肉毒桿菌知識資料庫

微整形

@ 肉毒桿菌分子作用機轉

@ JOURNAL OF ORTHOPAEDIC RESEARCH  2006; 1128

 

@ 肉毒桿菌的最新突破研究  JCB 2005, 168, 607
除了將其七種serotype之一的BoNT/C應用於建立chronic degenerative dz 模式, 還繼Finn 2000的研究, 用分子生物學的方法解釋了自西元1850年以來Waller所發現的現象[Wallerian degeneration].

 

也就是下述兩個觀點:
(1) an early neurite degeneration, which occurred independently of
trophic stimulation and the activation of death-signaling kinases, and which did not involve the apoptosis-executing machinery (caspases);
(2) a late apoptotic demise of the cell bodies, which was prevented by kinase inhibition and involved cytochrome c release and caspase activation.
特別的是它研究APOPTOSIS的方法, 除了一般的apoptosis%(TUNEL assay), DNA ladderring, 還從另一角度切入: Caspase的substrate分解物DEVD的活性, 並使用一些Caspase inhibitor如 zVAD-fluoromethylketone (fmk)

接下來因為神經變性會使得tau蛋白質不正常phosphorylation, 因此可以用antibody(AT-8–like antibody 11b directed against the phosphorylated epitope S202-205)來測它的量是否增高, 如下圖:

左圖可見neurite(也就是cell culture裏的axon or dendrite), 不管actin or tubulin都開始產生enlarged varicosities, bulb的現象. 左圖下也看到從原本的 very diffuse 到 highly fluorescent, punctuate staining, 這意味著 a disorganization/aggregation of tau filaments

 

 

@ Lowe NJ et al. Double-blind, randomized, placebo-controlled, dose-response study of the safety and efficacy of botulinum toxin type A in subjects with crow's feet. Dermatol Surg. 2005;31(3):257-62

RESULTS: A dose-dependent treatment effect for efficacy was observed, with higher doses having an increased magnitude and duration of effect. However, a clear differentiation between the 18 U and 12 U doses was not apparent. Few adverse events were reported, with no statistically significant differences between BTX-A and placebo in the incidence of subjects experiencing adverse events. CONCLUSION: 12 U per side suggested as the most appropriate dose.

 

@ 肉毒桿菌的適應症: Arq Neuropsiquiatr 2005;63(1):180-185

1, Movement Disorders: Dystonia, Hemifacial Spasm, Tremor, Tics, Bruxism, Re-innervation Synkinesias, Myokymia, Neuromyotonia, Stiff Person Syndrome
2, Spasticity
3, Hypersecretory Disorders
4, Hyperhidrosis: Sialorrhea, Hyperlacrimation, Rhinorrhea
5, Ophtalmic Disorders: Strabismus, Nystagmus, Exotropia, Esotropia, Entropium, Protective Ptosis
6, Pain: Tension Headache, Migraine, Myofacial Pain
7, Pelvic Floor and Gastrointestinal Disorders: Achalasia, Anal Fissures, Detrusor-Sphincter Dyssynergia, Vesical Sphincter Spasms, Sphyncter Odii Spasms, Anismus, Vaginismus
8, Cosmetic Applications: Muscular Facial Lines, Facial Assymetries
9, Others: Eye-Lid Opening Apraxia, Tetanus, Stuttering, Perioperative Fixations in Orthopedic Surgery

 

@ 肌肉的神經控制:

 

@ 肉毒桿菌抗體產生與劑量關係:

 

@ 肉毒桿菌的作用分子機轉

Botulinum toxin has a high affinity for the neuromuscular junction,
where motor nerve endings containing acetylcholine-filled synaptic vesicles come in close contact with muscle fibers. Under normal circumstances, synaptic vesicles fuse with the neural cell membrane and release their contents into the synaptic space through a calcium-dependent process known as exocytosis. Muscle contraction ensues when acetylcholine traverses the synaptic space and binds to receptors on muscle cells.
Docking of synaptic vesicles with the neural cell membrane is facilitated
by a complex of proteins known as “Soluble N-ethylmaleimide-sensitivefactor Attachment Protein Receptor”(SNARE) proteins, which include a 25-kD synaptosomal-associated protein (SNAP-25), vesicle-associated membrane protein (VAMP, or synaptobrevin), and syntaxin.

 肉毒桿菌知識資料庫
  作者:蔡豐州醫師   閱覽次數:16832 
 

                                                      作者: 蔡豐州 醫師 撰寫
@ 肉毒桿菌分子作用機轉

@ JOURNAL OF ORTHOPAEDIC RESEARCH  2006; 1128
 
@ 肉毒桿菌的最新突破研究  JCB 2005, 168, 607
除了將其七種serotype之一的BoNT/C應用於建立chronic degenerative dz 模式, 還繼Finn 2000的研究, 用分子生物學的方法解釋了自西元1850年以來Waller所發現的現象[Wallerian degeneration].
 

