Deltagranuloistaan

Deltagranuloistaan is the Finnish term for the dense granules of platelets, the small, electron-dense secretory organelles that play a key role in hemostasis. Dense granules, also known as delta granules, differ from the larger alpha granules in contents and function. The principal constituents stored in dense granules are adenosine diphosphate (ADP), adenosine triphosphate (ATP), calcium ions and serotonin. These molecules are released when platelets are activated at sites of vascular injury, enhancing platelet recruitment and amplification of the hemostatic response.

Functionally, the released ADP and ATP promote further platelet activation and aggregation, while calcium supports the coagulation cascade and cytoskeletal changes, and serotonin contributes to local vasoconstriction. Dense granules thus contribute to the secondary steps of platelet aggregation and stabilization of the growing plug.

Clinical relevance: Abnormalities of delta granules can cause bleeding disorders. Storage pool diseases involve reduced dense granule content or secretion, leading to impaired platelet aggregation, especially in response to secretagogues such as ADP, epinephrine and collagen. Hermansky-Pudlak syndrome also features deficiency of platelet dense bodies as part of a broader lysosome-related organelle dysfunction.

Diagnosis typically relies on platelet electron microscopy to quantify dense bodies; functional testing (platelet aggregation studies) can reveal diminished responses to secretagogues. Treatment focuses on managing bleeding risk, particularly during surgery or trauma, and may include hemostatic strategies as appropriate.