Changes in Oral Health and Dental Esthetic in Smokers Switching to Combustion-Free Nicotine Alternatives: Protocol for a Multicenter and Prospective Randomized Controlled Trial.

BACKGROUND: Although the detrimental effects of conventional combustible cigarettes on oral health and dental esthetics are well known, there is limited information about the long-term impact of combustion-free nicotine alternatives (C-F NA) such as e-cigarettes or heated tobacco products. OBJECTIVE: This multicenter, prospective, 3-parallel-arm randomized controlled trial will investigate whether switching from combustible cigarettes to C-F NA will lead to measurable improvements in oral health parameters and dental esthetics over 18 months in adult smokers with limited gum disease. METHODS: Regular smokers not intending to quit and without clinical signs of periodontitis will be randomly assigned (1:4 ratio) to either standard of care with brief cessation advice (control group; arm A) or C-F NA use (intervention group; arm B). The study will also include a reference group of never smokers (reference group; arm C). The primary end point is the change in the Modified Gingival Index (MGI) score from baseline between the control arm (arm A) and the intervention arm (arm B) at the 18-month follow-up. In addition, the study will analyze the within- and between-group (arms A, B, and C) changes in MGI assessment, plaque imaging, dental shade quantitation, tooth stain scores, and oral health-related quality of life questionnaires measured at each study time point. All participants will attend a total of 7 clinic visits: screening, enrollment, and randomization (visit 0); baseline visit-day 14 (visit 1); day 90 (visit 2); day 180 (visit 3); day 360 (visit 4); and day 540 (visit 5). This multicenter study will be conducted in 4 dental clinics in 4 countries. The statistical analysis will involve descriptive statistics for continuous and categorical data. Primary end points will undergo tests for normality and, based on distribution, either a 2-sided t test or Mann-Whitney U test. Linear mixed model with random factors center and study arms by center will also be applied. Secondary end points, including MGI assessment and quality of life, will be subjected to similar tests and comparisons. Only if one value of the parameter MGI is missing after day 1, the last available observation will be carried forward. The analysis will be performed on the substituted data. Secondary parameters will not have missing value replacement. RESULTS: Participant recruitment began in October 2021, and enrollment was completed in June 2023. Results will be reported in 2025. CONCLUSIONS: This will be the first study to provide key insights into oral health benefits or risks associated with using C-F NA in smokers who are seeking alternatives to cigarette smoking. TRIAL REGISTRATION: ClinicalTrials.gov NCT04649645; https://clinicaltrials.gov/ct2/show/NCT04649645. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/53222.

A selective reversible monoamine oxidase B inhibitor in smoking cessation: effects on its own and in association with transdermal nicotine patch.

RATIONALE: Monoamine oxidase B (MAO-B) activity is reduced in smokers. A MAO-B inhibitor alone or co-administered with nicotine may mimic the effects of smoking and be a candidate drug for smoking cessation. OBJECTIVE: This study aims to determine the efficacy and safety of EVT302, a selective reversible MAO-B inhibitor, alone and on top of nicotine patch (NP) in smoking cessation. METHODS: This was a randomised, double blind, placebo-controlled phase II, multicentre trial. Smokers (≥10 cigarettes/day) received either EVT302 (N = 145) or placebo (N = 145), or EVT302 (N = 61) or placebo (N = 61) on top of open label NP 21 mg/day for 8 weeks. The main comparison was between EVT302 and placebo without NP. The primary outcome measure was end-of-treatment 4-week continuous abstinence rate (CAR). SECONDARY OUTCOME MEASURES: point prevalence abstinence rate, saliva cotinine concentrations in the groups without NP, urge to smoke, nicotine withdrawal symptoms and assessment of subjective effects of cigarettes. RESULTS: The 4-week CAR was 15.2 % in the placebo, 17.2 % in the EVT302, 26.8 % in the NP + placebo and 32.8 % in the NP + EVT302 groups, respectively. There was no difference between EVT302 and placebo either alone (adjusted OR: 1.45, 95 % CI: 0.65-3.26) or when co-administered with NP. No statistically significant difference occurred for the secondary outcome measures. CONCLUSIONS: The selective, reversible MAO-B inhibitor EVT302 was not superior to placebo in helping smokers quit, in line with data with selegiline and confirms that MAO-B inhibitors are not effective in smoking cessation. Co-administration of NP does not provide a supplementary benefit.

Succinyl hydroxamates as potent and selective non-peptidic inhibitors of procollagen C-proteinase: design, synthesis, and evaluation as topically applied, dermal anti-scarring agents.

Succinyl hydroxamates 1 and 2 are disclosed as novel series of potent and selective inhibitors of procollagen C-proteinase (PCP) which may have potential as anti-fibrotic agents. Carboxamide 7 demonstrated good PCP inhibition and had excellent selectivity over MMPs involved in wound healing. In addition, 7 was effective in a cell-based model of collagen deposition (fibroplasia model) and was very effective at penetrating human skin in vitro. Compound 7 (UK-383,367) was selected as a candidate for evaluation in clinical studies as a topically applied, dermal anti-scarring agent.

Potent and selective nonpeptidic inhibitors of procollagen C-proteinase.

