COVID-19 and Dentistry in 72 Questions: An Overview of the Literature.

The outbreak of Coronavirus Disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has significantly affected the dental care sector. Dental professionals are at high risk of being infected, and therefore transmitting SARS-CoV-2, due to the nature of their profession, with close proximity to the patient's oropharyngeal and nasal regions and the use of aerosol-generating procedures. The aim of this article is to provide an update on different issues regarding SARS-CoV-2 and COVID-19 that may be relevant for dentists. Members of the French National College of Oral Biology Lecturers ("Collège National des EnseignantS en Biologie Orale"; CNESBO-COVID19 Task Force) answered seventy-two questions related to various topics, including epidemiology, virology, immunology, diagnosis and testing, SARS-CoV-2 transmission and oral cavity, COVID-19 clinical presentation, current treatment options, vaccine strategies, as well as infection prevention and control in dental practice. The questions were selected based on their relevance for dental practitioners. Authors independently extracted and gathered scientific data related to COVID-19, SARS-CoV-2 and the specific topics using scientific databases. With this review, the dental practitioners will have a general overview of the COVID-19 pandemic and its impact on their practice.

New insights into hidradenitis suppurativa diagnosis via salivary infrared biosignatures: A pilot study.

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease which can lead to a prolonged physical disability. HS diagnosis is exclusively clinical with the absence of biomarkers. Our study aims at assessing the HS-diagnostic potential of infrared spectroscopy from saliva, as a biofluid reflecting the body's pathophysiological state. Infrared spectra from 127 patients (57 HS and 70 non-HS) were processed by multivariate methods: principal component analysis coupled with Kruskal-Wallis or Mann-Whitney tests to identify discriminant spectral wavenumbers and linear discriminant analysis to evaluate the performances of HS-diagnostic approach. Infrared features, mainly in the 1300 cm-1 -1600 cm-1 region, were identified as discriminant for HS and prediction models revealed diagnostic performances of about 80%. Tobacco and obesity, two main HS risk factors, do not seem to alter the infrared diagnosis. This pilot study shows the potential of salivary "liquid biopsy" associated to vibrational spectroscopy to develop a personalized medical approach for HS patients' management.

Vibrational Spectroscopy Saliva Profiling as Biometric Tool for Disease Diagnostics: A Systematic Literature.

Saliva is a biofluid that can be considered as a "mirror" reflecting our body's health status. Vibrational spectroscopy, Raman and infrared, can provide a detailed salivary fingerprint that can be used for disease biomarker discovery. We propose a systematic literature review based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to evaluate the potential of vibrational spectroscopy to diagnose oral and general diseases using saliva as a biological specimen. Literature searches were recently conducted in May 2020 through MEDLINE-PubMed and Scopus databases, without date limitation. Finally, over a period of 10 years, 18 publications were included reporting on 10 diseases (three oral and seven general diseases), with very high diagnostic performance rates in terms of sensitivity, specificity, and accuracy. Thirteen articles were related to six different cancers of the following anatomical sites: mouth, nasopharynx, lung, esophagus, stomach, and breast. The other diseases investigated and included in this review were periodontitis, Sjögren's syndrome, diabetes, and myocardial infarction. Moreover, most articles focused on Raman spectroscopy (n = 16/18) and more specifically surface-enhanced Raman spectroscopy (n = 12/18). Interestingly, vibrational spectroscopy appears promising as a rapid, label-free, and non-invasive diagnostic salivary biometric tool. Furthermore, it could be adapted to investigate subclinical diseases-even if developmental studies are required.

Shedding light on confounding factors likely to affect salivary infrared biosignatures.

