1
|
Parittotokkaporn S. Smartphone generated electrical fields induce axon regrowth within microchannels following injury. Med Eng Phys 2022; 105:103815. [DOI: 10.1016/j.medengphy.2022.103815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 05/01/2022] [Accepted: 05/04/2022] [Indexed: 10/18/2022]
|
2
|
Parittotokkaporn S, Dravid A, Raos BJ, Rosset S, Svirskis D, O'Carroll SJ. Stretchable microchannel-on-a-chip: A simple model for evaluating the effects of uniaxial strain on neuronal injury. J Neurosci Methods 2021; 362:109302. [PMID: 34343573 DOI: 10.1016/j.jneumeth.2021.109302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 07/14/2021] [Accepted: 07/29/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND Axonal injury is a major component of traumatic spinal cord injury (SCI), associated with rapid deformation of spinal tissue and axonal projections. In vitro models enable us to examine these effects and screen potential therapies in a controlled, reproducible manner. NEW METHOD A customized, stretchable microchannel system was developed using polydimethylsiloxane microchannels. Cortical and spinal embryonic rat neurons were cultured within the microchannel structures, allowing a uniaxial strain to be applied to isolated axonal processes. Global strains of up to 52% were applied to the stretchable microchannel-on-a-chip platform leading to local strains of up to 12% being experienced by axons isolated in the microchannels. RESULTS Individual axons exposed to local strains between 3.2% and 8.7% developed beading within 30-minutes of injury. At higher local strains of 9.8% and 12% individual axons ruptured within 30-minutes of injury. Axon bundles, or fascicles, were more resistant to rupture at each strain level, compared to individual axons. At lower local strain of 3.2%, axon bundles inside microchannels and neuronal cells near entrances of them progressively swelled and degenerated over a period of 7 days after injury. COMPARISON WITH EXISTING METHOD(S) This method is simple, reliable and reproducible with good control and measurement of injury tolerance and morphological deformations using standard laboratory equipment. By measuring local strains, we observed that axonal injuries occur at a lower strain magnitude and a lower strain rate than previous methods reporting global strains, which may not accurately reflect the true axonal strain. CONCLUSIONS We describe a novel stretchable microchannel-on-a-chip platform to study the effect of varying local strain on morphological characteristics of neuronal injury.
Collapse
Affiliation(s)
- Sam Parittotokkaporn
- Department of Anatomy and Medical Imaging, School of Medical Sciences, Faculty of Medical and Health Sciences and The Centre for Brain Research, University of Auckland, New Zealand
| | - Anusha Dravid
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, New Zealand
| | - Brad J Raos
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, New Zealand
| | - Samuel Rosset
- Auckland Bioengineering Institute, University of Auckland, New Zealand
| | - Darren Svirskis
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, New Zealand
| | - Simon J O'Carroll
- Department of Anatomy and Medical Imaging, School of Medical Sciences, Faculty of Medical and Health Sciences and The Centre for Brain Research, University of Auckland, New Zealand.
| |
Collapse
|
3
|
Parittotokkaporn S, Varghese C, O'Grady G, Lawrence A, Svirskis D, O'Carroll SJ. Transcutaneous Electrical Stimulation for Neurogenic Bladder Dysfunction Following Spinal Cord Injury: Meta-Analysis of Randomized Controlled Trials. Neuromodulation 2021; 24:1237-1246. [PMID: 34013608 DOI: 10.1111/ner.13459] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 04/20/2021] [Accepted: 04/26/2021] [Indexed: 02/01/2023]
Abstract
OBJECTIVES To assess the efficacy of transcutaneous electrical nerve stimulation (TENS) for neurogenic bladder dysfunction secondary to spinal cord injury (SCI). MATERIALS AND METHODS A systematic search of MEDLINE, EMBASE, Web of Science, Scopus, and Cochrane libraries up to February 2021 was performed using PRISMA methodology. All randomized controlled trials (RCTs) that studied TENS for neurogenic bladder in a SCI population were included. The primary outcomes of interest were maximum cystometric capacity (MCC) and maximum detrusor pressure (Pdet). Meta-analysis was conducted with RevMan v5.3. RESULTS Six RCTs involving 353 participants were included. Meta-analysis showed that TENS significantly increased MCC (standardized mean difference 1.11, 95% confidence interval [CI] 0.08-2.14, p = 0.03, I2 = 54%) in acute SCI. No benefits were seen for maximum Pdet. TENS was associated with no major adverse events. CONCLUSIONS TENS may be an effective, safe intervention for neurogenic bladder dysfunction following SCI. Further studies are essential to confirm these results and more work is required to determine optimal stimulation parameters and duration of the treatment.
