable cell-specific differences in their abundance and enzyme content. We also observed that mouse parotid glands contain high levels of peroxisomal β-oxidation enzymes (including Acox1, Mfp2 and Acaa1), catalase and other peroxisomal anti-oxidative enzymes.

CONCLUSIONS

This data suggests that peroxisomes are highly abundant in the murine parotid gland and might help to protect against oxidative stress. This comprehensive description of peroxisomes in the parotid gland lays the groundwork for further research concerning their role in the pathogenesis of parotid gland diseases and tumors.

Smad7 attenuates TGF-β-mediated aging-related hypofunction of submandibular glands

Submandibular glands have essential functions in taste, mastication, swallowing, and digestion. Submandibular gland hypofunction is prevalent in the elderly, impairing the patients' quality of life. Current clinical treatment strategies have not decelerated or reversed the pathological process of submandibular gland hypofunction. Therefore, novel restoration strategies should be explored. However, studies on the mechanism of aging-related submandibular gland hypofunction remain very limited. The role of the TGF-β/Smad pathway in fibrosis has been studied in other organs. Therefore, this study aimed to elucidate the role of TGF-β/Smad signaling in the aging-related submandibular gland hypofunction. The results showed that Smad7 knockout in mice decreased the salivary flow rate. H&E, Masson trichrome, and immunohistochemistry staining of MCP-1 and α-SMA showed that Smad7 knockout in mice resulted in lymphocytic infiltration, acinar cell atrophy, and interstitial fibrosis. The Western blotting of collagen I and III also confirmed extensive fibrosis. We then found that Smad7 depletion resulted in the TGF-β-mediated fibrosis via mir-21, mir-29, and np_5318, and NFκB-driven inflammation activation. This study confirmed the inhibitory role of Smad7 in the aging-related submandibular gland hypofunction. Therefore, it provided a promising treatment target for aging-related dysfunction and sialadenitis of submandibular gland.

The Neuroimmune Role of Intestinal Microbiota in the Pathogenesis of Cardiovascular Disease

Currently, a bidirectional relationship between the gut microbiota and the nervous system, which is considered as microbiota-gut-brain axis, is being actively studied. This axis is believed to be a key mechanism in the formation of somatovisceral functions in the human body. The gut microbiota determines the level of activation of the hypothalamic-pituitary system. In particular, the intestinal microbiota is an important source of neuroimmune mediators in the pathogenesis of cardiovascular disease. This review reflects the current state of publications in PubMed and Scopus databases until December 2020 on the mechanisms of formation and participation of neuroimmune mediators associated with gut microbiota in the development of cardiovascular disease.

Pathology of salivary gland dysfunction and restoration of function

In this review, the author shows that simultaneous multiple disorders caused by reactivation of Epstein-Barr virus can lead to salivary gland disorders as part of Sjogren's syndrome (SS). Therefore, clinicians must differentiate SS from other diseases when diagnosing and treating salivary gland disorders. In particular, the author explains how microbial infection in SS overcomes immunological tolerance, leading to pathological changes, and how cytokine overexpression and endocrine disrupters contribute to glandular tissue injury. Also, the author suggests that involvement of reactive oxygen species is a common pathogenesis of salivary gland disorders and SS, so regulation of oxidative stress is an effective treatment for both. The results of clinical studies on restoring salivary gland function and regenerating salivary glands with tissue stem cells may provide clues on elucidating the cause of SS.

Chemokines Up-Regulated in Epithelial Cells Control Senescence-Associated T Cell Accumulation in Salivary Glands of Aged and Sjögren's Syndrome Model Mice

Immunosenescence is characterized by age-associated changes in immunological functions. Although age- and autoimmune-related sialadenitis cause dry mouth (xerostomia), the roles of immunosenescence and cellular senescence in the pathogenesis of sialadenitis remain unknown. We demonstrated that acquired immune cells rather than innate immune cells infiltrated the salivary glands (SG) of aged mice. An analysis of isolated epithelial cells from SG revealed that the expression levels of the chemokine CXCL13 were elevated in aged mice. Senescence-associated T cells (SA-Ts), which secrete large amounts of atypical pro-inflammatory cytokines, are involved in the pathogenesis of metabolic disorders and autoimmune diseases. The present results showed that SA-Ts and B cells, which express the CXCL13 receptor CXCR5, accumulated in the SG of aged mice, particularly females. CD4⁺ T cells derived from aged mice exhibited stronger in vitro migratory activity toward CXCL13 than those from young mice. In a mouse model of Sjögren’s syndrome (SS), SA-Ts also accumulated in SG, presumably via CXCL12-CXCR4 signaling. Collectively, the present results indicate that SA-Ts accumulate in SG, contribute to the pathogenesis of age- and SS-related sialadenitis by up-regulating chemokines in epithelial cells, and have potential as therapeutic targets for the treatment of xerostomia caused by these types of sialadenitis.

