Parameters of oxidative stress in saliva from patients with aggressive and chronic periodontitis.

OBJECTIVES: Free radicals play an important role in the onset and progression of many diseases. The aim of this study was to investigate the contribution of oxidative stress in the pathology of aggressive (AgP) and chronic (CP) periodontitis and its relation with the clinical periodontal status. METHODS: Eighty subjects were divided into two groups: 20 patients with AgP and 20 patients with CP with their 20 corresponding matched controls, based on clinical attachment loss (CAL), probing pocket depth (PPD), and bleeding on probing (BOP). Saliva reactive oxygen species (ROS), lipid peroxidation, and non-enzymatic antioxidant defences were measured by luminol-dependent chemiluminescence assay, as thiobarbituric acid-reactive substances (TBARs) and total radical-trapping antioxidant potential (TRAP), respectively. Pearson's correlation and multivariate analysis were used to determine the relationship between ROS and TBARs and the clinical parameters. RESULTS: ROS and TBARs were increased in AgP while TRAP was decreased, comparing with CP. In AgP, a strong and positive correlation was observed between ROS and TBARs and they were closely associated with CAL and PPD. DISCUSSION: In AgP, but not in CP, oxidative stress is a high contributor to periodontal pathology and it is closely associated with the clinical periodontal status.

Inflammation triggers constitutive activity and agonist-induced negative responses at M(3) muscarinic receptor in dental pulp.

The purpose of this study was to investigate whether the inflammation of rat dental pulp induces the muscarinic acetylcholine receptor (mAChR) constitutive receptor activity. Pulpitis was induced with bacterial lipolysaccharide in rat incisors dental pulp. Saturation assay with [(3)H]-quinuclidinyl benzilate ([(3)H] QNB), competitive binding with different mAChR antagonist subtypes, and nitric oxide synthase (NOS) activity were performed. A drastic change in expression and response to mAChR subtypes was observed in pulpitis. Inflamed pulp expressed high number of M(3) mAChR of high affinity, whereas the M(1) mAChR is the main subtype displayed in normal pulp. Consistent with the identification of the affinity constant (Ki) of M(3) and Ki of M(1) in both pulpitis and in normal pulps are the differences in the subtype functionality of these cells. In pulpitis, pilocarpine (1 × 10(-11) mol/L to 5 × 10(-9) mol/L) exerted an inhibitory action on NOS activity that was blocked by J 104129 fumarate (highest selective affinity to M(3) mAChR). In normal pulps, pilocarpine (1 × 10(-11) mol/L to 5 × 10(-9) mol/L) has no effect. NOS basal activity was 5.9 times as high in pulpitis as in the normal pulp as a result of the activation of inducible NOS. The irreversible pulpitis could induce a mAChR alteration, increasing the high-affinity receptor density and transduction-coupling efficiency of inducible NOS activity, leading to a spontaneously active conformation of the receptor. Pilocarpine acting as an inverse agonist might be useful therapeutically to prevent necrosis and subsequent loss of dental pulp.

Cholinoceptor modulation on nitric oxide regulates prostaglandin E(2) and metalloproteinase-3 production in experimentally induced inflammation of rat dental pulp.

The purpose of this study was to investigate the role of muscarinic acetylcholine receptor (mAChR) activity in the regulation of inducible nitric oxide synthase (iNOS) activity, prostaglandin E(2) (PGE(2)), and metalloproteinase-3 (MMP-3) in experimentally induced inflammation of rat incisors dental pulp. Inflammation was induced by application of bacterial lipopolysaccharide (LPS) to the pulp. Extirpated pulp tissue samples were incubated in saline solution until the various experiments were performed. Saline-treated pulp and healthy pulp were used as controls. NOS activity was measured by the production of [U-(14)C]-citrulline from [U-(14)C]-arginine. PGE(2) and MMP-3 production were evaluated by an enzyme-linked immunosorbent assay (ELISA) and cyclooxygenase (cox-1 and cox-2) messenger RNA levels were measured using a reverse-transcriptase polymerase chain reaction by coamplification of target complementary DNA with a single set of primers. The application of LPS to the pulp increased NOS activity, PGE(2), and MMP-3 production associated with iNOS overactivity. Moreover, PGE(2) and MMP-3 production were the result of cox-2 expression. Pilocarpine (5 x 10(-11) mol/L to 5 x 10(-9) mol/L), acting on mAChRs, triggered a negative effect on NOS activity, PGE(2), and MMP-3 production. In control pulp, no action of pilocarpine was observed. Pulpitis changed mAChR conformation, increasing its coupling efficiency to transducing molecules that in turn activate iNOS. The capacity of pilocarpine to prevent iNOS activity, PGE(2), and MMP-3 by acting on mAChR mutation induced by pulpitis might be useful therapeutically as a local treatment.

Anti-brain cholinergic auto antibodies from primary Sjögren syndrome sera modify simultaneously cerebral nitric oxide and prostaglandin biosynthesis.

The presence of circulating antibodies from primary Sjögren Syndrome (pSS) patients enable to interact with rat cerebral frontal cortex by activating muscarinic acetylcholine receptors (mAChR). ELISA assay for PGE2 generation, nitric oxide synthase (NOS) activity was measured in cerebral frontal cortex slices by production of [U-14C]-citruline and mRNA isolation/quantitative PCR for COX-1 and COX-2 gene expression were carried out. By ELISA assay, it was shown that IgG from pSS patients reacted to cerebral frontal cortex cell surface and with human M1 and M3 mAChR. Beside pSS IgG displayed an agonistic-like activity stimulating NOS activity and PGE2 production associated with an increased COX-1 mRNA gene expression, without affecting COX-2 mRNA levels. Inhibition of phospholipase A2 (PLA2) and NOS prevented pSS IgG effects upon both PGE2 production and COX-1 mRNA levels. The results support the notion that serum IgG auto antibodies in pSS patients target cerebral mAChR may have pathogenic role in immune neuroinflammation and on cognitive dysfunction present in pSS patients.