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McMillan CLD, Wijesundara DK, Choo JJY, Amarilla AA, Modhiran N, Fernando GJP, Khromykh AA, Watterson D, Young PR, Muller DA. Enhancement of cellular immunity following needle-free vaccination of mice with SARS-CoV-2 spike protein. J Gen Virol 2024; 105. [PMID: 38271027 DOI: 10.1099/jgv.0.001947] [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: 01/27/2024] Open
Abstract
The COVID-19 pandemic has highlighted the need for vaccines capable of providing rapid and robust protection. One way to improve vaccine efficacy is delivery via microarray patches, such as the Vaxxas high-density microarray patch (HD-MAP). We have previously demonstrated that delivery of a SARS-CoV-2 protein vaccine candidate, HexaPro, via the HD-MAP induces potent humoral immune responses. Here, we investigate the cellular responses induced by HexaPro HD-MAP vaccination. We found that delivery via the HD-MAP induces a type one biassed cellular response of much greater magnitude as compared to standard intramuscular immunization.
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Affiliation(s)
- Christopher L D McMillan
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
- Australian Infectious Diseases Research Centre, Global Virus Network Centre of Excellence, Brisbane, Queensland 4072 and 4029, Australia
| | - Danushka K Wijesundara
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
- Vaxxas Biomedical Facility, Hamilton, Queensland 4007, Australia
| | - Jovin J Y Choo
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Alberto A Amarilla
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Naphak Modhiran
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Germain J P Fernando
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
- Vaxxas Biomedical Facility, Hamilton, Queensland 4007, Australia
| | - Alexander A Khromykh
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
- Australian Infectious Diseases Research Centre, Global Virus Network Centre of Excellence, Brisbane, Queensland 4072 and 4029, Australia
| | - Daniel Watterson
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
- Australian Infectious Diseases Research Centre, Global Virus Network Centre of Excellence, Brisbane, Queensland 4072 and 4029, Australia
| | - Paul R Young
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
- Australian Infectious Diseases Research Centre, Global Virus Network Centre of Excellence, Brisbane, Queensland 4072 and 4029, Australia
| | - David A Muller
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
- Australian Infectious Diseases Research Centre, Global Virus Network Centre of Excellence, Brisbane, Queensland 4072 and 4029, Australia
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Wijesundara DK, Yeow A, McMillan CL, Choo JJ, Todorovic A, Mekonnen ZA, Masavuli MG, Young PR, Gowans EJ, Grubor-Bauk B, Muller DA. Superior efficacy of a skin-applied microprojection device for delivering a novel Zika DNA vaccine. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 34:102056. [PMID: 38028199 PMCID: PMC10630652 DOI: 10.1016/j.omtn.2023.102056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 10/11/2023] [Indexed: 12/01/2023]
Abstract
Zika virus (ZIKV) infections are spreading silently with limited global surveillance in at least 89 countries and territories. There is a pressing need to develop an effective vaccine suitable for equitable distribution globally. Consequently, we previously developed a proprietary DNA vaccine encoding secreted non-structural protein 1 of ZIKV (pVAX-tpaNS1) to elicit rapid protection in a T cell-dependent manner in mice. In the current study, we evaluated the stability, efficacy, and immunogenicity of delivering this DNA vaccine into the skin using a clinically effective and proprietary high-density microarray patch (HD-MAP). Dry-coating of pVAX-tpaNS1 on the HD-MAP device resulted in no loss of vaccine stability at 40°C storage over the course of 28 days. Vaccination of mice (BALB/c) with the HD-MAP-coated pVAX-tpaNS1 elicited a robust anti-NS1 IgG response in both the cervicovaginal mucosa and systemically and afforded protection against live ZIKV challenge. Furthermore, the vaccination elicited a significantly higher magnitude and broader NS1-specific T helper and cytotoxic T cell response in vivo compared with traditional needle and syringe intradermal vaccination. Overall, the study highlights distinctive immunological advantages coupled with an excellent thermostability profile of using the HD-MAP device to deliver a novel ZIKV DNA vaccine.
