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Rodriguez-Villamizar LA, Hellemans K, Jerrett M, Su J, Sandler DP, Villeneuve PJ. Neighborhood greenness and participation in specific types of recreational physical activities in the Sister Study. Environ Res 2024; 243:117785. [PMID: 38036213 PMCID: PMC10872543 DOI: 10.1016/j.envres.2023.117785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 11/07/2023] [Accepted: 11/23/2023] [Indexed: 12/02/2023]
Abstract
BACKGROUND Urban green spaces have been consistently shown to have important human health benefits across a range of outcomes. These benefits are thought to be achieved, in part, because urban greenness provides opportunities for participation in recreational activity. However, the findings from studies that have assessed links between exposure to greenness and physical activity have been mixed. To date, few studies have examined association between greenness and specific types of recreational physical activities. OBJECTIVE We evaluated associations between measures of greenness and specific types of recreational physical activities. Moreover, we explored the extent to which these associations were modified by socioeconomic conditions, and regionally. METHODS We analyzed cross-sectional data from 49,649 women in the Sister Study and assigned three residentially-based measures of greenness based on national land cover data at buffer distances of 250 m and 500 m. Data on participation in up to ten specific recreational physical activities, including time spent in each activity were collected. Logistic regression was used to estimate odds ratios (OR) and their 95% confidence intervals (CI) controlling for confounders. RESULTS Compared to those in the lowest tertile of greenness, participants in the upper tertile of greenness within a 500 m buffer, were more likely to garden (OR = 1.46, 95% CI = 1.25,1.69), participate in sports (OR = 1.28, 95% CI = 1.19,1.38), run (OR = 1.15, 95% CI = 1.04,1.27), walk (OR = 1.11, 95% CI = 1.06,1.16), and engage in conditioning exercises (OR = 1.10, 95% CI = 1.05,1.16) at least once a week for at least one month over the past year. These associations were modified by household income and US region. DISCUSSION Our findings suggest a beneficial effect of greenness on physical activity and provide additional information to inform planning of green environments that contribute to better health and wellbeing.
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Affiliation(s)
- Laura A Rodriguez-Villamizar
- Department of Neuroscience, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada; Department of Public Health, Universidad Industrial de Santander, Carrera 32 29,31, Bucaramanga, Santander, 68002, Colombia.
| | - Kim Hellemans
- Department of Neuroscience, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Michael Jerrett
- Fielding School of Public Health, University of California Los Angeles, 650 Charles E Young Dr S, Los Angeles, CA, 90095, USA
| | - Jason Su
- School of Public Health, University of California at Berkeley, 2121 Berkeley Way, Berkeley, CA, 94704, USA
| | - Dale P Sandler
- US National Institute of Environmental Health Sciences, RTP, NC, 27709, USA
| | - Paul J Villeneuve
- Department of Neuroscience, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
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Joyal-Desmarais K, Stojanovic J, Kennedy EB, Enticott JC, Boucher VG, Vo H, Košir U, Lavoie KL, Bacon SL, Granana N, Losada AV, Boyle J, Shawon SR, Dawadi S, Teede H, Kautzky-Willer A, Dash A, Cornelio ME, Karsten M, Matte DL, Reichert F, Abou-Setta A, Aaron S, Alberga A, Barnett T, Barone S, Bélanger-Gravel A, Bernard S, Birch LM, Bondy S, Booij L, Da Silva RB, Bourbeau J, Burns R, Campbell T, Carlson L, Charbonneau É, Corace K, Drouin O, Ducharme F, Farhadloo M, Falk C, Fleet R, Fournier M, Garber G, Gauvin L, Gordon J, Grad R, Gupta S, Hellemans K, Herba C, Hwang H, Jedwab J, Kakinami L, Kim S, Liu J, Norris C, Pelaez S, Pilote L, Poirier P, Presseau J, Puterman E, Rash J, Ribeiro PAB, Sadatsafavi M, Chaudhuri PS, Suarthana E, Tse S, Vallis M, Caceres NB, Ortiz M, Repetto PB, Lemos-Hoyos M, Kassianos A, Rod NH, Beraneck M, Ninot G, Ditzen B, Kubiak T, Codjoe S, Kpobi L, Laar A, Skoura T, Francis DL, Devi NK, Meitei S, Nethan ST, Pinto L, Saraswathy KN, Tumu D, Lestari S, Wangge G, Byrne M, Durand H, McSharry J, Meade O, Molloy G, Noone C, Levine H, Zaidman-Zait A, Boccia S, Hoxhaj I, Paduano S, Raparelli V, Zaçe D, Aburub A, Akunga D, Ayah R, Barasa C, Godia PM, Kimani-Murage EW, Mutuku N, Mwoma T, Naanyu V, Nyamari J, Oburu H, Olenja J, Ongore D, Ziraba A, Bandawe C, Yim L, Ajuwon A, Shar NA, Usmani BA, Martínez RMB, Creed-Kanashiro H, Simão P, Rutayisire PC, Bari AZ, Vojvodic K, Nagyova I, Bantjes J, Barnes B, Coetzee B, Khagee A, Mothiba T, Roomaney R, Swartz L, Cho J, Lee MG, Berman A, Stattin NS, Fischer S, Hu D, Kara Y, Şimşek C, Üzmezoğlu B, Isunju JB, Mugisha J, Byrne-Davis L, Griffiths P, Hart J, Johnson W, Michie S, Paine N, Petherick E, Sherar L, Bilder RM, Burg M, Czajkowski S, Freedland K, Gorin SS, Holman A, Lee J, Lopez G, Naar S, Okun M, Powell L, Pressman S, Revenson T, Ruiz J, Sivaram S, Thrul J, Trudel-Fitzgerald C, Yohannes A, Navani R, Ranakombu K, Neto DH, Ben-Porat T, Dragomir A, Gagnon-Hébert A, Gemme C, Jamil M, Käfer LM, Vieira AM, Tasbih T, Woods R, Yousefi R, Roslyakova T, Priesterroth L, Edelstein S, Snir R, Uri Y, Alyami M, Sanuade C, Crescenzi O, Warkentin K, Grinko K, Angne L, Jain J, Mathur N, Mithe A, Nethan S. How well do covariates perform when adjusting for sampling bias in online COVID-19 research? Insights from multiverse analyses. Eur J Epidemiol 2022; 37:1233-1250. [PMID: 36335560 PMCID: PMC9638233 DOI: 10.1007/s10654-022-00932-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 10/06/2022] [Indexed: 11/07/2022]
