Anti-inflammatory effects of Arnica montana (mother tincture and homeopathic dilutions) in various cell models

ETHNOPHARMACOLOGICAL RELEVANCE

The plant Arnica montana L. has been shown to alleviate inflammation, pain and swelling associated with trauma, and post-operative clinical conditions, yet the mechanism of action is not well understood.

AIM OF THE STUDY

The study was designed to investigate the effect of Arnica montana (A. montana) mother tincture and homeopathic dilutions on inflammation markers, oxidative stress and cell migration in diverse cell culture models.

MATERIALS AND METHODS

We tested A. montana mother tincture and a range of homeopathic dilutions in different human and murine cell culture models to demonstrate their anti-inflammatory properties by measuring the inflammatory markers: tumor necrosis factor alpha (TNFα), interleukin-6 (IL-6), cyclooxygenase-2 (COX-2), monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule (ICAM-1), reactive oxygen species (ROS) and cell migration. The inflammatory markers were measured by ELISA assays. The intracellular oxidative stress (ROS) in microglial cells was measured using Deep Red CellROX probe. The cell migration was examined by wound healing using the Oris Cell migration assay.

RESULTS

These data showed the ability of A. montana (mother tincture and mainly 1C dilution) to significantly reduce TNFα production in inflamed macrophages compared with vehicle (control). They significantly reduced both IL-6 and MCP-1 in inflamed human microglial cells and significantly decreased COX-2 expression in inflamed murine fibroblasts. Moreover, A. montana mother tincture reduced the cell migration whereas 9C dilution significantly enhanced the migration of fibroblast cells compared with vehicle. The expression of ICAM-1 was significantly reduced with A. montana mother tincture and 1C, 3C, 5C, and 9C dilutions in inflamed human endothelial cells compared with vehicle. A. montana mother tincture and 1C, 3C, 5C and 9C dilutions induced a significant and consistent effect on ROS production in inflamed murine microglial cells. A. montana 1C had the largest impact on ROS production.

CONCLUSIONS

Mother tincture and 1C dilution of A. montana showed anti-inflammatory properties assessed by measurement of several markers (pro-inflammatory cytokines, adhesion molecule, ROS) in various human and murine cell models. In addition, A. montana 3C, 5C, 9C dilutions have anti-inflammatory and antioxidant effects as highlighted on both primary endothelial cells and murine microglial cells.

A wave of deep intronic mutations in X-linked Alport Syndrome

X-linked Alport syndrome (XLAS) is an inherited kidney disease caused exclusively by pathogenic variants in the COL4A5 gene. In 10-20% of cases, DNA sequencing of COL4A5 exons or flanking regions cannot identify molecular causes. Here, our objective was to use a transcriptomic approach to identify causative events in a group of 19 patients with XLAS without identified mutation by Alport gene panel sequencing. Bulk RNAseq and/or targeted RNAseq using a capture panel of kidney genes was performed. Alternative splicing events were compared to those of 15 controls by a developed bioinformatic score. When using targeted RNAseq, COL4A5 coverage was found to be 23-fold higher than with bulk RNASeq and revealed 30 significant alternative splicing events in 17 of the 19 patients. After computational scoring, a pathogenic transcript was found in all patients. A causative variant affecting COL4A5 splicing and absent in the general population was identified in all cases. Altogether, we developed a simple and robust method for identification of aberrant transcripts due to pathogenic deep-intronic COL4A5 variants. Thus, these variants, potentially targetable by specific antisense oligonucleotide therapies, were found in a high percentage of patients with XLAS in whom pathogenic variants were missed by conventional DNA sequencing.

Copy number variations analysis in a cohort of 47 fetuses and newborns with congenital diaphragmatic hernia

OBJECTIVES

The congenital diaphragmatic hernia (CDH), characterized by malformation of the diaphragm and lung hypoplasia, is a common and severe birth defect that affects around 1 in 4000 live births. However, the etiology of most cases of CDH remains unclear. The aim of this study was to perform a retrospective analysis of copy number variations (CNVs) using a high-resolution array comparative genomic hybridization (array-CGH) in a cohort of fetuses and newborns with CDH.

METHODS

Forty seven fetuses and newborns with either isolated or syndromic CDH were analyzed by oligonucleotide-based array-CGH Agilent 180K technique.

