Reducing proteinuria is a cornerstone treatment for IgA nephropathy. Established medications, dietary changes, and emerging therapies provide new ways of preserving kidney function.
IgA nephropathy (IgAN) is an autoimmune condition that causes deposits of immunoglobulin A (IgA) antibodies to build up in your kidneys. These antibodies damage the small blood vessels of your kidneys, which are called glomeruli. As a result, glomeruli cannot properly filter your blood, so protein and blood leak into your urine.
Protein in the urine (proteinuria) is linked to a progressive loss of kidney function. Treatment for IgAN aims to keep protein levels in your urine as low as possible. Blood pressure medications and dietary changes are important parts of IgAN treatment, and new and emerging treatments offer new avenues to prevent kidney damage.
ACE inhibitors are blood pressure medications that can reduce proteinuria and protect the kidneys in people with conditions such as IgAN.
These drugs work on the hormone angiotensin 2, which helps control your blood pressure.
If your blood pressure is too low, angiotensin 2 increases it by causing your blood vessels to contract and narrow. But if you have IgAN, these blood vessels are already under stress due to the IgA deposits, so the narrowing of the blood vessels can further increase stress on your kidneys.
ACE inhibitors reduce your body’s production of angiotensin 2 and therefore help relax the blood vessels in your kidneys. As a result, they can slow kidney damage over time.
Two examples of ACE inhibitors are benazepril (Lotensin) and lisinopril (Zestril).
Like ACE inhibitors, ARBs target angiotensin 2 to lower blood pressure. But while ACE inhibitors decrease angiotensin 2 production, ARBs selectively block angiotensin 2 type 1 receptors, which angiotensin 2 would use to cause the blood vessels in your kidneys to narrow.
Two examples of ARBs are irbesartan (Avapro) and valsartan (Diovan).
Corticosteroids suppress your immune system and reduce inflammation. They can play a role in IgAN treatment, although doctors use caution when recommending them.
At high doses, corticosteroids carry a risk of serious side effects, so they should be used only in limited cases. A doctor might recommend that you avoid them altogether if you have any of the following conditions:
- diabetes
- obesity
- a glomerular filtration rate (eGFR) of less than 30 milliliters per minute per 1.73 meters squared
- secondary IgAN
- a latent or dormant infection, such as viral hepatitis
- a peptic ulcer
- an unmanaged mental health condition
- severe osteoporosis
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Sparsentan (Filspari) is a new medication that helps control angiotensin 2 and another hormone called endothelin-1 (ET-1). It reduces the effects of angiotensin 2 and ET-1 at cellular receptor sites.
In IgAN, IgA deposits in your kidneys cause increased production of ET-1 and angiotensin 2, and the increased production of each hormone promotes greater production of the other. Overproduction of these hormones can lead to scarring, inflammation, and high levels of protein in your urine, which can damage your kidneys.
This medication can reduce proteinuria in people with IgAN who have a high likelihood of disease progression. In clinical trial results
TRF-budesonide (Tarpeyo) is a novel, targeted formulation of a corticosteroid designed for use in IgAN. It works in your gut to reduce inflammation, but it has less effect on your entire body than other corticosteroids. Because of its targeted nature, it might be safer for long-term use than other corticosteroids.
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Health experts recommend that people with kidney disease limit their sodium intake.
As part of your overall IgAN treatment plan, reducing your salt intake can support kidney function by helping keep your blood pressure low and reducing fluid retention. Try to consume less than 2,000 milligrams of sodium per day.
Eating less protein can reduce the pressure on your kidneys. A low protein diet generally involves consuming 0.6 to 0.8 grams of protein per kilogram of body weight per day, but the amount you need depends on individual health factors.
Protein is necessary to keep your body working. You might want to consult a doctor or a registered dietitian for advice on the right amount for you.
Plant-based proteins can give you the amino acids your body needs to work well, as long as you eat from a variety of plant sources such as beans, lentils, nuts, and whole grains. Plant proteins are low in saturated fat and might especially benefit people with kidney disease.
Animal-based proteins also contain the necessary amino acids, but they vary in fat content. Fish and poultry are lower in saturated fats than other animal proteins. If you have kidney disease, you might need to limit your consumption of dairy foods to manage the phosphorus level in your blood.
Reducing proteinuria can help slow the progression of kidney damage in IgA nephropathy (IgAN). First-line medications such as angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) can work alongside a low salt, low protein diet to reduce pressure on your kidneys.
Emerging therapies such as sparsentan and budesonide are giving people with IgAN more options for preserving kidney function.