Maternal Periodontal Disease in Rats Decreases Insulin Sensitivity and Insulin Signaling in Adult Offspring

Effect of maternal true combined endodontic-periodontal lesion on insulin and inflammatory pathway in adult offspring

BACKGROUND

Maternal periodontal disease (PED) and apical periodontitis (AP) are associated insulin resistance (IR), increased tumor necrosis factor-α (TNF-α) levels, and alterations in insulin signaling (IS) in the gastrocnemius muscle (GM) of adult offspring. TNF-α stimulates I kappa B kinase (IKK) and c-Jun N-terminal protein kinase (JNK), resulting in IS attenuation. However, studies that investigated the maternal true endodontic-periodontal lesion (EPL) in offspring are scarce, and in this case, the impact could be even higher. This study aimed to evaluate the effects of EPL on the IR, IS, and inflammatory pathways on the offspring GM.

METHODS

Female Wistar rats were distributed into control, AP, PED, and EPL groups. After 30 days of oral inflammation induction, rats from all groups were allowed to mate with healthy rats. The bodyweight of the offspring was assessed from birth to 75 days of age. After 75 days, the following measurements were performed: glycemia, insulinemia, IR, TNF-α content, and IKKα/β, JNK, pp185 (Tyr), and IRS-1 (Ser) phosphorylation status in the GM.

RESULTS

Maternal PED and EPL were associated with low birth weights. All maternal oral inflammations promoted IR and IS impairment in the GM and only maternal PED and EPL caused an increase in TNF-α content and IKKα/β phosphorylation status in the GM of offspring. The EPL-o group showed worsening of metabolic changes when compared to offspring of rats with AP or PED.

CONCLUSION

Association of maternal AP and PED promoted a more pronounced worsening in the health of the adult offspring. This article is protected by copyright. All rights reserved.

Association between Maternal Periodontitis and Development of Systematic Diseases in Offspring

Periodontal disease (PD) is one of the most common oral conditions affecting both youths and adults. There are some research works suggesting a high incidence of PD in pregnant women. As an inflammatory disease of bacterial origin, PD may result in the activation of the pathways affecting the course and the pregnancy outcome. The authors, based on the literature review, try to answer the PICO question: Does maternal periodontitis (exposure) influence the incidence of complications rates in pregnancy and the development of systemic diseases in childhood and adult offspring (outcome) in the humans of any race (population) compared to the offspring of mothers with healthy periodontium (comparison)? The authors try to describe the molecular pathways and mechanisms of these interdependencies. There is some evidence that maternal periodontitis may affect the pregnancy course and outcome, resulting in preeclampsia, preterm delivery, vulvovaginitis and low birth weight. It can be suggested that maternal periodontitis may affect offspring epigenome and result in some health consequences in their adult life.

Effect of maternal apical periodontitis on the final step of insulin signalling and inflammatory pathway in the adult male offspring of rats

AIM

To evaluate the final step of insulin signalling, inflammatory pathway (related to the inhibition of insulin signalling), peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) protein content and DNA methylation in the Slc2a4 gene promoter region in the skeletal muscle of adult male offspring of rats with apical periodontitis (AP) in a single tooth or in four teeth.

METHODOLOGY

Female Wistar rats were distributed into three groups: a control group, a group with one tooth with AP and a group with four teeth with AP. Thirty days after induction of AP, female rats from all groups were mated with healthy male rats. When male offspring reached 75 days of age, the following analyses were performed in the gastrocnemius muscle (GM): insulin-stimulated Akt serine and threonine phosphorylation status; NF-κB p50 and p65 subunits phosphorylation status; GLUT4, TNF-α and PGC-1α protein content by Western blotting; GLUT4 and TNF-α gene expression by real-time polymerase chain reaction (PCR); and DNA methylation in the Slc2a4 gene promoter region by restriction digestion and real-time PCR. Analysis of variance was performed, followed by Tukey's post hoc test. p values <.05 were considered to be statistically significant.

RESULTS

Maternal AP in four teeth decreased insulin-stimulated Akt serine and threonine phosphorylation status, reduced GLUT4 gene expression and its protein content, and increased NF-κB p50 and p65 subunits phosphorylation status in the GM of adult offspring. There were no alterations in the parameters analysed in the GM of adult offspring of rats with AP in a single tooth. In addition, maternal AP did not affect TNF-α gene expression and its protein content, PGC-1α protein content and DNA methylation in the Slc2a4 gene promoter region in the GM of adult offspring.

