Vitamin D and Interstitial Cystitis

I think that interstitial cystitis (IC) must be one of the most distressing of conditions to have, and it is certainly one of the most challenging to treat. Outside the United States, it is more often called painful bladder syndrome (PBS).

IC is a condition that results in recurring discomfort or pain in the bladder and the surrounding pelvic region. The symptoms vary from person to person and even in the same individual. It can vary from an experience of mild discomfort, pressure, tenderness, to intense pain in the bladder and pelvic area. Symptoms may include an urgent need to urinate (urgency), a frequent need to urinate (frequency), or a combination of these symptoms. Both may be severe: I’ve seen people who had to urinate every ten minutes. Pain may change in intensity as the bladder fills with urine or as it empties. Women’s symptoms often get worse during menstruation, and some experience pain with vaginal intercourse. There is a good website provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), that is fairly up-to-date.

Because IC varies so much in symptoms and severity, most researchers believe that it is not one, but several diseases. There are clear links between IC and fibromyalgia, irritable bowel syndrome and chronic fatigue, and probably many other illnesses.

There is good evidence that inflammation in one pelvic organ can cause pain in other organs that share some of the same nerve supply. Inflammation of the colon may make some nerves coming from the spinal cord hyper-excitable, which in turn makes nerves running to the bladder hypersensitive. Because the same nerve plexus connects with the ovaries and uterus, it is no surprise to learn that phases of the menstrual cycle impact the way in which inflammation in one pelvic organ can cause inflammation in another.

IC appears to be becoming more common, although that is always a risky comment, because it was undoubtedly not often recognized in the past. The old teaching was that it was only something that occurred in menopausal women, but it is now being diagnosed in men as well as women, and in people as young as their late teens.

The cause of IC remains unknown, though there have been many theories: infections, allergy, autoimmunity, neurological and genetic. There have been recent claims of the discovery of responsible genes, but hey would most likely be susceptibility genes, rather than causative. Otherwise why should the rates of IC genuinely seem to be increasing? What seems clear is that the normal mucus lining of the bladder wall is damaged.

Multiple types of treatment have been tried, from medication to pelvic floor exercise, to neurological implants and homeopathy and acupuncture. The report of anything new that may help is always welcome.

So I was interested to see a report from investigators in Milan on the efficacy using a molecule that has been attracting a lot of interest recently: vitamin D. The active form of vitamin D is known as calcitriol or 1,25-dihydroxycholecalciferol (1,25(OH)2D3) that is manufactured in the kidney. Its in vivo biological effects include regulation of bone metabolism, control and modulation of the proliferation of cells and some aspects of the immune response. These characteristics have already led to therapeutic applications in osteoporosis, secondary hyperparathyroidism, and psoriasis. Many reports show beneficial effects of vitamin D in animal models of diabetes, organ graft rejection, experimental allergic encephalomyelitis, lupus nephritis, and in asthma. Despite what you may have seen in some advertisements, just taking extra vitamin D does not help, and may make matters worse: they key is to have the right form of vitamin D, that can reach and affect the right areas of the body.

The Milan team used a vitamin D3 analogue (BXL628) in a mouse model of chronic cystitis. What they found was that a specific inflammatory marker in the blood went down with treatment, and at the same time histological analysis showed a decrease in edema and white blood cell (leukocyte) infiltration in the bladder wall. This and some other biochemical evidence of what is known as “mast cell degranulation,”  is very encouraging and strongly supports the potential therapeutic use of BXL628 in diseases such as human interstitial cystitis.

This is the kind of mechanism-based research that holds out enormous promise for everyone’s welfare and will help us in our goal of using science to inform the development of the next generation of treatment, health and wellness.