RESULTS

A mean of 10.2 CNVs was detected by proband with a total number of 480 CNVs identified based on five categories: benign, likely benign, of uncertain signification, likely pathogenic, and pathogenic. Diagnostic performance was estimated at 19.15% (i.e., likely pathogenic and pathogenic CNVs) for both CDH types. We identified 11 potential candidate genes: COL25A1, DSEL, EYA1, FLNA, MECOM, NRXN1, RARB, SPATA13, TJP2, XIRP2, and ZFPM2.

CONCLUSION

We suggest that COL25A1, DSEL, EYA1, FLNA, MECOM, NRXN1, RARB, SPATA13, TJP2, XIRP2, and ZFPM2 genes may be related to CDH occurrence. Thus, this study provides a possibility for new methods of a positive diagnosis.

POS0538 PREDICTING VALUE OF CIRCULATING SEMAPHORIN 4A FOR RHEUMATOID ARTHRITIS PROGRESSION

Background

The lack of validated tools to predict rheumatoid arthritis (RA) disease course warrants the development of new reliable biomarkers. We have previously detected increased SEMA4A expression in endothelial cells, synovial tissue, and serum of patients with RA. In addition, SEMA4A serum levels correlated with multiple clinical, biological, and power doppler ultrasound markers of disease activity and angiogenesis (1).

Objectives

To evaluate the merit of circulating semaphorin 4A (SEMA4A) for the prediction of disease progression in RA patients.

Methods

Prospective monocentric observational study including consecutive RA patients between May 2016 and February 2018 with available SEMA4A concentrations, measured by quantitative ELISAs (Coud-Clone Corp, Katy, TX). Increased SEMA4A concentrations were defined as values >94 ng/mL, as previously reported (1). Patients were followed up on an annual basis until August 2021. Primary endpoints were the occurrence of patient-reported flares with swollen joints and the necessity to initiate or change a targeted biologic or synthetic disease-modifying anti-rheumatic drugs.

Results

A total of 101 patients (85 females, 84%) were included, with a mean age of 58±13 years and a mean disease duration of 14±11 years. During a follow-up period of 41±15 months, disease flares occurred in 38 patients and targeted therapy was added or modified in 26 patients because of insufficient disease control. Increased baseline SEMA4A levels were predictive of flares and treatment escalation (hazard ratio, HR: 2.43, 95% confidence interval, CI 1.27-4.68 and 2.73, 95%CI 1.24-5.96, respectively) (Figure 1A-B). Multivariate Cox analyses confirmed that SEMA4A was an independent predictors of flares and treatment escalation (HR: 2.12, 95%CI 1.04-4.32 and 2.71, 95%CI1.14-6.43, respectively), and revealed that DAS28-CRP and synovial hyperhemia were independent predictors of flares. Baseline age, disease duration, ACPA or RF positivity, smoking status, presence of erosions, line of targeted DMARDs, treatment with corticosteroids and CRP levels were not predictive of these outcomes. SEMA4A remained predictive of flares and treatment escalation in the 58 patients with a DAS28 <3.2 at baseline (HR: 3.68, 95%CI 1.33-10.17 and 3.50, 95%CI 1.02-12.01, respectively). Baseline SEMA4A levels also identified more active and difficult to treat patients who maintained higher mean DAS28-CRP values during the follow-up period (Figure 1C). The highest predictive value of flares and treatment escalation was obtained with the combination of increased circulating SEMA4A and/or DAS28-CRP>3.2 and/or the presence of synovial hyperemia on power-doppler ultrasound (HR:4.88, 95%CI 1.50-15.89 and 10.42, 95%CI 1.41-76.94, respectively).

Figure 1.

A-C: Predictive value of SEMA4A for the progression of rheumatoid arthritis. A, Disease flare-free survival according to circulating SEMA4A concentrations (≤ or > 94 ng/mL). B, Time to treatment escalation according to circulating SEMA4A concentrations (≤ or > 94 ng/mL). C, Course of the DAS28-CRP during the follow-up period according to baseline SEMA4A concentrations (≤ or > 94 ng/mL). All data are shown as the mean ± SEM. * p<0.05, ** p<0.01 and *** p<0.001, determined by Student’s t test.