Total human saliva is a biofluid which can be considered as a "mirror" reflecting the state of the body's health. The "spectral mid-infrared fingerprint" represents a snapshot of the intrinsic biomolecular composition of a saliva sample translating multiple information about the patient, and likely to be related not only to his physiopathological status but also to his behavioral habits or even current medical treatments. These different patient-related characteristics are "confounding factors," which may strongly affect the infrared data of salivary samples and disrupt the search for specific salivary biomarkers in the detection of diseases, especially in the case of complex pathologies influenced by multiple risk factors such as genetic factors and behavioral factors, and also other comorbidities. In this study, dealing with the processing of infrared saliva spectra from 56 patients, our aim was to highlight spectral features associated with some patient characteristics, namely tobacco smoking, periodontal diseases, and gender. By using multivariate statistical methods of feature selection (principal component analysis coupled with Kruskal-Wallis test, linear discriminant analysis coupled with randfeatures function), we were able to identify the discriminant vibrations associated with a specific factor and to assess the related spectral variability. Based on the methodology demonstrated here, it could be very valuable in the future to develop processing aimed at neutralizing these variabilities, in order to determine specific spectroscopic markers related to a multifactorial disease for diagnostic or follow-up purposes.

Combining Magnetic Resonance Imaging (MRI) and Medical Infrared Thermography (MIT) in the pre- and peri-operating management of severe Hidradenitis Suppurativa (HS).

Hidradenitis suppurativa (HS) is a chronic, inflammatory, and recurrent skin disease. Surgical excision of wounds appears to be the only curative treatment for the prevention of recurrence of moderate to severe stages. Magnetic resonance imaging (MRI) is a standard reference examination for the detection of HS peri-anal inflammatory fistula. In this case study, the use of real-time medical infrared thermography, in combination with MRI as appropriate imaging, is proposed. The aim is to assist surgeons in the pre- and peri-surgical management of severe perianal hidradenitis suppurativa with the intent to ensure that all diseased lesions were removed during surgery and therefore to limit recurrence. The results show that medical infrared thermography (MIT), coupled with MRI, could be highly effective strategy to address thermally distinguished health tissues and inflammatory sites during excision, as characterised by differential increases in temperature. Medical infrared thermography could be used to check the total excision of inflammatory lesions as a noninvasive method that is not painful, not radiant, and is easily transportable during surgery. Ultimately, this method could be complementary with MRI in providing clinicians with objective data on the status of tissues below the perianal skin surface in the pre- and per-operating management of severe hidradenitis suppurativa.

Regeneration of human dermis by a multi-headed peptide.

Skin aging is characterized by deterioration of the dermal collagen fiber network due to both decreased collagen expression and increased collagenolytic activity. We designed and evaluated in vitro and ex vivo the efficacy of a trifunctional peptide (TFP) to restore collagen and elastin fibers. TFP was constituted of an elastokine motif (VGVAPG)3, able to increase matrix constituent expression through the stimulation of the elastin-binding protein receptor, a GIL tripeptide occupying matrix metalloproteinase-1 subsites, and a RVRL linker domain acting as a competitive substrate for urokinase. The effects of TFP on type I, type III collagens, and elastin expression in dermal fibroblasts were determined by quantitative real-time reverse-transcriptase-PCR and western blotting. TFP's inhibitory capacity against MMP-1, plasmin, and urokinase was assessed using synthetic substrates, immunohistochemistry, and skin tissue sections as natural substrates. A skin explant model was used to recapitulate aging-induced dermal changes along culture extent. Collagen and elastin fiber structure was analyzed by two-photon fluorescence, second harmonic generation, and confocal microscopies. Compared with the different sections constituting the full peptide, we found that TFP activated the production of matrix constituents while inhibiting MMP-1 in vitro and ex vivo. It also induced a proper fiber network organization, reflecting the potency of TFP in skin remodeling and regeneration.

Mechanical forces-induced human osteoblasts differentiation involves MMP-2/MMP-13/MT1-MMP proteolytic cascade.

