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1.
Respir Res ; 24(1): 234, 2023 Sep 27.
Article in English | MEDLINE | ID: mdl-37759266

ABSTRACT

BACKGROUND: As the prevalence of OSA increases in older patients, the proportion of elderly patients treated with CPAP is expected to become even higher. We studied CPAP-adherence in a real-life cohort involving a large population of elderly patients with OSA. METHODS: eQUALISAS is a cross-sectional study of CPAP treated OSA patients for at least 4 months who received remote monitoring during 2021. CPAP adherence, device-reported residual AHI (AHICPAP) and 95th percentile non-intentional leaks were software collected during January 2021. Age and sex were also collected. RESULTS: Data from 26,343 patients including 1656 patients aged [80-85] years and 639 patients aged ≥ 85 years were analysed. Median CPAP adherence increases from 6.3 h (< 50 years) to 7 h (75-80 years) and decreases after this age (p < 0.001). The decrease in CPAP adherence observed after the age of 80 was associated with an increase in the proportion of patients with a CPAP-adherence < 4 h/day (p < 0.001). Proportion of CPAP treated female, patients having AHICPAP mean ≥ 10 events per hour or 95th percentile non-intentional leaks mean over 24 l/min increase with aging of the population. However, for patients over 80 years old, Chi square test showed no association of adherence with gender, AHICPAP and leaks (p > 0.05). CONCLUSION: This study demonstrates that adherence gradually increases with age until 80 years. The proportion of non-adherent patients grows with age after 80 years old. No significative relationship was found between adherence after 80 years old and gender, leaks and AHICPAP. TRIAL REGISTRATION: The study is registered on Health Data Hub platform (No. F20220715144543).


Subject(s)
Aging , Sleep Apnea, Obstructive , Aged , Humans , Female , Aged, 80 and over , Cross-Sectional Studies , Patient Compliance , Software
2.
J Prosthet Dent ; 2023 Oct 31.
Article in English | MEDLINE | ID: mdl-37919130

ABSTRACT

STATEMENT OF PROBLEM: Gingival displacement is used in prosthodontics to obtain an accurate impression. However, randomized clinical trials to analyze the performance of different gingival displacement products are lacking. PURPOSE: The purpose of this prospective, comparative randomized clinical trial was to evaluate the clinical effectiveness of 3 gingival displacement techniques: Racegel cordless, Racegel with a cord, and Racestyptine with a cord. MATERIAL AND METHODS: A prospective, multicenter randomized, open label, 3-arm parallel group study was carried out in private dental practices. Patients with prepared teeth with healthy gingiva were recruited to make impressions before and after gingival displacement, which were digitized. Lateral and vertical gingival displacements were measured with computer-aided 3-dimensional analysis performed by a single operator who was blinded to the technique and the patient. For mean lateral gingival displacement, each gingival displacement method was compared with a required clinical value of 200 µm with the Student t test. The comparison of means among the 3 groups was performed using an ANOVA. Periodontal indices were recorded immediately and 7 to 14 days after gingival displacement. The percentages were compared with the chi-squared test or the Fisher exact test (α=.05 for all tests). RESULTS: Eighty-eight participants were enrolled. The mean lateral gingival displacement obtained by Racestyptine with a cord (253 ±59 µm, P<.001) and by Racegel with a cord (247 ±61 µm, P<.001) were significantly higher than 200 µm. Lateral displacement observed with Racegel cordless was 207 ±57 µm (P=.53). For vertical gingival displacement, no difference among the 3 techniques was found. The astringent effect of these products was confirmed by the absence of crevicular fluid or bleeding. No periodontal damage was observed immediately or 7-14 days after displacement. CONCLUSIONS: The study showed that cord impregnated with Racestyptine and Racegel with or without a cord provided a sufficient sulcus opening before impression making in prosthodontics, consistent with the clinical requirements for lateral displacement.

