1
|
Stjernbrandt A, Pettersson H, Vihlborg P, Höper AC, Aminoff A, Wahlström J, Nilsson T. Raynaud's phenomenon in the feet of Arctic open-pit miners. Int J Circumpolar Health 2024; 83:2295576. [PMID: 38109321 PMCID: PMC10732197 DOI: 10.1080/22423982.2023.2295576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 12/12/2023] [Indexed: 12/20/2023] Open
Abstract
The literature on Raynaud's phenomenon (RP) in the feet is scarce, especially in the occupational setting. The primary aim of our study was to investigate the occurrence of RP in the feet of miners. As part of the MineHealth project, written surveys and clinical examinations were completed by 260 Arctic open-pit miners working in northern Sweden and Norway (participation rate 53.6%). Data on RP were collected using standardised colour charts and questionnaire items. Clinical examination included assessing the perception of vibration and pain in both feet. There were eight women and three men who reported RP in the feet. Four also had RP in their hands but none acknowledged any first-degree relatives with the condition. Nine reported exposure to foot-transmitted vibration and one to hand-arm vibration. Seven showed signs of neurosensory injury in the feet. To conclude, the occurrence of RP in the feet of miners was 4.4%. Most cases with RP in the feet did not report the condition in the hands and were exposed to vibration transmitted directly to the feet. There were no reports of a hereditary component. Most cases with RP in the feet also had clinical findings suggestive of peripheral neuropathy in the feet.
Collapse
Affiliation(s)
- Albin Stjernbrandt
- Section of Sustainable Health, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Hans Pettersson
- Section of Sustainable Health, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Per Vihlborg
- Department of Geriatrics, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Anje Christina Höper
- Department of Occupational and Environmental Medicine, University Hospital of North Norway, Tromsø, Norway
- Department of Community Medicine, UiT The Arctic University of Norway, Tromsø, Norway
| | - Anna Aminoff
- Department of Occupational and Environmental Medicine, University Hospital of North Norway, Tromsø, Norway
- Department of Community Medicine, UiT The Arctic University of Norway, Tromsø, Norway
| | - Jens Wahlström
- Section of Sustainable Health, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Tohr Nilsson
- Section of Sustainable Health, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| |
Collapse
|
2
|
Krajnak K, Farcas M, Richardson D, Hammer MA, Waugh S, McKinney W, Knepp A, Jackson M, Burns D, LeBouf R, Matheson J, Thomas T, Qian Y. Exposure to emissions generated by 3-dimensional printing with polycarbonate: effects on peripheral vascular function, cardiac vascular morphology and expression of markers of oxidative stress in male rat cardiac tissue. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2024; 87:541-559. [PMID: 38682597 DOI: 10.1080/15287394.2024.2346938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
Three-dimensional (3D) printing with polycarbonate (PC) plastic occurs in manufacturing settings, homes, and schools. Emissions generated during printing with PC stock and bisphenol-A (BPA), an endocrine disrupter in PC, may induce adverse health effects. Inhalation of 3D printer emissions, and changes in endocrine function may lead to cardiovascular dysfunction. The goal of this study was to determine whether there were any changes in markers of peripheral or cardiovascular dysfunction in animals exposed to PC-emissions. Male Sprague Dawley rats were exposed to PC-emissions generated by 3D printing for 1, 4, 8, 15 or 30 d. Exposure induced a reduction in the expression of the antioxidant catalase (Cat) and endothelial nitric oxide synthase (eNos). Endothelin and hypoxia-induced factor 1α transcripts increased after 30 d. Alterations in transcription were associated with elevations in immunostaining for estrogen and androgen receptors, nitrotyrosine, and vascular endothelial growth factor in cardiac arteries of PC-emission exposed animals. There was also a reduction eNOS immunostaining in cardiac arteries from rats exposed to PC-emissions. Histological analyses of heart sections revealed that exposure to PC-emissions resulted in vasoconstriction of cardiac arteries and thickening of the vascular smooth muscle wall, suggesting there was a prolonged vasoconstriction. These findings are consistent with studies showing that inhalation 3D-printer emissions affect cardiovascular function. Although BPA levels in animals were relatively low, exposure-induced changes in immunostaining for estrogen and androgen receptors in cardiac arteries suggest that changes in the action of steroid hormones may have contributed to the alterations in morphology and markers of cardiac function.
Collapse
Affiliation(s)
- Kristine Krajnak
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Mariana Farcas
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Diana Richardson
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Mary Anne Hammer
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Stacey Waugh
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Walter McKinney
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Alycia Knepp
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Mark Jackson
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Dru Burns
- Respiratory Health Division, Morgantown, WV, USA
| | - Ryan LeBouf
- Respiratory Health Division, Morgantown, WV, USA
| | | | - Treye Thomas
- Consumer Product Safety Commission, Rockville, MD, USA
| | - Yong Qian
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| |
Collapse
|
3
|
Krajnak K, Kan H, Thompson JA, McKinney W, Waugh S, South T, Burns D, Lebouf R, Cumpston J, Boots T, Fedan JS. Biological effects of diesel exhaust inhalation. III cardiovascular function. Inhal Toxicol 2024; 36:189-204. [PMID: 38466202 PMCID: PMC11099779 DOI: 10.1080/08958378.2024.2327364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 02/29/2024] [Indexed: 03/12/2024]
Abstract
OBJECTIVE Inhalation of diesel exhaust (DE) has been shown to be an occupational hazard in the transportation, mining, and gas and oil industries. DE also contributes to air pollution, and therefore, is a health hazard to the general public. Because of its effects on human health, changes have been made to diesel engines to reduce both the amounts of particulate matter and volatile fumes they generate. The goal of the current study was to examine the effects of inhalation of diesel exhaust. MATERIALS AND METHODS The study presented here specifically examines the effects of exposure to 0.2 and 1.0 mg/m3 DE or filtered air (6h/d for 4 d) on measures of peripheral and cardio-vascular function, and biomarkers of heart and kidney dysfunction in male rats. A Tier 2 engine used in oil and gas fracking operations was used to generate the diesel exhaust. RESULTS Exposure to 0.2 mg/m3 DE resulted in an increase in blood pressure 1d following the last exposure, and increases in dobutamine-induced cardiac output and stroke volume 1 and 27d after exposure. Changes in peripheral vascular responses to norepinephrine and acetylcholine were minimal as were changes in transcript expression in the heart and kidney. Exposure to 1.0 mg/m3 DE did not result in major changes in blood pressure, measures of cardiac function, peripheral vascular function or transcript expression. DISCUSSION AND CONCLUSIONS Based on the results of this study, we suggest that exposure to DE generated by a Tier 2 compliant diesel engine generates acute effects on biomarkers indicative of cardiovascular dysfunction. Recovery occurs quickly with most measures of vascular/cardiovascular function returning to baseline levels by 7d following exposure.