Abstract
COVID-19 research has relied heavily on convenience-based samples, which-though often necessary-are susceptible to important sampling biases. We begin with a theoretical overview and introduction to the dynamics that underlie sampling bias. We then empirically examine sampling bias in online COVID-19 surveys and evaluate the degree to which common statistical adjustments for demographic covariates successfully attenuate such bias. This registered study analysed responses to identical questions from three convenience and three largely representative samples (total N = 13,731) collected online in Canada within the International COVID-19 Awareness and Responses Evaluation Study ( www.icarestudy.com ). We compared samples on 11 behavioural and psychological outcomes (e.g., adherence to COVID-19 prevention measures, vaccine intentions) across three time points and employed multiverse-style analyses to examine how 512 combinations of demographic covariates (e.g., sex, age, education, income, ethnicity) impacted sampling discrepancies on these outcomes. Significant discrepancies emerged between samples on 73% of outcomes. Participants in the convenience samples held more positive thoughts towards and engaged in more COVID-19 prevention behaviours. Covariates attenuated sampling differences in only 55% of cases and increased differences in 45%. No covariate performed reliably well. Our results suggest that online convenience samples may display more positive dispositions towards COVID-19 prevention behaviours being studied than would samples drawn using more representative means. Adjusting results for demographic covariates frequently increased rather than decreased bias, suggesting that researchers should be cautious when interpreting adjusted findings. Using multiverse-style analyses as extended sensitivity analyses is recommended.
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Affiliation(s)
- Keven Joyal-Desmarais
- Department of Health, Kinesiology and Applied Physiology, Concordia University, 7141 Sherbrooke Street West, Montreal, QC H4B 1R6 Canada ,Montreal Behavioural Medicine Centre, CIUSSS-NIM, Montreal, Canada
| | - Jovana Stojanovic
- Montreal Behavioural Medicine Centre, CIUSSS-NIM, Montreal, Canada ,Canadian Agency for Drugs and Technologies in Health, Ottawa, Canada
| | - Eric B. Kennedy
- Disaster and Emergency Management, York University, Toronto, Canada
| | - Joanne C. Enticott
- Department of General Practice, Monash University, Melbourne, Australia ,Monash Partners, Advanced Health Research and Translation Centre, Melbourne, Australia
| | | | - Hung Vo
- Austin Health, Victoria, Australia
| | - Urška Košir
- Department of Health, Kinesiology and Applied Physiology, Concordia University, 7141 Sherbrooke Street West, Montreal, QC H4B 1R6 Canada ,Montreal Behavioural Medicine Centre, CIUSSS-NIM, Montreal, Canada
| | - Kim L. Lavoie
- Montreal Behavioural Medicine Centre, CIUSSS-NIM, Montreal, Canada ,Département de Psychologie, Université du Québec à Montréal, Montreal, Canada
| | - Simon L. Bacon
- Department of Health, Kinesiology and Applied Physiology, Concordia University, 7141 Sherbrooke Street West, Montreal, QC H4B 1R6 Canada ,Montreal Behavioural Medicine Centre, CIUSSS-NIM, Montreal, Canada
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Weinberg J, Raineki C, Bodnar T, Lan N, Uban K, Lam V, Hellemans K. Prenatal alcohol exposure: Fetal programming, alcohol-stress interactions, and sex differences in outcome. Alcohol 2017. [DOI: 10.1016/j.alcohol.2017.02.241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Marmolejo-Ramos F, Hellemans K, Comeau A, Heenan A, Faulkner A, Abizaid A, D’Angiulli A. Event-related potential signatures of perceived and imagined emotional and food real-life photos. Neurosci Bull 2015; 31:317-30. [PMID: 25895000 PMCID: PMC5563690 DOI: 10.1007/s12264-014-1520-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 12/12/2014] [Indexed: 11/30/2022] Open
Abstract
Although food and affective pictures share similar emotional and motivational characteristics, the relationship between the neuronal responses to these stimuli is unclear. Particularly, it is not known whether perceiving and imagining food and affective stimuli elicit similar event-related potential (ERP) patterns. In this study, two ERP correlates, the early posterior negativity (EPN) and the late positive potential (LPP) for perceived and imagined emotional and food photographs were investigated. Thirteen healthy volunteers were exposed to a set of food photos, as well as unpleasant, pleasant, and neutral photos from the International Affective Picture System. In each trial, participants were first asked to view a photo (perception condition), and then to create a visual mental image of it and to rate its vividness (imagery condition). The results showed that during perception, brain regions corresponding to sensorimotor and parietal motivational (defensive and appetitive) systems were activated to different extents, producing a graded pattern of EPN and LPP responses specific to the photo content - more prominent for unpleasant than pleasant and food content. Also, an EPN signature occurred in both conditions for unpleasant content, suggesting that, compared to food or pleasant content, unpleasant content may be attended to more intensely during perception and may be represented more distinctly during imagery. Finally, compared to LLP activation during perception, as well as imagery and perception of all other content, LPP activation was significantly reduced during imagery of unpleasant photos, suggesting inhibition of unwanted memories. Results are framed within a neurocognitive working model of embodied emotions.
