Submitted for Partial Fulfillment of Master Degree in Dermatology, Venereology and Andrology
MarwaHelal Mohammed El Hadary;
Abstract
Skin aging is the end result of both intrinsic aging, which
is the result of the passage of time, and photoaging, which
refers to alterations in skin structure and function that result
from chronic sun exposure, in addition to the passage of time. It
is important to distinguish between chronological skin aging
and photoaging.
Chronological skin aging can be summarized as atrophy
with structural and functional decline of the skin. Sun-protected
aged skin is finely wrinkled with exaggeration of facial
expression lines, laxity, and pallor.
Extrinsic skin aging involves hypertrophy as an
inflammatory, protective response to the damaging effects of
UV rays. Photoaging is manifested by xerosis, leathery skin,
irregular pigmentation (freckles, lentigines), and more
pronounced wrinkling. Telangiectasias, purpura, comedones,
and a variety of benign and premalignant skin tumors including
seborrheic keratoses, sebaceous gland hyperplasia, and actinic
keratoses are frequent findings. UV irradiation from the sun
damages human skin, causing it to age prematurely.
Matrix metalloproteinases are an important family of
enzymes involved in many different physiological and
pathological processes. They also play an important role in
various forms of skin aging.
Summary
130
In the past two decades, significant progress has been
made on both skin aging and MMP research. Thus it became
evident that MMPs play an important part in cutaneous aging as
well.
In both extrinsic and intrinsic aging, expression and
activation of MMPs can be induced by ROS, which are the
products of either the physiological function of the organism or
the extrinsic toxic effects like UV irradiation or tobacco
smoking.
Matrix metalloproteinases are potent proteases
collectively capable of degradation of all kinds of dermal ECM
proteins. In parallel with MMP activation, production of MMP
inhibitors is suppressed. Upon incomplete repair and chronic
imbalance of ECM synthesis and degradation, damage to the
collagen and elastic fibers might accumulate and lead to their
decomposition, which is the major molecular feature of dermal
is the result of the passage of time, and photoaging, which
refers to alterations in skin structure and function that result
from chronic sun exposure, in addition to the passage of time. It
is important to distinguish between chronological skin aging
and photoaging.
Chronological skin aging can be summarized as atrophy
with structural and functional decline of the skin. Sun-protected
aged skin is finely wrinkled with exaggeration of facial
expression lines, laxity, and pallor.
Extrinsic skin aging involves hypertrophy as an
inflammatory, protective response to the damaging effects of
UV rays. Photoaging is manifested by xerosis, leathery skin,
irregular pigmentation (freckles, lentigines), and more
pronounced wrinkling. Telangiectasias, purpura, comedones,
and a variety of benign and premalignant skin tumors including
seborrheic keratoses, sebaceous gland hyperplasia, and actinic
keratoses are frequent findings. UV irradiation from the sun
damages human skin, causing it to age prematurely.
Matrix metalloproteinases are an important family of
enzymes involved in many different physiological and
pathological processes. They also play an important role in
various forms of skin aging.
Summary
130
In the past two decades, significant progress has been
made on both skin aging and MMP research. Thus it became
evident that MMPs play an important part in cutaneous aging as
well.
In both extrinsic and intrinsic aging, expression and
activation of MMPs can be induced by ROS, which are the
products of either the physiological function of the organism or
the extrinsic toxic effects like UV irradiation or tobacco
smoking.
Matrix metalloproteinases are potent proteases
collectively capable of degradation of all kinds of dermal ECM
proteins. In parallel with MMP activation, production of MMP
inhibitors is suppressed. Upon incomplete repair and chronic
imbalance of ECM synthesis and degradation, damage to the
collagen and elastic fibers might accumulate and lead to their
decomposition, which is the major molecular feature of dermal
Other data
| Title | Submitted for Partial Fulfillment of Master Degree in Dermatology, Venereology and Andrology | Other Titles | التعـبيـرعـن مصفوفة البروتين الفلزي فى شيخوخـة الجلــد | Authors | MarwaHelal Mohammed El Hadary | Issue Date | 2014 |
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