purpose statement

This blog records the experience of a Catholic medical student.

Wednesday, September 10, 2014

Mitochondrial Transfer: Third Parents? Immoral?

Short answer: no. Long answer requires that we think about cellular anatomy and moral teaching. We will also reply to objections. Busy people read bold.

Cellular Anatomy

A mitochondrion (plural mitochondria) is a cellular organelle responsible for cellular respiration. Organelles are like the "organs" of cells (although they carry less inherent information).

Mitochondria are unique among organelles in that they carry a little bit of unique DNA encoding several key metabolic proteins not coded in the human genome. This may be because mitochondria were, in the distant evolutionary past, symbiotic organisms. These organisms lived inside other unicellular, then multicellular organisms, and eventually lost their independence. This DNA is human because the mitochondria are now parts of human cells, not independent organisms. However, this DNA is technically called "extragenomic."

Moral Teaching: Organelle Donation

There are no other examples of organelle donation apart from cloning (nuclear transfer to an egg before the egg is used in IVF). Cloning is directly addressed in Donum Vitae
Procedures designed to influence the genetic inheritance of a child, which are not therapeutic, are morally wrong. To try to correct a genetic disorder, such as cystic fibrosis, is morally permissible, whereas to manipulate the genetic structure to produce human beings selected by sex or some other quality is wrong. Attempts to produce a "breed" of humans through cloning, twin fission, or parthenogenesis outside the context of marriage or parenthood is immoral. These manipulations violate the personal dignity of the human being and attack his integrity and identity. 
(Emphasis mine.) From this quote, it might at first seem that the intention of producing a breed is the evil to be avoided, but the last sentence makes it pretty unavoidable: cloning violates human dignity.

But look closely at what Pope St. John Paul II says: "Procedures designed to influence the genetic inheritance of a child, which are not therapeutic, are morally wrong." (Emphasis mine.) This explicitly excludes mitochondrial transfer.

Mention is made of cystic fibrosis, which could be corrected cellularly at the early level by extragenomic gene therapy. The only difference between this and treatment of mitochondrial diseases is that the extragenomic DNA in genetic therapy for CF is carried by bacteria, while the extragenomic DNA in genetic therapy for mitochondrial diseases is carried by bacteria. (Makes mitochondrial transfer look downright natural and convenient, doesn't it?)

But this is not just about cells and molecules. It's about gametes and parenting, and that is why most people get antsy--because mitochondrial donors have been called third biological parents.

Moral Teaching: Parents

What is a parent? I'm not planning to hammer out a definition of "parent" today, especially since Catholic Encyclopedia can't. This is a dialectical argument to show you that parenting has to do with raising children, especially with the reproductive capacity at the beginning of the child's life.

Any definition of "parent" should be wide enough to include the following people:
  • a woman who, with her own egg, conceives a zygote in her own uterus (biological parenthood, simply speaking)
  • a man who, with his own sperm and body, fertilizes a woman who conceives a zygote in her own uterus (biological parenthood, simply speaking; this spectrum includes everything from rape to monogamous marriage)
  • a person who raises a child conceived by other persons as his or her own (technically modified by the word "adoptive" or "foster," as in scripture of St. Joseph)
Notice that biological parenthood, simply speaking, is all it takes for us to call someone a mother or father. However, this is based on reproductive tissue (gametes), not DNA. Gametes may have too many or too few chromosomes; chromosomes may have repeats, deletions, or nonsense mutations; eggs may carry many or fewer mitochondria; mitochondria may carry defective extragenomic DNA.

Key point: contribution to the DNA content of the zygote (which determines congenital disorders) does not matter as much as contribution of reproductive tissue. So what about this person:
  • a person who gives his or her own DNA-containing mitochondria for transplant into to a woman's egg before the woman's egg is used in IVF?
This person is donating cellular parts, not gametes (let alone years of time). I argue that this person belongs on a list of people who donate parts. A list like this:
  • a person who gives his or her own undifferentiated white blood cells to a hematology/oncology patient (bone marrow donor)
  • a person who gives his or her own red blood cells, platelets, or plasma to another person (blood donor)
  • a person who posthumously gives his or her own ocular tissue to another person (cornea donor)
  • a person who, living or posthumously, gives part of his or her own body to another person (organ donor)
In short, the person who gives their mitochondria for transfer is not violating human dignity. He or she saves the life of children conceived with mitochondrial disease, but he or she is an organelle donor, not a parent. 

