Ridecamp: Re: [RC] Bioengineered Endurance Athletes?

Debbie,


Good practical questions for which I wish I had a simple answer. As a basic
scientist I ammore like Phil Donahue, raising more questiosn than I ever
answer in my career.  In some ways the TB industry uses someone, I believe
a "nicker" who looks at the potential of the mare/stallion cross.

Because slow and fast fiber types, or cell types, are FAR more comlicated
than just mitochondria, there are many genes involved for the various
proteins of a muscle fiber that determine type.  Fiber type has been
simplified to pacify the masses.  We have in fact perhaps identified not
only slow and fast but w/in muscle up to 2 slow types and 4 fast types, and
hybrids of these as well.

Scientists have debated the "limiting" factor in endurance prformance and
there are essentially 2 camps: 1 the ability to use oxygen, or 2 the
ability to deliver oxygen.  The ability to use oxygen depends upon total
volume of mitochondria in muscle.  As mitochondria are the same in any
muscle the more you have the more oxygen you can consume and the more
energy you can derive to sustain muscle contractions. The delivery of
oxygen is predicated largely on cardiac ouput or the pump capacity of the
heart.  Now, there is fairly clear evidence that at low intensity (approx.
60-70% of maximum) that the ability to maintain performance is based upon
the ability to consume oxygen.  As intensity increases then delivery
becomes a larger factor.  So answering which is limiting depends on how you
ask the question.

So no I don't think that you can negate Dads contribution.  However, the
sustaining power, or the enduring capacity of an animal , might be more
heavily weighed to mom than Dad.  You also have to consider biomechanics of
gait, quality of bone, hoof, connective tissue strength, and many other
things, not the least of which is "heart" as it refers to will.  Thats all
beyond me.  My world has been inside the fiber for many years.  This world
is poorly understood and overly simplified by popular press, but I do find
it interesting that just like Pee Wee football, the horse industry as a
whole places much of the weight of genetic success to the stallion.  I tell
my students that if you are a great endurance athlete, make sure to thank
your mom.

Before I left my position at Ohio State I was looking into a more
discimminating method of looking at muscle proteins, know as myosin heavy
chains (MHC).  This form of fiber typing has been used in rodents and
humans and we have seen very subtle changes with training, gender, age,
hormones, etc that are not reflected by classical "fiber type" changes
first used in the 70's.  I was looking into characterizing MHC in various
distinct breeds such as arabians when compared to say racing quarter
horses, which is the classic sprinter vs endurance runner. Some work has
been done, but it is very limited.  I theorized that arabians aren't just
suited to endurance due to cooling mechanisms inherent to their desert
breeding, smaller lighter frames, larger heart and lungs, quality of hoof,
eye sight, etc........but that their MHC quality and mitochondria quantity
allow them to endure activity longer.  Alas, 2 years ago I told
administration to sing that famous Johhn Paycheck song and I left to teach
at a small college, play w/my kids, and enjoy my horses.........someone
else can solve the great mysteries of muscle, I want to ride and be Dad.

Jon K. Linderman, Ph.D., FACSM
Assistant Professor of Health and Sport Science
University of Dayton
300 College Park
Dayton, OH 45469-1210
Voice:(937) 229-4207
FAX: (937) 229-4244
jonlinderman@xxxxxxxxxxx
http://www.udayton.edu/~linderma




                                                                                                                                       
                      "Debbie T."                                                                                                      
                      <risingwind@socke        To:       <tprevatt@xxxxxxxxxxxxxx>, <Jon.Linderman@xxxxxxxxxxxxxxxxx>                  
                      t.net>                   cc:       "Lynne Glazer" <lglazer@xxxxxxxxxxxxxx>, <ridecamp@xxxxxxxxxxxxx>,            
                                                <ridecamp-owner@xxxxxxxxxxxxxxxxx>                                                     
                      08/19/2002 02:15         Subject:  Re: [RC]   Bioengineered Endurance Athletes?                                  
                      PM                                                                                                               
                                                                                                                                       
                                                                                                                                       




Jon:
  You said:

By the way the gene for the protein that makes the structure know as
mitochondria, which is where we use oxygen in the muscle cell, is
apparently a maternally linked gene.  Thus, great endurance capacity of
muscle comes from mom........not pops!