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Affiliation(s)
- Danushka K. Wijesundara
- Vaxxas Biomedical Facility, Hamilton, QLD 4007, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Arthur Yeow
- Discipline of Surgery, The University of Adelaide, Basil Hetzel Institute for Translational Health Research, Adelaide, SA 5005, Australia
| | - Christopher L.D. McMillan
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jovin J.Y. Choo
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Aleksandra Todorovic
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Zelalem A. Mekonnen
- Discipline of Surgery, The University of Adelaide, Basil Hetzel Institute for Translational Health Research, Adelaide, SA 5005, Australia
| | - Makutiro G. Masavuli
- Discipline of Surgery, The University of Adelaide, Basil Hetzel Institute for Translational Health Research, Adelaide, SA 5005, Australia
| | - Paul R. Young
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Eric J. Gowans
- Discipline of Surgery, The University of Adelaide, Basil Hetzel Institute for Translational Health Research, Adelaide, SA 5005, Australia
| | - Branka Grubor-Bauk
- Discipline of Surgery, The University of Adelaide, Basil Hetzel Institute for Translational Health Research, Adelaide, SA 5005, Australia
| | - David A. Muller
- Vaxxas Biomedical Facility, Hamilton, QLD 4007, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
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Baker B, Bermingham IM, Leelasena I, Hickling J, Young PR, Muller DA, Forster AH. Safety, Tolerability, and Immunogenicity of Measles and Rubella Vaccine Delivered with a High-Density Microarray Patch: Results from a Randomized, Partially Double-Blinded, Placebo-Controlled Phase I Clinical Trial. Vaccines (Basel) 2023; 11:1725. [PMID: 38006057 PMCID: PMC10675090 DOI: 10.3390/vaccines11111725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/18/2023] [Accepted: 08/24/2023] [Indexed: 11/26/2023] Open
Abstract
Microarray patches (MAPs) have the potential to be a safer, more acceptable, easier-to-use, and more cost-effective means for the administration of vaccines than injection by needle and syringe. Here, we report findings from a randomized, partially double-blinded, placebo-controlled Phase I trial using the Vaxxas high-density MAP (HD-MAP) to deliver a measles rubella (MR) vaccine. Healthy adults (N = 63, age 18-50 years) were randomly assigned 1:1:1:1 to four groups: uncoated (placebo) HD-MAPs, low-dose MR HD-MAPs (~3100 median cell-culture infectious dose [CCID50] measles, ~4300 CCID50 rubella); high-dose MR-HD-MAPs (~9300 CCID50 measles, ~12,900 CCID50 rubella); or a sub-cutaneous (SC) injection of an approved MR vaccine, MR-Vac (≥1000 CCID50 per virus). The MR vaccines were stable and remained viable on HD-MAPs when stored at 2-8 °C for at least 24 months. When MR HD-MAPs stored at 2-8 °C for 24 months were transferred to 40 °C for 3 days in a controlled temperature excursion, loss of potency was minimal, and MR HD-MAPs still met World Health Organisation (WHO) specifications. MR HD-MAP vaccination was safe and well-tolerated; any systemic or local adverse events (AEs) were mild or moderate. Similar levels of binding and neutralizing antibodies to measles and rubella were induced by low-dose and high-dose MR HD-MAPs and MR-Vac. The neutralizing antibody seroconversion rates on day 28 after vaccination for the low-dose HD-MAP, high-dose HD-MAP and MR-Vac groups were 37.5%, 18.8% and 35.7%, respectively, for measles, and 37.5%, 25.0% and 35.7%, respectively, for rubella. Most participants were seropositive for measles and rubella antibodies at baseline, which appeared to negatively impact the number of participants that seroconverted to vaccines delivered by either route. The data reported here suggest HD-MAPs could be a valuable means for delivering MR-vaccine to hard-to-reach populations and support further development. Clinical trial registry number: ACTRN12621000820808.
