scholarly journals Fighting against Skin Aging

2018 ◽  
Vol 27 (5) ◽  
pp. 729-738 ◽  
Author(s):  
Shoubing Zhang ◽  
Enkui Duan

As the most voluminous organ of the body that is exposed to the outer environment, the skin suffers from both intrinsic and extrinsic aging factors. Skin aging is characterized by features such as wrinkling, loss of elasticity, laxity, and rough-textured appearance. This aging process is accompanied with phenotypic changes in cutaneous cells as well as structural and functional changes in extracellular matrix components such as collagens and elastin. In this review, we summarize these changes in skin aging, research advances of the molecular mechanisms leading to these changes, and the treatment strategies aimed at preventing or reversing skin aging.

Author(s):  
Abdul Kader Mohiuddin

As the most voluminous organ of the body that is exposed to the outer environment, the skin suffers from both intrinsic and extrinsic aging factors. Skin aging is characterized by features such as wrinkling, loss of elasticity, laxity, and rough-textured appearance. This aging process is accompanied with phenotypic changes in cutaneous cells as well as structural and functional changes in extracellular matrix components such as collagens and elastin. With intrinsic aging, structural changes occur in the skin as a natural consequence of the biological changes over time and produce a certain number of histological, physiological, and biochemical modifications. Intrinsic aging is determined genetically (influence of gender and ethnic group), variable in function of skin site, and also influenced by hormonal changes. Visually it is characterized by fine wrinkles. By comparison, “photoaging” is the term used to describe the changes occurring in the skin, resulting from repetitive exposure to sunlight. The histological, physiological, and biochemical changes in the different layers of the skin are much more drastic. From a mechanical point of view, human skin appears as a layered composite containing the stiff thin cover layer presented by the stratum corneum, below which are the more compliant layers of viable epidermis and dermis and further below the much more compliant adjacent layer of subcutaneous white adipose tissue.


2007 ◽  
Vol 156 (2) ◽  
pp. 143-153 ◽  
Author(s):  
Alper Gürlek ◽  
Niki Karavitaki ◽  
Olaf Ansorge ◽  
John A H Wass

Prolactinoma is the most common pituitary tumour in adults. Macroprolactinomas, particularly in men, may occasionally exhibit a very aggressive clinical course as evidenced by progressive growth, invasion through bone into the sphenoid sinus, cavernous sinus, suprasellar region or the nasopharynx. Some may even progress to pituitary carcinoma with craniospinal or systemic metastases. Aggressive tumours have low cure rates despite appropriate medical and surgical treatment. The mechanisms underlying this aggressive biological behaviour have not yet been fully clarified. Recent immunohistochemical, molecular and genetic studies have provided some insight in this respect. Invasive prolactinomas may be associated with a high Ki-67/MIB-1 labelling index indicating increased cell proliferation, although this is not a universal finding. The AA polymorphism in the cyclin adenine (A)/guanine (G) gene is more frequently detected in invasive prolactinomas. Increased expression of the polysialylated neural cell adhesion molecule (NCAM) and reduced expression of the E-cadherin/catenin complex implies a contribution of altered cell-to-cell adhesion and cellular migration. Extracellular matrix components (ECM), matrix metalloproteinases (MMPs) and their inhibitors play important roles in the context of angiogenesis and invasion. The induction of fibroblast growth factor and vascular endothelial growth factor via oestrogen-induced overexpression of novel genes (PTTG, hst and Edpm5) enhance cell growth, proliferation and angiogenesis contributing to invasiveness in prolactinomas. Although mutations in proto-oncogenes like Ras are uncommon, loss of tumour suppressor genes at loci 11q13, 13q12–14, 10q and 1p seem to be associated with invasiveness. Of the described mechanisms, only reduced E-cadherin/catenin expression and overexpression of hst gene seem to be relatively specific markers for prolactinoma invasiveness compared with other pituitary adenomas. Further research is needed to clarify the molecular mechanisms behind the aggressive course of some prolactinomas to predict those with a potentially poor clinical outcome, and to devise treatments that will eventually enable the cure of these challenging tumours.


