Amyloidosis:

Proteins are important building blocks for all body parts, including muscles, bones, hair, and nails. Proteins circulate throughout the body in the blood and are normally harmless. Occasionally, cells produce abnormal proteins that can settle in body tissue, forming deposits and causing disease. When these deposits of abnormal proteins were first discovered, they were called amyloid, and the disease process amyloidosis.

Introduction

In recent years, researchers have discovered that different kinds of proteins can form amyloid deposits and have identified several types of amyloidosis. Two of these types are closely related to kidney disease. In primary amyloidosis, abnormal protein production occurs as a first step and can lead to kidney disease. Dialysis-related amyloidosis (DRA), on the other hand, is a result of kidney disease.

Primary Amyloidosis

Primary amyloidosis occurs when the body produces abnormal protein fibers, which join together to form amyloid deposits in different organs, including the kidneys, where they cause serious damage. Injured kidneys can't function effectively and may be unable to remove urea and other wastes from the blood. Elevated levels of these waste products can also damage the heart, lungs, brain, and digestive system.

One common sign of amyloidosis is the presence of abnormally high amounts of protein in the urine, a condition known as proteinuria. Healthy kidneys prevent protein from entering the urine, so the presence of protein may be a sign that the kidneys aren't working properly. A physician who finds large amounts of protein in the urine may also perform a biopsy--take a small sample of tissue for examination under a microscope--to confirm amyloidosis.

No effective treatment has been found to reverse the effects of amyloidosis. Combination drug therapy with melphalan (a cancer drug) and prednisone (an anti-inflammatory steroid drug) may improve organ function and survival rates by interrupting the growth of cells that produce amyloid protein. These are the same drugs used in chemotherapy to treat certain cancers, and they may have serious side effects, such as nausea and vomiting, hair loss, and fatigue.

Amyloid may build up in the wrist and cause bone cysts or carpal tunnel syndrome.

Unfortunately, no cure for DRA has been found, although a successful kidney transplant may stop the disease from progressing. However, DRA has caught the attention of dialysis engineers who are attempting to develop membranes that can more efficiently remove beta-2-microglobulin from the blood.

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