Boric acid alleviates periodontal inflammation induced by IL-1ß in human gingival fibroblasts.

BACKGROUND: Boric acid (BA) has been found to have therapeutic effects on periodontal disease through beneficially affecting antibacterial, anti-viral, and anti-inflammatory actions. METHODS: This study was conducted to determine the effect of BA on cell viability and on mRNA expressions of proinflammatory and anti-inflammatory cytokines and on oxidative stress enzymes induced by IL-1ß (1 ng/mL) in Human Gingival Fibroblasts (HGF) cultured for 24 and 72 h in DMEM media. The BA concentrations added to the media were 0.09 %, 0.18 %, 0.37 %, and 0.75 %. RESULTS: All of the BA concentrations increased the viability of cell cultured in DMEM media only, indicating that these concentrations were not toxic and actually beneficial to cell viability. The addition of 1 ng/m: of IL-1ß decreased cell viability that was overcome by all concentrations of BA at both 24 and 72 h. The IL-1ß addition to the media increased the expressions of the proinflammatory cytokines IL-1ß, IL-6, IL-8, and IL-17; the anti-inflammatory cytokine IL-10; and the oxidative stress enzymes superoxide dismutase (SOD0 and glutathione peroxidase (GPX). The IL-1ß induced increase mRNA expression of IL-1ß was decreased at 24 h by the 0.37 % and 0.75 % BA additions to the media and decreased in a dose-dependent manner by all concentrations of BA at 72 h. The IL-1ß induced increase in the expression of IL-6 was decreased in dose-dependent manner at 72 h by BA. All BA concentrations decreased the IL-1ß induced expression of IL-8 at both 24 and 72 h. The induced increase in IL-17 by IL-1ß was not significantly affected by the BA additions. The increase in the anti-inflammatory cytokine IL10 induced by IL-1ß was increased further by all BA additions in dose dependent manner at both 24 and 72 h. The mRNA expressions of SOD and GPX increased by IL-1ß were further increased by the 0.37 % and 0.75 % BA concentrations at 72 h. CONCLUSIONS: These findings indicate that BA can significantly modulate the cytokines that are involved in inflammatory stress and reactive oxygen species action and thus could be an effective therapeutic agent in the treatment of periodontal disease.

Perspective: Call for Re-evaluation of the Tolerable Upper Intake Level for Magnesium Supplementation in Adults.

In 1997, the US Institute of Medicine (IOM) dietary reference intakes (DRI) Committee established a magnesium (Mg) tolerable upper intake level (UL) for adults of 350 mg/d from supplemental intake alone. Diarrhea was the limiting factor. The safety of oral Mg dietary supplements exceeding the UL is currently in debate. Increasing the UL may result in more Mg supplementation, decreasing the prevalence of undernutrition for this nutrient and thus providing additional protection against numerous chronic diseases. This perspective aims to show that more recent and comprehensive evidence-based data on the occurrence of diarrhea indicate that the Mg UL for adults should be re-evaluated. To update the literature base to re-evaluate setting the Mg UL, a PubMed search was conducted to identify intervention studies published between 1997 and 2022 that used single-ingredient Mg products reporting a priori diarrhea adverse events among adults. The Food and Drug Administration Center for Food Safety and Adverse Event Reporting System (CAERS) was also searched for adverse events caused by Mg supplementation. The PubMed search identified 10 studies, including 5 meta-analyses and 5 randomized controlled trials, that met the search criteria. Seven studies (Mg intakes of 128-1200 mg/d) found no significant differences in diarrhea occurrence between the intervention and control groups. One meta-analysis found only minor differences in gastrointestinal disturbances between groups given placebo versus 520 mg Mg/d, but withdrawals were not significantly different between groups. Another meta-analysis found that 3 of 13 studies (120-973 mg/d) reported diarrhea that led to study withdrawal, but the treatment arm was not specified in 2 studies. The CAERS search, when limited to single-ingredient suspect Mg products, found only 40 attributable cases of gastrointestinal adverse events. Only one-third of these 40 cases noted a complaint of diarrhea. These updated data indicate that doses above the current UL for Mg supplements can be consumed without adverse events.

Boric Acid Reverses Nicotine-Induced Cytokine Expressions of Human Gingival Fibroblasts.

