Stem cell news: 自体脐血干细胞治疗婴幼儿听力丧失临床试验启动

kittybruce

由Cord Blood Registry资助的、由Memorial Hermann-Texas Medical Center开展的自体脐血干细胞治疗婴幼儿听力丧失I期临床试验获得批准。此前已有一名婴儿患者因存储了脐带血干细胞，于北卡州在1岁之内注射3次干细胞进行治疗取得效果。$ a/ Q8 W+ r9 d

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6 B5 x- J3 O$ P+ }, [% j6 B* ZUS begins stem cell trial for hearing loss
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By Kerry Sheridan (AFP) – 1 day ago ( O2 t( O9 g! }( o2 a

1 i# i  A: l% w) ?, B. nWASHINGTON — US researchers have begun a groundbreaking trial to test the potential of umbilical cord blood transplants, a kind of stem cell therapy, to treat and possibly reverse hearing loss in infants.0 e. h2 r$ w* q  M" q. w
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The phase I trial follows promising studies on mice showing that such transplants were able to rebuild the structures of the inner ear, and some anecdotal evidence from humans, sparking hope of a cure for some forms of deafness.% M7 R% L! s7 K& r
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One of those people is two-year-old Finn McGrath, who suffered brain damage after being deprived of oxygen during a prolonged and complicated delivery, according to his mother, Laura.
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" Z  [1 ~, I$ U9 J& W6 W8 y"His doctors told us he was at high risk for cerebral palsy, vision issues, hearing problems and mental retardation," she said in an interview with AFP.3 \; K3 t0 c9 ~1 p
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Finn's early days were an all-out struggle to survive, so for his parents, learning that he had failed his hearing tests and had damaged hair cells -- the sensory receptors in the inner ear that pick up sounds -- was almost an afterthought.
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# T6 |! `! R9 f$ k, Q' ?6 j2 NHe had organ failure, breathing problems, and his cerebral palsy left him unable to roll, crawl or walk, hold his head up, talk or eat.! [1 R2 d* [  N1 X) n+ i& r0 j
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As his parents searched for ways to help him, they came upon stories online that told of studies using cord blood to help children with cerebral palsy and other disorders.5 C2 s8 r7 W, l! e# e1 k
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Prior to his birth, the McGraths had arranged to privately bank his umbilical cord blood, a procedure that costs around $2,000 plus storage fees, and remains controversial among pediatricians.
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' X: @6 \" d) Y* v7 _Private companies such as the Cord Blood Registry, which is funding the Texas study on hearing loss, urge expecting parents to bank their umbilical cord blood and reserve it for personal use as a way to protect their family.5 M/ A& Y* Q: i1 F7 l8 n* z
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That advice runs counter to the guidelines issued by the American Academy of Pediatrics in 2007, which calls such claims "unsubstantiated" and says banking for personal or family use "should be discouraged" but is "encouraged" if it is to be stored in a bank for public use./ V% s' g6 r  R4 [7 T: p' @3 w
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Since Finn's parents had already banked his, they enrolled him in cord blood trial for cerebral palsy in North Carolina and he received his first transplant in November 2009 when he was about seven weeks old.+ A2 _$ z0 C0 f' Y/ g7 ~

8 H* N. |, {/ i3 s9 VA second transfusion followed and by May, his parents began to notice a change.* w+ O' q+ L! a' i, M; H

+ U% F6 v0 f& g5 ]4 p' `Nighttime noises, like an alarm on his food pump or the sound of ripping medical tape, would suddenly startle him awake, his mother recalled.% p# C2 M4 }& Y7 K) H9 r  `2 N
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"He started vocalizing sounds and we could tell that he was anticipating things that we would say. Like, if he had heard a story a number of times or a song, he would smile like he recognized the song or the story."
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Finn had a third infusion in September 2010, when he was one year old. Four months later, an otoacoustic emissions test (OAE), which plays a sound and picks up vibrations in the cochlea and hair cells, came back normal.; K1 B3 t/ J' _2 v; K

0 g% ]2 g/ w" F3 J' F0 FThe early hearing tests that showed hearing loss were not exactly the same as the later tests that came back normal, so McGrath is cautious about comparing them directly, but she believes the cord blood transfusions may have helped.
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0 @& |- d% P: K; k"All I can tell you is anecdotally he was not able to hear for probably the first three or four months of his life, and then when he was about six to eight months old, he started hearing."
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The hearing trial in Texas aims to take a first step in testing the safety, and later the efficacy, of transfusing cord blood in children age six weeks to 18 months who have sustained post-birth sensorineural hearing loss., u) @1 f8 A, O/ |2 E/ C- i

" y% ^9 F0 L# \; p: xSome reasons that children lose their hearing at or after birth may include oxygen deprivation, head injury, infection, strong doses of antibiotics or loud noises.
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$ F1 q+ f  k+ nSensorineural hearing loss affects approximately six per 1,000 children, and there is no available medical treatment. Hearing aids or cochlear implants are typically offered to boost the ability of the damaged tissues./ T% z/ K# d) X4 k6 Z, V+ b, Z
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"Stem cell therapy may potentially repair the damaged structures of the inner ear and restore normal hearing," lead investigator Samer Fakhri told AFP.. ?3 c* X( S2 z$ U* [

