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17 pages, 9582 KiB

Open AccessArticle

Effects of Bio-Aging on Mechanical Properties and Microbial Behavior of Different Resin Composites

by Yuke Shou, Lanzhi Deng, Xiaoyu Huang, Xinyu Peng, Xinxuan Zhou, Zheng Wang, Yannan Huang, Bina Yang, Haohao Wang, Min Zhang and Lei Cheng

Biomolecules 2023, 13(7), 1125; https://doi.org/10.3390/biom13071125 - 14 Jul 2023

Viewed by 1283

Abstract

Under challenging oral environments, the overall performance of resin composites is affected by bio-aging. This study investigated the effects of saliva biofilm-induced bio-aging on the mechanical properties and microbial behavior of composites with different filler types. Microhybrid, nanohybrid, nano-filled and nano-filled flowable composites [...] Read more.

Under challenging oral environments, the overall performance of resin composites is affected by bio-aging. This study investigated the effects of saliva biofilm-induced bio-aging on the mechanical properties and microbial behavior of composites with different filler types. Microhybrid, nanohybrid, nano-filled and nano-filled flowable composites were bio-aged with saliva biofilm for 30 days. Surface morphology, roughness, mechanical and aesthetic properties were determined. A 48 h saliva biofilm model was used to evaluate the microbial behavior of different composites in vitro. Biofilm metabolic activity, lactic acid production and live/dead bacterial staining were tested. Six volunteers were selected to wear intra-oral appliances with composite slabs for 24 h and biofilms were collected and analyzed using 16S rRNA sequencing to assess the biofilm formation over those materials in situ. Although there were increasing trends, surface roughness, water resorption and material solubility had no significant changes for all groups after bio-aging (p > 0.05). There were no significant changes in elastic modulus for all groups after aging (p > 0.05). However, a decrease in flexural strength in all groups was observed (p < 0.05), except for the nanoflow composite group (p > 0.05). The Vickers hardness remained stable in all groups after aging (p > 0.05), except for the nano-filled group (p < 0.05). The nanoflow composite showed distinct color changes compared to the micro-hybrid group after aging (p < 0.05). Biofilm metabolic activity and lactic acid production in vitro increased slightly after bio-aging in all groups, but with no statistical significance (p > 0.05). The Shannon index diversity of biofilms in situ decreased after aging (p < 0.05), while no significant difference was shown in species composition at the genus level in all groups (p > 0.05). Resin composites with different sized fillers displayed a relatively stable mechanical performance and uncompromised microbial behavior both in vitro and in situ after 30 days of bio-aging. Based on the results, composites with different filler types can be selected flexibly according to clinical needs. However, a longer time for bio-aging is still needed to confirm the mechanical properties and microbial behaviors of composites in the long run. Full article

(This article belongs to the Special Issue Interface of Aging and Biomaterials)

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24 pages, 6921 KiB

Open AccessFeature PaperArticle

Development of a Vascularized Human Skin Equivalent with Hypodermis for Photoaging Studies

by Martina M. Sanchez, Thamidul Islam Tonmoy, B. Hyle Park and Joshua T. Morgan

Biomolecules 2022, 12(12), 1828; https://doi.org/10.3390/biom12121828 - 07 Dec 2022

Cited by 1 | Viewed by 2089

Abstract

Photoaging is an important extrinsic aging factor leading to altered skin morphology and reduced function. Prior work has revealed a connection between photoaging and loss of subcutaneous fat. Currently, primary models for studying this are in vivo (human samples or animal models) or [...] Read more.