Nicotine, the major bioactive ingredient in tobacco, is a major risk factor for periodontal disease and destruction. Nicotine has been shown to stimulate the production of cytokines that are priming agents for inflammation that induces tissue destruction, such as IL-1ß, IL-6, and IL-8, by gingival keratinocytes and human gingival fibroblasts (HGF). Boron as boric acid has been found to decrease pro-inflammatory cytokines and increase anti-inflammatory cytokines in cells with inflammatory stress. Thus, a study was performed to determine whether boric acid reverses negative effects of nicotine on human gingival fibroblasts (HGFs). The viability and cytokine expressions of HGFs cultured for 24 and 72 h in control medium with no nicotine or boric acid added and in media containing only nicotine, only boric acid, or a combination of BA and nicotine were determined. Nicotine in concentrations of 10-1, 10-2, 10-3,10-4, 10-5, and 10-6 mM significantly reduced cell viability compared to the control. Boric acid at 10 and 50 ng/mL in the media partially restored and 100 ng/mL in the media fully restored the nicotine-depressed HGF cell viability to the same level as the control group. Nicotine elevated the expression of pro-inflammatory cytokines TNF-α, IL-1ß, IL-6, IL-8, and IL-17 and decreased the anti-inflammatory IL-10 in HGFs at 24 and 72 h. Boric acid at 100 ng/mL in the medium prevented the changes induced by nicotine alone. The findings indicate that boric acid can inhibit or reverse nicotine-induced pathology in periodontal tissue and thus may help maintain oral and periodontal health in tobacco users.

Nail Mineral Composition Changes Do Not Reflect Bone Mineral Changes Caused by Boron Supplementation.

Nails have been found to be a non-invasive and readily available tissue whose mineral content can change because of a change in dietary mineral intake. Thus, this study was undertaken to determine whether boron (B) supplementation would change the concentrations of some mineral elements in nails and whether these changes correlated with changes induced in bone. Female New Zealand White rabbits (aged 8 months, 2-2.5 kg weight) were fed a grain-based, high-energy diet containing 3.88 mg B/kg. The rabbits were divided into four treatment groups: controls receiving no supplemental B (N: 7; C) and three groups supplemented with 30 mg B/L in drinking water as borax decahydrate (Na2B4O7∙10H2O, N: 10; BD), borax anhydrous (Na2B4O7, N: 7; Bah), and boric acid (H3BO3, N: 7; BA). Boron, calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), phosphorus (P), potassium (K), sodium (Na), sulfur (S), and zinc (Zn) concentrations in nails were determined by inductively coupled plasma atomic emission spectroscopy. Parametric and non-parametric multiple group comparisons and post hoc tests were performed and whether a correlation between nail and tibia and femur mineral elements concentrations were determined. A p-value of < 0.05 was considered statistically significant. Boron was not detectable in control nails but was found in the nails of the three B supplemented groups. Boron supplementation markedly increased the Ca concentration in nails with the effect greatest in the BA and BD groups. The P and Mg concentrations also were increased by B supplementation with the effect most marked in the BA group. In contrast, B supplementation decreased the Na concentration with the effect most noticeable in the BD and Bah groups. The Zn concentration in nails was not affected by BA and BD supplementation but was decreased by Bah supplementation. Boron supplementation did not significantly affect the concentrations of Cu, Fe, Mo, K, and S in nails. No meaningful significant correlations were found between nail mineral elements and tibia and femur mineral elements found previously. Nails can be an indicator of the response to boron supplementation but are not useful to indicate changes in mineral elements in bone in response to B supplementation.

Borate and boric acid supplementation of drinking water alters teeth and bone mineral density and composition differently in rabbits fed a high protein and energy diet.