2 ?/ B# u$ n5 h' K0 V& o"We are at the initial stages of this process and the results are looking promising," Fakhri added.2 d5 a  ]$ J2 ?. h7 p
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Research using stem cells in cord blood, known as hematopoietic cells, is already under way on some types of brain injury, cerebral palsy, juvenile diabetes, kidney and lung disease, he said.
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The new study at Memorial Hermann-Texas Medical Center is being funded by the Cord Blood Registry, and those eligible must have already banked their own umbilical cord blood with CBR.
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- E" M6 Y. K' H% _1 d4 x! HBut to Stephen Epstein, an otolaryngologist in Maryland, that does not pose a conflict of interest, because separate medical institutions in Texas and Georgia are conducting the Food and Drug Administration-approved research.
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1 t; a, p) V4 u! X1 Y+ ?"If both of them can reproduce the same results then I would say it has some validity to it," said Epstein, who is not involved in the study.
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3 ~' Q  N7 B9 S) C: `"This is certainly a welcome, acceptable experiment, but it should be looked at with caution and time will tell."
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One patient is already enrolled and the study, which runs for one year, has room for nine more.& F% L; }' n; B  l: G* y4 }$ f% M
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While Finn McGrath still faces many challenges due to his cerebral palsy, his mother is grateful for the things he can do.
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+ f( N; W4 u+ m$ ~, v"I don't know how much worse off he would have been without the stem cell transfusion," McGrath said, pointing to his normal cognition, lack of seizures, good hearing and vision.  X: J$ h& _, k* S& M" z! B

9 ?$ R! A% R1 r7 g2 f, b, K8 r, x( M"We remain hopeful that he will continue to improve."
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. \' b, ^" d+ aWinnipeg Free Press" Z1 B% B5 F; q) A* b
Study looks at whether stem cells in cord blood might repair hearing loss in kids
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5 p, i7 }1 x" ~: O# XBy: Sheryl Ubelacker, The Canadian Press0 R! S6 L3 ]7 p' W0 y( w/ |* ^

$ r/ e( r/ z, i$ j0 x; KPosted: 02/9/2012 5:31 PM* _) `( ?6 H$ Z+ f1 _
TORONTO - Researchers have been given the go-ahead to test stem cells from cord blood with the ultimate goal of reversing hearing loss in infants and toddlers whose inner ears have been damaged.
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U.S. regulators have approved the Phase I study, which has a primary objective of determining the safety of the experimental stem cell therapy.
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  J" `6 Z( D' T) P0 ~The therapy involves transfusing a baby's own stem cells from umbilical cord blood, banked by parents after their child's birth. Ten children aged six weeks to 18 months old with sensorineural hearing loss will be recruited for the study by doctors at Children's Memorial Hermann Hospital in Houston.
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1 ]3 X% B* W% V; U" c) J"We're looking more at the ones that suffer an injury around birth or shortly after birth," said Dr. Samer Fakhri, a specialist in head and neck surgery and principal investigator of the study.- I, }, @$ J; A8 s$ x+ B3 A/ J

  w, H1 ]4 R5 V/ }Fakhri, a Montreal native who received his medical training at McGill University, said such injuries to the inner ear can be caused by viral infections and even some medications.
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7 R; c. {' f# sSensorineural hearing impairment occurs when structures in the inner ear or the nerve pathways between the inner ear and the brain are damaged. The critical structure in the inner ear is the snail-shell-shaped cochlea, which contains "hair cells" that gather electrical signals, which are transferred to the brain and perceived as sound.: |" k7 w5 h) X7 w1 G- {- ?8 d
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A child with this kind of hearing loss can suffer significant impairment, Fakhri said from Houston. "You may hear parts of sounds. You may not hear the sounds at all, or you may hear very faint sounds./ m4 u% Z+ J8 {

# s4 z- x3 D6 F1 ?! `"If they lose hearing at four weeks or five weeks due to a viral infection" — meningitis is a common cause — "we know that there is a tremendous impact," he said.3 z' L+ J" R8 O6 W2 M
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"There's a lot of research that has been done in child development that has determined that there's really a critical window for children to develop speech, language and social development, and it's probably in the first 18 months."
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The idea for the trial was triggered by a 2008 study by European scientists, who infused human cord blood into laboratory mice with induced sensorineural hearing loss. An examination of the treated animals about two months later showed "inner ear organization and structure were basically restored," said Fakhri.
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"That was the study that was a proof of concept ... That was such a dramatic result.": L' w9 i* u; C  E& a: t- A0 X0 P9 z

+ V8 u7 ~" u: A4 \6 RFakhri said the exact role of the stem cells in the repair of damaged tissue in the mice isn't known, but there are a couple of theories.
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Stem cells can give rise to many different types of cells in the body, so it may be they effect the repair by regenerating lost hair cells. But a more recent theory suggests that stem cells may go to the site of injury and set off the body's innate repair mechanisms.$ c7 p8 \! u; m+ Z; h

! C+ s  l( r& X8 Y; ~, J  w! h"In that sense, they play more of a supporting role," he said.
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While regenerating tissues is the great hope of stem cells — and they do appear to hold a lot of promise — the idea that they could restore damaged hearing in humans is still speculative, doctors say.8 {5 O- j. _" f* V2 a. c) ^

; ]& K% P$ k$ T"This study is really very, very preliminary," said Dr. Robert Harrison, a professor of head and neck surgery at the University of Toronto.
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$ W( w/ T. a9 K+ F"That's the safety issue," he said, stressing that the FDA-approved study must first ensure the stem cells do no harm to patients. Figuring out if they actually work to repair the organ of hearing would have to be proven in subsequent trials.
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"We're a long way from looking at the possible therapeutic value of this in terms of restoring some sort of hearing," said Harrison, a senior scientist at the Hospital for Sick Children and a director of the Hearing Foundation of Canada.
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' P) \# Y  q: _) i' {: ]3 t"It's a very theoretical concept, and in my opinion it's not going to happen soon."
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- t. O" O  v5 \) _Current treatment of sensorineural hearing loss in young children is pretty well restricted to hearing aids or cochlear implants, surgically implanted electronic devices, Fakhri said. Both are used to amplify any residual hearing., }+ r$ j+ n" y5 A. s6 z