The Relationship Between Salivary Redox, Diet, and Food Flavor Perception

The mouth is the gateway for entrance of food and microorganisms into the organism. The oral cavity is bathed by saliva, which is thus the first fluid that food and microorganisms will face after their entrance. As a result, saliva plays different functions, including lubrication, predigestion, protection, detoxification, and even transport of taste compounds to chemoreceptors located in the taste buds. To ensure its function of protection, saliva contains reactive harmful compounds such as reactive oxygen species that are controlled and neutralized by the antioxidant activity of saliva. Several antioxidant molecules control the production of molecules such as reactive oxygen compounds, neutralize them and/or repair the damage they have caused. Therefore, a balance between reactive oxidant species and antioxidant compounds exists. At the same time, food can also contain antioxidant compounds, which can participate in the equilibrium of this balance. Numerous studies have investigated the effects of different food components on the antioxidant capacity of saliva that correspond to the ability of saliva to neutralize reactive oxygen species. Contradictory results have sometimes been obtained. Moreover, some antioxidant compounds are also cofactors of enzymatic reactions that affect flavor compounds. Recent studies have considered the salivary antioxidant capacity to explain the release of flavor compounds ex vivo or in vivo. This article aims to review the effect of food on the antioxidant capacity of saliva and the impact of salivary antioxidant capacity on flavor perception after a brief presentation of the different molecules involved.

Salivary exosomes as a new therapy to ameliorate diabetes mellitus and combat xerostomia and submandibular salivary glands dysfunction in diabetic rats

Diabetes mellitus (DM) is one of the major metabolic diseases. Xerostomia and salivary gland dysfunction are of its common oral complications. Exosomes, as a new therapeutic potential containing nucleic acids, proteins and lipids, act as effective vehicles for target molecules delivery. Accordingly, their therapeutic use is gaining much interest. Therefore, this work aimed to assess the therapeutic efficacy of salivary exosomes in ameliorating DM and combating xerostomia as a complication of salivary gland dysfunction in diabetic rats. In the current study, salivary exosomes were injected intravenously to rats of group II (Salivary Exo-treated group) one week after diabetes induction. Group I (Diabetic group) was left untreated. Blood sugar level was checked weekly. Water intake, salivary flow rate, salivary amylase and serum nitric oxide were assessed before and after diabetes induction and at the end of the study. After 5 weeks from the beginning of the study, salivary gland tissues were dissected and examined histologically and ultrastructurally. Gene expression of the inflammatory markers NFκB/p65 and TNFα was assessed by polymerase chain reaction. The results showed that salivary exosomes reduced blood glucose levels and enhanced salivary glands' function. This was indicated by a decrease in water intake, salivary amylase and serum nitric oxide in addition to an increase in salivary flow rate. This was confirmed histologically, ultrastructurally and via downregulation of NFκB/p65 and TNFα gene expression. Our results concluded that salivary exosomes could be considered as a novel cell free based therapy in treatment of xerostomia and salivary gland dysfunction in DM.

Cognitive function improvement with astaxanthin and tocotrienol intake: a randomized, double-blind, placebo-controlled study

We examined the effects of the mixed ingestion of astaxanthin derived from Haematococcus pluvialis and tocotrienols on the cognitive function of healthy Japanese adults who feel a memory decline. Forty-four subjects were randomly but equally assigned to the astaxanthin-tocotrienols or placebo group. An astaxanthin-tocotrienols or placebo capsule was taken once daily before or after breakfast for a 12-week intervention period. The primary outcome was composite memory from the Cognitrax cognitive test, and the secondary outcomes were other cognitive functions and subjective symptoms for memory. Each group included 18 subjects in the efficacy analysis (astaxanthin-tocotrienols group, 55.4 ± 7.9 years; placebo group, 54.6 ± 6.9 years). The astaxanthin-tocotrienols group showed a significant improvement in composite memory and verbal memory in Cognitrax at Δ12 weeks compared with the placebo group. Additionally, the astaxanthin-tocotrienols group showed a significant improvement in the subjective symptom of "During the last week, have you had trouble remembering people's names or the names of things?" compared with the placebo group after 12 weeks. No adverse events were observed in this study. The results demonstrated that taking an astaxanthin-tocotrienols combination improves the composite memory and verbal memory of Japanese adults who feel a memory decline (UMIN 000031758).

