Daniela Milosheska . Robert Roskar

Received: August 17, 2022 / Accepted: September 6, 2022 / Published online: October 11, 2022

©The Author(s) 2022

ABSTRACT

      Nowadays, numerous skincare routines are used to rejuvenate aging skin. Retinoids are one of the most popular ingredients used in antiaging treatments. Among the representatives of retinoids, tretinoin is considered the most effective agent with proven antiaging effects on the skin and can be found in formulations approved as medicines for topical treatment of acne, facial wrinkles, and hyperpigmentation. Other retinoids present in topical medicines are used for various indications, but only tazarotene is also approved as adjunctive agent for treatment of facial fine wrinkling and pigmentation. The most commonly used retinoids such as retinol, retinaldehyde, and retinyl palmitate are contained in cosmeceuticals regulated as cosmetics. Since clinical efficacy studies are not required for marketing cosmetic formulations, there are concerns about the efficacy of these retinoids.

      From a formulation perspective, retinoids pose a challenge to researchers as a result of their proven instability, low penetration, and potential for skin irritation. Therefore, novel delivery systems based on nanotechnology are being developed to overcome the limitations of conventional formulations and improve user compliance. In this review, the clinical evidence for retinoids in conventional and nanoformulations for topical antiaging treatments was evaluated. In addition, an overview of the comparison clinical trials between tretinoin and other retinoids is presented. In general, there is a lack of evidence from properly designed clinical trials to support the claimed efficacy of the most commonly used retinoids as antiaging agents in cosmeceuticals. Of the other retinoids contained in medicines, tazarotene and adapalene have clinically evaluated antiaging effects compared to tretinoin and may be considered as potential alternatives for antiaging treatments. The promising potential of retinoid nanoformulations requires a more comprehensive evaluation with additional studies to support the preliminary findings.

Keywords: Antiaging; Clinical evidence; Cosmeceuticals; Nanoformulations; Retinoids; Retinol; Tretinoin

Key Summary Points

Tretinoin is the retinoid present in medicines for topical application with the strongest clinical evidence of antiaging Tazarotene and adapalene may be considered as tretinoin alternatives for antiaging treatments.

Clinical evidence is lacking for retinoids contained in cosmeceuticals for topical antiaging treatments.

Novel formulations based on nanotechnology are being developed to overcome the major drawbacks of retinoid Further evaluation with in vivo testing and clinical trials are needed to support the preclinical results for the developed nanoformulations containing retinoids.

D. Milosheska INSLAB, Maribor, Slovenia

R. Roskar (&)

University of Ljubljana, Faculty of Pharmacy, Askerceva cesta 7, 1000 Ljubljana, Slovenia

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Gérald J. Prud’homme1,2 *, Mervé Kurt 2 and Qinghua Wang3,4

1 Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada,

2 Department of Laboratory Medicine, Keenan Research Centre for Biomedical Science, Unity Health Toronto, Toronto, ON, Canada,

3 Department of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical School, Fudan University, Shanghai, China,

4 Shanghai Yinuo Pharmaceutical Co., Ltd., Shanghai, China

Edited by:

Cátia F. Lourenço, University of Coimbra, Portugal

Reviewed by:

Mujib Ullah, Stanford University, United States Taylor Landry, East Carolina University, United States

*Correspondence:

Gérald J. Prud’homme 该Email地址已收到反垃圾邮件插件保护。要显示它您需要在浏览器中启用JavaScript。

Specialty section:

This article was submitted to Molecular Mechanisms of Aging, a section of the journal Frontiers in Aging

Received: 28 April 2022

Accepted: 06 June 2022

Published: 12 July 2022

Citation:

Prud’homme GJ, Kurt M and Wang Q (2022) Pathobiology of the Klotho Antiaging Protein and Therapeutic Considerations. Front. Aging 3:931331.

doi: 10.3389/fragi.2022.931331

The α-Klotho protein (henceforth denoted Klotho) has antiaging properties, as first observed in mice homozygous for a hypomorphic Klotho gene (kl/kl). These mice have a shortened lifespan, stunted growth, renal disease, hyperphosphatemia, hypercalcemia, vascular calcification, cardiac hypertrophy, hypertension, pulmonary disease, cognitive impairment, multi-organ atrophy and fibrosis. Overexpression of Klotho has opposite effects, extending lifespan. In humans, Klotho levels decline with age, chronic kidney disease, diabetes, Alzheimer’s disease and other conditions. Low Klotho levels correlate with an increase in the death rate from all causes. Klotho acts either as an obligate coreceptor for fibroblast growth factor 23 (FGF23), or as a soluble pleiotropic endocrine hormone (s-Klotho). It is mainly produced in the kidneys, but also in the brain, pancreas and other tissues. On renal tubular-cell membranes, it associates with FGF receptors to bind FGF23. Produced in bones, FGF23 regulates renal excretion of phosphate (phosphaturic effect) and vitamin D metabolism. Lack of Klotho or FGF23 results in hyperphosphatemia and hypervitaminosis D. With age, human renal function often deteriorates, lowering Klotho levels. This appears to promote age-related pathology. Remarkably, Klotho inhibits four pathways that have been linked to aging in various ways: Transforming growth factor β (TGF-β), insulin-like growth factor 1 (IGF-1), Wnt and NF-κB. These can induce cellular senescence, apoptosis, inflammation, immune dysfunction, fibrosis and neoplasia. Furthermore, Klotho increases cell-protective antioxidant enzymes through Nrf2 and FoxO. In accord, preclinical Klotho therapy ameliorated renal, cardiovascular, diabetes-related and neurodegenerative diseases, as well as cancer. s-Klotho protein injection was effective, but requires further investigation. Several drugs enhance circulating Klotho levels, and some cross the blood-brain barrier to potentially act in the brain. In clinical trials, increased Klotho was noted with renin-angiotensin system inhibitors (losartan, valsartan), a statin (fluvastatin), mTOR inhibitors (rapamycin, everolimus), vitamin D and pentoxifylline. In preclinical work, antidiabetic drugs (metformin, GLP-1-based, GABA, PPAR-γ agonists) also enhanced Klotho. Several traditional medicines and/or nutraceuticals increased Klotho in rodents, including astaxanthin, curcumin, ginseng, ligustilide and resveratrol. Notably, exercise and sport activity increased Klotho. This review addresses molecular, physiological and therapeutic aspects of Klotho.

Keywords: aging, FGF23, hyperphosphatemia, klotho, IGF-1, NF-KappaB, TGF-beta, Wnt

Experts consensus on the application of medical radiofrequency incosmetic dermatology and treatment
中华医学会皮肤性病学分会皮肤激光医疗美容学组
中华医学会皮肤激光技术应用研究中心
中国医师协会美容与整形医师分会激光学组
中华医学会医学美学与美容学分会激光美容学组、皮肤美容学组
【关键词] 射频，医用;皮肤美容治疗;共识
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