Uncontrolled Diabetes Mellitus Has No Major Influence on the Platelet Transcriptome

Periodontitis impacts on thrombotic diseases: from clinical aspect to future therapeutic approaches

Periodontitis is a chronic inflammatory disease initiated by biofilm microorganisms and mediated by host immune imbalance. Uncontrolled periodontal infections are the leading cause of tooth loss in adults. Thrombotic diseases can lead to partial or complete obstruction of blood flow in the circulatory system, manifesting as organ or tissue ischemia and necrosis in patients with arterial thrombosis, and local edema, pain and circulatory instability in patients with venous thrombosis, which may lead to mortality or fatality in severe case. Recent studies found that periodontitis might enhance thrombosis through bacterial transmission or systemic inflammation by affecting platelet-immune cell interactions, as well as the coagulation, and periodontal therapy could have a prophylactic effect on patients with thrombotic diseases. In this review, we summarized clinical findings on the association between periodontitis and thrombotic diseases and discussed several novel prothrombotic periodontitis-related agents, and presented a perspective to emphasize the necessity of oral health management for people at high risk of thrombosis.

Platelet Rich Plasma Therapy in Achilles and Patellar Tendinopathies: Outcomes in Subjects with Diabetes (A Retrospective Case-Control Study)

Introduction: Diabetes mellitus (DM) is associated with a high risk of chronic degenerative Achilles (AT) and Patellar (PT) tendinopathies and ruptures. Growth factors (GFs) synthesis in diabetics is substantially decreased in human connective tissues, including in tendons. Platelet Rich Plasma (PRP), which is enriched in GFs, might prove of great help in tendon healing. The aim of the study was to assess whether pre-existent DM or Impaired Glucose Tolerance (IGT) could influence the clinical outcome in subjects undergoing PRP treatment. Methods: Sixty subjects with diabetes/pre-diabetes and sixty euglycemic controls, matched for sex and age, were enrolled. Patients suffering from proximal insertional PT and mid-portion AT, treated with PRP therapy, were included in the study. To assess the basal status and the efficacy of the therapy after 3 and 6 months, the Victorian Institute of Sport Assessment (VISA) questionnaire and the Ultrasound methodology study were used. Patient satisfaction was assessed by means of the Likert Scale. Results: In the population study at 6 months, the mean VISA-score increased (8.92 ± 0.67; p-value < 0.001). The improvement in the diabetic group was less evident compared to the controls (-2.76 ± 0.95; p-value = 0.003). Even though the improvement was poor, it was still significant. MCID analysis revealed that diabetics had higher risk of therapeutic unsuccess. Logistic regression analysis was applied to assess factors associated with unsatisfactory results (Likert-scale) of PRP treatment: AT (O.R.: 3.05; 95%CI: 1.40-6.64; p-value = 0.005), higher BMI values (O.R.: 1.02; 95%CI: 1.01-1.04; p-value = 0.01), and lower VISA score values at baseline (O.R.: 0.95; 95%CI: 0.90-0.99; p-value = 0.04). Conclusions: PRP treatment in AT and PT chronic tendinopathies resulted in less favorable results in subjects with diabetes compared with euglycemic subjects. Moreover, the subjects with PT showed better results than those with AT.

Impact of high platelet turnover on the platelet transcriptome: Results from platelet RNA-sequencing in patients with sepsis

Background

Sepsis is associated with high platelet turnover and elevated levels of immature platelets. Changes in the platelet transcriptome and the specific impact of immature platelets on the platelet transcriptome remain unclear. Thus, this study sought to address whether and how elevated levels of immature platelets affect the platelet transcriptome in patients with sepsis.

Methods

Blood samples were obtained from patients with sepsis requiring vasopressor therapy (n = 8) and from a control group of patients with stable coronary artery disease and otherwise similar demographic characteristics (n = 8). Immature platelet fraction (IPF) was determined on a Sysmex XE 2100 analyser and platelet function was tested by impedance aggregometry. RNA from leukocyte-depleted platelets was used for transcriptome analysis by Next Generation Sequencing integrating the use of unique molecular identifiers.

Results

IPF (median [interquartile range]) was significantly elevated in sepsis patients (6.4 [5.3–8.7] % vs. 3.6 [2.6–4.6] %, p = 0.005). Platelet function testing revealed no differences in adenosine diphosphate- or thrombin receptor activating peptide-induced platelet aggregation between control and sepsis patients. Putative circular RNA transcripts were decreased in platelets from septic patients. Leukocyte contamination defined by CD45 abundance levels in RNA-sequencing was absent in both groups. Principal component analysis of transcripts showed only partial overlap of clustering with IPF levels. RNA sequencing showed up-regulation of 524 and down-regulation of 118 genes in platelets from sepsis patients compared to controls. Upregulated genes were mostly related to catabolic processes and protein translation. Comparison to published platelet transcriptomes showed a large overlap of changes observed in sepsis and COVID-19 but not with reticulated platelets from healthy donors.

Conclusions

Patients with sepsis appear to have a less degraded platelet transcriptome as indicated by increased levels of immature platelets and decreased levels of putative circular RNA transcripts. The present data suggests that increased protein translation is a characteristic mechanism of systemic inflammation.

Platelets as Potent Signaling Entities in Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a multifactorial disease with a dysregulated circulating inflammatory molecule tendency. T2DM is closely associated with systemic inflammation, endothelial dysfunction, cardiovascular risk, and increased clotting susceptibility. Platelets have fundamental roles in the development and propagation of inflammation and cardiovascular risk. They signal through membrane receptors, resulting in (hyper)activation and release of inflammatory molecules from platelet compartments. This review highlights how circulating inflammatory molecules, acting as platelet receptor ligands, interact with platelets, causing platelets to be potent drivers of systemic inflammation. We conclude by suggesting that focused platelet research in T2DM is an important avenue to pursue to identify novel therapeutic targets, and that platelets could be used as cellular activity sensors themselves.

Platelet microRNAs and vascular injury

Vascular smooth muscle cell (VSMC) phenotype switching from a contractile state to a synthetic phenotype has been implicated in intimal remodeling during vascular injury. While multiple studies have focused on dedifferentiation of VSMCs, prevention of VSMC-mediated excessive repair remains poorly understood. In this issue of the JCI, Zeng et al. identified a mechanism by which platelet-derived microRNA-223 (miRNA-223) reverses VSMC dedifferentiation. The authors show that suppression of proliferation occurs after platelet internalization by VSMCs. Moreover, they demonstrate that miRNA-223 inhibits dedifferentiation and intimal hyperplasia in diabetic mice by decreasing PDGFRβ expression in VSMCs. Together, these results identify platelet-derived miRNA-223 as a potential therapeutic target in vascular injury.