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Affiliation(s)
| | - Kim Hellemans
- Department of Neuroscience, Carleton University, Ottawa, Ontario Canada
| | - Amy Comeau
- Department of Neuroscience, Carleton University, Ottawa, Ontario Canada
| | - Adam Heenan
- Department of Psychology, Queens University, Kingston, Ontario Canada
| | - Andrew Faulkner
- Department of Neuroscience, Carleton University, Ottawa, Ontario Canada
| | - Alfonso Abizaid
- Department of Neuroscience, Carleton University, Ottawa, Ontario Canada
| | - Amedeo D’Angiulli
- Department of Neuroscience, Carleton University, Ottawa, Ontario Canada
- Institute of Interdisciplinary Studies, Carleton University, Ottawa, Ontario Canada
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Cagno S, Hellemans K, Lind OC, Skipperud L, Janssens K, Salbu B. LA-ICP-MS for Pu source identification at Mayak PA, the Urals, Russia. Environ Sci Process Impacts 2014; 16:306-312. [PMID: 24424783 DOI: 10.1039/c3em00531c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Information on Pu in environmental samples is traditionally based on the determination of the (240+239)Pu activity via Alpha Spectrometry (AS). A large number of alpha spectrometry sources (planchettes) containing radiochemically separated Pu are therefore stored worldwide and are available for further analyses. These archive samples represent a resource from which valuable information on isotopic composition of alpha emitters including Pu can be obtained. The relative abundances of Pu isotopes can be used to trace specific Pu sources and characterize the relative contributions of different Pu sources in a sample. Thus, in addition to the total (239+240)Pu activity, determination of the (240)Pu/(239)Pu ratio can provide valuable information on the nature of the Pu emitting sources. The Pu isotopic ratios can be determined by mass spectrometry techniques such as Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICPMS) or Accelerator Mass Spectrometry (AMS) that require dissolution and complete destruction of the material deposited on the planchettes. In this study Laser Ablation (LA)-quadrupole-ICP-MS has been employed for the analysis of (239)Pu/(240)Pu ratios from alpha-planchettes prepared from samples originating from the Mayak PA nuclear facility, Russia. The results are compared with data from AMS and show that the (240)Pu/(239)Pu ratios obtained by LA-ICP-MS can be utilized to distinguish weapons-grade Pu from civil reprocessing sources. Moreover, isotope ratio mapping can also be performed across the planchettes, allowing e.g. the visualization of possible inhomogeneities in the Pu-isotope distribution on their surface. Thus, this solid sample technique can be applied to extract additional information from existing archives of samples.
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Affiliation(s)
- S Cagno
- CERAD, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway.
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Martens GA, Motté E, Kramer G, Stangé G, Gaarn LW, Hellemans K, Nielsen JH, Aerts JM, Ling Z, Pipeleers D. Functional characteristics of neonatal rat β cells with distinct markers. J Mol Endocrinol 2014; 52:11-28. [PMID: 24049066 DOI: 10.1530/jme-13-0106] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Neonatal β cells are considered developmentally immature and hence less glucose responsive. To study the acquisition of mature glucose responsiveness, we compared glucose-regulated redox state, insulin synthesis, and secretion of β cells purified from neonatal or 10-week-old rats with their transcriptomes and proteomes measured by oligonucleotide and LC-MS/MS profiling. Lower glucose responsiveness of neonatal β cells was explained by two distinct properties: higher activity at low glucose and lower activity at high glucose. Basal hyperactivity was associated with higher NAD(P)H, a higher fraction of neonatal β cells actively incorporating (3)H-tyrosine, and persistently increased insulin secretion below 5 mM glucose. Neonatal β cells lacked the steep glucose-responsive NAD(P)H rise between 5 and 10 mM glucose characteristic for adult β cells and accumulated less NAD(P)H at high glucose. They had twofold lower expression of malate/aspartate-NADH shuttle and most glycolytic enzymes. Genome-wide profiling situated neonatal β cells at a developmental crossroad: they showed advanced endocrine differentiation when specifically analyzed for their mRNA/protein level of classical neuroendocrine markers. On the other hand, discrete neonatal β cell subpopulations still expressed mRNAs/proteins typical for developing/proliferating tissues. One example, delta-like 1 homolog (DLK1) was used to investigate whether neonatal β cells with basal hyperactivity corresponded to a more immature subset with high DLK1, but no association was found. In conclusion, the current study supports the importance of glycolytic NADH-shuttling in stimulus function coupling, presents basal hyperactivity as novel property of neonatal β cells, and provides potential markers to recognize intercellular developmental differences in the endocrine pancreas.