Assessment of Salivary Flow Rate in Patients with Chronic Periodontitis

Background:

Chronic periodontitis (CP) is an infectious disease, primarily affecting the attachment apparatus of the dentition, and is categorized into mild, moderate, and severe periodontitis on the basis of its severity. It is a well-established and proven fact that an adequate level of saliva is essential for maintaining the integrity of oral tissues including the periodontium. Although various factors, such as stimulation, circadian rhythm, diet, age, and drugs, can affect the salivary flow rate, many recent studies have provided evidence that it can be altered by pathological inflammatory conditions such as periodontal diseases. Therefore, this study has been undertaken to assess the unstimulated and stimulated salivary flow rate in the different clinical stages of chronic periodontitis.

Materials and Methods:

This study comprised 60 study participants, who were divided into four groups depending on clinical attachment level (CAL). In all, both unstimulated and stimulated saliva were collected, and the flow rate was expressed in milliliter per minute.

Results:

Statistical analysis was accomplished with Statistical Package for the Social Sciences (SPSS) software. One-way analysis of variance (ANOVA) was used to analyze differences in salivary flow rate among the groups. Statistical significance was set at P < 0.05. The amount of unstimulated saliva in healthy subjects, in mild, moderate, and severe periodontitis was 0.766, 0.400, 0.270, and 0.146 mL/min, respectively. Likewise, the amount of stimulated saliva in healthy subjects, in mild, moderate, and severe periodontitis was 1.017, 0.494, 0.347, and 0.236 mL/min, respectively.

Conclusion:

The study identified a significant decrease in both unstimulated and stimulated salivary flow rate with the severity of progression of chronic periodontitis.

Ixeris dentata and Lactobacillus gasseri Extracts Improve Salivary Secretion Capability in Diabetes-Associated Dry Mouth Rat Model

Dry mouth, hyposalivation, or xerostomia is a significant problem in diabetic patients; however, there has been no way to relieve these symptoms. This study’s aim was to evaluate the effects of Ixeris dentata (IXD) in combination with lactobacillus extract on the salivation rate in diabetes-induced dry mouth, and its mechanism was also investigated. In the streptozotocin (STZ)-induced diabetes model, the dry mouth condition was established as a model. Here, rats were treated with water or IXD through the sublingual spray, and subsequently treated with or without a spray of lactobacillus extract. In diabetes condition, the salivary flow rate, amylase activity, and aquaporin-5 and Na⁺/H⁺ exchanger (NHE-1) expressions were markedly decreased, whereas they were more significantly recovered in the sequential treatment of IXD-lactobacillus extract than in each single treatment. Furthermore, oxidative stress and its related ER stress response were especially regulated in the IXD/lactobacillus extract condition, where the following anti-oxidative enzymes, glutathione assay (GSH: GSSG) ratio, superoxide dismutase (SOD), and glutathione peroxidase (GPx), were involved. This study suggests that the combination of IXD and lactobacillus would be a potential alternative medicine against diabetes-induced hyposalivation and xerostomia.

Mouth-Watering Results: Clinical Need, Current Approaches, and Future Directions for Salivary Gland Regeneration

Permanent damage to the salivary glands and resulting hyposalivation and xerostomia have a substantial impact on patient health, quality of life, and healthcare costs. Currently, patients rely on lifelong treatments that alleviate the symptoms, but no long-term restorative solutions exist. Recent advances in adult stem cell enrichment and transplantation, bioengineering, and gene transfer have proved successful in rescuing salivary gland function in a number of animal models that reflect human diseases and that result in hyposalivation and xerostomia. By overcoming the limitations of stem cell transplants and better understanding the mechanisms of cellular plasticity in the adult salivary gland, such studies provide encouraging evidence that a regenerative strategy for patients will be available in the near future.

