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.

We intended to reformulate an existing platelet-derived wound healing formula to target each phase of the healing wound with the appropriate phase-specific molecules. A decreased perfusion of the skin, often associated with conditions such as thalassemia, sickle cell disease, diabetes mellitus, and chronic vascular disease, is the most common etiology of cutaneous ulcers and chronic wounds. We had previously shown that a PDWHF topically applied to a chronic nonhealing ulcer of a β-thalassemia homozygote stimulated and accelerated closure of the wound. The PDWHF was prepared from a pooled platelet concentrate of a matching blood group, consisting of a combination of platelet α-granule-derived factors. Processing of the apheresis-pooled platelets yielded various amounts of proteins ( 3.36   g / mL ± 0.25 (SD) ( N = 10 )) by the better lysis buffer method. Immunoglobulin G was found to be the most abundant α-granule-secreted protein. Equally broad quantities of the IgG ( 10.76 ± 12.66 % (SD) ( N = 10 )) and IgG/albumin ratios ( 0.6 ± 0.4 (SD) ( N = 10 )) were quantified. We have developed a method using a reformulated lysis buffer followed by size exclusion chromatography and affinity chromatography to extract, identify, quantify, and purify IgG from activated platelets. IgG purification was confirmed by Western blot and flow cytometry. It was thought unlikely that the platelet IgG could be accounted for by adsorption of plasma protein, though the variable quantities could account for diversity in wound healing rates. The IgG could protect the wound even from subclinical infections and functionally advance healing. It may be useful in the management of skin ulcers in the early phase of wound healing.

In this study, DNA was extracted from whole blood which had been collected and stored at -20°C for 5–18 years, with the aim of determining the most suitable commercial DNA extraction kit for this purpose. DNA from nine cord blood samples collected in 1999, 2001 and 2012, with low blood volumes (<1 ml), and a partly dried adult blood sample collected in 2003, having a large blood volume (6 ml) was extracted using four different DNA extraction kits: Quick-DNA Miniprep Plus kit, DNeasy Blood & Tissue kit, MagAttract HMW DNA kit and QIAamp Blood Maxi kit. We concluded that high-quality DNA can be extracted from whole blood sample collections which have been stored for even up to 18 years in a biobank at −20°C.

Background: Chronic leg ulcerations are associated with Haemoglobin disorders, Type 2 Diabetes Mellitus, and long-term venous insufficiency. Mesenchymal stem cells (MSCs) ability to modulate the inflammatory response represents the fundamental requisite for their applicability as a treatment of chronic wounds.Methods: This study aimed to develop a novel bioactive platelet-rich plasma (PRP)-leukocytes-depleted scaffold to reproduce typical clinical wound of patients with poor chronic skin perfusion and low leucocytes infiltration. After scratching the wound model to mimic injury three conditions were compared; an untreated condition, a condition treated with recombinant TNF to mimic an inflammatory state and a condition treated with TNF and also with MSCs to evaluate how the latter’s immunomodulatory properties affect the therapeutic outcomes in an inflammatory state. Gene expression of IL8 and TGFA were analysed in biological triplicates of the three conditions. Statistical analysis was done through a paired student t-test and a p <0.05 was considered significant.Results: We set up a skin model that consisted of a leukocyte-depleted, platelet-rich plasma scaffold, with embedded fibroblasts as dermal equivalent and seeded keratinocytes on it as multi-layered epidermidis. IL8 expression increased upon scratching (p=0.014) and continued to increase up to day 1 (p=0.048). IL8 expression decreased upon administration of TNF (p=0.005) but then increased again. IL8 expression decreased in the untreated condition after day 1 as the natural healing process took place and was lower than in treated conditions in day 8 (p=0.048). TGFA expression decreased upon scratching (p=0.006) and increased again in day 1, more so in the untreated than in the treated conditions (p=0.02). TGFA expression decreased again in day 4 in the study group before increasing sharply (p=0.027) in day 8 to reach pre-scratch levels. Conclusion: This study found that a leukocyte-depleted PRP-based skin equivalent can be useful in the study of treatments of chronic wounds. This study also indicates that MSCs appear to modulate the expression of IL8 by switching from an immunosuppressive phenotype to a pro-inflammatory phenotype. These results indicate that the administration of MSCs could offer a potential therapeutic approach for the treatment of leg ulcers in patients with poor skin perfusion.