Conclusion

Circulating SEMA4A was a robust biomarker of disease progression in this cohort, complementary of the DAS28 and synovial hyperemia on power-doppler ultrasound. These results need to be confirmed in replication cohorts.

References

[1]Avouac et al, Arthritis Rheumatol 2021

Disclosure of Interests

None declared.

Mogamulizumab induces long term immune restoration and reshapes tumor heterogeneity in Sézary syndrome

BACKGROUND

Mogamulizumab, an anti-CCR4 monoclonal antibody, has been shown to increase progression-free survival in cutaneous T-cell lymphoma.

OBJECTIVES

We hypothesized that besides the targeted depletion of Sézary cells (SCs), mogamulizumab may reshape the immune tumor microenvironment.

METHODS

Both malignant and benign compartments from 26 Sézary patients with B2 stage before mogamulizumab initiation were prospectively analyzed using KIR3DL2 and TCR-Vβ markers, serological markers and molecular assessments of clonality.

RESULTS

Prior to mogamulizumab, the benign subset of CD4+ T-cells displayed exhausted phenotypes, with an increased gradient in PD1/TIGIT/DNAM/CD27/CD28 and CD70 expression from age- matched controls to patient benign CD4+T cells and to SCs. All patients presented SCs with heterogeneous phenotypes and differential expression of individual markers were found within distinct malignant subsets. Early complete blood response was observed in 17/26 patients and was associated to a higher baseline CCR4 expression. A drastic decrease in benign T cells and activated Treg counts was observed during the first 4 weeks. Long-term follow-up revealed the emergence of an immune restoration involving CD8+, naive and stem-memory CD4+T cells, with almost complete disappearance of exhausted lymphocytes. Development of resistance/tumor escape to mogamulizumab was associated to the emergence of CCR4- SCs in blood and skin, displaying significant changes in their heterogeneity patterns, and not univocally explained by mutations within CCR4 coding regions.

CONCLUSIONS

Mogamulizumab is likely contributing to the restoration of an efficient immunity and reshapes not only the malignant lymphocyte subset but also the benign subset. These results have potential implications for optimal therapeutic sequences and/or combinations.

AB0665 SWITCHING INTRAVENOUS ABATACEPT AND TOCILIZUMAB TO SUBCUTANEOUS INJECTIONS DURING THE COVID-19 PANDEMIC: A FRENCH EXPERIENCE

Background:

The COVID-19 pandemic requires measures to reduce patient exposure to the risk of contamination, in particular by limiting hospital admissions and promoting lockdown. In order to respond to these healthcare measures, patients were offered to replace intravenous infusions (IV) of abatacept (ABT) and tocilizumab (TCZ) to subcutaneous injections (SC).

Objectives:

To assess the outcome of patients who switched from IV ABT or TCZ to SC during the COVID-19 pandemic.

Methods:

A survey was conducted in December 2020 in partnership with the national AFP-RIC patient association to assess the outcome and satisfaction of patients who switched from ABT or TCZ IV to SC during the first wave of COVID-19 pandemic.

We also analysed the outcome of patients who switched from IV ABT or TCZ to SC in the rheumatology department of Cochin Hospital during the lockdown in April/may 2020. Articular activity parameters (swollen joint count, pain joint count, visual analogic pain scale, CRP, DAS-28 activity score) were assessed at medical visits before and 6 months after switching from IV to SC.

The data collected from the AFP-RIC patient association and the rheumatology department of Cochin Hospital were then aggregated and analyzed by Chi-square and Wilcoxon tests.

Results:

81 patients responded to the survey carried out by AFP-RIC patient association, including 29 treated with IV ABT (n=15, 52%) or TCZ (n=14, 48%). 17/29 (59%) were offered to switch from IV to SC, 14/17 patients (82%) accepted and 7 patients were still receiving ABT or TCZ SC injections in December 2020. In the rheumatology department of Cochin hospital, 71 patients were scheduled in April/May 2020 to receive IV ABT or TCZ, and 27 (38%) switched to SC. After 6 months, 19 patients (70%) had maintained SC injections, were satisfied with this injection route of administration and their articular activity parameters were unchanged (Table 1).

Table 1.