Cordycepin attenuates Salivary Hypofunction through the Prevention of Oxidative Stress in Human Submandibular Gland Cells

Xerostomia (dry mouth) is a significant age-related condition. Meanwhile, cordycepin, the natural therapeutic agent, has demonstrated an anti-aging effect. Therefore, the present study aimed to investigate the preventive effects of cordycepin on secretory function in an in vitro model of hydrogen peroxide (H₂O₂)-induced salivary hypofunction. After being exposed to H₂O₂, human submandibular gland (HSG) cells were treated with various concentrations of cordycepin (6.25-50 µM) for 24, 48, and 72h. To evaluate cell proliferation and reactive oxygen species (ROS) generation, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide and 2, 7'-dichlorodihydrofluorescein diacetate assays were performed. The amylase activity was kinetically measured by 2-chloro-p-nitrophenol linked with maltotrioside. The expression of salivary, antioxidant and apoptotic markers at mRNA and protein levels were performed by reverse transcriptase polymerase chain reaction (RT-PCR) and immunofluorescence analysis, respectively. We demonstrated that cordycepin (6.25-25 µM) contributed to significant increases in expression of the salivary marker genes, alpha-amylase 1 (AMY1A) and aquaporin-5 (AQP5), and in amylase secretion without changes in cell viability. Under oxidative stress, HSG cells showed remarkable dysfunction. Cordycepin rescued the protective effects partially by decreasing ROS generation and restoring the expression of the salivary proteins, AMY and AQP5 via anti-oxidant and anti-apoptotic activity. In addition, the amount of amylase that was secreted from HSG cells cultured in cordycepin was increased. In conclusion, cordycepin demonstrated a protective effect on H₂O₂ -induced HSG cells by decreasing ROS generation and upregulating the salivary function markers, AMY1A and AQP5, at both the transcriptional and translational levels.

The effects of isoflavone supplementation plus combined exercise on salivary markers of oxidative stress in postmenopausal women

This study tested the effect of isoflavone supplementation in addition to combined exercise training in salivary oxidative stress markers in non-obese postmenopausal women. Thirty-two postmenopausal women without hormone therapy were randomly assigned to exercise + placebo (n = 15) or exercise + isoflavone supplementation (n = 17) groups. They performed 30 sessions of combined exercises (aerobic plus resistance) over ten weeks and consumed 100 mg of isoflavone supplementation or placebo. Saliva samples were collected after an overnight fast. Superoxide dismutase, total antioxidant capacity, thiobarbituric acid reactive substances, catalase, total protein and nitrite were determined before and after ten weeks of the intervention. The ANOVA two-way analysis of variance was applied with α of 5%. Both groups increase (p<0.05) superoxide dismutase activity and decrease catalase levels. There was interaction (time × group) in both nitrite and thiobarbituric acid reactive substances results, with increase (p<0.05) in placebo group and decrease (p<0.05) in isoflavone group. No difference was found for total antioxidant capacity or total protein. The combination of isoflavone supplementation and exercise training can promote an antioxidant effect through reduction of lipid peroxidation and concentrations of salivary nitrite.

Synergistic effects of laminin-1 peptides, VEGF and FGF9 on salivary gland regeneration

Hyposalivation is associated with radiation therapy, Sjögren's syndrome and/or aging, and is a significant clinical problem that decreases oral health and overall health in many patients and currently lacks effective treatment. Hence, methods to regenerate salivary glands and restore saliva secretion are urgently needed. To this end, this study describes the modification of fibrin hydrogels with a combination of laminin-1 peptides (YIGSR and A99) and human growth factors (vascular endothelial growth factor and fibroblast growth factor 9) to enhance regeneration in a salivary gland injury mouse model. Our results indicate that these fortified hydrogels enhanced angiogenesis and neurogenesis while promoting formation of acinar structures, thereby leading to enhanced saliva secretion. Such functional recovery indicates salivary gland regeneration and suggests that our technology may be useful in promoting gland regeneration and reversing hyposalivation in a clinical setting. STATEMENT OF SIGNIFICANCE: We engineered Fibrin Hydrogels (FH) to contain multiple regenerative cues including laminin-1 peptides (L_1p) and growth factors (GFs). L_1p and GF modified FH were used to induce salivary gland regeneration in a wounded mouse model. Treatment with L_1p and GF modified FH promoted salivary epithelial tissue regeneration, vascularization, neurogenesis and healing as compared to L_1p-FH or FH alone. Results indicate that L_1p and GF modified FH can be used for future therapeutic applications.

