|
- 积分
- 94
- 威望
- 94
- 包包
- 3
|
http://www.newscientist.com/arti ... nics.html?full=true
% g& q# ~8 v7 u% eNEWSCIENTIST HEALTH" |0 q/ S a8 p2 j# A# O7 q
Death revives warnings about rogue stem cell clinics " D% S9 z: M# o- e6 ]( V
22:00 17 June 2010 by Andy Coghlan
6 u4 k; n- v* wFor similar stories, visit the Stem Cells Topic Guide $ g0 b$ `# J+ U
% J6 `9 ]; a# }6 p6 A* |
1 e b' l, y8 q7 n; w+ W. l, |
8 j3 {# m, B- E M1 Z5 X7 k
The death of a woman after she was treated with stem cells at a private clinic in Thailand has reinforced warnings for desperate sick people to avoid "stem-cell tourism" – the gamble of undergoing untested stem-cell treatments in unlicensed private clinics abroad.6 a: t+ `6 f' }. ]
5 a$ S& s+ ^. Z9 l
Post-mortem results reported this week reveal that the stem-cell treatment almost certainly killed the woman, who had been suffering from kidney disease. She developed strange lumps in the kidney, liver and adrenal gland.
# r7 T$ o: n' K6 C2 G3 d/ j1 G
- p4 i5 s. V4 Z- VSo what are the implications for stem cell research generally, and is it safe for clinical trials to continue? New Scientist has some answers.' j9 X3 n+ [( l4 n
! C" D' q8 Q" v6 W( u( N4 c6 C
What was wrong with the patient, and what treatment did she receive?7 `1 k3 h+ i8 ?7 B$ v6 h
* L8 C& z" S3 E. c
She had lupus nephritis, a condition in which the body's own immune system mistakenly attacks and destroys the kidneys. Usually it can be kept in check with immunosuppressive steroids, but when these failed, the woman turned to a private stem-cell clinic in Bangkok.
. \+ o( P, G7 S5 u& r( s. e* l/ ^2 r. S
How would stem cells help?
" C! S* b; e+ f+ Y
+ ?/ v$ w, i: L5 k- e( XBona-fide trials in European clinics about six years ago showed that some people with similar kidney disease benefited if stem cells from their own bone marrow were injected into their blood. The body's immune system was first deliberately destroyed with powerful immunosuppressive drugs, then the reinjected stem cells helped to stop the attacks on the kidney by rebuilding and rebalancing the immune system. About a third of the 50 recipients relapsed after a year or so, and 12 of these people died. But around two-thirds saw benefits, with some going into remission.
7 f/ U) ~6 y2 f% K: ]& Y7 C/ E% q5 z1 w
So what happened with the woman who went to Bangkok?! T! m2 ]" L4 i
- J2 U. q8 {3 S( [1 w) l/ zUnlike the European trial patients, who'd had their stem cells injected into the bloodstream, the woman had her stem cells repeatedly injected directly into both her kidneys. The aim seems to have been to get the cells to repair the kidney directly, rather than retune the immune system.
) {) A' W, `- Q
- p' S% {6 A. V$ gAnd the result?
$ r$ P) d& M% w
8 n! n& e6 ^* s \Three months after her treatment, her condition declined, and she went to the Chulanlongkorn University Hospital in Bangkok, where she received dialysis. Later, a kidney lump was identified in her left kidney; 11 months after her treatment, that kidney failed and she had it removed. Another year later, she died.+ i, [, {' i/ O
. J7 D7 [# @ @) F8 n* c. z
So what did examination of the kidney reveal?
' `- u$ H2 A; F J' b' U: V& s' J0 G8 M3 }
At the injection sites, the woman had developed strange lumps and lesions, which turned out to be mixtures of bone-marrow and blood-vessel tissue. Similar lumps had also developed in the liver and one adrenal gland. A team led by Duangpen Thirabanjasak of Chulanlongkorn University Hospital report this week that the lumps almost certainly came from the injected stem cells.