3.
Respirology ; 27(2): 161-169, 2022 02.
Article in English | MEDLINE | ID: mdl-34873795

ABSTRACT

BACKGROUND AND OBJECTIVE: Case reports have suggested that continuous positive airway pressure (CPAP) telemonitoring can detect the onset of acute cardiac events such as decompensated heart failure (HF) or atrial fibrillation through an increase in the apnoea-hypopnoea index (AHI) and onset of Cheyne-Stokes Respiration (CSR). This study addressed whether long-term remote CPAP treatment telemonitoring revealing CSR can help detect serious cardiac events (SCEs) in obstructive sleep apnoea (OSA) patients. METHODS: This monocentric prospective cohort study included adults receiving CPAP therapy for OSA with daily telemonitoring. Any sudden increase in AHI generated an alert for the home healthcare provider to download CPAP data to identify CSR. A medical consultation was scheduled if CSR was detected. RESULTS: We included 555 adults (412 men; 57% with known cardiovascular comorbidities). During the 1-year follow-up, 78 CSR episodes were detected in 74 patients (CSR+). The main conditions associated with incident CSR were HF (24 patients [30.8%]), ventilatory instability (21, 26.9%), leaks (13, 16.7%), medications inducing central apnoeas (baclofen, ticagrelor, opioids) (7, 9.0%), arrhythmias (6, 7.7%) and renal failure (2, 2.6%). Fifteen (20.3%) CSR+ patients had a confirmed SCE. In univariable analysis, a CSR episode increased the risk of an SCE by 13.8-fold (5.7-35.6) (p < 0.0001), with an adjusted OR of 5.7 (2.0-16.8) in multivariable analysis. CONCLUSION: Long-term telemonitoring of patients on CPAP treatment can alert CSR episodes and allows early detection of SCEs in patients with or without known cardiac comorbidities.


Subject(s)
Heart Failure , Sleep Apnea, Central , Sleep Apnea, Obstructive , Adult , Cheyne-Stokes Respiration/complications , Cheyne-Stokes Respiration/etiology , Continuous Positive Airway Pressure , Female , Heart Failure/complications , Heart Failure/diagnosis , Humans , Male , Prospective Studies , Sleep Apnea, Obstructive/complications , Sleep Apnea, Obstructive/diagnosis , Sleep Apnea, Obstructive/therapy
4.
Front Med (Lausanne) ; 11: 1302431, 2024.
Article in English | MEDLINE | ID: mdl-38435388

ABSTRACT

Through their effects on sleep duration, bedroom environments, and pollen allergies, seasonal variations may impact positive airway pressure (PAP) adherence. We analyzed daily PAP telemonitoring data from 25,846 adults (median age 64 years, 67.8% male) treated with PAP for at least 4 months [mean (standard deviation, SD) duration of PAP: 5.5 years (SD 4.1)] to examine seasonal changes in PAP adherence, leaks, and residual apnea-hypopnea index. We demonstrate a significant decrease in PAP adherence in June compared to January (mean (SD): 0.37 (1.54) h/night) that achieved the minimal clinically important difference (MCID) of 30 min in 13.9% of adults. Furthermore, we provide novel data supporting the association of rising temperatures with seasonal changes in PAP use. Indeed, the most pronounced decline in PAP adherence was observed during the hottest days, while PAP adherence was only slightly reduced during the coolest days of June. Clinicians should be aware of seasonal changes in PAP adherence that are likely to be exacerbated by climate change.

5.
Anal Bioanal Chem ; 403(7): 1983-93, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22538779

ABSTRACT

Human poisoning due to consumption of seafood contaminated with phycotoxins is a worldwide problem, and routine monitoring programs have been implemented in various countries to protect human consumers. Following successive episodes of unexplained shellfish toxicity since 2005 in the Arcachon Bay on the French Atlantic coast, a national research program was set up to investigate these atypical toxic events. Part of this program was devoted to fit-for-purpose cell-based assays (CBA) as complementary tools to collect toxicity data on atypical positive-mouse bioassay shellfish extracts. A collaborative study involving five laboratories was conducted. The responses of human hepatic (HepG2), human intestinal (Caco2), and mouse neuronal (Neuro2a) cell lines exposed to three known lipophilic phycotoxins-okadaic acid (OA), azaspiracid-1 (AZA1), and pectenotoxin-2 (PTX2)-were investigated. A screening strategy composed of standard operating procedures and a decision tree for dose-response modeling and assay validation were designed after a round of "trial-and-error" process. For each toxin, the shape of the concentration-response curves and the IC(50) values were determined on the three cell lines. Whereas OA induced a similar response irrespective of the cell line (complete sigmoid), PTX2 was shown to be less toxic. AZA1 induced cytotoxicity only on HepG2 and Neuro2a, but not on Caco2. Intra- and inter-laboratory coefficients of variation of cell responses were large, with mean values ranging from 35 to 54 % and from 37 to 48 %, respectively. Investigating the responses of the selected cell lines to well-known toxins is the first step supporting the use of CBA among the panel of methods for characterizing atypical shellfish toxicity. Considering these successful results, the CBA strategy will be further applied to extracts of negative, spiked, and naturally contaminated shellfish tissues.