CONCLUSIONS

Maternal AP in four teeth was associated with impairment in the final step of insulin signalling in the GM of adult male offspring in rats. An increase in NF-κB activity may be involved in this decrease in insulin signalling. This study demonstrates the impact of maternal AP on the health of offspring, demonstrating the importance of maintaining adequate maternal oral health to prevent diseases in adult offspring in rats.

Maternal Apical Periodontitis Increases Insulin Resistance and Modulates the Antioxidant Defense System in the Gastrocnemius Muscle of Adult Offspring

INTRODUCTION

Maternal apical periodontitis (AP) is associated with insulin resistance (IR) in adult offspring. Oxidative stress has been linked to IR. This study investigated insulin sensitivity (IS) and oxidative stress in the gastrocnemius muscle (GM) of adult offspring of rats with AP.

METHODS

Fifteen female Wistar rats were distributed into a control group, a group with 1 tooth with AP, and a group with 4 teeth with AP. Thirty days after AP induction, female rats were mated with healthy male rats. When male offspring reached 75 days of age, glycemia, insulinemia, and IS were determined. In the GM, the oxidative damage products (thiobarbituric acid reactive substances and carbonyl protein) and activities of enzymatic (superoxide dismutase, catalase, and glutathione peroxidase) and nonenzymatic (glutathione and total antioxidant capacity) antioxidants were quantified. Analysis of variance was performed followed by the Tukey post hoc test (P < .05).

RESULTS

Maternal AP was associated with decreased IS and changes in antioxidant activities (reduced superoxide dismutase and increased catalase, glutathione peroxidase, and glutathione) and decreased thiobarbituric acid reactive substance concentration in the GM of their adult offspring. However, maternal AP does not appear to affect glycemia, carbonyl protein concentration, and the nonenzymatic total antioxidant capacity in the GM of this offspring.

CONCLUSIONS

Maternal AP modulates the antioxidant defense system in the GM of their adult offspring, attenuating lipid peroxidation in this tissue. This reflects part of an adaptive response of the offspring to the stimulation of the maternal chronic oral inflammatory process in which the organism acts by decreasing oxidative tissue damage in the postnatal stage. The present study improves knowledge about the impact of maternal oral inflammation on healthy offspring.

Association between periodontal condition and the development of type 2 diabetes mellitus-Results from a 15-year follow-up study

AIM

To study whether periodontal condition is associated with the development of type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

A population-based follow-up study was conducted among persons born in 1935 and living in the city of Oulu, Finland (n = 395). The baseline examinations were done during 1990-1992, and the follow-up examinations were done during 2007-2008. The data were gathered by questionnaires, laboratory tests and clinical measurements. Poisson regression models were used in the data analyses.

RESULTS

The adjusted rate ratios (RR) with 95% confidence intervals (95% CI) for the incident T2DM among subjects with 4-5 mm deep periodontal pockets (n = 98), among subjects with 6 mm deep or deeper periodontal pockets (n = 91), and among edentulous subjects (n = 118) were 1.32 (95% CI: 0.69-2.53), 1.56 (95% CI: 0.84-2.92) and 1.00 (95% CI: 0.53-1.89), respectively, compared to dentate subjects without deepened (4 mm deep or deeper) periodontal pockets (n = 88). The adjusted RR per site (the number of sites with deepened periodontal pockets as a continuous variable) was 1.02 (95% CI: 1.00-1.04).

CONCLUSIONS

Poor periodontal condition may be a predictor of the development of T2DM. However, the causality between periodontal condition and the development of T2DM remains uncertain.

Melatonin promotes reduction in TNF levels and improves the lipid profile and insulin sensitivity in pinealectomized rats with periodontal disease

AIM

This study aimed to investigate the effects of melatonin (ME) on insulin resistance (IR) and signaling (IS), proinflammatory cytokine levels, and lipid profiles in pinealectomyzed (PNX) rats with periodontal disease (PD).

MAIN METHODS

One hundred and forty-four rats (age = 40 days) were distributed into 8 groups: 1) control (CN); 2) PD only; 3) PNX only; 4) PNX and PD (PNXPD); 5) CN treated with ME (CNM); 6) PD treated with ME (PDM); 7) PNX treated with ME(PNXM); 8) PNX and PD treated with ME(PNXPDM). The PNX groups were subjected to pinealectomy at 40 and at 60 days of age. The animals were then subjected to PD induction in the mandibular first molars. After PD induction, the ME replacement therapy (MERT-5 mg/kg body weight) was performed using water for 28 days. After this period, the plasma concentration of glucose, insulin, TNF, IL-6, triglycerides, total cholesterol, HDL-cholesterol, LDL-cholesterol, and VLDL-cholesterol and the HOMA-IR index were determined. Akt serine phosphorylation status in the white adipose tissue, gastrocnemius muscle, and rat liver were also evaluated.