>From this statement, do you mean that the gene for selecting for
muscle-fiber type (i.e. slow or fast twitch muscle fiber) is on
mitochondrial DNA, (which is only expressed in the female line) therefore
when making breeding decisions, it's more important to choose a MARE that
is
endurance proven than a STALLION that is endurance proven?  Would that mean
that the stallion could be just any conformationally desireable animal of
the breed of choice (say, Arab :-)  as long as the mare was a good
endurance
horse, and you would be more likely to get a foal with the right
muscle-fiber phenotype, therefore a more promising prospect?
Debbie Trimble





----- Original Message -----
From: <Jon.Linderman@xxxxxxxxxxxxxxxxx>
To: <tprevatt@xxxxxxxxxxxxxx>By the way the gene for the protein that makes
the structure know as
mitochondria, which is where we use oxygen in the muscle cell, is
apparently a maternally linked gene.  Thus, great endurance capacity of
muscle comes from mom........not pops!


Cc: "Lynne Glazer" <lglazer@xxxxxxxxxxxxxx>; <ridecamp@xxxxxxxxxxxxx>;
<ridecamp-owner@xxxxxxxxxxxxxxxxx>
Sent: Monday, August 19, 2002 8:20 AM
Subject: Re: [RC] Bioengineered Endurance Athletes?


>
> As one of "them" who has done work witrh muscle fiber type changes for
most
> of my career let me say that recent publications of changes in muscle
fiber
> types are really nothing new.  We knew since the 70's that rodent muscle
> could undergo dramatic changes from fast to slow with various
interventions
> that caused the muscle to be chronically recruited.  These interventions
> showed us the envelope to which a muscle can be changed.  A practical
> application of this in the training of mammals: dogs, rats, and humans is
> that prolonged periods of low intensity activity alters the fiber
> characterisitics of the muscle to be more slow twitch.......we have
called
> this LSD long slow distance training.
>
> It should be cautioned that slow twitch refers to the contraction speed
of
> the muscle, which normally goes hand in hand with the ability to use
oxygen
> to sustain energy use for prolonged periods of time.  However, as we age,
> muscle lose high power faster twitch fibers and actually become slow
twitch
> in nature making us more susceptible to falls etc.  However, in  this
case
> the aged slow twitch muscle changes actually results in a decreased
ability
> to use oxygen and we see reduced work capacity in the elderly.  In space
> w/the lack of gravity muscles get smaller (atrophy) and actually become
> faster twitch which causes them to fatigue more rapidly. In otherwords,
> contrary to popular myth we have know for a long time that muscle can
> undergo dramtic changes in many environments.
>
> Carl Lewis can not become frank shorter, and vice versa.  For those 2
young
> to remebver frank shorter won gold and silver in the marathon for the US.
> They have a genetic window that endows them with fiber characterisitcs of
> their muscles.  They can have changes through training, but w/out very
> severe, even painful procedures, it is nearly impossible to take a turkey
> breast (white; fast twitch muscle) and make it into a turkey leg (dark;
> slow twitch muscle).  By the way the dark comes from the rino containing
> proteins that bind oxygen in the muscle: myoglobin and the cytochromes
that
> are involved in the use of oxygen.  A turkey can walk all day, but can
fly
> but a few seconds before becoming exhausted.  A migratoryt duck or goose
> has dark breast meat due to its slow muscle capable of flying form Mexico
> to Canada.
>
> By the way the gene for the protein that makes the structure know as
> mitochondria, which is where we use oxygen in the muscle cell, is
> apparently a maternally linked gene.  Thus, great endurance capacity of
> muscle comes from mom........not pops!
>
>
>
> Jon K. Linderman, Ph.D., FACSM
> Assistant Professor of Health and Sport Science
> University of Dayton
> 300 College Park
> Dayton, OH 45469-1210
> Voice:(937) 229-4207
> FAX: (937) 229-4244
> jonlinderman@xxxxxxxxxxx
> http://www.udayton.edu/~linderma
>
>
>
>
>
>                       Truman Prevatt
>                       <tprevatt@mindspring.        To:       Lynne Glazer
<lglazer@xxxxxxxxxxxxxx>
>                       com>                         cc:
ridecamp@xxxxxxxxxxxxx
>                       Sent by:                     Subject:  Re: [RC]
Bioengineered Endurance Athletes?
>                       ridecamp-owner@xxxxxx
>                       durance.net
>
>
>                       08/19/2002 08:53 AM
>                       Please respond to
>                       tprevatt