Collapse
Affiliation(s)
- Kristine Krajnak
- Physical Effects Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Hong Kan
- Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Janet A. Thompson
- Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Walter McKinney
- Physical Effects Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Stacey Waugh
- Physical Effects Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Tim South
- Physical Effects Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Dru Burns
- Respiratory Health Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Ryan Lebouf
- Respiratory Health Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Jared Cumpston
- Animal Facilities, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Theresa Boots
- Risk Evaluation Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Jeffrey S. Fedan
- Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| |
Collapse
|
4
|
Moore KD, Wu JZ, Krajnak K, Warren C, Dong RG. Quantification of mechanical behavior of rat tail under compression. Biomed Mater Eng 2024; 35:337-349. [PMID: 38758990 DOI: 10.3233/bme-230170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2024]
Abstract
BACKGORUND The development of vibration-induced finger disorders is likely associated with combined static and dynamic responses of the fingers to vibration exposure. To study the mechanism of the disorders, a new rat-tail model has been established to mimic the finger vibration and pressure exposures. However, the mechanical behavior of the tail during compression needs to be better understood to improve the model and its applications. OBJECTIVE To investigate the static and time-dependent force responses of the rat tail during compression. METHODS Compression tests were conducted on Sprague-Dawley cadaver rat tails using a micromechanical system at three deformation velocities and three deformation magnitudes. Contact-width and the time-histories of force and deformation were measured. Additionally, force-relaxation tests were conducted and a Prony series was used to model the force-relaxation behavior of the tail. RESULTS The rat tails' force-deformation and stiffness-deformation relationships were strongly nonlinear and time-dependent. Force/stiffness increased with an increase in deformation and deformation velocity. The time-dependent force-relaxation characteristics of the tails can be well described using a Prony series. CONCULSIONS We successfully quantified the static and time-dependent force responses of rat tails under compression. The identified mechanical behavior of the tail can help improve the rat-tail model and its applications.
Collapse
Affiliation(s)
- Kevin D Moore
- Physical Effects Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety & Health, Morgantown, WV, USA
| | - John Z Wu
- Physical Effects Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety & Health, Morgantown, WV, USA
| | - Kristine Krajnak
- Physical Effects Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety & Health, Morgantown, WV, USA
| | - Christopher Warren
- Physical Effects Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety & Health, Morgantown, WV, USA
| | - Renguang G Dong
- Physical Effects Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety & Health, Morgantown, WV, USA
| |
Collapse
|
5
|
Dong RG, Wu JZ, Xu XS, Welcome DE, Krajnak K. A Review of Hand-Arm Vibration Studies Conducted by US NIOSH since 2000. VIBRATION 2021; 4:482-528. [PMID: 34414357 PMCID: PMC8371562 DOI: 10.3390/vibration4020030] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Studies on hand-transmitted vibration exposure, biodynamic responses, and biological effects were conducted by researchers at the Health Effects Laboratory Division (HELD) of the National Institute for Occupational Safety and Health (NIOSH) during the last 20 years. These studies are systematically reviewed in this report, along with the identification of areas where additional research is needed. The majority of the studies cover the following aspects: (i) the methods and techniques for measuring hand-transmitted vibration exposure; (ii) vibration biodynamics of the hand-arm system and the quantification of vibration exposure; (iii) biological effects of hand-transmitted vibration exposure; (iv) measurements of vibration-induced health effects; (iv) quantification of influencing biomechanical effects; and (v) intervention methods and technologies for controlling hand-transmitted vibration exposure. The major findings of the studies are summarized and discussed.
Collapse
Affiliation(s)
- Ren G. Dong
- Physical Effects Research Branch, Health Effects Laboratory Division (HELD), National Institute for Occupational Safety and Health (NIOSH), Morgantown, WV 26505, USA
| | - John Z. Wu
- Physical Effects Research Branch, Health Effects Laboratory Division (HELD), National Institute for Occupational Safety and Health (NIOSH), Morgantown, WV 26505, USA
| | - Xueyan S. Xu
- Physical Effects Research Branch, Health Effects Laboratory Division (HELD), National Institute for Occupational Safety and Health (NIOSH), Morgantown, WV 26505, USA
| | - Daniel E. Welcome
- Physical Effects Research Branch, Health Effects Laboratory Division (HELD), National Institute for Occupational Safety and Health (NIOSH), Morgantown, WV 26505, USA
| | - Kristine Krajnak
- Physical Effects Research Branch, Health Effects Laboratory Division (HELD), National Institute for Occupational Safety and Health (NIOSH), Morgantown, WV 26505, USA
| |
Collapse
|
6
|
Abstract
OBJECTIVE To investigate whether low molecular organic biomarkers could be identified in blood samples from vibration exposed workers using a metabolomics. METHODS The study population consisted of 38 metalworkers. All participants underwent a standardized medical examination. Blood samples were collected before and after work shift and analyzed with gas chromatography time-of-flight mass spectrometry. Multivariate modeling (orthogonal partial least-squares analysis with discriminant analysis [OPLS-DA]) were used to verify differences in metabolic profiles. RESULTS Twenty-two study participants reported vascular symptoms judged as vibration-related. The metabolic profile from participants with vibration-induced white fingers (VWF) was distinctly separated from participants without VWF, both before and after vibration exposure. CONCLUSION Metabolites that differed between the groups were identified both before and after exposure. Some of these metabolites might be indicators of health effects from exposure to vibrations. This is the first time that a metabolomic approach has been used in workers exposed to vibrations.