2019 ◽  
Author(s):  
Abdul Kader Mohiuddin

Skin is the barrier that segregates the body from the outer environment. Besides protecting the body from water loss and microorganism infection, it has an important cosmetic role. Young and beautiful appearance may have a positive influence on people’s social behavior and reproductive status. Cleopatra, the Egyptian queen is said to have indulged in daily donkey-milk baths, a practice which apparently required over 700 donkeys to accomplish. The alpha hydroxy acids in the milk is believed to be anti-aging and skin-softening agents. Tang-dynasty ruler and sole female emperor of China, Wu Zetia, maintained a lifelong interest in skincare formulas. She mixed her “fairy powder” (made of carefully harvested and prepared Chinese motherwort) with cold water in order to wash her face each morning. The empress was a famed beauty well into her old age. The most hair-raising entrant in this list, 16th century Hungarian countess Elizabeth Bather is infamous for being one of the world’s first documented female serial killers. Most of her life is shrouded in mystery and legend-the most famous story being that she would regularly bathe in the blood of her female victims. Mary, Queen of Scots, the ill-fated and attractive adversary of Elizabeth I, spent her sixteenth-century happier days on her estate in Edinburgh, Scotland, where her beauty regimen was said to include white-wine baths. In addition to wine’s antiseptic alcohol content, it was also was thought to improve complexion in general. Crème Celeste, a favorite product of empress Elisabeth (Sisi) of Austria, was a concoction of spermaceti (a wax found in the head of sperm whales), sweet almond oil, and rosewater. She would apply this daily and at night, she was known to coat her face in raw veal and crushed strawberries, kept in place with a custom-made leather mask. The skin folds are indicative of an aged personality, but not youthfulness. So, everyone wants to look younger for whole of the life, which lead to the discovery of many surgical and non-surgical treatment modalities to improve the youthfulness. Since the introduction of Botox in 2002 after FDA approval more aesthetic procedures using Botox were performed by aestheticisms involving plastic surgeons and dermatologists. However, many scientists are now starting to view physical aging as a disease process. The cellular and molecular mechanisms involved in aging reveal an intricate series of signals, markers, and pathways, all of which are programmed to monitor and control the lifespan of a cell as it ages. By studying these molecular events and pathways, the field of anti-aging will be furthered by the use of more and more cosmetics. Abstract As the most voluminous organ of the body that is exposed to the outer environment, the skin suffers from both intrinsic and extrinsic aging factors. Skin aging is characterized by features such as wrinkling, loss of elasticity, laxity, and rough-textured appearance. This aging process is accompanied with phenotypic changes in cutaneous cells as well as structural and functional changes in extracellular matrix components such as collagens and elastin. With intrinsic aging, structural changes occur in the skin as a natural consequence of the biological changes over time and produce a certain number of histological, physiological, and biochemical modifications. Intrinsic aging is determined genetically (influence of gender and ethnic group), variable in function of skin site, and also influenced by hormonal changes. Visually it is characterized by fine wrinkles. By comparison, “photoaging” is the term used to describe the changes occurring in the skin, resulting from repetitive exposure to sunlight. The histological, physiological, and biochemical changes in the different layers of the skin are much more drastic. From a mechanical point of view, human skin appears as a layered composite containing the stiff thin cover layer presented by the stratum corneum, below which are the more compliant layers of viable epidermis and dermis and further below the much more compliant adjacent layer of subcutaneous white adipose tissue. Upon exposure to a strain, such a multi-layer system demonstrates structural instabilities in its stiffer layers, which in its simplest form is the wrinkling. These instabilities appear hierarchically when the mechanical strain in the skin exceeds some critical values. Their appearance is mainly dependent on the mismatch in mechanical properties between adjacent skin layers or between the skin and subcutaneous white adipose tissue, on the adhesive strength and thickness ratios between the layers, on their bending and tensile stiffness as well as on the value of the stress existing in single layers. Gradual reduction of elastic fibers in aging significantly reduces the skin’s ability to bend, prompting an up to 4-fold reduction of its stability against wrinkling, thereby explaining the role of these fibers in skin aging. Anti-aging medicine is practiced by physicians, scientists, and researchers dedicated to the belief that the process of physical aging in humans can be slowed, stopped, or even reversed through existing medical and scientific interventions. This specialty of medicine is based on the very early detection and prevention of age-related diseases. Physicians practicing anti-aging medicine seek to enhance the quality of life as well as its length, limiting the period of illness and disability toward the end of one’s life. Anti-aging medicine encompasses lifestyle changes (diet and exercise); hormone replacement therapies, as needed, determined by a physician through blood testing (DHEA, melatonin, thyroid, human growth hormone, estrogen, testosterone); antioxidants and vitamin supplements; and testing protocols that can measure not only hormone levels and blood chemistry but every metabolic factor right down to the cellular level. Keywords: Skin Care; Anti-Aging; Photoaging; Wrinkles; Antioxidants; Keratinocytes; Retinoids


2019 ◽  
Vol 20 (7) ◽  
pp. 1634 ◽  
Author(s):  
Angela Puente ◽  
Jose Fortea ◽  
Joaquin Cabezas ◽  
Maria Arias Loste ◽  
Paula Iruzubieta ◽  
...  