Understanding How Dogs Age: Longitudinal Analysis of Markers of Inflammation, Immune Function, and Oxidative Stress

As in human populations, advances in nutrition and veterinary care have led to an increase in the lifespan of companion animals. Detrimental physiological changes occurring later in life must be understood before interventions can be made to slow or reduce them. One important aspect of human aging is upregulation of the inflammatory response and increase in oxidative damage resulting in pathologies linked to chronic inflammation. To determine whether similar processes occur in the aging dog, changes in markers of inflammation and oxidative stress were investigated in 80 Labrador retrievers from adulthood to the end of life. Serum levels of immunoglobulin M (p < .001) and 8-hydroxy-2-deoxyguanosine (p < .001) increased with age, whereas no effect of age was detected for immunoglobulin G or C-reactive protein unless the last year of life was included in the analysis (p = .002). Baseline levels of heat shock protein 70 decreased with age (p < .001) while those after exposure to heat stress were maintained (p = .018). However, when excluding final year of life data, a decline in the heat shock protein 70 response after heat stress was observed (p = .004). These findings indicate that aging dogs undergo changes similar to human inflammaging and offer the possibility of nutritional or pharmacological intervention to delay or reduce these effects.

Comparison of Oxidative Effects of Two Different Administration Form of Oxybutynin in the Potential Target Tissues

Oxybutynin is an important anticholinergic agent that prevents uncontrolled contractions in the treatment of overactive bladder (OAB). However, drugs containing oxybutynin have significant side effects such as dry eyes, dry mouth, increased heart rate, constipation, blurred vision, and confusion. In recent years, new delivery methods for this agent are being searched. One of them is vaginal delivery. In this study, we aimed to compare the effects of oxybutynin on oxidative parameters in the potential target tissues of the oral and vaginal delivery. Female New Zealand white rabbits (n=12) were divided into two groups: oral delivery and vaginal delivery. The animals were sacrificed 48 h after administration and nitric oxide (NOx), thiobarbituric acid-reactive substances (TBARs), and glutathione (GSH) levels were determined spectrophotometrically in the aorta, salivary gland, and small intestine tissue samples. Vaginal delivery significantly decreased NOx levels in all tissue samples as compared to oral delivery (p < 0.05). Moreover, it reduced TBARs levels in salivary gland and aorta tissue samples (p < 0.05). In the light on these findings, it can be said that vaginal delivery may decrease the oxidant-induced side effects of oxybutynin as compared to oral delivery.

Biomarkers of oxidative stress in saliva of sheep: Analytical performance and changes after an experimentally induced stress

Oxidative stress can affect animal's health and the quality of its final products. The oxidative status can be evaluated by the measurement of both oxidant and antioxidant biomarkers. The use of saliva as a sample is preferable to blood, as individuals with limited training can collect it easily and non-invasively with minimal stress to the animal. The aim of this study was to perform an analytical validation of automated assays of the ferric reducing ability of plasma (FRAP), the cupric reducing antioxidant capacity (CUPRAC), the Trolox equivalent antioxidant capacity (TEAC) and uric acid as antioxidant biomarkers and of the advanced oxidation protein products (AOPP) and hydrogen peroxide (H₂O₂) as oxidant biomarkers in saliva samples of sheep, and to evaluate their possible changes after stress induced by shearing. All assays produced acceptable results in the analytical validation, from which it can be concluded that oxidative stress biomarkers such as FRAP, CUPRAC, TEAC, uric acid and AOPP and H₂O₂ can be measured in sheep saliva. In addition, acute stress due to shearing could produce an oxidative stress response in sheep and subsequently increase antioxidants in order to protect cells from damage.