Subject(s)
Cooperative Behavior , Marine Toxins/analysis , Shellfish , Animals , Cell Line , Dose-Response Relationship, Drug , Humans , Inhibitory Concentration 50 , Marine Toxins/toxicity
6.
Anal Bioanal Chem ; 403(7): 1995-2007, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22535441

ABSTRACT

Successive unexplained shellfish toxicity events have been observed in Arcachon Bay (Atlantic coast, France) since 2005. The positive mouse bioassay (MBA) revealing atypical toxicity did not match the phytoplankton observations or the liquid chromatography-tandem mass spectrometry (LC-MS/MS) investigations used to detect some known lipophilic toxins in shellfish. The use of the three cell lines (Caco2, HepG2, and Neuro2a) allows detection of azaspiracid-1 (AZA1), okadaic acid (OA), or pectenotoxin-2 (PTX2). In this study, we proposed the cell-based assays (CBA) as complementary tools for collecting toxicity data about atypical positive MBA shellfish extracts and tracking their chromatographic fractionation in order to identify toxic compound(s). The present study was intended to investigate the responses of these cell lines to shellfish extracts, which were either control or spiked with AZA1, OA, or PTX2 used as positive controls. Digestive glands of control shellfish were extracted using the procedure of the standard MBA for lipophilic toxins and then tested for their cytotoxic effects in CBA. The same screening strategy previously used with pure lipophilic toxins was conducted for determining the intra- and inter-laboratory variabilities of the responses. Cytotoxicity was induced by control shellfish extracts whatever the cell line used and regardless of the geographical origin of the extracts. Even though the control shellfish extracts demonstrated some toxic effects on the selected cell lines, the extracts spiked with the selected lipophilic toxins were significantly more toxic than the control ones. This study is a crucial step for supporting that cell-based assays can contribute to the detection of the toxic compound(s) responsible for the atypical toxicity observed in Arcachon Bay, and which could also occur at other coastal areas.


Subject(s)
Cooperative Behavior , Marine Toxins/analysis , Shellfish , Animals , Cell Line , Chromatography, Liquid , Humans , Inhibitory Concentration 50 , Marine Toxins/toxicity , Reproducibility of Results , Tandem Mass Spectrometry
7.
J Hum Hypertens ; 36(6): 537-543, 2022 06.
Article in English | MEDLINE | ID: mdl-33963270

ABSTRACT

In stable coronary heart disease, uncontrolled risk factors are strongly associated with incident myocardial infarction. We analysed the management of hypertension in 746 stable coronary patients recruited between 2005 and 2015 in a single-centre prospective study. Risk factors and pharmacological treatments were documented prior to and immediately after cardiac rehabilitation, and 1 year later. One year post-cardiac rehabilitation, all cardiovascular risk factors were significantly better controlled with the notable exception of hypertension: blood pressure (BP) <140/90 mmHg in 60% of the total population vs 49% (N = 450) of hypertensive patients (20% or 10%, according to the ACC/AHA 2017 or ESH/ESC guidelines, respectively). Of those who had achieved normotension by the end of cardiac rehabilitation, 42% had uncontrolled hypertension again 1 year later; in addition, body weight had increased, while physical activity and antihypertensive drug use had dropped (differences between controlled or uncontrolled hypertension at 1 year post-cardiac rehabilitation, NS). Three factors were correlated with BP elevations: discontinuation of betablockade: +7.9 mmHg; age >65 years: +6.2 mmHg; diabetes mellitus: +7.6 mmHg. Only 48% hypertensive patients were on guideline-recommended antihypertensive polytherapy. Although 28% were still hypertensive post-cardiac rehabilitation, and hypertension remained uncontrolled in 70% 1 year later, 61% antihypertensive prescriptions were not adjusted post-cardiac rehabilitation. One year post-cardiac rehabilitation, hypertension was the only cardiovascular risk factor that had not improved. This can be attributed to three main reasons, all associated with BP elevations: precipitous reduction in betablockade, physicians' inertia when faced with uncontrolled hypertension and lack of adherence to international guidelines.