Collapse
|
7
|
Dauda Usman J, Isyaku UM, Magaji RA, Fasanmade AA. Assessment of electromagnetic fields, vibration and sound exposure effects from multiple transceiver mobile phones on oxidative stress levels in serum, brain and heart tissue. SCIENTIFIC AFRICAN 2020. [DOI: 10.1016/j.sciaf.2020.e00271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
|
8
|
Krajnak K. Frequency-dependent changes in mitochondrial number and generation of reactive oxygen species in a rat model of vibration-induced injury. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2020; 83:20-35. [PMID: 31971087 PMCID: PMC7737659 DOI: 10.1080/15287394.2020.1718043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Regular use of vibrating hand tools results in cold-induced vasoconstriction, finger blanching, and a reduction in tactile sensitivity and manual dexterity. Depending upon the length and frequency, vibration induces regeneration, or dysfunction and apoptosis, inflammation and an increase in reactive oxygen species (ROS) levels. These changes may be associated with mitochondria, this study examined the effects of vibration on total and functional mitochondria number. Male rats were exposed to restraint or tail vibration at 62.5, 125, or 250 Hz. The frequency-dependent effects of vibration on mitochondrial number and generation of oxidative stress were examined. After 10 days of exposure at 125 Hz, ventral tail arteries (VTA) were constricted and there was an increase in mitochondrial number and intensity of ROS staining. In the skin, the influence of vibration on arterioles displayed a similar but insignificant response in VTA. There was also a reduction in the number of small nerves with exposure to vibration at 250 Hz, and a reduction in mitochondrial number in nerves in restrained and all vibrated conditions. There was a significant rise in the size of the sensory receptors with vibration at 125 Hz, and an elevation in ROS levels. Based upon these results, mitochondria number and activity are affected by vibration, especially at frequencies at or near resonance. The influence of vibration on the vascular system may either be adaptive or maladaptive. However, the effects on cutaneous nerves might be a precursor to loss of innervation and sensory function noted in workers exposed to vibration.
Collapse
Affiliation(s)
- Kristine Krajnak
- Physical Effects Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| |
Collapse
|
9
|
Sheth AA, Honeybul S. Vertebral artery dissection following a posterior cervical foraminotomy. J Surg Case Rep 2017; 2017:rjx014. [PMID: 28458824 PMCID: PMC5400452 DOI: 10.1093/jscr/rjx014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/26/2017] [Indexed: 12/02/2022] Open
Abstract
Vertebral artery dissection following a posterior cervical foraminotomy with rhizolysis of the subaxial spine has not been described before. A 46-year-old lady underwent the procedure for a left C6 radiculopathy with a focal disc herniation with no intraoperative complications. Seven hours post-operatively, she developed a right homonymous hemianopia, thalamic dysphasia, gait and memory impairment. Imaging demonstrated an occlusion to the left vertebral artery from C7/T1 to C4 with a dissection flap noted at the inferior margin. This was further complicated with thrombosis of the dissected artery and subsequent emboli causing acute posterior circulation infarctions. Given that the dissection occurred at the level of the surgery, an indirect surgical cause is likely. We hypothesize that the vibration transmitted via bone from the high-speed drill led to arterial injury and dissection.
Collapse
Affiliation(s)
- Aniruddha A Sheth
- Department of Neurosurgery, Sir Charles Gairdner Hospital, Perth, WA 6009, Australia
| | - Stephen Honeybul
- Department of Neurosurgery, Sir Charles Gairdner Hospital, Perth, WA 6009, Australia
| |
Collapse
|
10
|
Hua Y, Lemerle P, Ganghoffer JF. A two scale modeling and computational framework for vibration-induced Raynaud syndrome. J Mech Behav Biomed Mater 2017; 71:320-328. [PMID: 28391171 DOI: 10.1016/j.jmbbm.2017.03.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/15/2017] [Accepted: 03/23/2017] [Indexed: 11/15/2022]
Abstract
Hand-Arm Vibration syndrome (HAVS), usually caused by long-term use of hand-held power tools, can in certain manifestations alter the peripheral blood circulation in the hand-arm region. HAVS typically occurs after exposure to cold, causing an abnormally strong vasoconstriction of blood vessels. A pathoanatomical mechanism suggests that a reduction of the lumen of the blood vessels in VWF (Vibration White Finger) subjects, due to either hypertrophy or thickening of the vessel wall, may be at the origin of the disease. However, the direct and indirect effects of the load of the hand-held tools on the structure of blood vessels remain controversial:.one hypothesis is the mechanical action of vibration on the local acral dysregulation and/or on the vessel histomorphological modifications. Another hypothesis is the participation of the sympathetic nervous system to this dysregulation. In this paper, we assume the modifications as mechanobiological growth and the load-effect relationship may be interpreted as directly or indirectly induced. This work is the first attempt to model the effect of vibration through soft tissues onto the distal capillaries, addressing the double paradigm of multi space-time scales, i.e. low period vibration versus high time constant of the growth phenomenon as well as vibrations propagating in the macroscopic tissue including the microscopic capillary structures subjected to a pathological microstructural evolution. The objective is to lay down the theoretical basis of growth modeling for the small distal artery, with the ability to predict the geometrical and structural changes of the arterial walls caused by vibration exposure. We adopt the key idea of splitting the problem into one global vibration problem at the macroscopic scale and one local growth problem at the micro level. The macroscopic hyperelastic viscous dynamic model of the fingertip cross-section is validated by fitting experimental data. It is then used in steady-state vibration conditions to predict the mechanical fields in the close vicinity of capillaries. The space scale transfer from macroscopic to microscopic levels is ensured by considering a representative volume element (RVE) embedding a single capillary in its center. The vibrations emitted by the hand held power tool are next linked to the capillary growth through the adopted biomechanical growth model at the capillary level. The obtained results show that vibrations induce an increase of the thickness of the capillary's wall, thereby confirming the scenario of vibrations induced reduction of the lumen of blood vessels.