>
>
>
>
>
>
> There was an article in Scientific American about a year or two ago on
> this work and some others. They believe they can change the muscle types
> either way.  This would produce either super sprinters or super
> endurance type muscles. One approach is to alter the genetic composition
> of the muscles on a one time basis to change the structure of the muscle
> fiblers. The IOC can throw all it's durg testing out the door since
> there is nothing to test for.
>
> A brave new world?
>
> Truman
>
> Lynne Glazer wrote:
>
> > Is the horse of the future a transgenic beast? <g>
> >
> > Scientists create 'endurance' mouse
> >
> > May lead to wonder drug for distance athletes
> > By Kate Tobin
> > CNN Sci-Tech
> >
> > BOSTON, Massachusetts (CNN) --Mighty Mouse lives, and the "new age"
> > version is downright buff.
> >
> > Researchers say they have created a transgenic mouse with muscles like
> > a marathoner, capable of enduring rigorous exercise for extended
> > periods of time.
> >
> > While so far the research has only been conducted on mice, scientists
> > say they expect the techniques they've developed to treat the mouse
> > muscle will also work on humans. Doctors say the discovery may one day
> > lead to new treatments for people who are bedridden or have
> > degenerative muscle disease, and could prove to be a wonder drug for
> > endurance athletes like long distance runners or cross country skiers.
> >
> > Bruce Spiegelman and colleagues at the Dana-Farber Cancer Institute
> > identified a biochemical called PGC-1 that operates as a molecular
> > switch, converting so-called "fast-twitch" muscle, which is strong but
> > tires quickly, into high-endurance "slow-twitch" muscle.
> >
> > "PGC-1 appears to be the switch, or a major component of it, that
> > enables your body's muscles to adjust to the demands being put on
> > them," said Spiegelman. "Understanding how this system works could
> > make it possible to develop a drug to manipulate this system."
> >
> > Muscle is made up of a combination of different types of fibers.
> > Endurance athletes train long and hard to build up slow-twitch muscle
> > fibers, called Type I fibers, which are long and lean and can keep
> > pumping for long periods of aerobic exercise. Sprinters or
> > weightlifters, on the other hand, have muscle rich in fast-twitch,
> > Type II fibers. These muscles are bulkier and stronger but tire
quickly.
> >
> > Further studies
> >
> > To create the endurance mouse, Spiegelman's group bioengineered PGC-1
> > into mouse muscle tissue. They expected that it would promote the
> > development of cellular power plants called mitochondria, which fuel
> > the growth and development of slow-twitch muscle fiber. But they were
> > surprised to find that PGC-1 appeared to be converting Type II
> > fast-twitch fibers into Type I slow-twitch fibers.
> >
> > The muscle itself actually changed color, taking on a reddish hue
> > characteristic of oxygen-rich tissue. Further, in an endurance test at
> > a Texas laboratory, the bioengineered muscle turned out to contract
> > efficiently two and a half times longer than regular muscle.
> >
> > Spiegelman cautions that there is still five to 10 years of work to be
> > done before PGC-1 based treatments will be available.
> >
> > The research is published in this week's edition of the journal Nature.
> >
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