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Affiliation(s)
- G A Martens
- Diabetes Research Center, Brussels Free University (VUB), Laarbeeklaan 103, B1090 Brussel, Belgium Department of Clinical Chemistry and Radioimmunology, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, B1090 Brussels, Belgium Department of Medical Biochemistry, Academisch Medisch Centrum, Amsterdam, The Netherlands Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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De Meester K, Das T, Hellemans K, Verbrugghe W, Jorens PG, Verpooten GA, Van Bogaert P. Impact of a standardized nurse observation protocol including MEWS after Intensive Care Unit discharge. Resuscitation 2012; 84:184-8. [PMID: 22796310 DOI: 10.1016/j.resuscitation.2012.06.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 06/08/2012] [Accepted: 06/20/2012] [Indexed: 11/25/2022]
Abstract
BACKGROUND Analysis of in-hospital mortality after serious adverse events (SAE's) in our hospital showed the need for more frequent observation in medical and surgical wards. We hypothesized that the incidence of SAE's could be decreased by introducing a standard nurse observation protocol. AIM To investigate the effect of a standard nurse observation protocol implementing the Modified Early Warning Score (MEWS) and a color graphic observation chart. METHODS Pre- and post-intervention study by analysis of patients records for a 5-day period after Intensive Care Unit (ICU) discharge to 14 medical and surgical wards before (n=530) and after (n=509) the intervention. RESULTS For the total study population the mean Patient Observation Frequency Per Nursing Shift (POFPNS) during the 5-day period after ICU discharge increased from .9993 (95% C.I. .9637-1.0350) in the pre-intervention period to 1.0732 (95% C.I. 1.0362-1.1101) (p=.005) in the post-intervention period. There was an increased risk of a SAE in patients with MEWS 4 or higher in the present nursing shift (HR 8.25; 95% C.I. 2.88-23.62) and the previous nursing shift (HR 12.83;95% C.I. 4.45-36.99). There was an absolute risk reduction for SAE's within 120h after ICU discharge of 2.2% (95% C.I. -0.4-4.67%) from 5.7% to 3.5%. CONCLUSION The intervention had a positive impact on the observation frequency. MEWS had a predictive value for SAE's in patients after ICU discharge. The drop in SAE's was substantial but did not reach statistical significance.
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Affiliation(s)
- K De Meester
- Antwerp University Hospital, Wilrijkstraat 10, 2650 Edegem, Belgium.
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Chintinne M, Stangé G, Denys B, In 't Veld P, Hellemans K, Pipeleers-Marichal M, Ling Z, Pipeleers D. Contribution of postnatally formed small beta cell aggregates to functional beta cell mass in adult rat pancreas. Diabetologia 2010; 53:2380-8. [PMID: 20645074 DOI: 10.1007/s00125-010-1851-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 06/24/2010] [Indexed: 01/09/2023]
Abstract
AIMS/HYPOTHESIS Neogenesis of beta cells and their clustering to small aggregates is a key process in prenatal development of beta cell mass. We investigated the contribution of postnatally formed small aggregates to functional beta cell mass in adult rats. METHODS Conditions were defined for (1) counting total beta cell number in pancreases with relative error of <10% and (2) determining their distribution over aggregates of different size and over functionally different subpopulations. RESULTS Pancreases of 10-week-old male Wistar rats contained 2.8 ± 0.2 × 10⁶ beta cells, of which >90% was generated postnatally, involving: (1) neo-formation of 30,000 aggregates with diameter <50 μm including single cells; and (2) growth of 5,500 aggregates to larger sizes, accounting for 90% of the increase in cell number, with number of growing aggregates in the tail 50% greater than elsewhere. At 10 weeks, 86% of aggregates were <50 μm; compared with aggregates >200 μm, their beta cells exhibited a higher basal insulin content that was also resistant to glibenclamide-induced degranulation. The pool of Ki67-positive beta cells was sixfold larger than at birth and distributed over all aggregate sizes. CONCLUSIONS/INTERPRETATION We describe a method for in situ counting of beta cell numbers and subpopulations with low relative error. In adult rats, >90% of beta cells and beta cell aggregates are formed after birth. Aggregates <50 μm are more than 100-fold more abundant than aggregates >200 μm, which are selected for isolated islet studies. Their topographic and functional properties contribute to the functional heterogeneity of the beta cell population; their growth to larger aggregates with characteristic beta cell functions may serve future metabolic needs.