Collapse
Affiliation(s)
- Yue Hua
- INRS, Institut National de Recherche et de Sécurité, 1, rue du Morvan, 54519 Vandœuvre Cedex, France; CNRS, LEMTA, UMR 7563, Université de Lorraine, 2, Avenue de la forêt de Haye, BP 90161, 54505 Vandoeuvre-lès-Nancy, France
| | - Pierre Lemerle
- INRS, Institut National de Recherche et de Sécurité, 1, rue du Morvan, 54519 Vandœuvre Cedex, France
| | - Jean-François Ganghoffer
- CNRS, LEMTA, UMR 7563, Université de Lorraine, 2, Avenue de la forêt de Haye, BP 90161, 54505 Vandoeuvre-lès-Nancy, France.
| |
Collapse
|
11
|
Wagner AP, Chinnathambi S, Titze IR, Sander EA. Vibratory stimulation enhances thyroid epithelial cell function. Biochem Biophys Rep 2016; 8:376-381. [PMID: 28955979 PMCID: PMC5614476 DOI: 10.1016/j.bbrep.2016.10.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 10/11/2016] [Accepted: 10/13/2016] [Indexed: 02/06/2023] Open
Abstract
The tissues of the body are routinely subjected to various forms of mechanical vibration, the frequency, amplitude, and duration of which can contribute both positively and negatively to human health. The vocal cords, which are in close proximity to the thyroid, may also supply the thyroid with important mechanical signals that modulate hormone production via mechanical vibrations from phonation. In order to explore the possibility that vibrational stimulation from vocalization can enhance thyroid epithelial cell function, FRTL-5 rat thyroid cells were subjected to either chemical stimulation with thyroid stimulating hormone (TSH), mechanical stimulation with physiological vibrations, or a combination of the two, all in a well-characterized, torsional rheometer-bioreactor. The FRTL-5 cells responded to mechanical stimulation with significantly (p<0.05) increased metabolic activity, significantly (p<0.05) increased ROS production, and increased gene expression of thyroglobulin and sodium-iodide symporter compared to un-stimulated controls, and showed an equivalent or greater response than TSH only stimulated cells. Furthermore, the combination of TSH and oscillatory motion produced a greater response than mechanical or chemical stimulation alone. Taken together, these results suggest that mechanical vibrations could provide stimulatory cues that help maintain thyroid function. Thyroid epithelial cells responded to mechanical vibrations similar to those from vocalization. This response was equivalent or greater compared to chemical stimulation. The combination of mechanical and chemical stimulation was synergistic. It may be possible to influence thyroid function with mechanical vibrations.
Collapse
Affiliation(s)
- A P Wagner
- Department of Biomedical Engineering, University of Iowa, IA, USA
| | - S Chinnathambi
- Department of Biomedical Engineering, University of Iowa, IA, USA
| | - I R Titze
- Department of Communication Sciences and Disorders, University of Iowa, IA, USA.,National Center for Voice and Speech, University of Utah, Salt Lake City, UT, USA
| | - E A Sander
- Department of Biomedical Engineering, University of Iowa, IA, USA
| |
Collapse
|
12
|
Eger T, Thompson A, Leduc M, Krajnak K, Goggins K, Godwin A, House R. Vibration induced white-feet: overview and field study of vibration exposure and reported symptoms in workers. Work 2015; 47:101-10. [PMID: 24004754 DOI: 10.3233/wor-131692] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Workers who stand on platforms or equipment that vibrate are exposed to foot-transmitted vibration (FTV). Exposure to FTV can lead to vibration white feet/toes resulting in blanching of the toes, and tingling and numbness in the feet and toes. OBJECTIVES The objectives are 1) to review the current state of knowledge of the health risks associated with foot-transmitted vibration (FTV), and 2) to identify the characteristics of FTV and discuss the associated risk of vibration-induced injury. PARTICIPANTS Workers who operated locomotives (n=3), bolting platforms (n=10), jumbo drills (n=7), raise drilling platforms (n=4), and crushers (n=3), participated. METHODS A tri-axial accelerometer was used to measure FTV in accordance with ISO 2631-1 guidelines. Frequency-weighted root-mean-square acceleration and the dominant frequency are reported. Participants were also asked to report pain/ache/discomfort in the hands and/or feet. RESULTS Reports of pain/discomfort/ache were highest in raise platform workers and jumbo drill operators who were exposed to FTV in the 40 Hz and 28 Hz range respectively. Reports of discomfort/ache/pain were lowest in the locomotive and crusher operators who were exposed to FTV below 10 Hz. These findings are consistent with animal studies that have shown vascular and neural damage in exposed appendages occurs at frequencies above 40 Hz. CONCLUSIONS Operators exposed to FTV at 40 Hz appear to be at greater risk of experiencing vibration induced injury. Future research is required to document the characteristics of FTV and epidemiological evidence is required to link exposure with injury.