The reported beneficial effects of boron on mineralized tissues in animals and humans vary. Thus, a study was performed to assess whether the variability was the result of different forms of boron supplementation, method of supplementation, and increased adiposity of the rabbit experimental model. Thirty-one female New Zealand White rabbits, (aged 8 months, 2-2.5 kg weight) were fed a grain-based high energy diet containing 11.76 MJ/kg (2850 kcal/kg) and 3.88 mg boron/kg. The rabbits were randomly divided into four treatment groups: Control group was not supplemented with boron (n:7; C), and three groups supplemented with 30 mg boron/L in drinking water in the forms of borax decahydrate (Na2O4B7 10H2O, n:10; BD), borax anhydrous (Na2O4B7, n:7; Bah) or boric acid (H2BO3, n:7; BA). Cone beam micro computed tomographic (micro-CT), histological and elemental analysis was used to evaluate the bones/teeth. Results of the experiments demonstrated that boron supplementation had beneficial effects on mineralized tissue but varied with the type of treatment. Mineral density of the femur was increased by the Bah and BA treatments (p < 0.001), but only BA increased mineral density in the tibia (p = 0.015). In incisor teeth, mineral density of dentin was increased by all boron treatments (p < 0.001), and mineral density of enamel was increased by the BD and Bah treatments. Mineral analysis found that all boron treatments increased the boron concentration in tibia and femur. In the tibia, both the BD and Bah treatments decreased the iron concentration, and the BD treatment decreased the magnesium concentration. Sodium and zinc concentrations in the tibia were decreased by the Bah and BA treatments. The boron treatments did not significantly affect the calcium, copper, molybdenum, potassium phosphorus, and sulfur concentrations. The findings show that boron supplementation can have beneficial effects on mineralized tissues in an animal model with increased adiposity, which is a model of increased inflammatory stress. However, this effect varies with the form of boron supplemented, the method of supplementation, and the mineralized tissue examined.

Voluntary running of defined distances alters bone microstructure in C57BL/6 mice fed a high-fat diet.

Obesity increases the risk for pathological conditions such as bone loss. On the other hand, physical exercise reduces body adiposity. To test the hypothesis that physical activity improves bone quality, we evaluated voluntary running of defined distances on trabecular and cortical microstructure in mice fed a high-fat diet (HFD). Sedentary mice were fed the standard AIN93G diet or the HFD. Mice fed the HFD remained sedentary or were assigned to unrestricted running or 75%, 50%, and 25% of unrestricted running with an average running activity at 8.3, 6.3, 4.2, and 2.1 km per day, respectively. The bone structural differences found in sedentary mice were that HFD, compared with the AIN93G diet, resulted in a lower bone volume fraction (BV/TV) and a higher structure model index (SMI) in vertebrae. Running had a greater effect on trabecular microstructure in femurs than in vertebrae; the decrease in SMI and an increase in trabecular thickness (Tb.Th) were in dose-dependent manners. Running was positively correlated with BV/TV and Tb.Th and inversely correlated with SMI in femurs. The HFD increased plasma concentrations of tartrate-resistant acid phosphatase 5b, a marker of bone resorption, in sedentary mice, while running decreased it in a dose-dependent manner. The findings show that voluntary running improves bone quality in young adult mice fed an HFD. Novelty: The high-fat diet alters bone microstructure by increasing bone resorption. Quantitative voluntary running improves bone microstructure through its attenuation of bone resorption in mice fed a high-fat diet.

Boron as Boric Acid Induces mRNA Expression of the Differentiation Factor Tuftelin in Pre-Osteoblastic MC3T3-E1 Cells.

The effects of boron on the formation and maintenance of mineralized structures at the molecular level are still not clearly defined. Thus, a study was conducted using MC3T3-E1 cells to determine whether boron affected mRNA expressions of genes associated with bone/alveolar bone formation around the teethMC3T3-E1 (clone 4) cells were cultured in media treated with boric acid at concentrations of 0, 0.1, 10, 100, or 1000 ng/ml. Total RNAs of each group were isolated on day 3. Gene expression profiles were determined by using RT2 Profiler PCR micro-array that included 84 genes associated with osteogenic differentiation. Tuftelin1 mRNA expression was upregulated by all boron treatments. The upregulation was confirmed by quantitative RT-PCR using the tuftelin probe. While 100 ng/ml had no effect on the integrin-α2 (Itga2) transcript and 1 ng/ml boric acid induced Itga2 mRNA expression (2.1-fold), 0.1, 10, and 1000 ng/ml boric acid downregulated the integrin-α2 gene transcript 2.2-, 1.5-, and 2.1-fold respectively. While 0.1 ng/ml boric acid induced BMP6, increased BMP1r mRNA expression (1.5 fold) was observed in 1000 ng/ml boric acid treatment. The findings suggest that boron affects the regulation of the tuftelin1 gene in osteoblastic cells. Further studies are needed to establish that the beneficial actions of boron on alveolar bone and tooth formation and maintenance include an effect on the expression of the tuftelin1 gene.

