The Causes and Symptoms of Peyronie's Disease

Peyronie's disease is a condition characterized by scarring or plaque that forms on the penis. The specific part of the penis which undergoes the scarring process is the tunica albuginea, the dense outer tissue composed of collagen. The build up of scar tissue prevents the penis from expanding during an erection, which causes a curvature deformity. The scar itself is benign, or noncancerous. A plaque on the top of the shaft (most common) causes the penis to bend upward; a plaque on the underside causes it to bend downward. In some cases, the plaque develops on both top and bottom, leading to indentation and shortening of the penis.

Common Symptoms of Peyronie's Disease

There are many symptoms of Peyronie's Disease. Because most symptoms affect the physicality of the penis, all of are readily identifiable by the individual.

1. Penile Deformity
   This is the most common symptom, in which the tunica albugiena causes restricted expansion. During erection, the penis bends toward the side of the scar. It is important to note that the bend or curvature of the penis is directly related to the size of the scar, meaning: the greater degree of curve, the bigger the scar is. The most common direction for curvature is upward, though downward and lateral directions are relatively common.
2. Indentation of the Penis
   If the scar is very small, it can cause an indentation rather than curvature. Like a curvature, the size of the scar indicates the depth of the indentation.
3. Hour-Glass Deformity
   When a scar is present on all sides, or two opposing sides of the shaft, the penis will mimic the shape of an hour glass. Because the indentations are symmetrical on each opposing side, the deformity can affect the overall stability of the penis.
4. Pain of the Penis
   With almost all cases of Peyronie's Disease, pain is present. While uncomfortable, most individuals do not experience discomfort after the first year of the condition. When first developed, pain can be the most intense as a result of the inflammation caused by the initial scarring. Once the scar is fully formed, pain is usually only experienced during an erection.
5. Erectile Dysfunction
   Erectile Dysfunction can sometimes be evident in older individuals, but usually is the result of other conditions (such as high blood pressure, diabetes, cholesterol levels).

Causes of Peyronie's Disease: An Imbalance Between Scar Formation --> Scar Remodeling

The absolute, factual statement regarding the exact cause of Peyronie's Disease does not exist, but evidence can give us a ballpark idea of how it can develop in the human body.

The most widely accepted theory of the cause of Peyronie's Disease is that the scarring develops following a trauma to the penis, which can occur during sexual activity. During sexual activity, the erect penis can develop pressures as high as 1200mm Hg. If the tissues are stretched beyond their capacity because of this high pressure, or have lost elasticity, a micro-fracture of the tunica albuginea can occur. This activates Peyronie's Disease.

Although it is sometimes apparent to the individual, this trauma can go undetected during the "enjoyment" of sexual intercourse. Once this trauma occurs, the would is developed and begins to heal.

During wound healing, 3 phases occur.

1. Enzymatic Clean-Up: Rids the area of damaged or dead tissue
2. Scar Formation: A Scar will heap-up to pull together the would and secure it
3. ** Scar Remodeling: Where the disorganized scar is broken down, and collagen fibers are realigned. This leaves a scar with normal tissue.

** Peyronie's Disease can be related to an individual's inability to balance scar formation and scar remodeling (or healing). Simply put, there is excessive scar formation relative to a very minor or even unnoticeable injury. Once this injury occurs, it is followed by continued scar formation without the ability to remodel tissue, leaving behind inelastic tissues.

Additional Research, Finding the Cause

Research has suggested that this process of excessive scar formation may be due to such factors as viral infections, although this has not been proven. There may also be deposition of certain proteins such as fibrin, which activate the cells responsible for making scar known as fibroblasts. Fibrin may also be responsible for activating special chemicals known as "cytokines", which are responsible for the second phase of wound healing. If the cytokines persist beyond their normal time, scar formation will continue resulting in the excessive deposition of collagen. The most recognized cytokine found to persist in Peyronie's plaque tissue is transformation growth factor - beta 1 (TGF-B1).

More recent research has suggested that there may be cellular abnormalities within the fibroblast resulting in increased production of various chemicals. The result is uncontrolled scar growth. Some of the proposed abnormalities include a factor known as p53, various DNA/RNA irregularities, and an abnormality in chemicals responsible for scavenging free oxygen radicals which activate the scarring process. One of these chemicals is known as inducible nitric oxide synthase (iNOS) which is being actively researched.

Would Healing and Scar Remodeling Research Continues

Recent research has looked at the third phase of wound healing: scar remodeling. These studies have examined the various enzymes known as proteases and collagenases, which are responsible for breaking down the immature scar, allowing normal remodeling to occur. Abnormalities in these proteases include a lack of production, abnormal production or premature destruction of these enzymes any of which may be responsible for the inability of the scar to be properly remodeled.

Lastly, examination of mature Peyronie's plaque tissue has stimulated research into other molecules and proteins such as biglycans, decorin, tenascin and elastin. These proteins are important in the regulation of collagen production and deposition within scar, and if they are abnormal, could contribute to abnormal wound healing.