Collapse
Affiliation(s)
- Sam Parittotokkaporn
- Department of Anatomy and Medical Imaging, School of Medical Sciences, Faculty of Medical and Health Sciences and the Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Chris Varghese
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Gregory O'Grady
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Anna Lawrence
- Auckland Spinal Rehabilitation Unit (ASRU), Counties Manukau Health, Auckland, New Zealand
| | - Darren Svirskis
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Simon J O'Carroll
- Department of Anatomy and Medical Imaging, School of Medical Sciences, Faculty of Medical and Health Sciences and the Centre for Brain Research, University of Auckland, Auckland, New Zealand
| |
Collapse
|
4
|
Parittotokkaporn S, de Castro D, Lowe A, Pylypchuk R. Carotid Pulse Wave Analysis: Future Direction of Hemodynamic and Cardiovascular Risk Assessment. JMA J 2021; 4:119-128. [PMID: 33997445 PMCID: PMC8119021 DOI: 10.31662/jmaj.2020-0108] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 11/30/2020] [Accepted: 01/29/2021] [Indexed: 01/13/2023] Open
Abstract
Evaluation of the hemodynamic function of the cardiovascular system via measurement of the mechanical properties of the large arteries may provide a substantial improvement over present techniques. Practitioners are familiar with the problem of low reproducibility of conventional sphygmomanometry, which exhibits reasonable accuracy but low precision owing to its marked variability over time and in different circumstances (e.g., the white coat effect). Arterial wall stiffness is a consequence of atherosclerosis developing over time; thus, it has little short-term variability and is thus preferable to be used as a prognostic marker. In particular, arterial stiffness can be evaluated at the carotid artery using noninvasive approaches based on wearable sensor technologies for pulse wave analysis. These enable the assessment of central pressures and pulse waveform parameters that are expected to replace peripheral blood pressure measurement using the inflatable cuff. In this study, we discuss this simple and inexpensive technique, which has been shown to be reliable with the clinical and epidemiological evidence for its use as a biomarker of cardiovascular risk.
Collapse
Affiliation(s)
- Sam Parittotokkaporn
- School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Denis de Castro
- Biomedical Consulting, Paris, France and Auckland, New Zealand
| | - Andrew Lowe
- Institute of Biomedical Technologies, Auckland University of Technology, Auckland, New Zealand
| | - Romana Pylypchuk
- School of Population Health, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| |
Collapse
|
5
|
Dravid A, Parittotokkaporn S, Aqrawe Z, O’Carroll SJ, Svirskis D. Determining Neurotrophin Gradients in Vitro To Direct Axonal Outgrowth Following Spinal Cord Injury. ACS Chem Neurosci 2020; 11:121-132. [PMID: 31825204 DOI: 10.1021/acschemneuro.9b00565] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
A spinal cord injury can damage neuronal connections required for both motor and sensory function. Barriers to regeneration within the central nervous system, including an absence of neurotrophic stimulation, impair the ability of injured neurons to reestablish their original circuitry. Exogenous neurotrophin administration has been shown to promote axonal regeneration and outgrowth following injury. The neurotrophins possess chemotrophic properties that guide axons toward the region of highest concentration. These growth factors have demonstrated potential to be used as a therapeutic intervention for orienting axonal growth beyond the injury lesion, toward denervated targets. However, the success of this approach is dependent on the appropriate spatiotemporal distribution of these molecules to ensure detection and navigation by the axonal growth cone. A number of in vitro gradient-based assays have been employed to investigate axonal response to neurotrophic gradients. Such platforms have helped elucidate the potential of applying a concentration gradient of neurotrophins to promote directed axonal regeneration toward a functionally significant target. Here, we review these techniques and the principles of gradient detection in axonal guidance, with particular focus on the use of neurotrophins to orient the trajectory of regenerating axons.