Ghost Heart (Decellularized)
Src: TED.
Replies to Objections

  1. But no other organ donation includes non-genomic DNA.
    False. Every donation that includes mitochondria includes non-genomic DNA. This is everything but decellularized organs, plasma, platelets, and stool.
  2. Okay, so no other organ donation includes only non-genomic DNA.
    True. But there are other organ donations that are exclusively for the purpose of transferring DNA and hoping to replace the recipient's phenotype with the donor's. The best example is bone marrow transplants.
  3. But mitochondrial transfer still requires IVF.
    Very, very true. Although I hold that mitochondrial transfer per se is morally licit, I cannot condone current methods of mitochondrial transfer which involve IVF.

Saturday, August 30, 2014

Organ Donation: Is Your Soul Gone when Your Brain Dies?

I had some experience while on my trauma/acute care rotation with brain death and organ harvesting. One of my good friends was on the transplant service at the same time. "I think there's a harvest tonight," I said to him one day. A patient on our service, who had come in with severe brain damage after a hallucinogen-associated accident, had been declared brain dead. His family had consented to donation. I saw the organ donation representative with his binder and papers hovering around the room. And the patient's name disappeared from our check-out list (the list we keep of the patients so that we can hand them off to the night team). Sure enough, there was a harvest that night.

It sounds macabre, and it is. Late one evening, I was walking down the long hall of operating rooms to get a snack out of the physician's lounge. I passed by the screen at the front of the OR that displays all ongoing surgeries. Each operating room has a row, and the cases stretch out like long ribbons along the row, with every hour taking about three inches on the screen. Because it was 7:00 or 8:00 in the evening, no elective cases were scheduled. There was a laparoscopic appendectomy posted for the near future: it was about eighteen inches long on the screen. But at the bottom of the screen stretched an enormous band of orange, disappearing to either end of the screen. "HARVEST" was the procedure.

I walked down the hall. Outside the room's door were many styrofoam crates with plastic bags labeled "human organ for transplant" and advisories about temperature and transport. There was a liver box, a kidney box, a heart box, a box for blood.... No shades were drawn over the windows, so I looked in. The body on the table looked pale; I later realized that this was because blood was being taken. And instead of a cot or hospital bed waiting outside the door, as in every surgery, there was a long box on wheels. A tank, from the morgue.

The Catechism, in 2296 (in the section on Respect for the Person in Scientific Research) has this to say about organ donation:
Organ transplants are in conformity with the moral law if the physical and psychological dangers and risks to the donor are proportionate to the good sought for the recipient. Organ donation after death is a noble and meritorious act and is to be encouraged as a expression of generous solidarity. It is not morally acceptable if the donor or his proxy has not given explicit consent. Moreover, it is not morally admissible to bring about the disabling mutilation or death of a human being, even in order to delay the death of other persons.
I had heard the horror stories about people (rather than bodies) being harvested. But med school gave us training to recognize legitimate brain death. This included forceful reminders that that two physicians must agree on the criteria. But is brain death a suitable way to determine that the soul is gone?

Maureen Condic, Ph.D. wrote a helpful essay entitled "Life: Defining the Beginning by the End." Published in 2003 by First Things, the essay discusses the beginning of life by considering death. I was already a Condic fan, because of her phenomenal (and unsung) white paper on the beginning of life, and because I was a Vita Institute participant.

Condic highlights the distinction between cellular (or even organ) life and life of the organism. (Busy people read the bold.)
Brain death occurs when there has been irreversible damage to the brain, resulting in a complete and permanent failure of brain function. Following the death of the brain, the person stops...sensing, moving, breathing...although many of the cells in the brain remain “alive” following loss of brain function. The heart can continue to beat spontaneously for some time following death of the brain (even hearts that have been entirely removed from the body will continue to beat for a surprisingly long period), but eventually the heart ceases to function due to loss of oxygen....