Course of Disease parameters evaluated in the 19 patients who maintained abatacept or tocilizumab SC injections in the Rheumatology department of Cochin Hospital

Parameter, mean(SD)Inclusion visitSwitch to SC(n=19)6 month visit (n=19)P-valueDAS282.3 (1.2)2.3 (0.7)0.62Tender joint count2.5 (3.5)1.3 (1.7)0.49Swollen joint count1.3 (2.5)0.9 (0.6)0.35Patient Global Health (cm)3.2 (1.9)2.6 (1.8)0.60CRP (mg/L)3.2 (4.1)5.2 (4.9)0.56

CRP: C-Reactive Protein, SD: Standard Deviation

The combined analysis of these two populations included 41 patients (33 rheumatoid arthritis, RA, 7 juvenile idiopathic arthritis, JIA and 1 polymyalgia rheumatica) who switched to SC ABT or TCZ. 26/41 (63.5%) patients maintained SC injections and IV was re-established in 15/41 (36.5%). Reasons for returning to IV were poor tolerance of SC injections (n=6, 40%), worsening symptoms (n=11, 73%), patient preference to see a rheumatologist in hospital (n=10, 67%) and the high number of SC injections (n=2, 13%). The proportion of patients returning to IV was higher in RA patients compared to patients with JIA (42% vs. 14%, p = 0.08). Age and disease duration were not significantly different between patients who maintained SC injections and those who returned to IV (respectively p=0.97 and p=0.63).

Conclusion:

Our study suggests that switching from IV ABT or TCZ to SC is an acceptable procedure during the COVID-19 pandemic, especially for patients with JIA.

Acknowledgements:

Association AFP-RIC (Angélique Hochedé, Cyrielle Beller, Sandrine Rollot) and the members of the association for their help in the conduction of the survey

Disclosure of Interests:

None declared.

Colistin in critically ill patients

Colistin is a re-emerging old antibiotic that is used as a salvage treatment against multidrug-resistant Gram-negative infections. Because it is administrated as an inactive prodrug, colistin methanesulfonate (CMS) that undergoes rapid hydrolyze to colistin, pharmacokinetic studies using biological assays are unreliable. With the recent development of new assays using high performance liquid chromatography (HPLC) accurate pharmacokinetic of CMS and formed colistin is now available in various populations. This article aims to update previous reports on pharmacodynamics, pharmacokinetics, safety and clinical use of colistin, with a special focus on data useful to treat critically ill patients.

An inventory of trace elements inputs to French agricultural soils

The inputs of ten trace elements (As, Cd, Cu, Cr, Hg, Mo, Ni, Pb, Se, Zn) to French agricultural soils have been assessed. The six main sources considered were: pesticides, mineral fertilizers, animal manure, liming materials, sludge and composts and atmospheric deposition. Data were collected to compute inputs at both national and regional (departmental) scales. The inventory methodology is based on two principles: data are traceable and easy to update. At a national scale, the inventory showed that trace elements inputs can be ranked: Zn≫Cu≫Cr>Pb>Ni>As=Mo>Se>Cd>Hg. Animal manure, mineral fertilizers and pesticides are the predominant sources of TEs. These results are globally in agreement with literature data though atmospheric deposition is shown to be lower than in more industrial countries such as China and United Kingdom where similar surveys were conducted. The inputs of trace elements vary strongly between regions in relation with agricultural activities. This inventory (and the related database) provides basis for developing and monitoring policies to control and reduce trace elements contamination of agricultural soils at both national and regional (departmental) scales.

[Practice assessment of central venous lines care in surgical ICU of French university hospitals]

INTRODUCTION

Recommendations on insertion and maintenance of central venous catheters (CVC) in intensive care unit (ICU) patients were updated in 2002. The aim of this study was to estimate their knowledge and/or application by physicians in French university hospital ICUs.

METHODS

Two forms were sent to 124 professors of anaesthesia and intensive care encouraging them to participate to the survey. The first one was completed by the physician in charge of each unit and concerned the structure and activity of the unit in 2006. The second one was filled by each junior or senior physician working in the units and asked for experience, CVC insertion modalities and knowledge of CVC care protocols.