Dietary Selenium Supplementation Does Not Attenuate Mammary Tumorigenesis-Mediated Bone Loss in Male MMTV-PyMT Mice.

Bone wasting occurs during the progression of breast cancer and contributes to breast cancer mortality. We evaluated the effect of methylseleninic acid (MSeA), an anti-carcinogenic form of selenium, on bone microstructural changes in the presence of mammary tumors in a male breast cancer model of mouse mammary tumor virus-polyomavirus middle T-antigen (MMTV-PyMT). In this study, we performed microcomputed tomographic analysis of femurs and vertebrae collected from a study showing that dietary supplementation with MSeA reduces mammary tumorigenesis in male mice. Compared to age-matched, non-tumor-bearing mice (MMTV-PyMT negative), the presence of mammary tumors significantly reduced the bone volume fraction, trabecular thickness, and bone mineral density while it increased the structure model index in femurs, but not in vertebrae. Moreover, mammary tumorigenesis decreased plasma concentrations of osteocalcin. Supplementation with MSeA did not affect these changes in MMTV-PyMT mice. In conclusion, mammary tumorigenesis caused bone loss in MMTV-PyMT mice. However, dietary supplementation with MSeA did not attenuate mammary tumor-associated bone loss in this model of male breast cancer.

The Association Between Some Macro and Trace Elements in Saliva and Periodontal Status.

Changes in the macro and trace element composition of saliva might be indicative for pathological changes in periodontal tissues. However, there is a lack of evidence in the literature showing associations between mineral elements and periodontal status. The aim of this study was to determine whether such associations occur. Totally, 190 systemically healthy non-smoker participants (mean age 32.2 ± 6.02; 50 periodontally healthy, 50 gingivitis, 50 chronic periodontitis, and 40 aggressive periodontitis individuals) were included in this cross-sectional study. Salivary levels of some macro and trace elements were measured by using inductively coupled plasma mass spectrometry (ICP-MS). Kruskal-Wallis's test was used for statistical analysis. Statistically significant differences were found in sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), vanadium (V), chromium Cr), manganese (Mn), iron (Fe), rubidium (Rb), strontium (Sr), and selenium (Se) concentrations among the groups. Significant increases in the essential minerals Na, Mg, K, Ca, Fe, and Se occurred in both periodontitis groups when compared to the gingivitis and periodontally healthy groups. Lower Se, Sr, Fe, Mn, and V concentrations were found in the aggressive periodontitis group than in the chronic periodontitis group. The results of this study demonstrated that assessment of mineral element concentrations in saliva might be useful in assessing periodontal health and disease. However, further studies are required to determine whether the change in a specific mineral element is the result of periodontal disease or is involved in its pathogenesis.

The Problematic Use of Dietary Reference Intakes to Assess Magnesium Status and Clinical Importance.

Determination of the public health concern about magnesium (Mg) in health and disease has been confounded by the lack of a practical measure of status. This has resulted in a lack of consistency in associating Mg deficiency with specific pathological conditions. Some attempts at associating Mg with a chronic disease have used the Dietary Reference Intakes (DRIs) as a status assessment measure. Use of current DRIs for Mg is problematic because recent evidence suggests that they should be updated and based on body weight. An evidence-based suggested Estimated Average Requirement (EAR) and Recommended Dietary Allowance (RDA) for a 70-kg individual is 175 and 250 mg/day, respectively. However, numerous dietary and physiological factors can affect the need for Mg and thus affect the use of the current or suggested new DRIs to assess Mg status. Calcium intakes above normal requirements can decrease Mg balance and exacerbate signs of Mg deficiency. Mg deficiency apparently occurs often in obesity because of increased need to counteract the inflammatory stress induced by adipose tissue dysfunction. Deficiency in anti-oxidant nutrients such as vitamin E and selenium can exacerbate a response to low dietary Mg indicated by increased oxidative stress which can lead to chronic disease. Dietary modifiers of Mg absorption and excretion affect balance and thus the need for Mg. Factors decreasing Mg balance include low dietary protein and non-fermentable fiber, while factors that can increase balance include fructose and fermentable fiber and fructose-containing oligosaccharides. Use of the DRIs to assess the Mg status of a population or group needs to consider their physiological characteristics and dietary habits and be aware that the DRIs may need updating. The DRIs only can be considered a component of a toolbox that presently includes serum Mg concentration and the daily urinary Mg excretion to assess the Mg status of an individual.