KEY FINDINGS

PD, PNX, and PNXPD groups showed an increase in IR with elevated plasma levels of insulin and TNF compared to CN group. PNX and PNXPD groups presented alteration in lipid profile compared to CN group. MERT improved all of the analyzed parameters. No difference was observed in the IS among different groups.

SIGNIFICANCE

The results suggest that MERT efficiently prevents IR, improves lipid profile, and increases plasma levels of insulin and TNF in PD and PNX rats.

Relationship among Periodontal Disease, Insulin Resistance, Salivary Cortisol, and Stress Levels during Pregnancy

Pregnancy is a period involving important metabolic changes that enable the maintenance of the mother's health and development of the fetus. This study aimed to assess the relationship among periodontal disease, insulin resistance, salivary cortisol concentration and level of perceived stress in pregnant women. This was a cross-sectional study. The sample comprised 96 pregnant women between the fifth and seventh month of pregnancy registered at the Basic Health Units of the Unified Health System (SUS). The periodontal condition was assessed after obtainment free and informed consent from the participants. Participants were divided into three groups: control subjects with a healthy periodontal condition (CN; n=46), patients with gingivitis (GI; n=26), and patients with periodontitis (PI; n=24). Saliva and blood samples were collected for evaluation of salivary cortisol concentration, glycemia, insulinemia and Homeostasis Model Assessment-Insulin Resistance index. A validated survey for the assessment of perceived stress levels was also performed. PI group showed significantly higher (p<0.05) blood glucose levels (CN: 4.43±0.05; GI: 4.46±0.04; PI: 4.68±0.08), insulinemia (CN: 6.93±0.45; GI: 8.87±0.79; PI: 12.77±1.30), insulin resistance (CN: 1.40±0.10; GI: 1.81±0.18; PI: 2.66±0.29) compared with the CN and GI groups. The levels of perceived stress were higher (p<0.05) in PI and GI groups when compared to CN group (CN: 20.5±1.26; GI: 25.8±1.95; PI: 26.6±1.36). There was no significant difference in the concentration of salivary cortisol between the groups (CN: 11.13±0.58; GI: 11.96±0.74; PI: 11.47±0.74). It was concluded that there is a relationship between higher levels of perceived stress, insulin resistance and the occurrence of periodontal disease during pregnancy. This study emphasizes the importance of preventing periodontitis in order to avoid insulin resistance and stress during pregnancy since these can cause systemic complications for the mother and the fetus.

Effect of Sodium Fluoride on Bone Biomechanical and Histomorphometric Parameters and on Insulin Signaling and Insulin Sensitivity in Ovariectomized Rats

Osteoporosis is a systemic disease characterized by bone degradation and decreased bone mass that promotes increased bone fragility and eventual fracture risk. Studies have investigated the use of sodium fluoride (NaF) for the treatment of osteoporosis. However, fluoride can alter glucose homeostasis. The aim of this study was to evaluate the effects of NaF intake (50 mg/L) from water on the following parameters of ovariectomized (OVX) rats: (1) tyrosine phosphorylation status of insulin receptor substrate (pp185 (IRS-1/IRS-2)) in white adipose tissue; (2) insulin sensitivity; (3) plasma concentrations of glucose, insulin, total cholesterol, triglyceride, TNF-α, IL-6, osteocalcin, calcium, and fluoride; (4) bone density and biomechanical properties in the tibia; and (5) tibia histomorphometric analysis. Fifty-two Wistar rats (2 months old) were ovariectomized and distributed into two groups: control group (OVX-C) and NaF group (OVX-F), which was subjected to treatment with NaF (50 mg/L) administered in drinking water for 42 days. The chronic treatment with NaF promoted (1) a decrease in pp185 (IRS-1/IRS-2) tyrosine phosphorylation status after insulin infusion in white adipose tissue and in insulin sensitivity; (2) an increase in the plasma concentration of insulin, fluoride, osteocalcin, calcium, triglyceride, VLDL-cholesterol, TNF-α, and IL-6; (3) a reduction in the trabecular width, bone area, stiffness, maximum strength, and tenacity; (4) no changes in body weight, food and water intake, plasma glucose, total cholesterol, HDL-cholesterol, LDL-cholesterol, bone mineral content, and bone mineral density. It was concluded that chronic treatment with NaF (50 mg/L) in OVX rats causes a decrease in insulin sensitivity, insulin signaling transduction, and biochemical, biomechanical, and histomorphometric bone parameters.