Collapse
Affiliation(s)
- Tammy Eger
- School of Human Kinetics, Laurentian University, Sudbury, ON, Canada Centre for Research in Occupational Safety and Health, Laurentian University, Sudbury, ON, Canada
| | - Aaron Thompson
- Department of Medicine, Division of Occupational Medicine, University of Toronto, Toronto, ON, Canada Department of Occupational and Environmental Health, St. Michael's Hospital, Toronto, ON, Canada
| | - Mallorie Leduc
- School of Human Kinetics, Laurentian University, Sudbury, ON, Canada
| | - Kristine Krajnak
- Engineering and Controls Technology Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Katie Goggins
- School of Human Kinetics, Laurentian University, Sudbury, ON, Canada
| | - Alison Godwin
- School of Human Kinetics, Laurentian University, Sudbury, ON, Canada Centre for Research in Occupational Safety and Health, Laurentian University, Sudbury, ON, Canada
| | - Ron House
- Department of Medicine, Division of Occupational Medicine, University of Toronto, Toronto, ON, Canada Department of Occupational and Environmental Health, St. Michael's Hospital, Toronto, ON, Canada
| |
Collapse
|
13
|
Krajnak K, Waugh S, Johnson C, Miller RG, Welcome D, Xu X, Warren C, Sarkisian S, Andrew M, Dong RG. Antivibration gloves: effects on vascular and sensorineural function, an animal model. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2015; 78:571-82. [PMID: 25965192 PMCID: PMC4700820 DOI: 10.1080/15287394.2015.1014079] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Anti-vibration gloves have been used to block the transmission of vibration from powered hand tools to the user, and to protect users from the negative health consequences associated with exposure to vibration. However, there are conflicting reports as to the efficacy of gloves in protecting workers. The goal of this study was to use a characterized animal model of vibration-induced peripheral vascular and nerve injury to determine whether antivibration materials reduced or inhibited the effects of vibration on these physiological symptoms. Rats were exposed to 4 h of tail vibration at 125 Hz with an acceleration 49 m/s(2). The platform was either bare or covered with antivibrating glove material. Rats were tested for tactile sensitivity to applied pressure before and after vibration exposure. One day following the exposure, ventral tail arteries were assessed for sensitivity to vasodilating and vasoconstricting factors and nerves were examined histologically for early indicators of edema and inflammation. Ventral tail artery responses to an α2C-adrenoreceptor agonist were enhanced in arteries from vibration-exposed rats compared to controls, regardless of whether antivibration materials were used or not. Rats exposed to vibration were also less sensitive to pressure after exposure. These findings are consistent with experimental findings in humans suggesting that antivibration gloves may not provide protection against the adverse health consequences of vibration exposure in all conditions. Additional studies need to be done examining newer antivibration materials.
Collapse
Affiliation(s)
- K Krajnak
- a Engineering and Controls Technology Branch , National Institute for Occupational Safety and Health , Morgantown , West Virginia , USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Wang YJ, Huang XL, Yan JW, Wan YN, Wang BX, Tao JH, Chen B, Li BZ, Yang GJ, Wang J. The association between vibration and vascular injury in rheumatic diseases: a review of the literature. Autoimmunity 2014; 48:61-8. [PMID: 25112484 DOI: 10.3109/08916934.2014.947477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Vascular manifestations can be seen early in the pathogenesis of inflammatory rheumatic diseases. Animal experiments, laboratory and clinical findings indicated that acute or long-term vibration exposure can induce vascular abnormalities. Recent years, in addition to Raynaud's phenomenon (RP), vibration as a risk factor for other rheumatic diseases has also received corresponding considered. This review is concentrated upon the role of vibration in the disease of systemic sclerosis (SSc). In this review, we are going to discuss the main mechanisms which are thought to be important in pathophysiology of vascular injury under the three broad headings of "vascular", "neural" and "intravascular". Aspects on the vibration and vascular inflammation are briefly discussed. And the epidemiological studies related to vibration studies in SSc and other rheumatic diseases are taken into account.
Collapse
Affiliation(s)
- Yu-Jie Wang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University , Hefei , China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Krajnak K, Waugh S, Miller GR, Johnson C. Recovery of vascular function after exposure to a single bout of segmental vibration. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2014; 77:1061-9. [PMID: 25072825 PMCID: PMC4505626 DOI: 10.1080/15287394.2014.903813] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Work rotation schedules may be used to reduce the negative effects of vibration on vascular function. This study determined how long it takes vascular function to recover after a single exposure to vibration in rats (125 Hz, acceleration 5 g). The responsiveness of rat-tail arteries to the vasoconstricting factor UK14304, an α2C-adrenoreceptor agonist, and the vasodilating factor acetylcholine (ACh) were measured ex vivo 1, 2, 7, or 9 d after exposure to a single bout of vibration. Vasoconstriction induced by UK14304 returned to control levels after 1 d of recovery. However, re-dilation induced by ACh did not return to baseline until after 9 d of recovery. Exposure to vibration exerted prolonged effects on peripheral vascular function, and altered vascular responses to a subsequent exposure. To optimize the positive results of work rotation schedules, it is suggested that studies assessing recovery of vascular function after exposure to a single bout of vibration be performed in humans.