Matrix metalloproteinase (MMP) family proteins play diverse roles in many aspects of cellular processes such as osteoblastic differentiation. Besides, mechanical forces that occur in 3D collagen gel promote the osteoblastic phenotype and accelerate matrix mineralization. Although MMPs have been involved in bone differentiation, the proteolytic cascades triggered by mechanical forces are still not well characterized. In this study, we have investigated the contribution of both proteolytic cascades, MMP-3/MMP-1 and MMP-2/MMP-13/MT1-MMP in the differentiation of human osteoblasts cultured in a floating type I collagen lattice (FL) versus an attached collagen lattice (AL). Compared to AL, contraction of human osteoblasts-populated FL led to a fast (1 day) induction of alkaline phosphatase (ALP), bone sialoprotein (BSP), osteoprotegerin (OPG), and Runx-2 expression. At day 4, osteocalcin (OC) overexpression preceded the formation of calcium-containing nodule formation as assessed by X-ray analyses. MMP-1 and MMP-3 were produced to similar extent by cells cultured in FL and AL, whereas contraction of collagen lattices triggered both mRNA overexpression of MMP-2, MMP-13, and MT1-MMP (i.e., MMP-14), and their activation as evidenced by Western blotting or zymographic analyses. Down-regulating MT1-MMP expression or activity either by siRNA transfection or supplementation of culture medium with TIMP-1 or TIMP-2 highlighted the contribution of that enzyme in OC, ALP, and OPG expression. MMP-2 and MMP-13 were more directly involved in BSP expression. So, these results suggest that the main proteolytic cascade, MMP-2/MMP-13/MT1-MMP, and more particularly, its initial regulator MT1-MMP is involved in osteoblast differentiation through mechanical forces.

Inhibition of human leukocyte elastase, plasmin and matrix metalloproteinases by oleic acid and oleoyl-galardin derivative(s).

Molecular modeling was undertaken at aims to analyze the interactions between oleic acid and human leukocyte elastase (HLE), plasmin and matrix metalloproteinase-2 (MMP-2), involved in the inhibitory capacity of fatty acid towards those proteases. The carboxylic acid group of the fatty acid was found to form a salt bridge with Arg(217) of HLE while unsaturation interacted with Phe(192) and Val(216) at the S(3) subsite, and alkyl end group occupied S(1) subsite. In keeping with the main contribution of kringle 5 domain in plasmin-oleic acid interaction [Huet E et al. Biochem Pharmacol 2004;67(4):643-54], docking computations revealed that the long alkyl chain of fatty acid inserted within an hydrophobic groove of this domain with the carboxylate forming a salt bridge with Arg(512). Finally, blind docking revealed that oleic acid could occupy both S'(1) subsite and Fn(II)(3) domain of MMP-2. Several residues involved in Fn(II)(3)/oleic acid interaction were similarly implicated in binding of this domain to collagen. Oleic acid was covalently linked to galardin (at P'(2) position): OL-GAL (CONHOH) or to its carboxylic acid counterpart: OL-GAL (COOH), with the idea to obtain potent MMP inhibitors able to also interfere with elastase and plasmin activity. OL-GALs were found less potent MMP inhibitors as compared to galardin and no selectivity for MMP-2 or MMP-9 could be demonstrated. Docking computations indicated that contrary to oleic acid, OL-GAL binds only to MMP-2 active site and surprisingly, hydroxamic acid was unable to chelate Zn, but instead forms a salt bridge with the N-terminal Tyr(110). Interestingly, oleic acid and particularly OL-GALs proved to potently inhibit MMP-13. OL-GAL was found as potent as galardin (K(i) equal to 1.8nM for OL-GAL and 1.45nM for GAL) and selectivity for that MMP was attained (2-3 log orders of difference in inhibitory potency as compared to other MMPs). Molecular modeling studies indicated that oleic acid could be accommodated within S'(1) pocket of MMP-13 with carboxylic acid chelating Zn ion. OL-GAL also occupied such pocket but hydroxamic acid did not interact with Zn but instead was located at 2.8Å from Tyr(176). Since these derivatives retained, as their oleic acid original counterpart, the capacity to inhibit the amidolytic activity of HLE and plasmin as well as to decrease HLE- and plasmin-mediated pro MMP-3 activation, they might be of therapeutic value to control proteolytic cascades in chronic inflammatory disorders.

Role of the elastin receptor complex (S-Gal/Cath-A/Neu-1) in skin repair and regeneration.