6-Cyclohexyl-N-hydroxy-3-(1,2,4-oxadiazol-5-yl)hexanamides were previously disclosed as inhibitors of procollagen C-proteinase (PCP) culminating in the identification of amide 1. Our objective was to discover a second inhibitor that would have improved affinity for PCP and to optimize properties for transepidermal delivery (TED) to intact skin. Further investigation of this template identified a number of potent PCP inhibitors (IC50 values of 2-6 nM) with improved TED flux. Sulfonamide 56 had excellent PCP enzyme activity when measured with a peptide substrate (Ki 8.7 nM) or with the endogenous substrate procollagen (IC50 3.4 nM) and demonstrates excellent selectivity over MMPs involved in wound healing (>10 000-fold). In the fibroplasia model, 56 inhibited deposition of insoluble collagen by 76 +/- 2% at 10 microM and was very effective at penetrating human skin in vitro with a TED flux of 1.5 microg/cm2/h, which compares favorably with values for agents that are known to penetrate skin well in vivo. Based on this profile, 56 (UK-421,045) was selected as a candidate for further preclinical evaluation as a topically applied, dermal anti-scarring agent.

Fibroblast invasive migration into fibronectin/fibrin gels requires a previously uncharacterized dermatan sulfate-CD44 proteoglycan.

After tissue injury, fibroblast migration from the peri-wound collagenous stroma into the fibrin-laden wound is critical for granulation tissue formation and subsequent healing. Recently we found that fibroblast transmigration from a collagen matrix into a fibrin matrix required the presence of fibronectin. Several integrins-alpha 4 beta 1, alpha 5 beta 1, and alpha v beta 3-with known fibronectin binding affinity were necessary for this invasive migration. Here we examined another family of cell surface receptors: the proteoglycans. We found that dermatan sulfate was required for fibroblast migration into a fibronectin/fibrin gel. This conclusion was based on beta-xyloside inhibition of glycanation and specific glycosaminoglycan degradation. CD44, a cell surface receptor known to bind hyaluronan, not infrequently exists as a proteoglycan, decorated with various glycosaminoglycan chains including heparan sulfate and chondroitin sulfate, and as such can bind fibronectin. We found that CD44H, the non-spliced isoform of CD44, was necessary for fibroblast invasion into fibronectin/fibrin gels. Resting fibroblasts expressed mostly nonglycanated CD44H core protein, which became glycanated with chondroitin sulfate and dermatan sulfate, but not heparan sulfate, after a 24 h incubation with platelet-derived growth factor, the stimulus used in the migration assay. These results demonstrate that dermatan sulfate-CD44H proteoglycan is essential for fibroblast migration into fibrin clots and that platelet-derived growth factor, the stimulus for migration, induces the production of chondroitin-sulfate- and dermatan-sulfate-glycanated CD44H.

Fibroblast migration on fibronectin requires three distinct functional domains.

Mesenchymal cell movement is normally constrained; however, fibronectin can provide a pathway for stromal cell migration during embryogenesis, morphogenesis, and wound healing. Cells can adhere to fibronectin via integrin and nonintegrin receptors, which bind multiple unique peptide sequences. Synthetic peptides and recombinant proteins were used to delineate the functional domains needed for human fibroblast migration over fibronectin. The 9th and 10th fibronectin type III repeats, which contain RGD and PHSRN synergy cell attachment sequences, support almost maximal fibroblast attachment, but not migration of primary dermal fibroblasts. Specific sequences within the heparin domain and the IIICS region are also required for migration. These findings predict and additional data confirm the necessity for the cooperation of multiple integrin and nonintegrin receptors for fibroblast migration on fibronectin. Such stringency of migration most likely imposes an immense constraint on normal mesenchymal cell mobility in unperturbed tissue. Loss of such restraint may be critical for the migration cancer cells through the extracellular matrix.

Increased skin collagen extractability and proportions of collagen type III are not normalized after 6 months healing of human excisional wounds.

In an attempt to identify potential staging markers of effective healing, changes in connective tissue properties were measured in a human skin excisional wound healing model in which tissue was re-excised at intervals up to 6 months after injury. The proportion of collagen III relative to collagen I increased significantly (p<0.001) up to 6 weeks after initial injury and remained elevated up to 6 months, at which time the proportion of collagen III was 70% above baseline values. Extractability of biopsy tissue collagen by pepsin increased significantly throughout the study (baseline, 32.8+/-6.8%; 6 months, 89.1+/-8.9%), with inverse changes in the mature skin cross-link, histidinohydroxylysinonorleucine (baseline, 1.18+/-0.11 mol/mol collagen; 6 months, 0.27+/-0.09 mol/mol collagen). Pyridinoline content increased over the period of the study, although remaining at relatively low concentrations (baseline, 0.037+/-0.011; 6 months, 0.063+/-0.014 mol/mol collagen), and the pyridinoline/deoxypyridinoline ratio was significantly higher (baseline, 3.5+/-0.6; 6 months, 10.3+/-2.2). Elastin content, measured as desmosine cross-links, decreased significantly in the first 3 weeks and continued to decline over the period of study. Overall, the data suggest that remodeling of the wound tissue continues at least up to 6 months after injury. The close inverse correlation between histidinohydroxylysinonorleucine concentrations and extractability by pepsin (r2=0.89, p<0.0001) suggests a causal relationship, consistent with the likely effects of a substantial network of mature, inter-helical bonds in collagen.