A 63-year-old woman comes to the office for a routine preventive examination. She has no significant medical problems and takes no medications. The patient consumes a balanced diet; gets regular exercise; and does not use tobacco, alcohol, or illicit drugs. She is up to date on breast, colon, cervical, and lipid screenings. Her physical examination findings are unremarkable. The patient expresses concern about wrinkles around her eyes that make her "look old." A decrease in which of the following is most likely responsible for this patient's complaint?

Question

A 63-year-old woman comes to the office for a routine preventive examination.  She has no significant medical problems and takes no medications.  The patient consumes a balanced diet; gets regular exercise; and does not use tobacco, alcohol, or illicit drugs.  She is up to date on breast, colon, cervical, and lipid screenings.  Her physical examination findings are unremarkable.  The patient expresses concern about wrinkles around her eyes that make her "look old."  A decrease in which of the following is most likely responsible for this patient's complaint?

Quizplus · Accepted Answer

Multiple environmental factors, especially exposure to ultraviolet (UV) light, contribute to aging of the skin. UVB wavelengths are predominantly absorbed in the upper dermis and contribute to sunburn and increased risk of malignancy. UVA wavelengths penetrate deeper into skin and cause photoaging. UVA produces reactive oxygen species, which activate multiple inflammatory cell-surface receptors and nuclear transcription factors. This leads to decreased collagen fibril production, along with upregulation of matrix metalloproteinases (including collagenases) that subsequently degrade type I and III collagen and elastin (Choices C and D). Photoaging may be visible by age 30-35. Gradual thinning of the epidermis is seen, with reduction in subcutaneous fat, blood vessels, hair follicles, sweat ducts, and sebaceous glands. Rete ridges at the dermoepidermal junction become flattened. This loss of subcutaneous tissue causes the skin to become atrophic and more vulnerable to damage. In addition, there is increased crosslinking of collagen (Choice A), with deposition of collagen breakdown products. The atrophic dermis and increased collagen crosslinking, along with desiccation of the stratum corneum, produce the characteristic wrinkling of photoaged skin. (Choice E) Post-translational hydroxylation of proline residues contributes to the stability of the collagen triple helix. This reaction requires ascorbic acid (vitamin C); deficiency of vitamin C leads to scurvy, which is characterized by impaired production and reduced tensile strength of collagen. Educational objective: Photoaging is a product of excess exposure to ultraviolet A wavelengths and is characterized by epidermal atrophy with flattening of rete ridges. In addition, there is decreased collagen fibril production and increased degradation of collagen and elastin in the dermis. __________ References: Looking older: fibroblast collapse and therapeutic implications. (http://www.ncbi.nlm.nih.gov/pubmed/18490597)

A 63-Year-Old Woman Comes to the Office for a Routine