The fact that the cells and organs of the body can be maintained after the death of the individual is a disturbing concept. The feeling that corpses are being kept artificially “alive” as medical zombies for the convenient culture of transplantable organs can be quite discomforting, especially when the body in question is that of a loved one. Nonetheless, it is important to realize that this state of affairs is essentially no different from what occurs naturally following death by any means. On a cellular and molecular level, nothing changes in the instant of death. Immediately following death, most of the cells in the body are still alive, and for a time at least, they continue to function normally. Maintaining heartbeat and artificial respiration simply extends this period of time. Once the “plug is pulled,” and the corpse is left to its own devices, the cells and organs of the body undergo the same slow death by oxygen deprivation they would have experienced had medical science not intervened.

What has been lost at death is not merely the activity of the brain or the heart, but more importantly the ability of the body’s parts (organs and cells) to function together as an integrated whole. Failure of a critical organ results in the breakdown of the body’s overall coordinated activity, despite the continued normal function (or “life”) of other organs. Although cells of the brain are still alive following brain death, they cease to work together in a coordinated manner to function as a brain should. Because the brain is not directing the [diaphragm] to contract, the heart is deprived of oxygen and stops beating. Subsequently, all of the organs that are dependent on the heart for blood flow cease to function as well. The order of events can vary considerably (the heart can cease to function, resulting in death of the brain, for example), but the net effect is the same. Death occurs when the body ceases to act in a coordinated manner to support the continued healthy function of all bodily organs. Cellular life may continue for some time following the loss of integrated bodily function, but once the ability to act in a coordinated manner has been lost, “life” cannot be restored to a corpse”no matter how “alive” the cells composing the body may yet be.
If that sounded interesting to you, I encourage you to read the rest. Condic goes on to talk about how this definition excludes persistent vegetative state (i.e. we can't argue that Terry Schiavo should die from agreeing that brain death = death), and that this definition does not hang on consciousness or cognitive function (i.e. we can't euthanize the unborn, the disabled, or the demented because we agreed that brain death = death). I disagree with a few of Condic's assertions, notably that we cease to think upon brain death. (who, with the light of faith on matters like the communion of saints, would say that the soul, separated, cannot think without the brain?) But the rest of her work is medically excellent as far as I, eight months from M.D., can see. This is also philosophically sound as far as I, a bachelor in philosophy, can see.

When I initally got my driver's license, I was still undecided about organ donation. I renewed it recently, and I'm now a donor. I encourage you to prayerfully consider donation, too. Besides saving up to 8 lives, you could also bring closure to your family after your death, all in accord with Catholic teaching, sound philosophy, and accurate medicine.

(Spoiler alert: that's not my license at left.)

Thursday, August 7, 2014

Mini Post: Living downtown is awesome

I haven't been able to sit down and blog for so long! I have a bunch of ideas for posts all piled up on my phone's "To Do" list, but so little time to sit and execute them. I'm on a subspecialty away right now and (aside from the fact that I missed an emergency surgery last night), I'm doing what I need to do with pretty liberal free time.

Therefore, we will now have a moment to spit out all the blog post ideas in miniature.

I've moved several times since I started med school. Suburb 1 (my first location) was very quiet. The only remarkable thing I ever experienced among my neighbors or in my apartment complex was the messy morning relationship fight I accidentally witnessed across the street while on my balcony one morning for breakfast. (It was a lot like the movies: the guy slams out the door with a suitcase, the girl comes out after him very distressed, pleading loudly....) Suburb 2 was even quieter. Now I live downtown in one of the country's largest cities. And I'm living with a different population, since I'm living in a lower socioeconomic area. I see homeless people daily, I see broke people daily, I see mentally ill people frequently, I see people with much narrower prospects than mine all around me.

But I love it. I feel like I'm appropriately living the way an alter ecclesia should live: poor and with the poor.

And sometimes it's pretty funny. While biking home one day, I stopped at a light and smiled at the man sitting at the nearby bus stop. "Wher' yo' husband at?" he asked, without any other greeting.

"I'm married to Jesus," I answered.

"Oh," he replied, not knowing what else to say. "That's coo'."

"I thought so," I answered. The light turned green and I moved on. That was already the second time someone had asked me where my husband was.

Another time, I was finishing a conversation with a homeless man after Mass at the cathedral. I introduced myself and he said, "All ri', mmatins, my holla' sista."

I love to be with the people in my neighborhood. Just being in the same place, shopping at the same stores, using the same laundry machines, putting up with the same pigeons, and walking the same streets is teaching me about how hard these people work and how much love we all need. It's humbling and exciting. (That may or may not be where I'm living; I didn't even check before I used the picture; thanks to Kim Briggs)