Saturday, May 23, 2009

Stem Cells in Urology?

There is hot debate about stem cell use, their ethics and potential for curing diseases. Although promising, the application to disease states should not be overblown. We may all feel bad for Christopher Reeve, but injecting him with stem cells is simply not going to make him miraculously walk. Some cold water needs to be thrown on the loudest proponents, since common sense dictates that all advancements in science don’t always happen out of sheer will and hope. Like all medical experiments, we ask the question: will it work and is it safe, and this applies equally to stem cells.

Stem cells are regarded as the ideal resource for tissue regeneration, outside of formal organ transplantation. Stem cells have the following properties: they self-renew, they can form any cell type in the body, and they can multiply into clonal populations.

There are many sources of stem cells:

Adult stem cells exist in adult tissues throughout the body such as bone marrow, brain, muscle, and GI tract. Research with these cells has progressed slowly because they are difficult to maintain in culture. Their advantage is that they will not provoke an immune response such as rejection.

Embryonic stem cells are obtained from the inner cells of the blastocyst, an early stage in human embryonic development formed 5 days after fertilization of the egg by the sperm. The ethical and political controversy dates back to 1998 when human embryonic stem cells were first isolated from donated human embryos. Although they can differentiate into any cell type (except placenta), their growth is not well controlled and can provoke an immune reaction.

Amniotic fluid and placental stem cells can be obtained from amniotic fluid, can self-renew and can differentiate into all types of cells. They are less studied but have properties between adult and embryonic stem cells, and importantly, unlike embryonic stem cells, they do not form teratomas, a type of tumor.

Stem cells for urinary incontinence is a potentially exciting application. The external sphincter can become weak and allow urine to leak past it with coughing, sneezing, laughing and exercise. Age, menopause and childbirth are common risk factors for stress incontinence. Several groups in the US and Germany have performed animal studies showing improvement in sphincter function. There are small series of human trials showing some improvement as well. Upper arm muscle biopsies from female patients are taken, and the muscle cells and connective tissue cells are grown in culture and then injected into the urethra of the same women. One early study showed a 60% cure rate and a 28% improvement rate. Another small series of 8 patients showed some modest improvement at 12 months after injection, and several needed repeat injections.

Onset of improvement was between 3 and 8 months after the injections were performed.
Despite these early modest findings, stem cells are a promising avenue for medical treatment if/when some of the ethical considerations are settled.

Saturday, May 9, 2009

Mesh Complications and Vaginal Surgery: Part 1

In all realms of medicine, advancement in patient care is a learning process, with the ultimate goal being better patient care. New technologies abound, and scientists and physicians are often at the cutting edge to adapt these technologies to patients through experiments in the labs and trials in the real world. However, new technology comes with responsibility and proper patient counseling prior to any procedure helps to define the risks and benefits of all surgeries, including those involved in mesh repair of hernia throughout the body.

Mesh is a common and safe synthetic product that can be surgically placed in many areas throughout the body to reinforce a hernia or defect that occurs over time or as a result of injury. The classic example is a groin or inguinal hernia in a man. It is painful and can occur in 10% of men, usually after repetitive straining. A mesh patch or plug is placed through a small incision and reinforces the weak tissue and significantly reduces recurrence rates. It has been widely adopted by general surgeons over the last 2 decades.

Repairing or lifting dropped pelvic organs have been common surgeries in women. The most common is the bladder (cystocele), but the uterus, small intestine or rectum can also drop and push out the vagina. It can be painful and lead to urinary and defecatory problems, pain with sex, and other issues. Many surgeries have been devised to “lift” the bladder, but unfortunately, recurrence rates for cystocele repair is quite high, approximately 30% at 4 years. It is the most common organ to drop after hysterectomy. Naturally, mesh has been considered to reinforce these repairs to reduce recurrence rates and prevent an unnecessary second and even third operation.

Many types of mesh exist, and not all mesh are created equal, nor appropriate for the vagina. Some mesh are synthetic and others are biological, from human or animal. The ultimate questions when approaching a patient with pelvic floor weakness, such as stress incontinence or bladder drop, are: Is surgery indicated, what type of surgery is indicated, what are the alternatives, how is the surgery to be done, and what are the complications that go along with it, is the surgeon comfortable and highly trained to perform it, and is the patient’s condition appropriate in order to place mesh?

There has been an explosion and revolution in women’s pelvic health in the last decade and many mesh products are available to the physician to choose from to fix incontinence and dropped organs. Subjects that older women were embarrassed to discuss are now out in the open, and since women are living longer and healthier with more active lifestyles, there is a demand for sustaining and improving quality of life in regards to the bladder. Incontinence affects a woman’s self esteem, and is restricting. Women often will stay at home in order to avoiding embarrassing odor or accidents in public, will not socialize and avoid sex. It’s a common an underreported problem with less than half of women even bringing it up for discussion with their family doctor.

The TVT (tension-free vaginal tape) mainstreamed mesh into common use for correcting stress incontinence. It has been on the market since 1996 with millions done worldwide. It is relatively easy to place, is minimally invasive, has a short recovery period and a low complication rate, and high success rate. Most urologists and gynecologists now use some type of TVT copycat to treat stress incontinence.

The question is then asked, can mesh for bladder repair, or other pelvic organs do the same thing?