Collapse
Affiliation(s)
- Kristine Krajnak
- a Engineering and Controls Technology Branch , Health Effects Laboratory Division, National Institute for Occupational Safety and Health , Morgantown , West Virginia , USA
| | | | | | | |
Collapse
|
16
|
KRAJNAK KM, WAUGH S, JOHNSON C, MILLER GR, XU X, WARREN C, DONG RG. The effects of impact vibration on peripheral blood vessels and nerves. INDUSTRIAL HEALTH 2013; 51:572-80. [PMID: 24077447 PMCID: PMC4202742 DOI: 10.2486/indhealth.2012-0193] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 07/30/2013] [Indexed: 05/03/2023]
Abstract
Research regarding the risk of developing hand-arm vibration syndrome after exposure to impact vibration has produced conflicting results. This study used an established animal model of vibration-induced dysfunction to determine how exposure to impact vibration affects peripheral blood vessels and nerves. The tails of male rats were exposed to a single bout of impact vibration (15 min exposure, at a dominant frequency of 30 Hz and an unweighted acceleration of approximately 345 m/s(2)) generated by a riveting hammer. Responsiveness of the ventral tail artery to adrenoreceptor-mediated vasoconstriction and acetylcholine-mediated re-dilation was measured ex vivo. Ventral tail nerves and nerve endings in the skin were assessed using morphological and immunohistochemical techniques. Impact vibration did not alter vascular responsiveness to any factors or affect trunk nerves. However, 4 days following exposure there was an increase in protein-gene product (PGP) 9.5 staining around hair follicles. A single exposure to impact vibration, with the exposure characteristics described above, affects peripheral nerves but not blood vessels.
Collapse
Affiliation(s)
- Kristine M. KRAJNAK
- Engineering and Controls Technology Branch, National
Institutes for Occupational Safety and Health, USA
| | - Stacey WAUGH
- Engineering and Controls Technology Branch, National
Institutes for Occupational Safety and Health, USA
| | - Claud JOHNSON
- Engineering and Controls Technology Branch, National
Institutes for Occupational Safety and Health, USA
| | - G. Roger MILLER
- Engineering and Controls Technology Branch, National
Institutes for Occupational Safety and Health, USA
| | - Xueyan XU
- Engineering and Controls Technology Branch, National
Institutes for Occupational Safety and Health, USA
| | - Christopher WARREN
- Engineering and Controls Technology Branch, National
Institutes for Occupational Safety and Health, USA
| | - Ren G. DONG
- Engineering and Controls Technology Branch, National
Institutes for Occupational Safety and Health, USA
| |
Collapse
|
17
|
Goenka S, Peelukhana SV, Kim J, Stringer KF, Banerjee RK. Dependence of vascular damage on higher frequency components in the rat-tail model. INDUSTRIAL HEALTH 2013; 51:373-385. [PMID: 23518603 DOI: 10.2486/indhealth.2012-0060] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Hand-Arm Vibration Syndrome (HAVS) is caused by hand-transmitted vibration in industrial workers. Current ISO guidelines (ISO 5349) might underestimate vascular injury associated with range of vibration frequencies near resonance. A rat-tail model was used to investigate the effects of higher frequencies >100 Hz on early vascular damage. 13 Male Sprague-Dawley rats (250 ± 15 gm) were used. Rat-tails were vibrated at 125 Hz and 250 Hz (49 m/s(2)) for 1D, 5D and 10D; D=days (4 h/day). Structural damage of the ventral artery was quantified by vacuole count using Toluidine blue staining whereas biochemical changes were assessed by nitrotyrosine (NT) staining. The results were analyzed using one-way repeated measures mixed-model ANOVA at p<0.05 level of significance. The structural damage increased at 125 Hz causing significant number of vacuoles (40.62 ± 9.8) compared to control group (8.36 ± 2.49) and reduced at 250 Hz (12.33 ± 2.98) compared to control group (8.36 ± 2.49). However, the biochemical alterations (NT-signal) increased significantly for 125 Hz (143.35 ± 5.8 gray scale value, GSV) and for 250 Hz (155.8 ± 7.35 GSV) compared to the control group (101.7 ± 4.18 GSV). Our results demonstrate that vascular damage in the form of structural and bio chemical disruption is significant at 125 Hz and 250 Hz. Hence the current ISO guidelines might underestimate vascular damage at frequencies>100 Hz.
Collapse
Affiliation(s)
- Shilpi Goenka
- School of Energy, Environmental, Biological and Medical Engineering, Materials Engineering Program, University of Cincinnati, USA
| | | | | | | | | |
Collapse
|
18
|
Krajnak K, Riley DA, Wu J, McDowell T, Welcome DE, Xu XS, Dong RG. Frequency-dependent effects of vibration on physiological systems: experiments with animals and other human surrogates. INDUSTRIAL HEALTH 2012; 50:343-53. [PMID: 23060248 PMCID: PMC4694567 DOI: 10.2486/indhealth.ms1378] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Occupational exposure to vibration through the use of power- and pneumatic hand-tools results in cold-induced vasospasms, finger blanching, and alterations in sensorineural function. Collectively, these symptoms are referred to as hand-arm vibration syndrome (HAVS). Currently the International Standards Organization (ISO) standard ISO 5349-1 contains a frequency-weighting curve to help workers and employers predict the risk of developing HAVS with exposure to vibration of different frequencies. However, recent epidemiological and experimental evidence suggests that this curve under-represents the risk of injuries to the hands and fingers induced by exposure to vibration at higher frequencies (>100 Hz). To improve the curve, better exposure-response data need to be collected. The goal of this review is to summarize the results of animal and computational modeling studies that have examined the frequency-dependent effects of vibration, and discuss where additional research would be beneficial to fill these research gaps.