3 v0 z, @" Z) X; [/ B5 T# x$ Z9 I5 p3 U1 ~
Did the injected cells do any good at all?' w$ n0 H4 H$ J
' K& d7 ~! P+ U$ v \
No. Because they weren't circulating in the bloodstream, they couldn't rebalance the body's immune system to halt attacks on the kidney. One explanation for the strange lumps could be that the kidney was already heavily scarred and poorly supplied with oxygen. Injected into this oxygen "desert", the stem cells seem to have begun making new blood vessels to rebuild a new supply system for themselves. They were suspected to be benign, but no one knows whether they would have eventually turned cancerous.
4 F& o; g) d: e
3 A8 p2 a. a! W) b- g5 @; OIs the case a one-off?
2 J3 h) q x+ ]! Q! L# A/ w8 c6 w" L/ w$ s
Susan Quaggin of the Mount Sinai Hospital in Toronto, Canada, and co-author of a commentary on the results in Journal of the American Society of Nephrology, says that treatment by direct injection of stem cells into the kidney is highly unlikely to be contemplated or undertaken in bona-fide scientific trials. "There's no scientific rationale for doing it that way," she says.
2 {, R' Y( Q5 n: D+ O% i% {+ S E& D+ K! s5 w/ v) H1 @
So no need to panic then, and halt all stem-cell trials?
Q t5 b0 h; r' G9 I* }4 M
! F) h @0 g' t6 A0 B) A- [# C; RAbsolutely not, according to Quaggin. All bona-fide trials must receive ethical approval beforehand and are scrupulously monitored, and the results must be peer-reviewed for publication. But she says that the Thai results are yet another reminder that sick people should not gamble with their safety, and money, by turning to stem-cell tourism peddled by unscrupulous operators.
" R; R/ n8 ?$ H f4 g% ?
, N7 o9 p; Y, z, z& G"The sad part is that many people are desperate, and what makes it even worse is that it costs lots of money," says Quaggin, who urges all prospective patients to access new advice on the internet by the International Society for Stem Cell Research, a body based in Deerfield, Illinois, which has also issued a set of guidelines for ethical stem-cell research.
! d. g- q- K0 V% S! L: B+ r5 P/ f. U2 ^) f1 L2 S8 \% g& V t
What are other stem-cell researchers saying?
" \6 B9 m; w8 P$ F9 {3 y. L0 J/ e
5 f( f' p) p& }$ G"It's a dreadful reminder reinforcing the absolute necessity for robust safety data in animal models before entering regulated clinical trials," says Chris Mason, director of regenerative medicine at University College London.
9 [. c( J9 u+ f2 p; ^
9 j2 Q0 Z& i6 w) R3 T5 _2 g h"For years we've been warning that this kind of thing was going to happen," says Robert Lanza, chief scientific officer at the stem-cell company Advanced Cell Technology in Worcester, Massachusetts. "I suspect this is just the tip of the iceberg: that there have been other dangerous side effects that haven't been diagnosed or reported to the scientific community."
2 v+ ^: P- L0 z/ W& z3 ~; [. X! h1 d6 {$ o& j1 m' L- D
Is the company that treated the woman now closed down?& C4 F5 Q7 ~# ]" e9 h! q0 o+ a
v; F# ?& E1 K4 U3 D2 `3 B
The researchers don't know which clinic provided the therapy in 2006. But private clinics around the world have recently come under pressure. A clinic run by Cell Medicine in Costa Rica was recently closed by the Costa Rican health ministry. And last year, Chinese authorities promised to clamp down on private clinics offering untested treatments in their country.
" A- O! q: E+ @ N* l: N J
. s6 r {. q2 lBut the show must go on? 0 L) C0 X0 x$ J
8 i2 u8 \# U2 P) pIndeed. The consensus seems to be that this is a timely warning of the dangers posed by unregulated clinics. But there's confidence that this was a somewhat freak result, and that most stem-cell treatments under trial are unlikely to pose such serious risks.. t8 c' e( D* i/ G% N; w& k
' A; h0 z2 G/ M' s, v9 uJournal reference: Journal of the American Society of Nephrology, DOI: 10.1681/asn.2009111156 |
-
总评分: 威望 + 5
包包 + 10
查看全部评分
|
发表于 2010-6-26 13:44