Photoaging is an important extrinsic aging factor leading to altered skin morphology and reduced function. Prior work has revealed a connection between photoaging and loss of subcutaneous fat. Currently, primary models for studying this are in vivo (human samples or animal models) or in vitro models, including human skin equivalents (HSEs). In vivo models are limited by accessibility and cost, while HSEs typically do not include a subcutaneous adipose component. To address this, we developed an “adipose-vascular” HSE (AVHSE) culture method, which includes both hypodermal adipose and vascular cells. Furthermore, we tested AVHSE as a potential model for hypodermal adipose aging via exposure to 0.45 ± 0.15 mW/cm² 385 nm light (UVA). One week of 2 h daily UVA exposure had limited impact on epidermal and vascular components of the AVHSE, but significantly reduced adiposity by approximately 50%. Overall, we have developed a novel method for generating HSE that include vascular and adipose components and demonstrated potential as an aging model using photoaging as an example. Full article

(This article belongs to the Special Issue Interface of Aging and Biomaterials)

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10 pages, 2496 KiB

Open AccessArticle

Hydrogel-Encapsulated Heterogenous Mesoporous Resin Catalyst for In Situ Anti-Cancer Agent Production under Biological Conditions

by Mahboubeh Nabavinia, Baishali Kanjilal, Manoj Pandey, Subash Jonnalagadda, Robert Hesketh, Manuela Martins-Green and Iman Noshadi

Biomolecules 2022, 12(12), 1796; https://doi.org/10.3390/biom12121796 - 01 Dec 2022

Cited by 2 | Viewed by 1248

Abstract

A heterogenous Palladium anchored Resorcinol-formaldehyde-hyperbranched PEI mesoporous catalyst, made by one-pot synthesis, was used successfully for in situ Suzuki-Miyaura cross coupling synthesis of anticancer prodrug PP-121 from iodoprazole and boronic ester precursors. The mesoporous catalyst with the non-cytotoxic precursors were tested in 2D [...] Read more.

A heterogenous Palladium anchored Resorcinol-formaldehyde-hyperbranched PEI mesoporous catalyst, made by one-pot synthesis, was used successfully for in situ Suzuki-Miyaura cross coupling synthesis of anticancer prodrug PP-121 from iodoprazole and boronic ester precursors. The mesoporous catalyst with the non-cytotoxic precursors were tested in 2D in vitro model with excellent cytocompatibility and a strong suppression of PC3 cancer cell proliferation, underscored by 50% reduction in PC3 cells viability and 55% reduction in cell metabolism activity and an enhanced rate of early and late apoptosis in flow cytometry, that was induced only by successful in situ pro drug PP121 synthesis from the precursors. The 3D gelatin methacrylate hydrogel encapsulated in vitro cell models underscored the results with a 52% reduction in cell metabolism and underscored apoptosis of PC3 cells when the Pd anchored catalyst was combined with the precursors. In situ application of Suzuki-Miyaura cross coupling of non-cytotoxic precursors to cancer drug, along with their successful encapsulation in an injectable hydrogel could be applied for tumor point drug delivery strategies that can circumvent deleterious side effects and poor bioavailability chemotherapy routes with concomitant enhanced efficacy. Full article

(This article belongs to the Special Issue Interface of Aging and Biomaterials)

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12 pages, 3995 KiB

Open AccessArticle

How Streptococcus mutans Affects the Surface Topography and Electrochemical Behavior of Nanostructured Bulk Ti

by Agata Sotniczuk, Agnieszka Jastrzębska, Adrian Chlanda, Agnieszka Kwiatek and Halina Garbacz

Biomolecules 2022, 12(10), 1515; https://doi.org/10.3390/biom12101515 - 19 Oct 2022

Cited by 1 | Viewed by 1411

Abstract

The metabolization of carbohydrates by Streptococcus mutans leads to the formation of lactic acid in the oral cavity, which can consequently accelerate the degradation of dental implants fabricated from commercially available microcrystalline Ti. Microstructure influences surface topography and hence interaction between bacteria cells [...] Read more.