Collapse
Affiliation(s)
- Anusha Dravid
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Sam Parittotokkaporn
- Department of Anatomy and Medical Imaging, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Zaid Aqrawe
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
- Department of Anatomy and Medical Imaging, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Simon J. O’Carroll
- Department of Anatomy and Medical Imaging, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Darren Svirskis
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| |
Collapse
|
6
|
Dravid A, Raos B, Aqrawe Z, Parittotokkaporn S, O'Carroll SJ, Svirskis D. A Macroscopic Diffusion-Based Gradient Generator to Establish Concentration Gradients of Soluble Molecules Within Hydrogel Scaffolds for Cell Culture. Front Chem 2019; 7:638. [PMID: 31620430 PMCID: PMC6759698 DOI: 10.3389/fchem.2019.00638] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [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: 06/28/2019] [Accepted: 09/04/2019] [Indexed: 01/28/2023] Open
Abstract
Concentration gradients of soluble molecules are ubiquitous within the living body and known to govern a number of key biological processes. This has motivated the development of numerous in vitro gradient-generators allowing researchers to study cellular response in a precise, controlled environment. Despite this, there remains a current paucity of simplistic, convenient devices capable of generating biologically relevant concentration gradients for cell culture assays. Here, we present the design and fabrication of a compartmentalized polydimethylsiloxane diffusion-based gradient generator capable of sustaining concentration gradients of soluble molecules within thick (5 mm) and thin (2 mm) agarose and agarose-collagen co-gel matrices. The presence of collagen within the agarose-collagen co-gel increased the mechanical properties of the gel. Our model molecules sodium fluorescein (376 Da) and FITC-Dextran (10 kDa) quickly established a concentration gradient that was maintained out to 96 h, with 24 hourly replenishment of the source and sink reservoirs. FITC-Dextran (40 kDa) took longer to establish in all hydrogel setups. The steepness of gradients generated are within appropriate range to elicit response in certain cell types. The compatibility of our platform with cell culture was demonstrated using a LIVE/DEAD® assay on terminally differentiated SH-SY5Y neurons. We believe this device presents as a convenient and useful tool that can be easily adopted for study of cellular response in gradient-based assays.
Collapse
Affiliation(s)
- Anusha Dravid
- Faculty of Medical and Health Sciences, School of Pharmacy, University of Auckland, Auckland, New Zealand
| | - Brad Raos
- Faculty of Medical and Health Sciences, School of Pharmacy, University of Auckland, Auckland, New Zealand
| | - Zaid Aqrawe
- Faculty of Medical and Health Sciences, School of Pharmacy, University of Auckland, Auckland, New Zealand
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Sam Parittotokkaporn
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Simon J. O'Carroll
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Darren Svirskis
- Faculty of Medical and Health Sciences, School of Pharmacy, University of Auckland, Auckland, New Zealand
| |
Collapse
|
7
|
Parittotokkaporn S, Dravid A, Bansal M, Aqrawe Z, Svirskis D, Suresh V, O’Carroll SJ. Make it simple: long-term stable gradient generation in a microfluidic microdevice. Biomed Microdevices 2019; 21:77. [DOI: 10.1007/s10544-019-0427-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|