Trans-aortic left ventricular thrombo-embolectomy following COVID-19 infection.

Left ventricular thrombosis is a known complication of myocardial infarction. COVID 19 has been shown to produce a procoagulant state resulting in venous and less commonly arterial thrombosis. Here, we describe a patient who presented with a non-ST elevation myocardial infarction (NSTEMI), in the context of a COVID 19 infection. This NSTEMI resulted in the formation of a large pedunculated apical thrombus, which was initially managed conservatively, however ultimately required surgical thromboembolectomy. Access to the left ventricle was gained via the transaortic route in order to avoid ventriculotomy in a patient with a reduced LV systolic function. Post-operative imaging confirmed complete resection of thrombus.

Novel leukocyte-depleted platelet-rich plasma-based skin equivalent as an in vitro model of chronic wounds: a preliminary study.

BACKGROUND: Chronic leg ulcerations are associated with Haemoglobin disorders, Type2 Diabetes Mellitus, and long-term venous insufficiency, where poor perfusion and altered metabolism develop into a chronic inflammation that impairs wound closure. Skin equivalent organotypic cultures can be engineered in vitro to study skin biology and wound closure by modelling the specific cellular components of the skin. This study aimed to develop a novel bioactive platelet-rich plasma (PRP) leukocyte depleted scaffold to facilitate the study of common clinical skin wounds in patients with poor chronic skin perfusion and low leukocyte infiltration. A scratch assay was performed on the skin model to mimic two skin wound conditions, an untreated condition and a condition treated with recombinant tumour necrotic factor (rTNF) to imitate the stimulation of an inflammatory state. Gene expression of IL8 and TGFA was analysed in both conditions. Statistical analysis was done through ANOVA and paired student t-test. P < 0.05 was considered significant. RESULTS: A skin model that consisted of a leukocyte-depleted, platelet-rich plasma scaffold was setup with embedded fibroblasts as dermal equivalents and seeded keratinocytes as multi-layered epidermis. Gene expression levels of IL8 and TGFA were significantly different between the control and scratched conditions (p < 0.001 and p < 0.01 respectively), as well as between the control and treated conditions (p < 0.01 and p < 0.001 respectively). The scratch assay induced IL8 upregulation after 3 h (p < 0.05) which continued to increase up to day 1 (p < 0.05). On the other hand, the administration of TNF led to the downregulation of IL8 (p < 0.01), followed by an upregulation on day 2. IL8 gene expression decreased in the scratched condition after day 1 as the natural healing process took place and was lower than in the treated condition on day 8 (p < 0.05). Both untreated and treated conditions showed a downregulation of TGFA 3 h after scratch when compared with the control condition (p < 0.01). Administration of rTNF showed significant downregulation of TGFA after 24 h when compared with the control (p < 0.01) and treated conditions (p < 0.05). CONCLUSION: This study suggests that a leukocyte-depleted PRP-based skin equivalent can be a useful model for the in vitro study of chronic skin wounds related to poor skin perfusion.

Possible Role of Circulating Bone Marrow Mesenchymal Progenitors in Modulating Inflammation and Promoting Wound Repair.

Circulating bone marrow mesenchymal progenitors (BMMPs) are known to be potent antigen-presenting cells that migrate to damaged tissue to secrete cytokines and growth factors. An altered or dysregulated inflammatory cascade leads to a poor healing outcome. A skin model developed in our previous study was used to observe the immuno-modulatory properties of circulating BMMP cells in inflammatory chronic wounds in a scenario of low skin perfusion. BMMPs were analysed exclusively and in conjunction with recombinant tumour necrosis factor alpha (TNFα) and recombinant hepatocyte growth factor (HGF) supplementation. We analysed the expression levels of interleukin-8 (IL-8) and ecto-5'-nucleotidase (CD73), together with protein levels for IL-8, stem cell factor (SCF), and fibroblast growth factor 1 (FGF-1). The successfully isolated BMMPs were positive for both hemopoietic and mesenchymal markers and showed the ability to differentiate into adipocytes, chondrocytes, and osteocytes. Significant differences were found in IL-8 and CD73 expressions and IL-8 and SCF concentrations, for all conditions studied over the three time points taken into consideration. Our data suggests that BMMPs may modulate the inflammatory response by regulating IL-8 and CD73 and influencing IL-8 and SCF protein secretions. In conclusion, we suggest that BMMPs play a role in wound repair and that their induced application might be suitable for scenarios with a low skin perfusion.

Plucked human hair shafts and biomolecular medical research.

The hair follicle is a skin integument at the boundary between an organism and its immediate environment. The biological role of the human hair follicle has lost some of its ancestral importance. However, an indepth investigation of this miniorgan reveals hidden complexity with huge research potential. An essential consideration when dealing with human research is the awareness of potential harm and thus the absolute need not to harm--a rule aptly qualified by the Latin term "primum non nocere" (first do no harm). The plucked hair shaft offers such advantages. The use of stem cells found in hair follicles cells is gaining momentum in the field of regenerative medicine. Furthermore, current diagnostic and clinical applications of plucked hair follicles include their use as autologous and/or three-dimensional epidermal equivalents, together with their utilization as surrogate tissue in pharmacokinetic and pharmacodynamics studies. Consequently, the use of noninvasive diagnostic procedures on hair follicle shafts, posing as a surrogate molecular model for internal organs in the individual patient for a spectrum of human disease conditions, can possibly become a reality in the near future.

Empyema thoracis caused by a foreign body inhaled 30 years previously.

We present the case of a 73 year old Caucasian male who developed a left sided pneumonia and empyema secondary to a foreign body inhaled 30 years before. The foreign body, a bone fragment, was lodged at the bifurcation of the left main bronchus and could only be removed via bronchotomy. The patient experienced a swift recovery and was well at follow-up 6 months later.