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Affiliation(s)
- Ben Baker
- Vaxxas Pty Ltd., Hamilton, QLD 4007, Australia; (B.B.)
| | | | - Indika Leelasena
- University of the Sunshine Coast Clinical Trials Centre, Sippy Downs, QLD 4556, Australia
| | | | - Paul R. Young
- School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, QLD 4072, Australia
| | - David A. Muller
- School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, QLD 4072, Australia
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Berger MN, Mowbray ES, Farag MWA, Mathieu E, Davies C, Thomas C, Booy R, Forster AH, Skinner SR. Immunogenicity, safety, usability and acceptability of microarray patches for vaccination: a systematic review and meta-analysis. BMJ Glob Health 2023; 8:e012247. [PMID: 37827725 PMCID: PMC10583062 DOI: 10.1136/bmjgh-2023-012247] [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: 03/09/2023] [Accepted: 09/10/2023] [Indexed: 10/14/2023] Open
Abstract
BACKGROUND Microarray patches (MAPs) deliver vaccines to the epidermis and the upper dermis, where abundant immune cells reside. There are several potential benefits to using MAPs, including reduced sharps risk, thermostability, no need for reconstitution, tolerability and self-administration. We aimed to explore and evaluate the immunogenicity, safety, usability and acceptability of MAPs for vaccination. METHODS We searched CINAHL, Cochrane Library, Ovid Embase, Ovid MEDLINE and Web of Science from inception to January 2023. Eligibility criteria included all research studies in any language, which examined microarrays or microneedles intended or used for vaccination and explored immunogenicity, safety, usability or acceptability in their findings. Two reviewers conducted title and abstract screening, full-text reviewing and data extraction. RESULTS Twenty-two studies were included (quantitative=15, qualitative=2 and mixed methods=5). The risk of bias was mostly low, with two studies at high risk of bias. Four clinical trials were included, three using influenza antigens and one with Japanese encephalitis delivered by MAP. A meta-analysis indicated similar or higher immunogenicity in influenza MAPs compared with needle and syringe (N&S) (standardised mean difference=10.80, 95% CI: 3.51 to 18.08, p<0.00001). There were no significant differences in immune cell function between MAPs and N&S. No serious adverse events were reported in MAPs. Erythema was more common after MAP application than N&S but was brief and well tolerated. Lower pain scores were usually reported after MAP application than N&S. Most studies found MAPs easy to use and highly acceptable among healthcare professionals, laypeople and parents. CONCLUSION MAPs for vaccination were safe and well tolerated and evoked similar or enhanced immunogenicity than N&S, but further research is needed. Vaccine uptake may be increased using MAPs due to less pain, enhanced thermostability, layperson and self-administration. MAPs could benefit at-risk groups and low and middle-income countries. PROSPERO REGISTRATION NUMBER CRD42022323026.
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Affiliation(s)
- Matthew N Berger
- Specialty of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Westmead, New South Wales, Australia
- Centre for Population Health, Western Sydney Local Health District, North Parramatta, New South Wales, Australia
- Sydney Infectious Diseases Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Ellen S Mowbray
- Specialty of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Westmead, New South Wales, Australia
| | - Marian W A Farag
- Hillarys Plaza Medical Centre, Perth, Western Australia, Australia
| | - Erin Mathieu
- School of Public Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Cristyn Davies
- Specialty of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Westmead, New South Wales, Australia
- Sydney Infectious Diseases Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Claire Thomas
- Centre for Population Health, Western Sydney Local Health District, North Parramatta, New South Wales, Australia
| | - Robert Booy
- Sydney Infectious Diseases Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
- Children's Hospital Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, Westmead, New South Wales, Australia
| | | | - S Rachel Skinner
- Specialty of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Westmead, New South Wales, Australia
- Sydney Infectious Diseases Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
- Kids Research, The Children's Hospital at Westmead, Sydney Children's Hospitals Network, Westmead, New South Wales, Australia
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Nguyen HX, Nguyen CN. Microneedle-Mediated Transdermal Delivery of Biopharmaceuticals. Pharmaceutics 2023; 15:277. [PMID: 36678906 PMCID: PMC9864466 DOI: 10.3390/pharmaceutics15010277] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/05/2023] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Transdermal delivery provides numerous benefits over conventional routes of administration. However, this strategy is generally limited to a few molecules with specific physicochemical properties (low molecular weight, high potency, and moderate lipophilicity) due to the barrier function of the stratum corneum layer. Researchers have developed several physical enhancement techniques to expand the applications of the transdermal field; among these, microneedle technology has recently emerged as a promising platform to deliver therapeutic agents of any size into and across the skin. Typically, hydrophilic biomolecules cannot penetrate the skin by passive diffusion. Microneedle insertion disrupts skin integrity and compromises its protective function, thus creating pathways (microchannels) for enhanced permeation of macromolecules. Microneedles not only improve stability but also enhance skin delivery of various biomolecules. Academic institutions and industrial companies have invested substantial resources in the development of microneedle systems for biopharmaceutical delivery. This review article summarizes the most recent research to provide a comprehensive discussion about microneedle-mediated delivery of macromolecules, covering various topics from the introduction of the skin, transdermal delivery, microneedles, and biopharmaceuticals (current status, conventional administration, and stability issues), to different microneedle types, clinical trials, safety and acceptability of microneedles, manufacturing and regulatory issues, and the future of microneedle technology.