RESULTS

Forty-one (75 %) university hospitals with at least one adult surgical ICU took part to the study. A questionnaire was filled by 124 senior (75 % of the staff) and 53 junior (43 % of the staff) physicians inserting an average of 10 CVC per month (range, 1-35). A written protocol for CVC insertion was known by 127 (72 %) of them. CVC insertion was done while wearing sterile gown (97 %), cap (100 %) and surgical mask (100 %) and using large sterile drapes (96 %). The antiseptic solution used for cutaneous antisepsis was povidone iodine in aqueous (36 %) or alcoholic solution (40 %), or an alcoholic solution of chlorhexidine (24 %) applied one (9 %), two (64 %) or three (27 %) times before insertion. A 4-times disinfection sequence (washing, rinsing, drying and disinfection) was performed by 161 (91 %) physicians. Ultrasound-guided insertion was realized by only eight (5 %) operators. CVCs were made of polyurethane (84 %), usually multi-lumens (>96 %) and rarely tunnelised (14 %). Only two physicians (1 %) sometimes use catheters coated with antibiotics or antiseptics. The site for catheter insertion was mostly the sub-clavian (47 %) or internal jugular vein (34 %), and rarely the femoral vein (20 %). CVCs were secured with a thread (99 %) and covered with a semi-permeable dressing (76 %). Concerning CVCs maintenance, 91 % of physicians acknowledged the existence of a written protocol in the unit. Dressings were changed every day (10 %), every two days (49 %), every three days (29 %) or every four days or more (12 %) by using the same antiseptic solution and semi-permeable transparent dressing in 78 % of cases. Venous lines changes were done during dressing maintenance (48 %), every day in case of administration of lipids (32 %) or just after administration of blood products via the catheter (32 %). Routine change of CVC was rarely recommended (11 %).

CONCLUSION

The high number of answers allows setting of a precise state of CVCs insertion practices in adult surgical ICUs. Recommendations for central venous catheter insertion and maintenance are not still known and\or applied.

Transplantation of adipose derived stromal cells is associated with functional improvement in a rat model of chronic myocardial infarction

AIMS

To determine the effect of transplantation of undifferentiated and cardiac pre-differentiated adipose stem cells compared with bone marrow mononuclear cells (BM-MNC) in a chronic model of myocardial infarction.

METHODS

Ninety-five Sprague-Dawley rats underwent left coronary artery ligation and after 1 month received by direct intramyocardial injection either adipose derived stem cells (ADSC), cardiomyogenic cells (AD-CMG) or BM-MNC from enhanced-Green Fluorescent Protein (eGFP) mice. The control group was treated with culture medium. Heart function was assessed by echocardiography and 18F-FDG microPET. Cell engraftment, differentiation, angiogenesis and fibrosis in the scar tissue were also evaluated by (immuno)histochemistry and immunofluorescence.

RESULTS

One month after cell transplantation, ADSC induced a significant improvement in heart function (LVEF 46.3+/-9.6% versus 27.7+/-8% pre-transplant) and tissue viability (64.78+/-7.2% versus 55.89+/-6.3% pre-transplant). An increase in the degree of angiogenesis and a decrease in fibrosis were also detected. Although transplantation of AD-CMG or BM-MNC also had a positive, albeit smaller, effect on angiogenesis and fibrosis in the infarcted hearts, this benefit did not translate into a significant improvement in heart function or tissue viability.

CONCLUSION

These results indicate that transplantation of adipose derived cells in chronic infarct provides a superior benefit to cardiac pre-differentiated ADSC and BM-MNC.

Partial sequences of nitrogen metabolism genes in hexaploid wheat

Our objective was to partially sequence genes controlling nitrogen metabolism in wheat species in order to find sequence polymorphism that would enable their mapping. Primers were designed for nitrate reductase, nitrite reductase, glutamate dehydrogenase and glutamate synthase (GOGAT), and gene fragments were amplified on Triticum aestivum, T. durum, T. monococcum, T. speltoides and T. tauschii. We obtained more than 8 kb of gene sequences, mainly as coding regions (60%). Polymorphism was quantified by comparing two-by-two the three genomes of the hexaploid cultivar Arche and genomes of diploid wheat species. On average, the polymorphism rate was higher for non-coding regions, where it ranged from 1/60 to 1/23, than for coding regions (range: 1/110-1/40) except when the hexaploid D genome was compared to that of T. tauschii (1/800 and 1/816, respectively). Genome-specific primers were devised for the ferredoxin-dependent (Fd)-GOGAT gene, and they enabled the mapping of this gene on homoeologous chromosomes of group 2 using Chinese Spring deletion lines. A single nucleotide polymorphism (SNP) detected between the two hexaploid wheat cultivars Arche and Recital was used to genetically map Fd-GOGAT on chromosome 2D using a population of dihaploid lines. Fd-GOGAT-specific primers were used to estimate the SNP rate on a set of 11 hexaploid and nine Durum wheat genotypes leading to the estimate of 1 SNP/515 bp. We demonstrate that polymorphism detection enables heterologous, homeologous and even paralogous copies to be assigned, even if the elaboration of specific primer pairs is time-consuming and expensive because of the sequencing.