Impaired elastic fiber assembly constitutes one major problem in skin wound healing. Recent data indicate that a ternary complex involving a splicing form of beta-galactosidase associated with cathepsin-A and neuraminidase-1 directs the transport of tropoelastin to the fibroblast plasma membrane and participates in the deposition of the elastin precursor onto a microfibrillar scaffold. In addition, this elastin receptor complex is ubiquitously expressed and also acts as a true receptor for elastin-derived peptides produced during the initial stage of wound repair following elastase-mediated proteolysis action. Among the peptides generated, those having a x.G.x.x.P.G. motif upregulate (i) keratinocyte migration, (ii) endothelial cell angiogenic phenotype, (iii) fibroblast proliferation, and (iv) induction of the expression of matrix metalloproteinases, type I collagen, and tropoelastin. All of these properties could accelerate the different stages of wound repair. Elastin-derived peptides from a chemical or a proteolytic digest of insoluble elastin alone or linked to the collagen scaffold significantly improve skin wound healing and dermal regeneration in vivo in several animal models. Such a beneficial influence has been recently extended to the treatment of burn patients. In this respect, recent investigations have focused on the design of elastin-derived peptides or elastin-building blocks, as obtained from peptide chemistry or by genetic engineering, to elaborate biocompatible elastin peptides, which are considered as ideal biomaterials for "catalyzing" skin repair and regeneration following injury.

Impact of carbamylation on type I collagen conformational structure and its ability to activate human polymorphonuclear neutrophils.

Carbamylation by urea-derived cyanate is a posttranslational modification of proteins increasing during chronic renal insufficiency, which alters structural and functional properties of proteins and modifies their interactions with cells. We report here the major structural alterations of type I collagen induced by carbamylation. Biophysical methods revealed that carbamylated collagen retained its triple-helical structure, but that slight changes destabilized some regions within the triple helix and decreased its ability to polymerize into normal fibrils. These changes were associated with the incapacity of carbamylated collagen to stimulate polymorphonuclear neutrophil oxidative functions. This process involved their interaction with LFA-1 integrin, but no subsequent p(125)FAK phosphorylation. Carbamylation of collagen might alter interactions between collagen and inflammatory cells in vivo and interfere with the normal remodeling of extracellular matrix, thus participating in the pathophysiological processes occurring during renal insufficiency.

Elastin-derived peptides enhance angiogenesis by promoting endothelial cell migration and tubulogenesis through upregulation of MT1-MMP.

Elastin-derived peptides display a wide range of biological activities in a number of normal and transformed cells but their involvement in angiogenesis has not been reported. In the present study, we show that kappa-elastin and VGVAPG hexapeptide elastin motif accelerated angiogenesis in the chick chorio-allantoic membrane in an in vivo model. They also stimulated pseudotube formation from human vascular and microvascular endothelial cells in the matrigel and collagen models as well as cell migration in an in vitro wound healing assay. Confocal and scanning electron microscopy analyses revealed the main reorganization of actin filaments mediated by elastin-derived peptides and changes in cell shape that correlated with a decrease of the cell form factor determined by computerized image analysis. Such elastin-derived peptide effects were attributed to upregulation of proMT1-MMP and proMMP-2 expression and activation at both the mRNA and protein levels. Batimastat, an inhibitor of furin convertase and TIMP-2, but not TIMP-1, totally abolished the influence of elastin-derived peptides (EDPs) on cell migration and tubulogenesis, thus favoring the involvement of MT1-MMP in such processes. To assess its contribution to EDP-mediated angiogenesis further, we used a small interfering RNA (siRNA) approach for specifically silencing MT1-MMP in human microvascular endothelial cells. Four sets of 21 bp siRNA duplexes targeting MT1-MMP mRNA were synthesized by in vitro transcription. Two of them proved to inhibit MT1-MMP expression efficiently but did not affect MT2-, MT3- and MT5-MMP expression. Seventy-two hours after transfection with 25 nM siRNAs EDP-induced MT1-MMP expression at the mRNA and protein levels was decreased fourfold. In parallel, proMMP-2 activation was inhibited. A scrambled siRNA, used as a negative control, had no effect. Finally, the effect of elastin peptides on pseudotube formation in MT1-MMP-siRNA transfected cells was totally abolished. These data emphasise the crucial role of MT1-MMP in the elastin-induced angiogenic phenotype of endothelial cells.