"Stem cells are like little kids who, when they grow up, can enter a variety of professions," Dr. Marc Hedrick of the UCLA School of Medicine says. "A child might become a fireman, a doctor or a plumber, depending on the influences in their life -- or environment. In the same way, these stem cells can become many tissues by making certain changes in their environment."

Nice analogy yahh . stem cells sekarang bnyk dipake buat pengobatan leukemia, jaringan ikat, trus kemungkinan buat Alzheimer's, diabetes n kanker. Stem cells itu inti dari regenerative medicine. Nah yang gw masih binun sebenernya, pengaruh apa aja yg bisa bikin si stem cell ini jadi sel tulang, sel otot, kartilago dan laen2. Bingung ga sih, dari zigot jadi dua sel, 4, 8, 16, blastula, morula, eh jadi bayi.... nah lho, kok bisa dari satu sel yang sama, ada yg jadi sel tulang, otot, tulang, otak, dll? Gimana caranya yahh 

Okie, lanjut

1. Apa itu stem cells?

Stem cells atau sel tunas adalah sel muda yang berpotensi untuk berdiferensiasi menjadi sel2 lainnya. Misalnya stem cell bisa berkembang jadi sel darah, sel kulit, syaraf, sel otot, dll. Secara teori, stem cells dapat membelah berkali2 tanpa batas. Setiap kali membelah, stem cells dapat tetap menjadi stem cells atau berdiferensiasi menjadi sel2 lainnya.

Ada tiga tipe stem cells yang penting : embryonic stem cells, adult stem cells, dan         umbilical cord stem cells.

2. Kenapa namanya stem cells?

"stem" means the main ascending (going up) stalk of a plant. Similarly there are main cells that grow through time, a main stem from which other stems can branch out from.

Artinya, kalau kita runut suatu sel darimana sel itu berasal, kita akan sampai pada titik di mana setiap sel memiliki karakteristik biokimia yang identik. Ini mirip dengan arti kata "stem" sebenarnya.

Dan juga sebagai tambahan :

The word "stem" is thought to be from the old english but the word also can sometimes mean 'to stop or to slow down' (from old Norse) so it could be that stem cells tend to stop at a particular point and doesn't continue in the same direction for ever. As tem slows down and changes direction. For stem cells they tend to stop and slow down and turn into other types of cells.

3. Kenapa stem cells penting dibahas?

Stem cells penting karena dapat digunakan untuk kepentingan terapeutik seperti pengobatan diabetes, Parkinson, multiple sclerosis, dan kanker.

Saat ini, masih dilakukan banyak riset untuk menjawab bagaimana suatu sel dapat berubah fungsi dari satu sel ke sel lainnya. Hehe... ini pertanyaannya kan yahh? Justru itu juga yang saat ini masih dicari ... Mengetahui bagaimana suatu sel dapat menyimpan satu informasi dan kemudian berubah menjadi sel yang sangat berbeda dari sel asalnya adalah inti dari riset yang dilakukan saat ini dan salah satu upaya untuk mengetahui tentang siapa kita sebenarnya.


Sampai sejauh mana riset yang sudah dilakukan?

bersambung

Latest research on stem cells :
    
Discovery Of Cardiac Stem Cells May Advance Regenerative Heart Therapy

An immediate early publication of the journal Cell, published by Cell Press, on Nov. 22, 2006 points to the possible existence of master cardiac stem cells with the capacity to produce all three major tissues of the mammalian heart. A companion Cell paper also published online reports the discovery of a second population of cardiac progenitors, which are capable of forming both cardiac muscle and the smooth muscle found in the heart's blood vessel walls.

Together with similar findings reported in the November issue of the journal Developmental Cell, also a Cell Press publication, the findings challenge the notion that the heart's diverse cell types--including cardiac muscle, smooth muscle, and the endothelial cells that line blood vessels--stem from "non-overlapping embryonic precursors derived from distinct origins," according to the researchers.

The findings may also have important implications for regenerative medicine aimed at cardiac repair in patients with congenital or acquired heart disease, according to the researchers.

"It's a surprise that a single cell can give rise to all of these tissues and structures in the heart," said Kenneth Chien of Massachusetts General Hospital and Harvard Medical School. "The heart may look more like blood than we thought," he added, referring to the fact that single so-called hematopoietic stem cells can give rise to all of the cell types found in blood.

"This changes the way we think about organ development," said Howard Hughes Medical Institute investigator Stuart Orkin, the author of the companion paper from the Children's Hospital Boston. "Rather than different cell types coming together, the heart appears to develop from a common set of progenitors or stem cells. This may be a more economical method."