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Affiliation(s)
- M Chintinne
- Diabetes Research Center, Brussels Free University-VUB, Laarbeeklaan 103, 1090, Brussels, Belgium
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Reynaert H, Vaeyens F, Qin H, Hellemans K, Chatterjee N, Winand D, Quartier E, Schuit F, Urbain D, Kumar U, Patel YC, Geerts A. Somatostatin suppresses endothelin-1-induced rat hepatic stellate cell contraction via somatostatin receptor subtype 1. Gastroenterology 2001; 121:915-30. [PMID: 11606505 DOI: 10.1053/gast.2001.27971] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND & AIMS Hepatic stellate cells (HSCs) are considered therapeutic targets to decrease portal hypertension. To elucidate some of the hemodynamic effects of somatostatin (SST) on portal pressure, the presence and function of SST receptors (SSTRs) on HSCs were investigated. METHODS SSTR messenger RNA expression, and SSTR presence was investigated using reverse-transcription polymerase chain reaction, real-time quantitative polymerase chain reaction, Western blotting, and immunohistochemistry. The function of SSTRs was studied by examining the effects of SST and specific SSTR agonists on endothelin-1(ET-1)-induced HSC contraction. RESULTS Specific amplicons for SSTR subtypes 1, 2, and 3 were demonstrated in rat liver and in activated HSCs. The presence of SSTR subtypes 1, 2, and 3 was confirmed by Western blotting. With immunohistochemistry, a strong staining of HSCs was obtained for SSTR subtypes 1, 2, and 3 in CCl4-treated rats, but not in normal rat liver. Incubation of HSCs on collagen gels with buffer, 10(-8) mol/L SST, and 2 x 10(-8) mol/L ET-1 resulted in collagen surface area decreases of 5.5% +/- 3.3%, 6.8% +/- 4.4%, and 49.8% +/- 8.3%, respectively. Relative contraction of gels preincubated with 10(-8) mol/L SST followed by 2 x 10(-8) mol/L ET-1 or vice versa as compared with maximal contraction (100%) with 2 x 10(-8) mol/L ET-1 were 72.6% +/- 17.9% and 76.2% +/- 12.6%, respectively (P < 0.05). SSTR agonist 1, but not SSTR agonist 2 or 3, was able to counteract the contractile effect of ET-1. CONCLUSIONA: Activated rat HSCs bear SSTR subtypes 1, 2, and 3. SST causes significant partial inhibition of ET-1-induced contraction of activated HSCs, mainly by stimulation of SSTR subtype 1.
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Affiliation(s)
- H Reynaert
- Laboratory for Molecular Liver Cell Biology, Free University of Brussels (VUB), Belgium.
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Rombouts K, Wielant A, Hellemans K, Schuppan D, Geerts A. Influence of aldosterone on collagen synthesis and proliferation of rat cardiac fibroblasts. Br J Pharmacol 2001; 134:224-32. [PMID: 11522615 PMCID: PMC1572936 DOI: 10.1038/sj.bjp.0704247] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. Previous in vivo studies in men and experimental animal models have shown that hyperaldosteronemia is correlated with cardiac fibrosis due to increased total collagen synthesis. As yet, it is unclear whether aldosterone has direct pro-fibrogenic effect on cardiac fibroblasts, the fibrogenic effector cell in the myocardium, and if so which procollagens specifically are synthesized at higher rates. 2. The present study aims at establishing whether de novo collagen synthesis by cardiac fibroblasts is enhanced following exposure for 2x24 h to pharmacological (10(-7) - 10(-8) M), near-physiological (10(-9) M) or physiological (10(-10) - 10(-11) M) aldosterone concentrations. During the last 24 h, cells were metabolically labelled with [35S]-methionine/[35S]-cysteine. Labelled procollagens were immunoprecipitated quantitatively using antibodies against specific procollagens. Contrary to expectations, 10(-7) M aldosterone inhibited significantly de novo synthesis of procollagens type I and IV (-35% and -42%, respectively). For procollagen type III, only a tendency towards inhibition was observed. At lower concentrations of aldosterone (10(-8) - 10(-10) M), synthesis of procollagens type I, III or IV was unaffected. 3. Cellular DNA synthesis under influence of aldosterone was evaluated by measuring BrdU incorporation. Cells were treated with aldosterone, while BrdU was added during the last 16 h of treatment. Aldosterone had no demonstrable effect on cellular proliferation. 4. Reverse transcription-polymerase chain reaction (RT - PCR) clearly demonstrated the presence of mineralocorticoid receptor mRNA in cardiac fibroblasts. 5. In spite of the expression of the mineralocorticoid receptor by cultured cardiac fibroblasts, the pro-fibrogenic effect of aldosterone as observed in vivo, is not likely to be due to a direct effect of this hormone in cardiac fibroblasts.
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Affiliation(s)
- K Rombouts
- Laboratory for Molecular Liver Cell Biology, Faculty of Medicine and Pharmacy, Free University of Brussels (VUB), Belgium.