Collapse
Affiliation(s)
- Kristine Krajnak
- Engineering and Controls Technology Branch, National Institute for Occupational Safety and Health, USA.
| | | | | | | | | | | | | |
Collapse
|
19
|
Cho JG, Witting PK, Verma M, Wu BJ, Shanu A, Kairaitis K, Amis TC, Wheatley JR. Tissue vibration induces carotid artery endothelial dysfunction: a mechanism linking snoring and carotid atherosclerosis? Sleep 2011; 34:751-7. [PMID: 21629363 DOI: 10.5665/sleep.1042] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES We have previously identified heavy snoring as an independent risk factor for carotid atherosclerosis. In order to explore the hypothesis that snoring-associated vibration of the carotid artery induces endothelial dysfunction (an established atherogenic precursor), we utilized an animal model to examine direct effects of peri-carotid tissue vibration on carotid artery endothelial function and structure. DESIGN In supine anesthetized, ventilated rabbits, the right carotid artery (RCA) was directly exposed to vibrations for 6 h (peak frequency 60 Hz, energy matched to that of induced snoring in rabbits). Similarly instrumented unvibrated rabbits served as controls. Features of OSA such as hypoxemia, large intra-pleural swings and blood pressure volatility were prevented. Carotid endothelial function was then examined: (1) biochemically by measurement of tissue cyclic guanosine monophosphate (cGMP) to acetylcholine (ACh) and sodium nitroprusside (SNP); and (2) functionally by monitoring vessel relaxation with acetylcholine in a myobath. MEASUREMENT AND RESULTS Vessel cGMP after stimulation with ACh was reduced in vibrated RCA compared with unvibrated (control) arteries in a vibration energy dose-dependent manner. Vibrated RCA also showed decreased vasorelaxation to ACh compared with control arteries. Notably, after addition of SNP (nitric oxide donor), cGMP levels did not differ between vibrated and control arteries, thereby isolating vibration-induced dysfunction to the endothelium alone. This dysfunction occurred in the presence of a morphologically intact endothelium without increased apoptosis. CONCLUSIONS Carotid arteries subjected to 6 h of continuous peri-carotid tissue vibration displayed endothelial dysfunction, suggesting a direct plausible mechanism linking heavy snoring to the development of carotid atherosclerosis.
Collapse
Affiliation(s)
- Jin-Gun Cho
- Ludwig Engel Centre for Respiratory Research, Westmead Millennium Institute, Westmead, NSW, Australia.
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Chotani MA, Flavahan NA. Intracellular α(2C)-adrenoceptors: storage depot, stunted development or signaling domain? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:1495-503. [PMID: 21605601 DOI: 10.1016/j.bbamcr.2011.05.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 05/03/2011] [Accepted: 05/06/2011] [Indexed: 12/11/2022]
Abstract
G-protein coupled receptors (GPCRs) are generally considered to function as cell surface signaling structures that respond to extracellular mediators, many of which do not readily access the cell's interior. Indeed, most GPCRs are preferentially targeted to the plasma membrane. However, some receptors, including α(2C)-Adrenoceptors, challenge conventional concepts of GPCR activity by being preferentially retained and localized within intracellular organelles. This review will address the issues associated with this unusual GPCR localization and discuss whether it represents a novel sub-cellular niche for GPCR signaling, whether these receptors are being stored for rapid deployment to the cell surface, or whether they represent immature or incomplete receptor systems.
Collapse
Affiliation(s)
- Maqsood A Chotani
- Center for Cardiovascular and Pulmonary Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | | |
Collapse
|
21
|
Abstract
AIM Assessment of the specific clinical manifestations of hand-arm vibration syndrome (HAVS) or whole-body vibration syndrome (WBVS). PATIENTS AND METHODS Seventy-six patients (34 with HAVS and 33 with WBVS) were examined analysing the data from their medical history, clinical examinations and autonomic nervous system study, capillaroscopy, distal Doppler ultrasound study, vibrotactile sense, roentgenography, and electromyography. RESULTS HAVS manifests mainly in the upper limbs as microcirculatory disturbances: RR 2.59; 95% CI (1.64-4.10), Raynaud's syndrome: RR 16.50; 95% CI (2.33-117.04), increased vascular resistance in the digital arteries of the hands: RR 9.71; 95% CI (3.28-28.75); distal autonomic neuropathy of the upper limbs: RR 15.04; 95% CI (3.91-57.88); sensory polyneuropathy predominantly of the upper limbs: RR 21.00; 95% CI (3.01-146.57); median neuropathy: RR 14.56; 95% CI (2.04-104.06); cervical spondylosis with/without osteochondrosis: RR 2.09; 95% CI (1.33-3.28). In patients with WBVS we observed predominantly degenerative changes of the lumbar spine segment: RR 2.49; 95% CI (1.55-3.99); lumbosacral radicular symptoms: RR 8.53; 95% CI (3.73-19.52). CONCLUSION Dose-dependant, microcirculatory, peripheral vascular, peripheral nerve and musculoskeletal disorders of the upper limbs were found in HAVS and musculoskeletal and peripheral nerve injuries of the spine and the lower limbs were found in WBVS.