The metabolization of carbohydrates by Streptococcus mutans leads to the formation of lactic acid in the oral cavity, which can consequently accelerate the degradation of dental implants fabricated from commercially available microcrystalline Ti. Microstructure influences surface topography and hence interaction between bacteria cells and Ti surfaces. This work offers the first description of the effect of S. mutans on the surface topography and properties of nanostructured bulk Ti, which is a promising candidate for modern narrow dental implants owing to its superior mechanical strength. It was found that S. mutans incubation resulted in the slight, unexpected decrease of surface nanoroughness, which was previously developed owing to privileged oxidation in areas of closely spaced boundaries. However, despite the changes in nanoscale surface topography, bacteria incubation did not reduce the high level of protection afforded by the oxide layer formed on the nanostructured Ti surface. The results highlight the need–hitherto ignored–to consider Ti microstructure when analyzing its behavior in the presence of carbohydrate-metabolizing bacteria. Full article

(This article belongs to the Special Issue Interface of Aging and Biomaterials)

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10 pages, 1699 KiB

Open AccessArticle

Andrographolide Inhibits Corneal Fibroblast to Myofibroblast Differentiation In Vitro

by Vanessa Rozo, Melinda Quan, Theint Aung, Jennifer Kang, Sara M. Thomasy and Brian C. Leonard

Biomolecules 2022, 12(10), 1447; https://doi.org/10.3390/biom12101447 - 09 Oct 2022

Viewed by 1629

Abstract

Corneal opacification due to fibrosis is a leading cause of blindness worldwide. Fibrosis occurs from many causes including trauma, photorefractive surgery, microbial keratitis (infection of the cornea), and chemical burns, yet there is a paucity of therapeutics to prevent or treat corneal fibrosis. [...] Read more.

Corneal opacification due to fibrosis is a leading cause of blindness worldwide. Fibrosis occurs from many causes including trauma, photorefractive surgery, microbial keratitis (infection of the cornea), and chemical burns, yet there is a paucity of therapeutics to prevent or treat corneal fibrosis. This study aimed to determine if andrographolide, a labdane diterpenoid found in Andrographis paniculate, has anti-fibrotic properties. Furthermore, we evaluated if andrographolide could prevent the differentiation of fibroblasts to myofibroblasts in vitro, given that the transforming growth factor beta-1(TGF-β1) stimulated persistence of myofibroblasts in the cornea is a primary component of fibrosis. We demonstrated that andrographolide inhibited the upregulation of alpha smooth muscle actin (αSMA) mRNA and protein in rabbit corneal fibroblasts (RCFs), thus, demonstrating a reduction in the transdifferentiation of myofibroblasts. Immunofluorescent staining of TGF-β1-stimulated RCFs confirmed a dose-dependent decrease in αSMA expression when treated with andrographolide. Additionally, andrographolide was well tolerated in vivo and had no impact on corneal epithelialization in a rat debridement model. These data support future studies investigating the use of andrographolide as an anti-fibrotic in corneal wound healing. Full article

(This article belongs to the Special Issue Interface of Aging and Biomaterials)

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Review

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17 pages, 1165 KiB

Open AccessReview

Particulate Matter in Human Elderly: Higher Susceptibility to Cognitive Decline and Age-Related Diseases

by Caridad López-Granero, Leona Polyanskaya, Diego Ruiz-Sobremazas, Angel Barrasa, Michael Aschner and Matilde Alique

Biomolecules 2024, 14(1), 35; https://doi.org/10.3390/biom14010035 - 26 Dec 2023

Viewed by 1441

Abstract

This review highlights the significant impact of air quality, specifically particulate matter (PM), on cognitive decline and age-related diseases in the elderly. Despite established links to other pathologies, such as respiratory and cardiovascular illnesses, there is a pressing need for increased attention to [...] Read more.

This review highlights the significant impact of air quality, specifically particulate matter (PM), on cognitive decline and age-related diseases in the elderly. Despite established links to other pathologies, such as respiratory and cardiovascular illnesses, there is a pressing need for increased attention to the association between air pollution and cognitive aging, given the rising prevalence of neurocognitive disorders. PM sources are from diverse origins, including industrial activities and combustion engines, categorized into PM₁₀, PM_2.5, and ultrafine PM (UFPM), and emphasized health risks from both outdoor and indoor exposure. Long-term PM exposure, notably PM_2.5, has correlated with declines in cognitive function, with a specific vulnerability observed in women. Recently, extracellular vesicles (EVs) have been explored due to the interplay between them, PM exposure, and human aging, highlighting the crucial role of EVs, especially exosomes, in mediating the complex relationship between PM exposure and chronic diseases, particularly neurological disorders. To sum up, we have compiled the pieces of evidence that show the potential contribution of PM exposure to cognitive aging and the role of EVs in mediating PM-induced cognitive impairment, which presents a promising avenue for future research and development of therapeutic strategies. Finally, this review emphasizes the need for policy changes and increased public awareness to mitigate air pollution, especially among vulnerable populations such as the elderly. Full article

