Inherited Thrombotic Thrombocytopenic Purpura Revealed by Recurrent Strokes in a Male Adult: Case Report and Literature Review

ADAM and ADAMTS disintegrin and metalloproteinases as major factors and molecular targets in vascular malfunction and disease

A Disintegrin and Metalloproteinase (ADAM) and A Disintegrin and Metalloproteinase with Thrombospondin Motifs (ADAMTS) are two closely related families of proteolytic enzymes. ADAMs are largely membrane-bound enzymes that act as molecular scissors or sheddases of membrane-bound proteins, growth factors, cytokines, receptors and ligands, whereas ADAMTS are mainly secreted enzymes. ADAMs have a pro-domain, and a metalloproteinase, disintegrin, cysteine-rich and transmembrane domain. Similarly, ADAMTS family members have a pro-domain, and a metalloproteinase, disintegrin, and cysteine-rich domain, but instead of a transmembrane domain they have thrombospondin motifs. Most ADAMs and ADAMTS are activated by pro-protein convertases, and can be regulated by G-protein coupled receptor agonists, Ca²⁺ ionophores and protein kinase C. Activated ADAMs and ADAMTS participate in numerous vascular processes including angiogenesis, vascular smooth muscle cell proliferation and migration, vascular cell apoptosis, cell survival, tissue repair, and wound healing. ADAMs and ADAMTS also play a role in vascular malfunction and cardiovascular diseases such as hypertension, atherosclerosis, coronary artery disease, myocardial infarction, heart failure, peripheral artery disease, and vascular aneurysm. Decreased ADAMTS13 is involved in thrombotic thrombocytopenic purpura and microangiopathies. The activity of ADAMs and ADAMTS can be regulated by endogenous tissue inhibitors of metalloproteinases and other synthetic small molecule inhibitors. ADAMs and ADAMTS can be used as diagnostic biomarkers and molecular targets in cardiovascular disease, and modulators of ADAMs and ADAMTS activity may provide potential new approaches for the management of cardiovascular disorders.

Thrombocytopenia: Effect in Ischemic and Hemorrhagic Stroke

BACKGROUND

There are 2 classification of strokes: ischemic, if caused by an arterial occlusion from a clot or obstruction by atherosclerosis, and hemorrhagic, if caused by the rupture of a vessel and subsequent bleeding. Each type of stroke is influenced by platelet counts and platelet function. The intention of this article is to discuss the role of the platelet in the pathophysiology of acute stroke processes. This serves as a prelude to discussing these processes as disrupted with thrombocytopenia (low platelet counts). Platelets initiate clot formation and obstruct blood flow through the creation of a platelet plug. They also extend the penumbra in ischemic and hemorrhagic strokes. Thrombocytopenia can be a causal factor in an ischemic stroke, a risk factor for hemorrhagic stroke, and a risk factor for hemorrhagic stroke conversion.

METHODS

The aims of this study were to review 1 case study that illustrates the pivotal role of the platelet in strokes and to review the aspect that was impacted by autoimmune thrombocytopenia.

DISCUSSION

Thrombocytopenia is a hematologic disorder not often included in stroke care discussions. Thrombocytopenia sets up strokes to occur and, paradoxically, may also set the patient up for bleeding complications in the brain or groin.

CONCLUSION

Acknowledging the impact of both platelet and thrombocytopenia on stroke causation, stroke interventions, and outcomes is a pivotal aspect of comprehensive stroke care. Platelet function processes are impactful in each point of the continuum of stroke care, prevention, intervention, and discharge.

Cerebrovascular manifestations in hematological diseases: an update

Patients with hematological diseases often experience cerebrovascular complications including ischemic stroke, intracerebral and subarachnoid hemorrhage, microbleeds, posterior reversible encephalopathy syndrome, and dural sinus and cerebral vein thrombosis (CVT). In this update, we will review recent advances in the management of cerebrovascular diseases in the context of myeloproliferative neoplasms, leukemias, lymphomas, multiple myeloma, POEMS, paroxysmal nocturnal hemoglobinuria (PNH), thrombotic thrombocytopenic purpura (TTP), and sickle-cell disease. In acute ischemic stroke associated with hematological diseases, thrombectomy can in general be applied if there is a large vessel occlusion. Intravenous thrombolysis can be used in myeloproliferative neoplasms and sickle-cell anemia, but in other diseases, a case-by-case evaluation of the bleeding risks is mandatory. Patients with sickle-cell disease and acute stroke need very often to be transfused. In PNH, acute ischemic stroke patients must be anticoagulated. Most patients with CVT can be treated with low-molecular weight heparin (LMWH) acutely, even those with leukemias. Prevention of recurrence of cerebral thrombotic events depends on the control of the underlying disease, combined in some conditions with antithrombotic drugs. The recent introduction of specific monoclonal antibodies in the treatment of PHN and TTP has dramatically reduced the risk of arterial and venous thrombosis.