MRI contrast agents change stem cell proliferation

Tampa, Fla. (Nov. 01, 2010) — When researchers tested three different labeling agents on three different stem cell populations to determine what effect the labeling agents had on stem cell phenotype, biological behavior and migration abilities, they found changes in stem cell proliferation depending on the type of contrast agent used.

The team of researchers from Belgium and Spain tested USPIO (ultra small superparamagnetic iron oxide) contrast agents Resovist ®, Endorem ® and Sinerem ® on mouse embryonic stem cells (mESC), rat multipotent adult progenitor cells (rMAPC) and mouse mensenchymal stem cells (mMSC). Their study is published in the current issue of Cell Transplantation (19:8), now freely available on-line at http://www.ingentaconnect.com/content/cog/ct/.

The researchers found the labeling efficiency with each of the (U)SPIOs varied significantly when different stem cell populations were compared.

“This means that labeling methods will likely need to be optimized for every cell type,” said Dr. Crabbe. “Over time we saw a dilution of (U)SPIOs and a decrease of iron in the cells.”

Non-invasive imaging plays an important post-transplantation role in stem cell research, but questions regarding whether the contrast agents used to track transplanted stem cells in vivo via MRI have an impact on the cells had largely gone unanswered until this study.

On the issue of whether (U)SPIO labeling has a biological affects on cells, the researchers discovered “no significant alterations” in cell phenotypes and that the label “does not significantly alter stem cell differentiation.”

“Sinerem ® decreased proliferation of mMSC while both Sinerem ® and Endorem ® affected the proliferation rate of rMAPC, although prolonged culture, until seven days, resulted in restoration of the proliferation rate,” noted Dr. Crabbe. “We also found that higher concentrations of Sinerem ® and Endorem ® were needed for cell labeling to achieve similar MRI detectability.”

The researchers concluded that it will be necessary to evaluate the efficiency of cell labeling for every new contrast agent combination aimed at being followed in vivo by MRI. Also, the effect on biological behavior of cells should be examined. They noted that their results were limited to examining the effects of labeling on proliferation, not differentiation.

“Although labeling of stem cells with MRI is promising, there are some limitations,” concluded Dr. Crabbe. “More optimal particles are needed that can be taken up without the need of potentially toxic agents. Also, there is the problem of particle dilution over time as cells divide. When grafted cells continue to proliferate, loss of signal occurs.”

According to Dr. Julio Voltarelli, professor of clinical medicine and clinical immunology at the University of Sao Pãulo, Brazil and section editor for Cell Transplantation there has been a knowledge gap regarding the survival and distribution of stem cell populations used for in vivo therapy.

“Many studies have tried to close this gap by using radioactive or nonradioactive labeling of the cells in order to follow their fate in the organism,” said Dr. Voltarelli. “However, this paper demonstrates that such labeling may alter stem cell behavior, such as proliferative potential, and give biased information when compared to nonlabeled cells.”

Contact: Dr. Annelies Crabbe, Stem Cell Institute. K.U. Leuven, O&N1- Herestraat 49, bus 804, 3000 Leuven, Belgium

Tel: 003216330292 Fax: 003216330294

Email [email protected]

The editorial offices for Cell Transplantation are at the Center of Excellence for Aging and Brain Repair, College of Medicine, the University of South Florida and the Diabetes Research Institute, University of Miami Miller School of Medicine. Contact, David Eve, PhD. at [email protected] or Camillo Ricordi, MD at [email protected]

News release by Florida Science Communications, www.sciencescribe.net

1 COMMENT

  1. my name clive mcnally i inovated the i phone and this is what has been happerning to me science

    point 1 biology

    if i state that there are 21 nerves in the upper and the lower jaws of a human body in the teeth and this data
    can be confirmed by any dentists or biologist or an anotomy book {fact}

    point 2 muscle controll
    the nerve endings of the human body are controlled by light produced by the chemicials of the human body {fact}
    all facts can be varifyied by medical journals

    point 3 {science}
    light and audio and broadcast signals are infinitly balenced out of oxygen and light and audio and broadcast
    signals pass through carbon hense when we speak we ossolate oxygen to produce our voices {fact} how do speakers
    in a sterio work they ossolate oxygen {air} to generate the audio all facts can be varifyied

    point 4 {signals}
    fact broadcast signals pass through nearly everything and how do you caculate between two points with no fixed
    referance noting all broadcast signals can be picked up in any property or building ect you would use 6 points
    to 6 points with the centre points as your start and destination as in navagating through space

    point 5 audio
    if i can generate audio anywhere by caculating between points and intensifying a signal at any points plus
    i can caculate where any objects are or weather they are moving or as to weather they are static and by
    ossolating oxygen by using a particular frequency ranges anywhere means on the return signal i would know
    what anybody was saying any where on the planet both inside there heads and outside as in both cases we
    ossolate oxygen outside and inside in h2o hense inner vocals can be detected as the ossolation of carbon
    ferrious oxide in the blood movement as the inner voice then also ossolates oxygen hense internal voice

    point 6
    finally if i can detect any oxygen ossolations on the return signal if i put copper sulphate in to water
    it changes the ossolation frequencys of oxygen and so i can tell when i have blue water and if i put carbon
    ferrious oxide in water i can tell when it is red and if i add other chemicials to water the same happens
    oxygen at those points has a differant frequencys

    light and audio and broadcast signals are infinitly balenced out of oxygen and that in the nose of humans
    light and oxygen passes through hydrogen of h2o with light and oxygen passing through hydrogen inside the
    body and that carbon c 12 6 referance the time on a clock 12/6 and that h2ococo = oxygen in the periodic
    table the differances on the periodic table = 42 same as the sequencing for the human body take a look plus
    another the 6 6 6 has 33 33 33 4 3 s and 2 threes and that 9 9 9 3 lots of 3 x 3 is 9 9 9 and that if the
    clock has 12 at the top then there is 2 6s and 1 at the bottem then there is a b c d e f g h i j ect but
    as a = 1 b = 2 ect to z = 26 and that 12345 +1-1 |+1-1 67890 gives the equasion 12345 = 5 and 67890 = 5

    there are 4 quardrants of the mouth, 1, 2 , 3, 4. The upper right corner is 1, the upper left is 2, bottom
    left is 3, and the bottom right is 4. so in quadrant one, the first tooth is 11(one one), then 12(one two),
    then 13(one three) etc this goes to 18(one eight). 11 starts from the front tooth. then you go to quad 2, 21
    (two one), 22(two two) etc for each quarant.

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