Platelet microaggregation in sepsis examined by quartz crystal microbalance with dissipation technology.

Antiplatelet therapies remain an area of potential interest for the treatment of sepsis; however, studies of platelet aggregation in sepsis have yielded conflicting results. We examined platelet aggregation patterns in patients with septic shock using quartz crystal microbalance with dissipation technology, a microfluidic device capable of measuring platelet microaggregate formation under flow conditions. Platelet aggregation was increased in the washed platelet samples of septic patients. Conversely, these same platelets aggregated less than healthy controls when examined in their plasma.

No difference in 6-month functional outcome between early and late decompressive craniectomies following acute ischaemic stroke in a national neurosurgical centre: a single-centre retrospective case-cohort study.

BACKGROUND: Decompressive craniectomies (DCs) are recommended for the treatment of raised intracranial pressure after acute ischaemic stroke. Some studies have demonstrated improved outcomes with early decompressive craniectomy (< 48 h from onset) in patients with malignant cerebral oedema following middle cerebral artery infarction. Limited data is available on suboccipital decompressive craniectomy after cerebellar infarction. AIMS: Our primary objective was to determine whether the timing of DCs influenced functional outcomes at 6 months. Our secondary objectives were to analyse whether age, gender, the territory of stroke, or preceding thrombectomy impacts functional outcome post-DC. METHODS: We conducted a retrospective study of patients admitted between January 2014 and December 2020 who had DCs post-acute ischaemic stroke. Data was collected from ICU electronic records, individual patient charts, and the stroke database. RESULTS: Twenty-six patients had early DC (19 anterior/7 posterior) and 21 patients had late DC (17 anterior/4 posterior). There was no difference in the modified Rankin Scale (mRS) score of the two groups at 90 (p = 0.318) and 180 (p = 0.333) days post early vs late DC. Overall outcomes were poor, with 5 out of 46 patients (10.9%) having a mRS score ≤ 3 at 6 months. There was no difference in mRS scores between the patients who had hemicraniectomies for anterior circulation stroke (n = 35) and suboccipital DC for posterior circulation stroke (n = 11) (p = 0.594). CONCLUSION: In this single-centre retrospective study, we found no significant difference in functional outcomes between patients who had early or late DC after ischaemic stroke.

Role of matrix metalloproteinases 2 and 9, toll-like receptor 4 and platelet-leukocyte aggregate formation in sepsis-associated thrombocytopenia.

BACKGROUND: The development of thrombocytopenia in sepsis is a poor prognostic indicator associated with a significantly increased mortality risk. Mechanisms underlying this phenomenon remain to be clearly elucidated. Matrix metalloproteinases (MMPs) are enzymes that regulate the turnover of the extra-cellular matrix. MMP-2 is recognised as a platelet agonist with MMP-9 proposed as an inhibitor of platelet activation. The existence of MMP-9 in platelets is a subject of debate. There is limited evidence thus far to suggest that toll-like receptor 4 (TLR-4) and platelet-leukocyte aggregate (PLA) formation may be implicated in the development of sepsis-associated thrombocytopenia. OBJECTIVES: To investigate whether MMP -2/-9, toll-like receptor 4 (TLR-4) or platelet-leukocyte aggregate (PLA) formation are implicated in a decline in platelet numbers during septic shock. METHODS: This was an observational study which recruited healthy controls, non-thrombocytopenic septic donors and thrombocytopenic septic donors. MMP-2, MMP-9 and TLR-4 platelet surface expression as well as PLA formation was examined using flow cytometry. In addition MMP-2 and MMP-9 were examined by gelatin zymography and enzyme-linked immunosorbent assay (ELISA) using a 3 compartment model (plasma, intraplatelet and platelet membrane). RESULTS: There was no difference found in MMP-2, MMP-9 or TLR-4 levels between non-thrombocytopenic and thrombocytopenic septic donors. PLA formation was increased in thrombocytopenic patients. MMP-9 was detected in platelets using flow cytometry, gelatin zymography and ELISA techniques. CONCLUSIONS: Platelet consumption into PLAs may account for the development of thrombocytopenia in septic shock. MMP-9 is found in platelets and it is upregulated during septic shock.