Subject(s)
Cardiac Rehabilitation , Hypertension , Aged , Antihypertensive Agents/adverse effects , Blood Pressure , Humans , Hypertension/diagnosis , Hypertension/drug therapy , Hypertension/epidemiology , Prospective Studies
8.
Respirol Case Rep ; 8(8): e00666, 2020 Nov.
Article in English | MEDLINE | ID: mdl-32999724

ABSTRACT

We report the case of a 71-year-old obese continuous positive airway pressure (CPAP)-treated man who developed an acute cardiac failure (ACF) triggered by atrial fibrillation. CPAP data downloaded from the CPAP software (Rescan®) retrospectively demonstrated the progressive development of a high residual central apnoea-hypopnoea index (AHI) with Cheyne-Stokes respiration (CSR). The AHI decreased after cardioversion allowing normalization of cardiac rhythm and function. Raw data extracted from CPAP software showed a gradual decrease in the periodic breathing cycle length related to a simultaneous improvement in left ventricular ejection fraction (LVEF) after cardioversion. During this clinical period of respiratory instability in the presence of cardiac failure, CSR episodes were exacerbated by ventilation overshoots followed by micro-arousals induced by leaks. This might explain the high night to night variability of CSR occurrence in susceptible patients with impaired cardiac function. Beyond attempts to improve cardiac function, leak reduction might represent an important target for CSR management.

9.
J Cosmet Dermatol ; 18(6): 2027-2036, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31033133

ABSTRACT

BACKGROUND: Polar lipids from wheat (Triticum vulgare/aestivum) extract oil (WEO) are known to improve skin hydration. AIMS: These studies aimed to assess WEO benefits on the skin appearance of middle-aged women. METHODS: A double-blind, randomized, placebo-controlled clinical study was carried out on 64 healthy women, aged from 45 to 60 years, to investigate antiaging effects and benefits for the skin. The study lasted 20 weeks including 12 weeks of oral supplementation with WEO or placebo and 8 weeks of follow-up. Wrinkles in the "crow's-feet" area were evaluated by the Lemperle score. Skin hydration was measured using a corneometer, while roughness and radiance were determined by clinical scoring. Collagen content was quantified in human skin explants exposed to ultraviolet (UV) irradiations and treated with WEO or vehicle control. RESULTS: Compared to the placebo group, the Lemperle score was significantly reduced in the WEO group between W0 and W8 to reach a clinically significant 1 grade at W12. Facial hydration was significantly improved in the WEO group from W0 to W12, whereas leg hydration was significantly increased after 4 weeks and lasted throughout the supplementation period. Skin roughness and radiance were also significantly improved from W0 to W8 in the WEO group compared to placebo group. A higher collagen content was measured in the UV-irradiated skin explants treated with WEO compared to the untreated ones. CONCLUSION: These results confirmed the moisturizing effect of WEO and, for the first time, revealed its potential antiaging properties.


Subject(s)
Plant Extracts/pharmacology , Plant Oils/pharmacology , Skin Aging/drug effects , Triticum , Double-Blind Method , Female , Humans , In Vitro Techniques , Lipids/pharmacology , Middle Aged
10.
Nutrition ; 36: 33-40, 2017 Apr.
Article in English | MEDLINE | ID: mdl-28336105