The concept of liver fibrosis and cirrhosis being static and therefore irreversible is outdated. Indeed, both human and animal studies have shown that fibrogenesis is a dynamic and potentially reversible process that can be modulated either by stopping its progression and/or by promoting its resolution. Therefore, the study of the molecular mechanisms involved in the pathogenesis of liver fibrosis is critical for the development of future antifibrotic therapies. The fibrogenesis process, common to all forms of liver injury, is characterized by the increased deposition of extracellular matrix components (EMCs), including collagen, proteoglycans, and glycoproteins (laminin and fibronectin 2). These changes in the composition of the extracellular matrix components alter their interaction with cell adhesion molecules, influencing the modulation of cell functions (growth, migration, and gene expression). Hepatic stellate cells and Kupffer cells (liver macrophages) are the key fibrogenic effectors. The antifibrogenic mechanism starts with the activation of Ly6Chigh macrophages, which can differentiate into macrophages with antifibrogenic action. The research of biochemical changes affecting fibrosis irreversibility has identified lysyl oxidase-like 2 (LOXL2), an enzyme that promotes the network of collagen fibers of the extracellular matrix. LOXL2 inhibition can decrease cell numbers, proliferation, colony formations, and cell growth, and it can induce cell cycle arrest and increase apoptosis. The development of a new humanized IgG4 monoclonal antibody against LOXL2 could open the window of a new antifibrogenic treatment. The current therapeutic target in patients with liver cirrhosis should focus (after the eradication of the causal agent) on the development of new antifibrogenic drugs. The development of these drugs must meet three premises: Patient safety, in non-cirrhotic phases, down-staging or at least stabilization and slowing the progression to cirrhosis must be achieved; whereas in the cirrhotic stage, the objective should be to reduce fibrosis and portal pressure.


Physiology ◽  
1995 ◽  
Vol 10 (3) ◽  
pp. 117-122
Author(s):  
JM Ross ◽  
LV McIntire

Mural adhesion and aggregation of blood platelets are crucial for hemostasis but in pathological situations can lead to myocardial infarction and stroke. The specific platelet surface receptors employed are determined by the local fluid dynamic conditions and extracellular matrix components exposed at the site of a vascular wound.


2021 ◽  
Vol 22 (22) ◽  
pp. 12489
Author(s):  
Hyunji Lee ◽  
Yongjun Hong ◽  
Miri Kim

Skin aging is a complex process influenced by intrinsic and extrinsic factors. Together, these factors affect the structure and function of the epidermis and dermis. Histologically, aging skin typically shows epidermal atrophy due to decreased cell numbers. The dermis of aged skin shows decreased numbers of mast cells and fibroblasts. Fibroblast senescence contributes to skin aging by secreting a senescence-associated secretory phenotype, which decreases proliferation by impairing the release of essential growth factors and enhancing degradation of the extracellular matrix through activation of matrix metalloproteinases (MMPs). Several molecular mechanisms affect skin aging including telomere shortening, oxidative stress and MMP, cytokines, autophagic control, microRNAs, and the microbiome. Accumulating evidence on the molecular mechanisms of skin aging has provided clinicians with a wide range of therapeutic targets for treating aging skin.


1993 ◽  
Vol 289 (1) ◽  
pp. 221-226 ◽  
Author(s):  
R E Gates ◽  
S K Hanks ◽  
L E King

The lack of procedures for isolating or reconstituting intact focal adhesions has hindered studies of how focal adhesions are organized and of how their assembly/disassembly is controlled. A method for isolating large quantities of the ventral portion of plasma membranes from transformed keratinocytes (A-431 cells) in culture is described. Plasma membranes are stabilized using Zn2+ and the ventral portion isolated attached to the culture substratum after the body of the cell has been sheared away. Compared with complete plasma membranes isolated from cells scraped from the dish, these ventral-membrane preparations are enriched 18.5-fold and 5.1-fold in the focal-adhesion components talin and vinculin respectively. While the epidermal-growth-factor receptor-kinase is less abundant in preparations of ventral membranes, a recently described tyrosine kinase which localizes to focal adhesions in mouse fibroblasts is enriched 19.9-fold. Extracellular matrix components, as well as their integrin receptors, are also enriched in these preparations of the ventral portion of plasma membranes compared with preparations of complete plasma membranes.