(This article belongs to the Special Issue Interface of Aging and Biomaterials)

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16 pages, 1366 KiB

Open AccessReview

Human Skin Aging and the Anti-Aging Properties of Retinol

by Taihao Quan

Biomolecules 2023, 13(11), 1614; https://doi.org/10.3390/biom13111614 - 04 Nov 2023

Viewed by 6281

Abstract

The skin is the most-extensive and -abundant tissue in the human body. Like many organs, as we age, human skin experiences gradual atrophy in both the epidermis and dermis. This can be primarily attributed to the diminishing population of epidermal stem cells and [...] Read more.

The skin is the most-extensive and -abundant tissue in the human body. Like many organs, as we age, human skin experiences gradual atrophy in both the epidermis and dermis. This can be primarily attributed to the diminishing population of epidermal stem cells and the reduction in collagen, which is the primary structural protein in the human body. The alterations occurring in the epidermis and dermis due to the aging process result in disruptions to the structure and functionality of the skin. This creates a microenvironment conducive to age-related skin conditions such as a compromised skin barrier, slowed wound healing, and the onset of skin cancer. This review emphasizes the recent molecular discoveries related to skin aging and evaluates preventive approaches, such as the use of topical retinoids. Topical retinoids have demonstrated promise in enhancing skin texture, diminishing fine lines, and augmenting the thickness of both the epidermal and dermal layers. Full article

(This article belongs to the Special Issue Interface of Aging and Biomaterials)

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52 pages, 4727 KiB

Open AccessReview

Counteracting Immunosenescence—Which Therapeutic Strategies Are Promising?

by Christoph Hieber, Stephan Grabbe and Matthias Bros

Biomolecules 2023, 13(7), 1085; https://doi.org/10.3390/biom13071085 - 06 Jul 2023

Cited by 3 | Viewed by 2663

Abstract

Aging attenuates the overall responsiveness of the immune system to eradicate pathogens. The increased production of pro-inflammatory cytokines by innate immune cells under basal conditions, termed inflammaging, contributes to impaired innate immune responsiveness towards pathogen-mediated stimulation and limits antigen-presenting activity. Adaptive immune responses [...] Read more.

Aging attenuates the overall responsiveness of the immune system to eradicate pathogens. The increased production of pro-inflammatory cytokines by innate immune cells under basal conditions, termed inflammaging, contributes to impaired innate immune responsiveness towards pathogen-mediated stimulation and limits antigen-presenting activity. Adaptive immune responses are attenuated as well due to lowered numbers of naïve lymphocytes and their impaired responsiveness towards antigen-specific stimulation. Additionally, the numbers of immunoregulatory cell types, comprising regulatory T cells and myeloid-derived suppressor cells, that inhibit the activity of innate and adaptive immune cells are elevated. This review aims to summarize our knowledge on the cellular and molecular causes of immunosenescence while also taking into account senescence effects that constitute immune evasion mechanisms in the case of chronic viral infections and cancer. For tumor therapy numerous nanoformulated drugs have been developed to overcome poor solubility of compounds and to enable cell-directed delivery in order to restore immune functions, e.g., by addressing dysregulated signaling pathways. Further, nanovaccines which efficiently address antigen-presenting cells to mount sustained anti-tumor immune responses have been clinically evaluated. Further, senolytics that selectively deplete senescent cells are being tested in a number of clinical trials. Here we discuss the potential use of such drugs to improve anti-aging therapy. Full article

(This article belongs to the Special Issue Interface of Aging and Biomaterials)

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