Chien's team earlier found a group of cardiac muscle progenitors called islet-1 (isl1+) cells in heart tissue from newborn rats, mice, and humans. The cells are defined by the presence of an isl1 protein.

To further examine the developmental potential of these isl1 progenitor cells in the current study, the researchers traced the fate of these cells in the hearts of mice. They found that the isl1 precursors produce not only cardiac muscle but also smooth muscle, endothelial, pacemaker, and other nonmuscle cell lineages. They then showed that the isl1 cells could be obtained from embryonic stem cells.

"These studies document a developmental paradigm for cardiogenesis, where muscle and endothelial lineage diversification arises from a single cell-level decision of a multipotent isl1+ cardiovascular progenitor cell," Chien said.

In the second study, Orkin and his colleagues isolated cells from a mouse embryo that expressed a cardiac-specific gene, called Nkx2.5+. They found that the Nkx2.5 cells spontaneously differentiated primarily into cardiac muscle cells and conduction system cells. The heart's conduction system carries the electrical impulses that allow it to beat.

Surprisingly, they found, some of the precursor cells took on a smooth muscle fate.

They then isolated Nkx2.5 cells derived from embryonic stem cells and found that some of the cells also expressed a second gene, c-kit. It was the c-kit+Nkx2.5+ cells that had the ability to expand and produce both cardiac muscle and smooth muscle cells from a single cell. The team confirmed that finding by isolating cells in which both genes were active and demonstrating their ability to form both heart muscle types in living animals.

"In summary, we have established the existence of a common myogenic precursor cell that gives rise to both myocardial and smooth muscle lineages," Orkin wrote. "This bipotential progenitor cell makes a lineage choice decision at a single-cell level. These findings reveal a hierarchy for myogenic differentiation in vivo and suggest a new developmental paradigm for cardiogenesis where a single multipotent progenitor cell gives rise to cells of diverse lineages within the heart."

While the Isl1+ cells studied by Chien may give rise to the c-kit+Nkx2.5+ cells examined by Orkin, the precise relationship between the progenitor cells investigated in the two studies is an open question requiring further study, the researchers noted.

"It's unknown what the relationship between these cells is, if any. One may be the predecessor of the other, or they might be quite separate," Orkin said, noting that the cells under study in the two papers appear to be derived from two separate pools, or fields, of heart progenitors. The primary and secondary heart fields are thought from previous studies to generate structures of the left and right side of the heart, respectively.

The discovery of cardiovascular-specific progenitors may hold promise for cardiac stem cell therapies, the researchers said.

"Embryonic stem cells are difficult to use for heart regeneration because of the danger of teratomas," Chien said. Teratomas are cancers that result from the uncontrolled growth of embryonic stem cells. "If we can get around that threat by cloning master cardiovascular stem cells, that would be a major advance."

"Regenerative stem cell therapies for heart disease will require an understanding of and an ability to manipulate the molecular mechanisms that govern the fates, differentiation, and morphogenesis of the myriad cell types that comprise the heart," wrote Daniel Garry and Eric Olson in a minireview that will accompany the new studies in Cell's Dec. 15 issue. These studies offer a "step toward this goal" by providing "evidence for common multipotential progenitors of the three major cell types of the heart."

source : http://www.sciencedaily.com/

Update lagi tentang stem cells :


Cancer-Killing Invention Also Harvests Stem Cells
(Associate Professor Michael King, Biomedical Engineering)
by Lois. H. Gresh

Abstract:

December 6, 2006:  Associate Professor Michael King of the University of Rochester Biomedical Engineering Department has invented a device that filters the blood for cancer and stem cells.  When he captures cancer cells, he kills them.  When he captures stem cells, he harvests them for later use in tissue engineering, bone marrow transplants, and other applications that treat human disease and improve health.  With Nichola Charles, Jared Kanofsky, and Jane L. Liesveld of the University of Rochester, King wrote about his discoveries in "Using Protein-Functionalized Microchannels for Stem Cell Separation," Paper No. ICNMM2006-96228, Proceedings of the ASME, June 2006.  King’s team includes scientists at StemCapture, Inc., a Rochester company that bought the University patent for King’s technique in November 2005 to build the cancer-killing and stem cell-harvesting devices.  The technique can be used in vivo, meaning a device is inserted in the body, or in vitro, in which case the device resides outside of the body – either way, the device kills cancer cells and captures stem cells, which grow into blood cells, bone, cartilage, and fat.