Potential Application of Ixeris dentata in the Prevention and Treatment of Aging-Induced Dry Mouth

Dry mouth is a common complaint among the elderly population. The aim of this study was to investigate the effect of Ixeris dentata (IXD) extract on aging-induced dry mouth. We used young (two months) and aged (20 months) SD rats in our study. Using water as the vehicle, IXD extract (25, 50, and 100 mg/kg) was given via oral gavage to the young and aged rats for eight weeks. We found that the salivary flow rate relative to the submandibular gland weight was differently influenced by IXD extract treatment. IXD extract augmented the submandibular gland acinar cells, which are depleted during aging. In addition, the decreased salivary alpha-amylase, inositol triphosphate receptor, and aquaporin-5 in the aging rats were upregulated by IXD treatment. Free radical-induced oxidative stress in the aging rats was also alleviated in the IXD-treated group. The formation of high molecular weight complexes of protein disulfide isomerase, decreased expression of an ER chaperone (GRP78), and increased ER stress response (ATF-4, CHOP and p-JNK) in aging rats was regulated with IXD treatment, and eventually increased salivary secretions from the aging submandibular glands. These are the first data to suggest that IXD extract might ameliorate aging-associated oral dryness by regulating the ER environment.

Markers of oxidative stress and antioxidant status in the plasma, urine and saliva of healthy mice

Oxidative stress markers are usually measured in plasma, a stable environment for biomarkers. Blood collection is invasive, but the use of alternative biofluids is limited, due to high variability. In this study, we aimed to establish reference values for oxidative stress markers in plasma, urine and saliva of adult, healthy mice and to identify some sources of variability. Samples were obtained from 41 female and 37 male adult, healthy mice of the CD-1 strain, aged 95-480 days, weighing 21-55 grams. Reference ranges of TBARS (thiobarbituric acid reactive substances), AOPP (advanced oxidation protein products), fructosamine, GSH/GSSG (reduced and oxidized glutathione) ratio, TAC (total antioxidant capacity), and FRAP (ferric reducing antioxidant power) were measured in plasma and urine, and TBARS, GSH/GSSG ratio, TAC and FRAP in saliva, using standard spectrophotometric and fluorometric methods. Salivary GSH/GSSG and urinary AOPP were higher in females. Urinary fructosamine, GSH/GSSG and FRAP were higher in males. Urinary TAC and FRAP negatively correlated with age, and urinary GSH/GSSG positively correlated with weight. We determined that urine and saliva can be obtained non-invasively from mice, in sufficient amounts for reliable oxidative status assessment. Further studies are needed to uncover whether these biofluids reflect systemic oxidative status in diseases.

Whey Protein Concentrate WPC-80 Improves Antioxidant Defense Systems in the Salivary Glands of 14-Month Wistar Rats

Whey protein concentrate (WPC) is characterized by powerful antioxidant properties, but its effect on redox homeostasis of salivary glands of aging organisms is still unknown. In this study, we are the first to evaluate the antioxidant barrier of salivary glands of 14-month Wistar rats fed WPC-80. Total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT) as well as concentrations of reduced glutathione (GSH) are estimated in the submandibular and parotid glands of rats administered WPC-80 intragastrically for a period of 7 and 14 days. We demonstrate a significant increase in GSH, GPx and SOD in the salivary glands of rats fed WPC-80 for 14 days and a significant increase in TAS, GPx and SOD in the parotid glands of rats fed WPC-80 for 7 days compared to control rats. The beneficial effects of WPC-80 on salivary glands are also demonstrated by lower TOS and OSI in the parotid glands of rats fed WPC-80 compared to the submandibular glands. In summary, we demonstrate that WPC-80 improves redox homeostasis in salivary glands, particularly in the parotid glands of old rats.

Microbiome and intestinal ischemia/reperfusion injury

Intestinal ischemia/reperfusion injury is a severe disease associated with a high mortality. The mechanisms that cause ischemia/reperfusion injury are complex and many factors are involved in the injury formation process; however, the only available treatment is surgical intervention. Recent studies demonstrated that the intestinal microbiome plays a key role in intestinal ischemia/reperfusion injury and there are many factors associated with intestinal bacteria during the formation of the intestinal ischemia/reperfusion injury. Among the Toll-like receptors (TLR), TLR2, TLR4, and their adaptor protein, myeloid differentiation primary-response 88 (MyD88), have been reported to be involved in intestinal ischemia/reperfusion injury. Oxidative stress and nitric oxide are also associated with intestinal bacteria during the formation of the intestinal ischemia/reperfusion injury. This review focuses on our current understanding of the impact of the microbiome, including the roles of the TLRs, oxidative stress, and nitric oxide, on intestinal ischemia/reperfusion injury.