2000 ◽  
Vol 13 (2) ◽  
pp. 318-331 ◽  
Author(s):  
Martha Espinosa-Cantellano ◽  
Adolfo Martínez-Palomo

SUMMARY In spite of a wealth of knowledge on the biochemistry and cellular and molecular biology of Entamoeba histolytica, little has been done to apply these advances to our understanding of the lesions observed in patients with intestinal amebiasis. In this review, the pathological and histological findings in acute amebic colitis are related to the molecular mechanisms of E. histolytica pathogenicity described to date. Infection of the human colon by E. histolytica produces focal ulceration of the intestinal mucosa, resulting in dysentery (diarrhea with blood and mucus). Although a complete picture has not yet been achieved, the basic mechanisms involved in the production of focal lytic lesions include complex multifactorial processes in which lectins facilitate adhesion, proteases degrade extracellular matrix components, porins help nourish the parasite and may also kill incoming polymorphonuclear leukocytes and macrophages, and motility is used by the parasite to invade deeper layers of the colon. In addition, E. histolytica has developed mechanisms to modulate the immune response during acute infection. Nevertheless, much still needs to be unraveled to understand how this microscopic parasite has earned its well-deserved histolytic name.


Author(s):  
Amanda Phuong Tran ◽  
Philippa Mary Warren ◽  
Jerry Silver

AbstractSevere spinal cord injury causes permanent loss of function and sensation throughout the body. The trauma causes a multifaceted torrent of pathophysiological processes which ultimately act to form a complex structure, permanently remodeling the cellular architecture and extracellular matrix. This structure is traditionally termed the glial/fibrotic scar. Similar cellular formations occur following stroke, infection, and neurodegenerative diseases of the central nervous system (CNS) signifying their fundamental importance to preservation of function. It is increasingly recognized that the scar performs multiple roles affecting recovery following traumatic injury. Innovative research into the properties of this structure is imperative to the development of treatment strategies to recover motor function and sensation following CNS trauma. In this review, we summarize how the regeneration potential of the CNS alters across phyla and age through formation of scar-like structures. We describe how new insights from next-generation sequencing technologies have yielded a more complex portrait of the molecular mechanisms governing the astrocyte, microglial, and neuronal responses to injury and development, especially of the glial component of the scar. Finally, we discuss possible combinatorial therapeutic approaches centering on scar modulation to restore function after severe CNS injury.


2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Junichi Saito ◽  
Makoto Kaneko ◽  
Yoshihiro Ishikawa ◽  
Utako Yokoyama

There is urgent demand for biologically compatible vascular grafts for both adult and pediatric patients. The utility of conventional nonbiodegradable materials is limited because of their thrombogenicity and inability to grow, while autologous vascular grafts involve considerable disadvantages, including the invasive procedures required to obtain these healthy vessels from patients and insufficient availability in patients with systemic atherosclerosis. All of these issues could be overcome by tissue-engineered vascular grafts (TEVGs). A large body of evidence has recently emerged in support of TEVG technologies, introducing diverse cell sources (e.g., somatic cells and stem cells) and novel fabrication methods (e.g., scaffold-guided and self-assembled approaches). Before TEVG can be applied in a clinical setting, however, several aspects of the technology must be improved, such as the feasibility of obtaining cells, their biocompatibility and mechanical properties, and the time needed for fabrication, while the safety of supplemented materials, the patency and nonthrombogenicity of TEVGs, their growth potential, and the long-term influence of implanted TEVGs in the body must be assessed. Although recent advances in TEVG fabrication have yielded promising results, more research is needed to achieve the most feasible methods for generating optimal TEVGs. This article reviews multiple aspects of TEVG fabrication, including mechanical requirements, extracellular matrix components, cell sources, and tissue engineering approaches. The potential of periodic hydrostatic pressurization in the production of scaffold-free TEVGs with optimal elasticity and stiffness is also discussed. In the future, the integration of multiple technologies is expected to enable improved TEVG performance.


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