也就是下述兩個觀點:
(1) an early neurite degeneration, which occurred independently of
trophic stimulation and the activation of death-signaling kinases, and which did not involve the apoptosis-executing machinery (caspases);
(2) a late apoptotic demise of the cell bodies, which was prevented by kinase inhibition and involved cytochrome c release and caspase activation.
   特別的是它研究APOPTOSIS的方法, 除了一般的apoptosis%(TUNEL assay), DNA ladderring, 還從另一角度切入: Caspase的substrate分解物DEVD的活性, 並使用一些Caspase inhibitor如 zVAD-fluoromethylketone (fmk)
 接下來因為神經變性會使得tau蛋白質不正常phosphorylation, 因此可以用antibody(AT-8–like antibody 11b directed against the phosphorylated epitope S202-205)來測它的量是否增高, 如下圖:

  左圖可見neurite(也就是cell culture裏的axon or dendrite), 不管actin or tubulin都開始產生enlarged varicosities, bulb的現象. 左圖下也看到從原本的 very diffuse 到 highly fluorescent, punctuate staining, 這意味著 a disorganization/aggregation of tau filaments

 
@ Lowe NJ et al. Double-blind, randomized, placebo-controlled, dose-response study of the safety and efficacy of botulinum toxin type A in subjects with crow's feet. Dermatol Surg. 2005;31(3):257-62

RESULTS: A dose-dependent treatment effect for efficacy was observed, with higher doses having an increased magnitude and duration of effect. However, a clear differentiation between the 18 U and 12 U doses was not apparent. Few adverse events were reported, with no statistically significant differences between BTX-A and placebo in the incidence of subjects experiencing adverse events. CONCLUSION: 12 U per side suggested as the most appropriate dose.

 

@ 肉毒桿菌的適應症: Arq Neuropsiquiatr 2005;63(1):180-185

1, Movement Disorders: Dystonia, Hemifacial Spasm, Tremor, Tics, Bruxism, Re-innervation Synkinesias, Myokymia, Neuromyotonia, Stiff Person Syndrome
2, Spasticity
3, Hypersecretory Disorders
4, Hyperhidrosis: Sialorrhea, Hyperlacrimation, Rhinorrhea
5, Ophtalmic Disorders: Strabismus, Nystagmus, Exotropia, Esotropia, Entropium, Protective Ptosis
6, Pain: Tension Headache, Migraine, Myofacial Pain
7, Pelvic Floor and Gastrointestinal Disorders: Achalasia, Anal Fissures, Detrusor-Sphincter Dyssynergia, Vesical Sphincter Spasms, Sphyncter Odii Spasms, Anismus, Vaginismus
8, Cosmetic Applications: Muscular Facial Lines, Facial Assymetries
9, Others: Eye-Lid Opening Apraxia, Tetanus, Stuttering, Perioperative Fixations in Orthopedic Surgery

 

@ 肌肉的神經控制:
 

@ 肉毒桿菌抗體產生與劑量關係:
 

@ 肉毒桿菌的作用分子機轉
 

Botulinum toxin has a high affinity for the neuromuscular junction,
where motor nerve endings containing acetylcholine-filled synaptic vesicles come in close contact with muscle fibers. Under normal circumstances, synaptic vesicles fuse with the neural cell membrane and release their contents into the synaptic space through a calcium-dependent process known as exocytosis. Muscle contraction ensues when acetylcholine traverses the synaptic space and binds to receptors on muscle cells.
Docking of synaptic vesicles with the neural cell membrane is facilitated
by a complex of proteins known as “Soluble N-ethylmaleimide-sensitivefactor Attachment Protein Receptor”(SNARE) proteins, which include a 25-kD synaptosomal-associated protein (SNAP-25), vesicle-associated membrane protein (VAMP, or synaptobrevin), and syntaxin.
 
These proteins anchor the vesicle membrane to the neural cell membrane by linking to form what is known as a synaptic fusion complex. Botulinum toxin induces reversible cholinergic blockade at the neuromuscular junction (i.e., chemical denervation) by inhibiting vesicle exocytosis, thereby reducing acetylcholine release into the synapse and muscle contraction. The toxin first binds to acceptors (i.e., receptors) in the neural cell membrane, and the toxin then is internalized in the neural cell. The acceptors have not yet been identified, but they appear to vary for the different serotypes. The botulinum toxin heavy chain is responsible for binding to the acceptor and subsequent endocytosis. During this process, the neural cell plasma membrane invaginates around the toxin-receptor complex, forming a toxin-containing vesicle within the neural cell. The vesicle then releases the light chain, a zinc dependent endopeptidase (i.e., metalloprotease) that cleaves SNARE proteins, thereby interfering with vesicle docking and exocytosis. The enzymatic activity of the light chain depends on the serotype. Serotype A cleaves SNAP-25, and serotype B cleaves VAMP.8 All botulinum toxins inhibit vesicle exocytosis and muscle contraction. They do not affect the synthesis or storage of acetylcholine or the conduction of electrical signals along the nerve fiber.
The effect of botulinum toxin is only temporary because collateral axonal sprouts develop over time at the nerve terminal. (de Paiva A, et al. Functional repair of motor endplates after botulinum neurotoxin type A poisoning: biphasic switch of synaptic activity between nerve sprouts and their parent terminals. Proc Natl Acad Sci U S A. 1999;
96:3200-5.) These sprouts can release acetylcholine into the synaptic space so that muscle activity returns. The motor end plate eventually regains normal function, and the nerve sprouts then regress. These phenomena explain why repeated administration of botulinum toxin may be required to maintain a therapeutic effect.

 

 

 

洽談諮詢