ABSTRACT

BACKGROUND: Polyamines have been identified as pain agonists and interact with N-methyl-D-aspartate receptors. A prospective, randomized, multicenter, and blinded phase II clinical trial was conducted to evaluate a polyamine-deficient diet for the treatment of perioperative pain in patients during spinal surgery. METHODS: All analyses followed the intention-to-treat principle. The trial was designed to evaluate the dose-ranging effect of a low polyamine diet with respect to a total (group 1) or partial (group 2) polyamine diet on perioperative pain (7 d before and 5 d after surgery). Pain (numerical scale at rest and motion), quality of life questionnaires (Brief Pain Inventory, EIFEL questionnaire, and Short Form-12 acute questionnaire), and tolerance of and compliance with the nutritional program were measured. RESULTS: Compliance (preoperatively: 100% in group 1 and 83% in group 2; postoperatively: 83% in group 1 and 71% in group 2) and tolerance were good. After 7 d following the diet before surgery, decreased pain was observed in group 1 whereas no effect was observed in group 2 (P = 0.144). This analgesic effect became significant in group 1 in the subgroup of patients with initial high levels of pain (NS ≥ 4) at rest (P = 0.03) and during motion (P = 0.011). Quality of life was significantly improved in group 1 (P = 0.0465). In the postoperative period, pain was significantly decreased in group 1 compared to group 2 at rest (P = 0.022) and during motion (P = 0.029). The effect was significantly better on patients with higher initial pain both at rest (P = 0.013) and during motion (P = 0.005) in group 1 compared to group 2. CONCLUSION: Suppression of polyamines from the diet offers a nutrition-based treatment option for perioperative pain reduction independent of and complementary to typical analgesic approaches.


Subject(s)
Diet , Pain/diet therapy , Perioperative Care , Polyamines/administration & dosage , Adult , Aged , Dose-Response Relationship, Drug , Female , Humans , Male , Middle Aged , Patient Compliance , Prospective Studies , Quality of Life , Surveys and Questionnaires , Treatment Outcome
11.
Gene ; 296(1-2): 11-20, 2002 Aug 21.
Article in English | MEDLINE | ID: mdl-12383498

ABSTRACT

F-box proteins, a critical component of the evolutionary conserved ubiquitin-protein ligase complex SCF (Skp1/Cdc53-Cullin1/F-box), recruit substrates for ubiquitination and consequent degradation through their specific protein-protein interaction domains. Here, we report the identification of full-length cDNAs encoding three novel human F-box proteins named FBG3, FBG4 and FBG5 which display similarity with previously identified NFB42 (FBX2) and FBG2 (FBX6) proteins. All five proteins are characterized by an approximately 180-amino-acid (aa) conserved C-terminal domain and thus constitute a third subfamily of mammalian F-box proteins. Analysis of genomic organization of the five FBG genes revealed that all of them consist of six exons and five introns. FBG1, FBG2 and FBG3 genes are located in tandem on chromosome 1p36, and FBG4 and FBG5 are mapped to chromosome 19q13. FBG genes are expressed in a limited number of human tissues including kidney, liver, brain and muscle tissues. Expression of rat FBG2 gene was found related to differentiation/proliferation status of hepatocytes. Specifically, FBG2 mRNA was expressed in foetal liver, decreased after birth and re-accumulated in adult liver. Expression of FBG2 was strongly inhibited in hepatoma cells by okadaic acid.


Subject(s)
Cell Cycle Proteins/genetics , Multigene Family/genetics , Amino Acid Sequence , Animals , Base Sequence , Chromosome Mapping , Chromosomes, Human, Pair 1/genetics , Chromosomes, Human, Pair 19/genetics , Cloning, Molecular , DNA, Complementary/chemistry , DNA, Complementary/genetics , Exons , Female , Gene Expression , Gene Expression Regulation, Developmental , Genes/genetics , Humans , Introns , Liver/embryology , Liver/metabolism , Male , Molecular Sequence Data , Phylogeny , Pregnancy , Protein Isoforms/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Rats, Sprague-Dawley , Sequence Alignment , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Tumor Cells, Cultured
12.
Health Phys ; 99(4): 547-52, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20838097