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Affiliation(s)
- Hiep X. Nguyen
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA 30341, USA
| | - Chien N. Nguyen
- National Institute of Pharmaceutical Technology, Hanoi University of Pharmacy, Hanoi 100000, Vietnam
- Faculty of Pharmaceutics and Pharmaceutical Technology, Hanoi University of Pharmacy, Hanoi 100000, Vietnam
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Skin Vaccination with Ebola Virus Glycoprotein Using a Polyphosphazene-Based Microneedle Patch Protects Mice against Lethal Challenge. J Funct Biomater 2022; 14:jfb14010016. [PMID: 36662063 PMCID: PMC9860647 DOI: 10.3390/jfb14010016] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/23/2022] [Accepted: 12/24/2022] [Indexed: 12/29/2022] Open
Abstract
Ebolavirus (EBOV) infection in humans is a severe and often fatal disease, which demands effective interventional strategies for its prevention and treatment. The available vaccines, which are authorized under exceptional circumstances, use viral vector platforms and have serious disadvantages, such as difficulties in adapting to new virus variants, reliance on cold chain supply networks, and administration by hypodermic injection. Microneedle (MN) patches, which are made of an array of micron-scale, solid needles that painlessly penetrate into the upper layers of the skin and dissolve to deliver vaccines intradermally, simplify vaccination and can thereby increase vaccine access, especially in resource-constrained or emergency settings. The present study describes a novel MN technology, which combines EBOV glycoprotein (GP) antigen with a polyphosphazene-based immunoadjuvant and vaccine delivery system (poly[di(carboxylatophenoxy)phosphazene], PCPP). The protein-stabilizing effect of PCPP in the microfabrication process enabled preparation of a dissolvable EBOV GP MN patch vaccine with superior antigenicity compared to a non-polyphosphazene polymer-based analog. Intradermal immunization of mice with polyphosphazene-based MN patches induced strong, long-lasting antibody responses against EBOV GP, which was comparable to intramuscular injection. Moreover, mice vaccinated with the MN patches were completely protected against a lethal challenge using mouse-adapted EBOV and had no histologic lesions associated with ebolavirus disease.
