Related Experiment Video
Updated: Jul 15, 2026
08:52
Software-Assisted Quantitative Measurement of Osteoarthritic Subchondral Bone Thickness
Published on: March 18, 2022
Is there a correlation between age and D-aspartic acid in human knee cartilage?
G Fisher1, S Lopez, K Peterson
1Department of Chemistry, Barry University, Miami Shores, Florida 33161, USA. gfisher@mail.barry.edu
Amino Acids
|May 1, 2007
Summary
The abnormal D-aspartic acid (D-Asp) form accumulates in human knee cartilage with age. While present in normal cartilage, the correlation between D-Asp levels and age was weak, particularly in females.
Area of Science:
- Biochemistry
- Human Physiology
- Gerontology
Background:
- L-Aspartic acid (L-Asp) is an amino acid known for rapid racemization.
- The abnormal D-aspartic acid (D-Asp) isomer is found in stable human tissues like teeth, the eye lens, and the brain.
- Previous studies indicated a correlation between age and D-Asp levels in dental tissues.
Purpose of the Study:
- To investigate the accumulation of D-Asp in normal human knee cartilage.
- To determine if D-Asp levels correlate with the age of individuals.
- To explore potential sex-based differences in D-Asp accumulation in knee cartilage.
Main Methods:
- Analysis of approximately 100 normal knee cartilage samples.
- Quantification of D-Asp levels (as a percentage of total Asp) and in nmoles/g.
- Statistical analysis to assess the correlation between age and D-Asp levels, including subgroup analysis by sex.
Main Results:
- Detectable amounts of D-Asp (2-4% of total Asp) were found in normal knee cartilage.
- A slight overall correlation (r = 0.35) was observed between age and D-Asp levels.
- A stronger correlation between age and D-Asp was found in males (r = 0.57) compared to females (r = 0.21).
Conclusions:
- D-Asp is present in normal human knee cartilage.
- The accumulation of D-Asp in knee cartilage shows a weak correlation with age overall.
- Sex influences the correlation between age and D-Asp accumulation in knee cartilage, with males exhibiting a stronger association.
Related Concept Videos
01:09Changes in the Appendicular Skeleton with Age
The upper and lower limb initially develops as a small bulge called a limb bud, which appears on the lateral side of the early embryo. The upper limb bud appears near the end of the fourth week of development, with the lower limb bud appearing shortly after.
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
01:19The Effect of Aging on Tissues
Several body functions deteriorate with age. The external signs of aging are easily identifiable. For example, the skin becomes dry, less elastic, and thins out, forming wrinkles. The skin of the face begins to appear looser due to a decrease in the levels of elastic and collagen fibers in the connective tissue. Additionally, melanin production in the hair follicle decreases with age, resulting in gray hair. Moreover, the senses of sight and hearing decline, so glasses and hearing aids may...
01:29Bone Disorders
Aging and its effect on bone remodeling is the most common cause of bone disorders. In young and healthy people, bone deposition and resorption happen at an equal rate to maintain optimal bone health.
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
01:27Growth of Cartilage and Bone Tissue
Chondrocytes form a temporary cartilaginous model by dividing and secreting a thick gel-like extracellular matrix. Once the chondrocytes undergo programmed cell death, osteoblasts enter the site of the cartilaginous model. The process of replacing the temporary cartilaginous model with bone in an ordered manner is called endochondral ossification. In endochondral ossification, not all of the cartilage is replaced by bone tissue. Some cartilage that performs a protective and supportive function...
01:27Degenerative Disc Disease I: Introduction
Degenerative disc disease is a chronic condition in which intervertebral discs gradually lose structure and function. It is not infectious or autoimmune; rather, it results from age-related biochemical and mechanical changes, influenced by genetic, metabolic, and environmental factors.Structure and Function of DiscsThe spine contains 23 intervertebral discs that absorb load, distribute forces, maintain spacing, and allow flexibility. Each disc consists of a nucleus pulposus, a gel-like core...