ABSTRACT

Diethylene Triamine Pentaacetic Acid (DTPA) is used for decorporation of plutonium because it is known to be able to enhance its urinary excretion for several days after treatment by forming stable Pu-DTPA complexes. The decorporation prevents accumulation in organs and results in a dosimetric benefit, which is difficult to quantify from bioassay data using existing models. The development of a biokinetic model describing the mechanisms of actinide decorporation by administration of DTPA was initiated as a task in the European COordinated Network on RAdiation Dosimetry (CONRAD). The systemic biokinetic model from Leggett et al. and the biokinetic model for DTPA compounds of International Commission on Radiological Protection Publication 53 were the starting points. A new model for biokinetics of administered DTPA based on physiological interpretation of 14C-labeled DTPA studies from literature was proposed by the group. Plutonium and DTPA biokinetics were modeled separately. The systems were connected by means of a second order kinetics process describing the chelation process of plutonium atoms and DTPA molecules to Pu-DTPA complexes. It was assumed that chelation only occurs in the blood and in systemic compartment ST0 (representing rapid turnover soft tissues), and that Pu-DTPA complexes and administered forms of DTPA share the same biokinetic behavior. First applications of the CONRAD approach showed that the enhancement of plutonium urinary excretion after administration of DTPA was strongly influenced by the chelation rate constant. Setting it to a high value resulted in a good fit to the observed data. However, the model was not yet satisfactory since the effects of repeated DTPA administration in a short time period cannot be predicted in a realistic way. In order to introduce more physiological knowledge into the model several questions still have to be answered. Further detailed studies of human contamination cases and experimental data will be needed in order to address these issues. The work is now continued within the European Radiation Dosimetry Group, EURADOS.


Subject(s)
Models, Biological , Pentetic Acid/pharmacology , Plutonium/pharmacokinetics , Radiation Injuries/metabolism , Radiometry/methods , Body Burden , Carbon Radioisotopes , Chelating Agents/administration & dosage , Chelating Agents/pharmacology , Decontamination , Humans , Lymph/drug effects , Lymph/metabolism , Pentetic Acid/administration & dosage , Plutonium/blood , Plutonium/urine , Radiation Injuries/chemically induced , Radiation Injuries/prevention & control , Relative Biological Effectiveness , Staining and Labeling
13.
Eur J Med Chem ; 43(12): 2768-77, 2008 Dec.
Article in English | MEDLINE | ID: mdl-18313802

ABSTRACT

A library of bisphosphonate-based ligands was prepared using solution-phase parallel synthesis and tested for its uranium-binding properties. With the help of a screening method, based on a chromophoric complex displacement procedure, 23 dipodal and tripodal chelates bearing bisphosphonate chelating functions were found to display very high affinity for the uranyl ion and were selected for evaluation of their in vivo uranyl-removal efficacy. Among them, 11 ligands induced a huge modification of the uranyl biodistribution by deviating the metal from kidney and bones to liver. Among the other ligands, the most potent was the dipodal bisphosphonate 3C which reduced the retention of uranyl and increased its excretion by around 10% of the injected metal.


Subject(s)
Chelating Agents/chemical synthesis , Chelating Agents/pharmacology , Diphosphonates/chemical synthesis , Diphosphonates/pharmacology , Uranium/chemistry , Uranium/pharmacokinetics , Animals , Binding Sites , Bone and Bones/drug effects , Bone and Bones/metabolism , Chelating Agents/chemistry , Diphosphonates/chemistry , Kidney/drug effects , Kidney/metabolism , Ligands , Liver/drug effects , Liver/metabolism , Male , Molecular Structure , Rats , Rats, Sprague-Dawley , Small Molecule Libraries/chemical synthesis , Small Molecule Libraries/chemistry , Small Molecule Libraries/pharmacology , Stereoisomerism , Tissue Distribution/drug effects , Uranium/urine
14.
Hepatology ; 41(3): 478-86, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15723438