Mo baca lebih lanjut : http://www.seas.rochester.edu/~gresh/bme/bme_120606.html

Di situ ada penjelasan dilengkapi streaming movienya

WASHINGTON (Reuters) - Japanese researchers said on Sunday they had grown normal-looking teeth from single cells in lab dishes, and transplanted them into mice.

They used primitive cells, not quite as early as stem cells, and injected them into a framework of collagen, the material that holds the body together.

After growing them, they found their structures had matured into the components that make teeth, including dentin, enamel, dental pulp, blood vessels, and periodontal ligaments.

They were "arranged appropriately when compared with a natural tooth," the researchers reported in the journal Nature Methods.

The teeth grew and developed normally when transplanted into a mouse, said Takashi Tsuji of the Tokyo University of Science in Chiba, Japan and colleagues.

They said their method was the first to show an entire organ could be replaced using just a few cells.

"To restore the partial loss of organ function, stem cell transplantation therapies have been developed," they wrote.
"The ultimate goal of regenerative therapy, however, is to develop fully functioning bioengineered organs that can replace lost or damaged organs after disease, injury or aging."

The researchers went after the "organ germ" -- the early cells made using partially differentiated cells known as epithelial and mesenchymal cells. In this case the cells were taken from what is known as the tooth germ, the little bud that appears before an animal grows a tooth.

"Our reconstituted tooth germ generates a complete and entirely bioengineered tooth," they wrote.

"This study thus provides the first evidence of a successful reconstitution of an entire organ via the transplantation of bioengineered material," they added.

"Our present findings should also encourage the future development of organ replacement by regenerative therapy."

*Reuters.com

husshh.... jangan dibahas rahasia itu

hehehe...

ntar deh ya kalo dah rada longgar, ikutan ngramein stem cells ... sementara yaa... advisor dulu deh 

udah rada jarang online dia sekarang. 

btw, tepatnya gimana caranya menggunakan stem cells utk terapeutik? kayanya memang prospektif banget yah? kalo gak salah, perusahaan obat2 besar spt kalbe farma jg mulai melirik bidang ini (*kejutan... biasa perusahaan obat indo khan formulasi doang  )

3. Kenapa stem cells penting dibahas?

Stem cells penting karena dapat digunakan untuk kepentingan terapeutik seperti pengobatan diabetes, Parkinson, multiple sclerosis, dan kanker.

Saat ini, masih dilakukan banyak riset untuk menjawab bagaimana suatu sel dapat berubah fungsi dari satu sel ke sel lainnya. Hehe... ini pertanyaannya kan yahh? Justru itu juga yang saat ini masih dicari  ... Mengetahui bagaimana suatu sel dapat menyimpan satu informasi dan kemudian berubah menjadi sel yang sangat berbeda dari sel asalnya adalah inti dari riset yang dilakukan saat ini dan salah satu upaya untuk mengetahui tentang siapa kita sebenarnya.

Bukannya belum ada terapi dengan stem cells sampe saat ini? Selain belum punya data2 yang cukup juga sering terbentur masalah etika kan?

ehhm... ehmm... yang farmasi siapa yahh  Melirik gmn nih? Kalo cuma lirik malu2 kucing sama aja 

lho, kayanya aq gak pernah cerita soal farmasi 

Pernah ah. Yang di post itu tuh, pendidikan mahal kalo gak salah. Atau salah yahh 


Dari http://stemcells.nih.gov/

Have human embryonic stem cells successfully treated any human diseases?

Scientists have been able to do experiments with human embryonic stem cells (hESC) only since 1998, when a group led by Dr. James Thompson at the University of Wisconsin developed a technique to isolate and grow the cells. Moreover, Federal funds to support hESC research have been available since only August 9, 2001, when President Bush announced his decision on Federal funding for hESC research. Because many academic researchers rely on Federal funds to support their laboratories, they are just beginning to learn how to grow and use the cells. Thus, although hESC are thought to offer potential cures and therapies for many devastating diseases, research using them is still in its early stages.

Adult stem cells, such as blood-forming stem cells in bone marrow (called hematopoietic stem cells, or HSCs), are currently the only type of stem cell commonly used to treat human diseases. Doctors have been transferring HSCs in bone marrow transplants for over 40 years. More advanced techniques of collecting, or "harvesting," HSCs are now used in order to treat leukemia, lymphoma and several inherited blood disorders.

The clinical potential of adult stem cells has also been demonstrated in the treatment of other human diseases that include diabetes and advanced kidney cancer. However, these newer uses have involved studies with a very limited number of patients.

clinical trials using stem cells : http://www.clinicaltrials.gov/