Effects of Nutritional Deficiency of Boron on the Bones of the Appendicular Skeleton of Mice.

Scientific evidence has shown the nutritional importance of boron (B) in the remodeling and repair of cancellous bone tissue. However, the effects of the nutritional deficiency of B on the cortical bone tissue of the appendicular skeleton have not yet been described. Thus, a study was performed to histomorphometrically evaluate the density of osteocyte lacunae of cortical bone of mouse femora under conditions of nutritional deficiency of B and to analyze the effects of the deficiency on the biomechanical properties of mouse tibiae. Weaning, 21-day-old male Swiss mice were assigned to the following two groups: controls (B+; n = 10) and experimental (B-; n = 10). Control mice were fed a basal diet containing 3 mg B/kg, whereas experimental mice were fed a B-deficient diet containing 0.07 mg B/kg for 9 weeks. The histological and histomorphometric evaluations of the mice fed a B-deficient diet showed a decrease in the density of osteocyte lacunae in the femoral cortical bone tissue and the evaluation of biomechanical properties showed lower bone rigidity in the tibia.

Dietary Magnesium and Chronic Disease.

Although official magnesium (Mg) dietary reference intakes are open to question, a significant number of adults likely have intakes that are in the range of 50%-99% of the requirement. This moderate or marginal (subclinical) deficient Mg intake generally is asymptomatic. Animal studies, however, indicate that moderate or subclinical Mg deficiency primes phagocytic cells for the release of proinflammatory cytokines leading to chronic inflammatory and oxidative stress. Human studies have found that dietary Mg is inversely related to serum or plasma C-reactive protein (CRP). Individuals with apparently deficient Mg intakes have an increased likelihood of serum or plasma CRP ≥3.0 mg/L, considered an indicator of chronic inflammatory stress that increases the risk for chronic disease. In addition, elevated serum or plasma CRP in individuals with chronic disease is decreased by Mg supplementation, which suggests that Mg decreases the risk for chronic disease. The importance of dietary Mg intake on the risk for chronic disease through affecting inflammatory and oxidative stress is supported by numerous meta-analyses and systematic reviews that have found dietary Mg is inversely associated with chronic diseases such hypertension, ischemic heart disease, stroke, metabolic syndrome, diabetes, and colorectal cancer.

The History and Future of Dietary Guidance in America.

Evidence-based dietary guidance in the United States has progressed substantially since its inception >100 y ago. This review describes the historical development and significance of dietary guidance in the United States, including the Dietary Guidelines for Americans (DGAs), and emphasizes the foundations upon which they were developed, the process in the formation of past and current guidelines, and present and future applications. Dietary guidance during the first half of the 20th century was focused primarily on food groups in a healthy diet, food safety, safe food storage, and the role of some minerals and vitamins in the prevention of disease. This was punctuated by World War II messaging to reduce food waste and increase food storage. In 1980, the first DGA report was released, and later, the USDA and the Department of Health and Human Services (HHS) were given a mandate for reissuance and reassessment every 5 y. An ad hoc advisory committee made up of nongovernmental experts was established for each edition to review the scientific evidence and provide content recommendations to the Secretaries of the USDA and the HHS. Wording was changed from negative (avoid) to positive (choose) and emphasis was increasingly placed on reducing the prevalence of overweight and obesity and prevention of chronic diseases. Today, the DGAs guide all federally funded feeding and educational programs, including food policies, food assistance programs, and consumer education programs, as well as these programs at the regional, state, and local levels. Additional users include dietitians and other health professionals, food service personnel, food and beverage manufacturers, schools, and day care facilities. Currently, the DGAs are intended for individuals aged ≥2 y. Future editions of the DGAs will include guidance for infants and children <2 y, as well as pregnant women.