AN Boing

AR Crow

JJ Lopez

KD Mason

Markus Schmugge

O Speer

Oliver Speer

PF Piguet

S Song

V Leytin

V Siragam

English

PubMed

Speer, O

Schmugge, M

ZORA

Investigating caspases and other markers of apoptosis in ITP

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BASIC SCIENCE
Investigating caspases and other markers of apoptosis in ITP
Oliver Speer & Markus Schmugge
Received: 28 October 2009 /Accepted: 1 December 2009 /Published online: 22 April 2010
# The Author(s) 2010. This article is published with open access at Springerlink.com
Apoptosis is the main mechanism that regulates cell life
span and the elimination of damaged or infected nucleated
cells. Although platelets are enucleate cells, they express at
least part of the apoptotic machinery known from nucleated
cells. In addition, they have been observed to undergo
apoptotic-like events. This has been demonstrated by the
activation and translocation of Bcl-2 family members,
cytochrome c release, activation of caspase-9 and of
caspase-3 [1–10]. These observations indicate that platelets
contain the essential components needed to undergo
programmed cell death executed in the cytoplasm. Recent-
ly, in a murine model of ITP, it has been shown that
apoptotic-like processes can be induced by anti-platelet
antibodies: injection of anti-GPIIb antibodies caused
apoptotic-like events as well as profound thrombocytopenia
[7, 11–14].In this murine ITP model, IVIg treatment was
able to decrease the apoptotic-like events and to improve
the low platelet count [7, 11–13].
As no such study has been performed in paediatric ITP
so far, we started to investigate whether in children with
primary ITP, an enhanced expression of markers of
apoptotic processes can be found. Furthermore, we are
interested to see if such markers correlate to platelet count
and most important to clinical symptoms and if they
decrease after IVIg treatment.
So far, we have shown in a limited number of patients
that caspase-3 is activated in 40% of the platelets in patients
with primary ITP and decreases to 10% after IVIg treatment
([15], manuscript in preparation). In parallel to caspase-3
activation also bleeding signs decreased after IVIg therapy.
In ongoing studies, we investigate caspase-3, caspase-9,
caspase-8, PS-exposure and mitochondrial membrane po-
tential by flow cytometry and caspases by Western blot. We
further will develop an immuno-fluorescence microscopy
protocol for the detection and quantification of activated
caspases in bone marrow smears. Investigating and com-
paring levels of activated caspases and other signs of
apoptosis in platelets and bone marrow samples is
important to understand the initiation of apoptotic pro-
cesses in platelets, whether apoptosis is already triggered in
bone marrow or only in platelets in ITP patients. Further-
more, it is important to understand whether apoptosis
might contribute to the destruction of platelets in ITP
patients.
To increase patient numbers, we invite other clinicians or
laboratories treating respectively investigating ITP to
collaborate with us.
Open Access This article is distributed under the terms of the
Creative Commons Attribution Noncommercial License which per-
mits any noncommercial use, distribution, and reproduction in any
medium, provided the original author(s) and source are credited.
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effect of cyclosporin A, an inhibitor of the mitochondrial
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3. Leytin V et al (2008) Platelet activation and apoptosis are different
phenomena: evidence from the sequential dynamics and the
O. Speer (*) :M. Schmugge
University Children’s Hospital Zürich,
Zürich, Switzerland
e-mail: oliver.speer@kispi.uzh.ch
M. Schmugge
e-mail: markus.schmugge@kispi.uzh.ch
Ann Hematol (2010) 89 (Suppl 1):S45–S46
DOI 10.1007/s00277-009-0886-4
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S46 Ann Hematol (2010) 89 (Suppl 1):S45–S46


Apoptosis in platelets from pediatric patients with acute immune thrombocytopenic purpura (ITP) ist ameliorated by IVIg, ASH annual meeting supplement.

Can antibodies with specificity for soluble antigens mimic the therapeutic effects of intravenous IgG in the treatment of autoimmune disease?

Higher thrombin concentrations are required to induce platelet apoptosis than to induce platelet activation.

Intravenous immunoglobulin inhibits anti-glycoprotein IIb-induced platelet apoptosis in a murine model of immune thrombocytopenia.

IVIG induces dose-dependent amelioration of ITP in rodent models. Blood 101(4):1658–1659, Author reply 1659

Mitochondrial control of platelet apoptosis: effect of cyclosporin A, an inhibitor of the mitochondrial permeability transition pore.

Modulation of platelet caspases and life-span by anti-platelet antibodies in mice.

Monoclonal IgG can ameliorate immune thrombocytopenia in a murine model of ITP: an alternative to IVIG.

Pathologic high shear stress induces apoptosis events in human platelets.

Platelet activation and apoptosis are different phenomena: evidence from the sequential dynamics and the

Platelet apoptosis in stored platelet concentrates and other models.

Platelet microparticles contain active caspase 3.

Programmed anuclear cell death delimits platelet life span.

Thrombin induces activation and translocation of Bid, Bax and Bak to the mitochondria in human platelets.

Thrombin-triggered platelet apoptosis.

https://link.springer.com/content/pdf/10.1007%2Fs00277-009-0886-4.pdf

Investigating caspases and other markers of apoptosis in ITP

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