ABSTRACT

During liver regeneration, hepatocytes proliferate under the control of both proinflammatory cytokines such as tumor necrosis factor alpha (TNFalpha) and growth factors, in parallel to extracellular matrix remodeling. This study investigated mechanisms by which mitogen and extracellular matrix signals are linked for inducing proliferation of differentiated hepatocytes. The authors used adult rat hepatocytes in coculture with liver biliary cells, because cells are stably differentiated for several weeks, capable of extracellular matrix deposition, and unable to divide in response to growth factor alone. This work demonstrated that hepatocytes could undergo several proliferation waves without loss of differentiation by using alternating periods of TNFalpha/growth factor stimulation and deprivation. Three days after stimulation with TNFalpha and epidermal growth factor (EGF), up to 35% of hepatocytes divided. Demonstration was also provided that EGF alone only promoted cell progression up to late G(1), whereas TNFalpha was necessary for G(1)/S transition and Cdk1 induction. TNFalpha promoted an extracellular matrix (ECM) degradation that involved the matrix metalloproteinase MMP-9 induction through activation of NF-kappaB pathway. Finally, the authors showed that ECM remodeling signal was required for initiating any new hepatocyte division wave, in presence of mitogen. In conclusion, these results highlight that hepatocyte division is dependent on ECM deposition associated with differentiation status, and that ECM degradation signal is critical in controlling G(1)/S transition and Cdk1 induction. These results provide new insights for understanding the unique hepatocyte proliferation control and improving regeneration in patients suffering from liver damage.


Subject(s)
Extracellular Matrix/metabolism , Hepatocytes/cytology , Tumor Necrosis Factor-alpha/pharmacology , Animals , CDC2 Protein Kinase/biosynthesis , Cell Cycle/drug effects , Cell Differentiation , Cells, Cultured , Epidermal Growth Factor/pharmacology , Male , Matrix Metalloproteinase 9/genetics , NF-kappa B/metabolism , Rats , Rats, Sprague-Dawley
15.
Carcinogenesis ; 26(12): 2086-94, 2005 Dec.
Article in English | MEDLINE | ID: mdl-16033771

ABSTRACT

Growth factors are known to favor both proliferation and survival of hepatocytes. In the present study, we investigated if c-FLIP(L) (cellular FLICE-inhibitory protein, long isoform) could be involved in epidermal growth factor (EGF)-stimulated proliferation of rat hepatocytes since c-FLIP(L) regulates both cell proliferation and procaspase-8 maturation. Treatment with MEK inhibitors prevented induction of c-FLIP(L) by EGF along with total inhibition of DNA replication. However, EGF failed to inhibit processing of procaspase-8 in the presence of EGF suggesting that c-FLIP(L) does not play its canonical anti-apoptotic role in this model. Downregulation of c-FLIP expression using siRNA oligonucleotides strongly reduced DNA replication but did not result in enhanced apoptosis. Moreover, intermediate cleavage products of c-FLIP(L) and caspase-8 were found in EGF-treated hepatocytes in the absence of caspase-3 maturation and cell death. To determine whether the Fas/FADD/caspase-8/c-FLIP(L) complex was required for this activity, Fas, procaspase-8 and Fas-associated death domain protein (FADD) expression or function was inhibited using siRNA or constructs encoding dominant negative mutant proteins. Inhibition of any of these components of the Fas/FADD/caspase-8 pathway decreased DNA replication suggesting a function of these proteins in cell-cycle arrest. Similar results were obtained when the IETD-like caspase activity detectable in EGF-treated hepatocytes was inhibited by the pan-caspase inhibitor, z-ASP. Finally, we demonstrated co-immunoprecipitation between EGFR and Fas within 15 min following EGF stimulation. In conclusion, our results indicate that the Fas/FADD/c-FLIP(L)/caspase-8 pathway positively controls the G(1)/S transition in EGF-stimulated hepatocytes. Our data provide new insights into the mechanisms by which apoptotic proteins participate to mitogenic signals during the G(1) phase.


Subject(s)
Caspases/metabolism , Cell Proliferation , Hepatocytes/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Adaptor Proteins, Signal Transducing/antagonists & inhibitors , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Animals , CASP8 and FADD-Like Apoptosis Regulating Protein , Caspase 8 , Cells, Cultured , DNA Replication , Enzyme Inhibitors/pharmacology , Epidermal Growth Factor/pharmacology , ErbB Receptors , Fas-Associated Death Domain Protein , G1 Phase , Humans , Immunoprecipitation , Intracellular Signaling Peptides and Proteins/genetics , MAP Kinase Kinase 1/metabolism , Male , RNA, Small Interfering/pharmacology , Rats , Rats, Sprague-Dawley , S Phase , Signal Transduction , fas Receptor/metabolism
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