Collapse
|
22
|
Chen X, Green PG, Levine JD. Neuropathic pain-like alterations in muscle nociceptor function associated with vibration-induced muscle pain. Pain 2010; 151:460-466. [PMID: 20800357 DOI: 10.1016/j.pain.2010.08.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 08/03/2010] [Accepted: 08/04/2010] [Indexed: 11/26/2022]
Abstract
We recently developed a rodent model of the painful muscle disorders induced by occupational exposure to vibration. In the present study we used this model to evaluate the function of sensory neurons innervating the vibration-exposed gastrocnemius muscle. Activity of 74 vibration-exposed and 40 control nociceptors, with mechanical receptive fields in the gastrocnemius muscle, were recorded. In vibration-exposed rats ∼15% of nociceptors demonstrated an intense and long-lasting barrage of action potentials in response to sustained suprathreshold mechanical stimulation (average of 2635 action potentials with frequency of ∼44Hz during a 1min suprathreshold stimulus) much greater than that has been reported to be produced even by potent inflammatory mediators. While these high-firing nociceptors had lower mechanical thresholds than the remaining nociceptors, exposure to vibration had no effect on conduction velocity and did not induce spontaneous activity. Hyperactivity was not observed in any of 19 neurons from vibration-exposed rats pretreated with intrathecal antisense for the IL-6 receptor subunit gp130. Since vibration can injure peripheral nerves and IL-6 has been implicated in painful peripheral neuropathies, we suggest that the dramatic change in sensory neuron function and development of muscles pain, induced by exposure to vibration, reflects a neuropathic muscle pain syndrome.
Collapse
Affiliation(s)
- Xiaojie Chen
- Department Oral and Maxillofacial Surgery, University of California San Francisco, San Francisco, CA 94143, USA Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | | | | |
Collapse
|
23
|
Goel A, Su B, Flavahan S, Lowenstein CJ, Berkowitz DE, Flavahan NA. Increased endothelial exocytosis and generation of endothelin-1 contributes to constriction of aged arteries. Circ Res 2010; 107:242-51. [PMID: 20522806 DOI: 10.1161/circresaha.109.210229] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
RATIONALE Circulating levels of endothelin (ET)-1 and endogenous ET(A)-mediated constriction are increased in human aging. The mechanisms responsible are not known. OBJECTIVE Investigate the storage, release, and activity of ET-1 system in arteries from young and aged Fischer-344 rats. METHODS AND RESULTS After NO synthase inhibition (L-NAME), thrombin contracted aged arteries, which was inhibited by endothelial denudation, ET(A) receptor antagonism (BQ123), and ECE inhibition (phosphoramidon, SM19712) or by inhibiting exocytosis (TAT-NSF, N-ethylmaleimide-sensitive factor inhibitor). Thrombin did not cause endothelium-dependent contraction of young arteries. In aged but not young arteries, thrombin rapidly increased ET-1 release, which was abolished by endothelium denudation or TAT-NSF. L-NAME did not affect ET-1 release. ET-1 immunofluorescent staining was punctate and distinct from von Willebrand factor (VWF). VWF and ET-1 immunofluorescent intensity was similar in young and aged quiescent arteries. Thrombin rapidly increased ET-1 staining and decreased VWF staining in aged but had no effect in young aortas. After L-NAME, thrombin decreased VWF staining in young aortas. NO donor DEA-NONOate (1 to 100 nmol/L) reversed thrombin-induced exocytosis in young (VWF) but not aged L-NAME-treated aortas (VWF, ET-1). Expression of preproET-1 mRNA and ECE-1 mRNA were increased in aged compared to young endothelium. BigET-1 levels and contraction to exogenous BigET-1 (but not ET-1) were also increased in aged compared to young arteries. CONCLUSIONS The stimulated exocytotic release of ET-1 is dramatically increased in aged endothelium. This reflects increased reactivity of exocytosis, increased expression and storage of ET-1 precursor peptides, and increased expression of ECE-1. Altered endothelial exocytosis of ET-1 and other mediators may contribute to cardiovascular pathology in aging.
Collapse
Affiliation(s)
- Aditya Goel
- Department of Anesthesiology, Johns Hopkins University, Baltimore, MD 21205, USA
| | | | | | | | | | | |
Collapse
|
24
|
Characterization of Frequency-Dependent Responses of the Vascular System to Repetitive Vibration. J Occup Environ Med 2010; 52:584-94. [DOI: 10.1097/jom.0b013e3181e12b1f] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
25
|
Krajnak K, Waugh S, Johnson C, Miller R, Kiedrowski M. Vibration disrupts vascular function in a model of metabolic syndrome. INDUSTRIAL HEALTH 2009; 47:533-542. [PMID: 19834263 DOI: 10.2486/indhealth.47.533] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Vibration-induced white finger (VWF) is a disorder seen in workers exposed to hand-transmitted vibration, and is characterized by cold-induced vasospasms and finger blanching. Because overweight people with metabolic syndrome are pre-disposed to developing peripheral vascular disorders, it has been suggested that they also may be at greater risk of developing VWF if exposed to occupational vibration. We used an animal model of metabolic syndrome, the obese Zucker rat, to determine if metabolic syndrome alters vascular responses to vibration. Tails of lean and obese Zucker rats were exposed to vibration (125 Hz, 49 m/s(2) r.m.s.) or control conditions for 4 h/d for 10 d. Ventral tail arteries were collected and assessed for changes in gene expression, levels of reactive oxygen species (ROS) and for responsiveness to vasomodulating factors. Vibration exposure generally reduced the sensitivity of arteries to acetylcholine (ACh)-induced vasodilation. This decrease in sensitivity was most apparent in obese rats. Vibration also induced reductions in vascular nitric oxide concentrations and increases in vascular concentrations of ROS in obese rats. These results indicate that vibration interferes with endothelial-mediated vasodilation, and that metabolic syndrome exacerbates these effects. These findings are consistent with idea that workers with metabolic syndrome have an increased risk of developing VWF.
Collapse
Affiliation(s)
- Kristine Krajnak
- Engineering and Controls Technology Branch, National Institute for Occupational Safety and Health, 1095 Willowdale Rd, Morgantown, WV 26505, USA.
| | | | | | | | | |
Collapse
|