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Rombouts K, Niki T, Wielant A, Hellemans K, Geerts A. Trichostatin A, lead compound for development of antifibrogenic drugs. Acta Gastroenterol Belg 2001; 64:239-46. [PMID: 11680040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Eukaryotic gene expression has mainly been studied in the context of trans-acting transcription factors and their interaction with regulatory cis-elements. Evidence is accumulating, that the higher order structure of chromatin also plays an essential role in eukaryotic gene expression. Hepatic stellate cells are the major cellular source of extracellular matrix synthesis in chronic liver diseases leading to fibrosis. We explored the antifibrogenic effect of the histone deacetylase inhibitor trichostatin A (TSA) on hepatic stellate cells in vitro. Primary hepatic stellate cells as well as activated, subcultured stellate cells were exposed to 10(-7) M-10(-9) M TSA. Collagens type I and III, and smooth muscle alpha-actin (alpha-SMA), a marker for transdifferentiation, were investigated at the protein and mRNA level by performing Northern hybridisation and quantitative immunoprecipitation. The antiproliferative effect was examined by 3H-thymidine incorporation and cell counting. Hyperacetylation of histone H4 was demonstrated by acid urea Triton-X-100 (AUT) polyacrylamide gel electrophoresis. TSA at 10(-7) M retarded the morphological changes characteristics for activation of primary stellate cells. Synthesis of collagens type I and III, and alpha-SMA was strongly inhibited at both protein and mRNA level. The proliferation rate of primary hepatic stellate cells was strongly suppressed by 10(-7) M TSA. Hyperacetylation of histone H4 showed to be maximal at 10(-7) M TSA. Primary hepatic stellate cells were more affected by TSA than subcultured stellate cells.
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Affiliation(s)
- K Rombouts
- Laboratory for Molecular Liver Cell Biology, Free University of Brussels (VUB), Laarbeeklaan 103, 1090 Brussels-Jette, Belgium.
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Bataller R, Gasull X, Ginès P, Hellemans K, Görbig MN, Nicolás JM, Sancho-Bru P, De Las Heras D, Gual A, Geerts A, Arroyo V, Rodés J. In vitro and in vivo activation of rat hepatic stellate cells results in de novo expression of L-type voltage-operated calcium channels. Hepatology 2001; 33:956-62. [PMID: 11283860 DOI: 10.1053/jhep.2001.23500] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Following chronic liver injury, hepatic stellate cells (HSCs) transdifferentiate into myofibroblast-like cells, which develop contractile properties and contribute to increased resistance to blood flow. We investigated whether this phenotypic activation includes changes in the expression of L-type voltage-operated Ca2+ channels (VOCC), which mediate Ca2+ influx and regulate cell contraction in vascular cell types. Rat HSCs were studied in the quiescent phenotype and after their activation in vitro (cultured on plastic for 14 days) and in vivo (isolated from rats with CCl(4)-induced cirrhosis). Patch-clamp studies showed Ca2+ currents through L-type VOCC in HSCs activated both in vitro and in vivo, whereas no currents were detected in quiescent HSCs. Moreover, binding studies with (3)H-isradipine, a specific L-type VOCC antagonist, showed a large number of binding sites in activated HSCs, while no specific binding was found in quiescent HSCs. Finally, messenger RNA (mRNA) encoding L-type VOCC was not detected in quiescent HSCs as assessed by reverse transcription-polymerase chain reaction (RT-PCR) and Northern blot analysis, whereas it was present in activated HSCs. Stimulation of L-type VOCC with KCl resulted in a marked increase in [Ca2+](i) followed by cell contraction in HSCs activated both in vitro and in vivo, whereas no effects were observed in quiescent HSCs. We conclude that the activation of HSCs is associated with up-regulation of L-type VOCC that mediate Ca2+ influx and cell contraction. These results may be relevant to the pathogenesis of portal hypertension.
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Affiliation(s)
- R Bataller
- Liver Unit, Hospital Clinic, IDIBAPS, University of Barcelona School of Medicine, Catalunya, Spain
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Rombouts K, Niki T, Wielant A, Hellemans K, Schuppan D, Kormoss N, Geerts A. Effect of aldosterone on collagen steady state levels in primary and subcultured rat hepatic stellate cells. J Hepatol 2001; 34:230-8. [PMID: 11281551 DOI: 10.1016/s0168-8278(00)00087-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
BACKGROUND/AIMS Activation of the renin-angiotensin-aldosterone system can lead to collagen accumulation and reactive myocardial fibrosis. This study aims at evaluating the effect of aldosterone on extracellular matrix synthesis by rat hepatic stellate cells. METHODS Cultured cells were treated with different concentrations of aldosterone (10(-6)-10(-10) M) and metabolically labeled with 35S-methionine/35S-cysteine. Procollagen types I, III and IV, laminin and fibronectin were specifically immunoprecipitated and quantified by phosphor imaging. Using the reverse transcription-polymerase chain reaction, we investigated the expression of the mineralocorticoid receptor in hepatic stellate cells. RESULTS Quantitation showed that 10(-6) M aldosterone induced procollagen type I synthesis significantly, whereas procollagen type IV expression was significantly affected by 10(-9) and 10(-10) M aldosterone, both in primary hepatic stellate cells. RT-PCR experiments clearly demonstrated a lack of expression of the mineralocorticoid receptor in hepatic stellate cells. CONCLUSION We demonstrated that aldosterone altered moderately procollagen type I and IV synthesis by primary hepatic stellate cells, but not by activated stellate cells which are the principal cellular sources of extracellular matrix proteins in chronic liver disease. Moreover, hepatic stellate cells do not express the mineralocorticoid receptor, suggesting that the observed modest changes of extracellular matrix synthesis are probably due to mineralocorticoid receptor unrelated mechanisms.