Valeur de la cholestérolémie chez l’enfant

INTRODUCTION

There is a need to dispose of normal cholesterol levels in young children. In view of the paucity of such data in France, we analysed the results of screening conducted in children.

METHOD

We analysed the cholesterol levels of 4697 children, with a mean age of 4.3 years, attending a medical check-up in a Child Health Unit in a National Health Scheme centre in Paris. All the children were recruited consecutively during the year 2002.

RESULTS

The mean cholesterol level was of 4.4 mmol/L +/- 0.75. We detected a slight gender-related variation (the mean in girls and boys were of 4.5 +/- 0.76 and 4.4 +/- 0.74 respectively). The 95 percentile in girls and boys were 5.7 and 5.6 mmol/L, respectively.

DISCUSSION

For the first time in France, we now have access to data on normal cholesterol levels in a large cohort of 4 year-old children. Screening for hypercholesterolaemia in children provides the opportunity to discuss dietary counselling.

The Arabidopsis AtEPR1 extensin-like gene is specifically expressed in endosperm during seed germination

Screening of 10 000 Arabidopsis transgenic lines carrying a gene-trap (GUS) construct has been undertaken to identify markers of seed germination. One of these lines showed GUS activity restricted to the endosperm, at the micropylar end of the germinating seed. The genomic DNA flanking the T-DNA insert was cloned by walking PCR and the insertion was shown to be located 70 bp upstream of a 2285 bp open reading frame (AtEPR1) sharing strong similarities with extensins. The AtEPR1 open reading frame consists of 40 proline-rich repeats and is expressed in both wild-type and mutant lines. The expression of the AtEPR1 gene appears to be under positive control of gibberellic acid, but is not downregulated by abscisic acid during seed germination. No expression was detected in organs other than endosperm during seed germination. The putative role of AtEPR1 is discussed in the light of its specific expression in relation to seed germination.

Electroshock afterdischarges are related to neuronal oscillability: neuronal models of Aplysia

Identifiable giant neurons of Aplysia explored intracellularly behave differently at the offset of an intracellular electroshock (IES) or after a synaptic 'tetanization', according to their functional type: neurons of the stable type depolarize and fire at the offset of the IES, anodal or cathodal, thus eliciting an afterdischarge (AD). The threshold of this AD is lowered if the neuron is destabilized, i.e. converted from the stable to an oscillatory type (for instance by decalcification). Neurons normally of the tonic type are more sensitive to an IES, eliciting a longer afterdischarge than the stable neurons. Extracellular electroshock (EES) anodal or cathodal, applied directly on desheathed somata of Helix give long-lasting afterdischarges at the offset. In addition, EES stimulating presynaptic terminals or axons leads to a high frequency synaptic input on remote neurons. At the offset of this input either prolonged synaptic afterdischarges or postsynaptic rebounds of the membrane potential sustaining bursts of decreasing amplitude denote apparent oscillatory properties of the synaptically activated neuron. Finally, any conversion by convulsants of tonic neurons to oscillators highly facilitates the elicitation of afterdischarges of axons simultaneous to paroxysmal depolarization shifts of the homologous somata. These results indicate that afterdischarge elicitation is highly facilitated (low threshold) in normal oscillatory neurons and/or chemically destabilized neurons.

Collagen synthesis in rat gingiva during tooth movement

The response of the gingiva to an increased interdental space was studied by creating a diastema between the central incisors of rats and analyzing autoradiographically the incorporation of H3 proline in the gingiva to detect increased collagen production. In addition, conventional histologic methods were used to determine changes in the gingival architecture. The results indicate that the gingiva responds to an increased space in at least two ways. One is the production of more collagen fibers. The other involves the reorientation of the existing fibers in a horizontal plane as the gingival papilla becomes flattened.