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Shin Y, Kim J, Seok JH, Park H, Cha HR, Ko SH, Lee JM, Park MS, Park JH. Development of the H3N2 influenza microneedle vaccine for cross-protection against antigenic variants. Sci Rep 2022; 12:12189. [PMID: 35842468 PMCID: PMC9287697 DOI: 10.1038/s41598-022-16365-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 07/08/2022] [Indexed: 11/25/2022] Open
Abstract
Due to the continuously mutating nature of the H3N2 virus, two aspects were considered when preparing the H3N2 microneedle vaccines: (1) rapid preparation and (2) cross-protection against multiple antigenic variants. Previous methods of measuring hemagglutinin (HA) content required the standard antibody, thus rapid preparation of H3N2 microneedle vaccines targeting the mutant H3N2 was delayed as a result of lacking a standard antibody. In this study, H3N2 microneedle vaccines were prepared by high performance liquid chromatography (HPLC) without the use of an antibody, and the cross-protection of the vaccines against several antigenic variants was observed. The HA content measured by HPLC was compared with that measured by ELISA to observe the accuracy of the HPLC analysis of HA content. The cross-protection afforded by the H3N2 microneedle vaccines was evaluated against several antigenic variants in mice. Microneedle vaccines for the 2019–20 seasonal H3N2 influenza virus (19–20 A/KS/17) were prepared using a dip-coating process. The cross-protection of 19–20 A/KS/17 H3N2 microneedle vaccines against the 2015–16 seasonal H3N2 influenza virus in mice was investigated by monitoring body weight changes and survival rate. The neutralizing antibody against several H3N2 antigenic variants was evaluated using the plaque reduction neutralization test (PRNT). HA content in the solid microneedle vaccine formulation with trehalose post-exposure at 40℃ for 24 h was 48% and 43% from the initial HA content by HPLC and ELISA, respectively. The vaccine was administered to two groups of mice, one by microneedles and the other by intramuscular injection (IM). In vivo efficacies in the two groups were found to be similar, and cross-protection efficacy was also similar in both groups. HPLC exhibited good diagnostic performance with H3N2 microneedle vaccines and good agreement with ELISA. The H3N2 microneedle vaccines elicited a cross-protective immune response against the H3N2 antigenic variants. Here, we propose the use of HPLC for a more rapid approach in preparing H3N2 microneedle vaccines targeting H3N2 virus variants.
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Affiliation(s)
- Yura Shin
- Department of BioNano Technology, Gachon University, Seongnam, Republic of Korea
| | - Jeonghun Kim
- Department of Microbiology, Institute for Viral Diseases, Chung Mong-Koo Vaccine Innovation Center, College of Medicine, Korea University, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Jong Hyeon Seok
- Department of Microbiology, Institute for Viral Diseases, Chung Mong-Koo Vaccine Innovation Center, College of Medicine, Korea University, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Heedo Park
- Department of Microbiology, Institute for Viral Diseases, Chung Mong-Koo Vaccine Innovation Center, College of Medicine, Korea University, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Hye-Ran Cha
- Department of Microbiology and Immunology, Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Si Hwan Ko
- Department of Microbiology and Immunology, Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Jae Myun Lee
- Department of Microbiology and Immunology, Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Man-Seong Park
- Department of Microbiology, Institute for Viral Diseases, Chung Mong-Koo Vaccine Innovation Center, College of Medicine, Korea University, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea.
| | - Jung-Hwan Park
- Department of BioNano Technology, Gachon University, Seongnam, Republic of Korea. .,QuadMedicine R&D Centre, QuadMedicine Co., Ltd, Seongnam, Republic of Korea.
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Local Response and Barrier Recovery in Elderly Skin Following the Application of High-Density Microarray Patches. Vaccines (Basel) 2022; 10:vaccines10040583. [PMID: 35455332 PMCID: PMC9031416 DOI: 10.3390/vaccines10040583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/07/2022] [Accepted: 04/07/2022] [Indexed: 02/01/2023] Open
Abstract
The high-density microneedle array patch (HD-MAP) is a promising alternative vaccine delivery system device with broad application in disease, including SARS-CoV-2. Skin reactivity to HD-MAP applications has been extensively studied in young individuals, but not in the >65 years population, a risk group often requiring higher dose vaccines to produce protective immune responses. The primary aims of the present study were to characterise local inflammatory responses and barrier recovery to HD-MAPs in elderly skin. In twelve volunteers aged 69−84 years, HD-MAPs were applied to the forearm and deltoid regions. Measurements of transepidermal water loss (TEWL), dielectric permittivity and erythema were performed before and after HD-MAP application at t = 10 min, 30 min, 48 h, and 7 days. At all sites, TEWL (barrier damage), dielectric permittivity (superficial water);, and erythema measurements rapidly increased after HD-MAP application. After 7 days, the mean measures had recovered toward pre-application values. The fact that the degree and chronology of skin reactivity and recovery after HD-MAP was similar in elderly skin to that previously reported in younger adults suggests that the reactivity basis for physical immune enhancement observed in younger adults will also be achievable in the older population.
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