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Affiliation(s)
- K Rombouts
- Laboratory for Molecular Liver Cell Biology, Faculty of Medicine and Pharmacy, Free University of Brussels (VUB), Jette, Belgium.
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Van den Branden C, Ceyssens B, De Craemer D, Pauwels M, Vanden Houte K, De Bleser P, Hellemans K, Geerts A, Verbeelen D. Renal antioxidant enzymes and fibrosis-related markers in the rat adriamycin model. Nephron Clin Pract 2000; 86:167-75. [PMID: 11014987 DOI: 10.1159/000045736] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Excessive generation of reactive oxygen intermediates can induce changes in the cellular antioxidant defence system. In this study we examine the antioxidant enzyme status and the expression of fibrosis-related marker proteins in the Adriamycin model of chronic renal failure in the rat. Twenty weeks after Adriamycin treatment, rats have overt nephrotic syndrome and renal failure with development of tubulo-interstitial fibrosis and glomerulosclerosis. Lipids accumulate in blood and in both glomeruli and tubulo-interstitial tissue. Desmin and alpha-smooth muscle actin expression increases in glomeruli and in the tubulo-interstitial area. Renal cortex antioxidant enzyme activities are decreased 20 weeks after Adriamycin injection (to 41% for catalase, to 56% for total superoxide dismutase and to 69% for glutathione peroxidase). The mRNA levels of catalase, Cu/Zn-superoxide dismutase and glutathione peroxidase-1 evaluated by Northern blot are decreased by more than 50% for catalase, Cu/Zn-superoxide dismutase and glutathione peroxidase-1. We conclude that in the rat Adriamycin-induced model of chronic renal failure with fibrosis, the combination of decreased antioxidant enzyme status in renal cortex with high concentrations of lipids in blood and renal tissue facilitates oxidative damage. Development of fibrosis is paralleled by increased expression of desmin and alpha-smooth muscle actin.
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Van Den Branden C, Ceyssens B, De Craemer D, De Bleser P, Hellemans K, Geerts A, Verbeelen D. Antioxidant enzyme gene expression in rats with remnant kidney induced chronic renal failure. Exp Nephrol 2000; 8:91-6. [PMID: 10729748 DOI: 10.1159/000020654] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Reactive oxygen intermediates play a role in chronic renal injury and glomerulosclerosis. We investigate changes in renal cortex antioxidant enzyme gene expression in the rat remnant-kidney model of chronic renal failure and compare the new data to enzyme activities published earlier. Antioxidant enzyme gene expression is evaluated by Northern blot analysis of cortex mRNA, using cDNA probes for catalase, copper/zinc-containing superoxide dismutase, and glutathione peroxidase. Catalase gene expression decreases during development of renal failure; this decrease is accompanied by decreased catalase activity during the glomerulosclerosis phase of the remnant-kidney model. Copper/zinc superoxide dismutase and glutathione peroxidase gene expression remain at a normal level during progression of the model, whereas their activities show a temporary decrease in the early remnant kidney. In the remnant-kidney model, catalase seems to be more vulnerable to reactive oxygen intermediates than superoxide dismutase and glutathione peroxidase. Our results show that antioxidant enzyme activity and gene expression do not change in the same direction at all times during disease development and that all antioxidant enzymes do not respond in the same way.
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Affiliation(s)
- C Van Den Branden
- Department of Human Anatomy, Vrije Universiteit Brussel and Academic Hospital, Brussel, Belgium.
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Abstract
BACKGROUND Hepatic stellate cells exert specific functions in the liver: storage of large amounts of retinyl esters, synthesis and breakdown of hepatic extracellular matrix, secretion of a variety of cytokines, and control of the diameter of the sinusoids. AIMS To examine the influence of all-trans retinoic acid (ATRA) and 9-cis retinoic acid (9RA) on extracellular matrix production and proliferation of activated hepatic stellate cells. METHODS Cells were isolated using collagenase/pronase, purified by centrifugation in nycodenz, and cultured for two weeks. At this time point the cells exhibited the activated phenotype. Cells were exposed to various concentrations of ATRA and 9RA. The expression of procollagens I, III, and IV, of fibronectin and of laminin were analysed by immunoprecipitation and northern hybridisation. RESULTS ATRA exerted a significant inhibitory effect on the synthesis of procollagens type I, III, and IV, fibronectin, and laminin, but did not influence stellate cell proliferation, whereas 9RA showed a clear but late effect on proliferation. 9RA increased procollagen I mRNA 1.9-fold, but did not affect the expression of other matrix proteins. CONCLUSION Results showed that ATRA and 9RA exert different, often contrary effects on activated stellate cells. These observations may explain prior divergent results obtained following retinoid administration to cultured stellate cells or in animals subjected to fibrogenic stimuli.
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Affiliation(s)
- K Hellemans
- Laboratory for Cell Biology and Histology, Faculty of Medicine and Pharmacy, Free University of Brussels (VUB), Belgium
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Niki T, Pekny M, Hellemans K, Bleser PD, Berg KV, Vaeyens F, Quartier E, Schuit F, Geerts A. Class VI intermediate filament protein nestin is induced during activation of rat hepatic stellate cells. Hepatology 1999; 29:520-7. [PMID: 9918930 DOI: 10.1002/hep.510290232] [Citation(s) in RCA: 220] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Hepatic stellate cells are considered to be liver-specific pericytes that play a key role in liver fibrosis. Because these cells express desmin and smooth muscle alpha-actin, they were assumed to be of myogenic origin. This hypothesis became doubtful when it was reported that stellate cells also express glial fibrillary acidic protein and neural cell adhesion molecule. In the present study, we show that activated stellate cells express nestin, a class VI intermediate filament protein originally identified as a marker for neural stem cells. Expression of nestin was first studied during spontaneous activation of stellate cells in culture. Immunohistochemistry showed that nestin-positive stellate cells already appeared at day 3, and nearly all the cells became positive for nestin at day 6 and 15. The immunoreaction was present in filaments except in dividing cells. The presence of messenger RNA transcript for nestin was shown by reverse transcription polymerase chain reaction and sequencing of amplified complementary DNA. We then compared the presence of nestin with that of other intermediate filament proteins and smooth muscle alpha-actin. Immunoblotting showed that the relative concentrations of nestin, desmin, and vimentin increased between day 2 and 6 in primary culture. After the initial increase vimentin leveled off, while nestin and desmin showed a tendency to decrease. This pattern was quite different from that of glial fibrillary acidic protein, which kept declining, and smooth muscle alpha-actin, which increased continuously up to day 13 in culture. We then studied the presence of nestin in normal and CCl4-injured rat liver. In normal liver, minimal immunoreaction for nestin was observed within the liver parenchyma. During induction of fibrosis by carbon tetrachloride, nestin-positive stellate cells appeared at 6 weeks, which was late in comparison with the induction of desmin and smooth muscle alpha-actin. We conclude that nestin is induced in stellate cells during transition from the quiescent to the activated phenotype; culture activation is a stronger stimulus than in vivo activation by injection of CCl4. Taken together with reports on expression of glial fibrillary acidic protein and neural cell adhesion molecule by stellate cells, new experimental studies on the embryonic origin of these cells are required.
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Affiliation(s)
- T Niki
- Laboratory for Cell Biology and Histology, Faculty of Medicine and Pharmacy, Free University of Brussels (VUB), Belgium
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Geerts A, Niki T, Hellemans K, De Craemer D, Van Den Berg K, Lazou JM, Stange G, Van De Winkel M, De Bleser P. Purification of rat hepatic stellate cells by side scatter-activated cell sorting. Hepatology 1998; 27:590-8. [PMID: 9462662 DOI: 10.1002/hep.510270238] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In this study, we present a new method to obtain pure, viable, freshly isolated hepatic stellate cells. Stellate cells were purified by cell sorting using their high side scatter (SSC) of incident light. Purity of the cells was established by light and transmission electron microscopy (TEM). Starting from stellate cells that were 50% to 70% enriched by centrifugation in 11% Nycodenz, the cell purity after sorting was found to be 96.6% +/- 2.9%. Viability of the sorted cells was 90.8% +/- 2.2% as measured by the Trypan blue exclusion test and was confirmed by cell culturing. Per hour of sorting, 1.4 +/- 0.4 million stellate cells were obtained. Sorting runs of up to 4 hours were practically feasible, resulting in yields of 5 to 6 million cells per rat liver. Cells attached to plastic substratum within 24 hours. Subsequently, they spread and underwent spontaneous transition into myofibroblast-like cells. The purity of sorted cells was documented by reverse-transcriptase polymerase chain reaction (RT-PCR) experiments using specific primer pairs for messenger RNA (mRNA) species that were only present in parenchymal (preproalbumin), endothelial (endothelial cell nitric oxide synthase [eNOS]), stellate (desmin), or Kupffer cells (77- to 88-kd fucose receptor). Contaminating mRNA species were absent in sorted stellate cells. Next, we examined freshly sorted stellate cells by Western blotting to confirm the presence of relevant cytoskeletal proteins. Cells were positive for vimentin, desmin, and glial fibrillary acidic protein (GFAP), but negative for alpha-smooth muscle actin (alpha-SMA). Sorted and cultured cells were immunophenotyped for the presence of collagen types I, III, and IV, laminin, and the cytoskeletal proteins, alpha-SMA, desmin, vimentin, and GFAP. At 90 hours in culture, cells expressed all the investigated extracellular matrix proteins. Desmin was present in 82% +/- 1%, vimentin in 96% +/- 2.5%, and GFAP in 91% +/- 4.5% of cells. Alpha-SMA was present in 91% +/- 2% of cultured cells. We conclude that cell sorting based on SSC of incident light is a convenient method to obtain virtually pure stellate cells that can be used for direct analysis or for culturing. Although the yields obtained with this method are lower than with standard methods, and additional equipment is required, SSC-activated sorting offers the possibility of very pure cells when essential for analyses based on sensitive detection methods such as RT-PCR.
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Affiliation(s)
- A Geerts
- Laboratory for Cell Biology and Histology, Free University Brussels, Brussels-Jette, Belgium
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