Increased expression of tissue factor procoagulant by peripheral blood monocytes has been implicated in a number of thrombotic disorders. The present studies were undertaken to determine whether stable analogues of prostacyclin, a potent endothelium-derived platelet inhibitor and vasodilator, could inhibit tissue factor expression by human monocytic cells. Exposure of monocytic tumor THP-1 cells to 100 ng/ml endotoxin, 2 units/ml interleukin-1 beta, or 5 ng/ml tumor necrosis factor-alpha for 4 hours led to increased tissue factor procoagulant activity. Preincubation for 30 minutes with iloprost, ciprostene, and carbacyclin led to a dose-dependent inhibition of tissue factor expression induced by all three challenging agents. Iloprost was the most potent: 50% inhibition occurred at 5 nM, a concentration close to the reported dissociation constant for iloprost binding to the platelet prostacyclin receptor. An orally active analogue, cicaprost, was equally effective against endotoxin-induced tissue factor expression. Carbacyclin and ciprostene were 100 times less potent. Iloprost prevented the endotoxin-induced expression of tissue factor antigen on the surface of THP-1 cells, as determined by flow cytometry. Iloprost (500 pM-50 nM) increased intracellular levels of cyclic AMP. This effect was potentiated by isobutylmethylxanthine, an inhibitor of phosphodiesterase. The inhibitory effects of iloprost on tissue factor expression were also potentiated by isobutylmethylxanthine and mimicked by forskolin and dibutyryl cyclic AMP but not dibutyryl cyclic GMP. These results suggest that prostacyclin may play a role in downregulating tissue factor expression in monocytes, at least in part via elevation of intracellular levels of cyclic AMP.

Summary. This paper describes evidence that an extracellular matrix (ECM) secreted by human umbilical vein endothelial cells (HUVECs) assembled on gelatin coated plates overlaid by a mixed matrix secreted by human dermal microvascular endothelial cells (HDMECs) and human dermal fibroblasts provides a viable acellular scaffold for use in wound healing. Trypsinized epidermal keratinocytes or colonies from Dispase-digested fresh and cadaver skin tissue adhered and proliferated on either HUVECs ECM/gelatin or mixed matrix overlaid on HUVECs ECM/gelatin. An epithelial±mesenchymal interaction, previously thought to be tissue-specific, was exposed as well as concomitant integrin versatility. Furthermore, heterologous HDMECs and dermal fibroblasts attached and proliferated on the mixed matrix as well as HUVECs ECM. The conditioned medium from HUVECs (HUVECs CM) was found to neutralize the lingering after effects of Dispase, and could be used for the tissue culture of epidermal keratinocytes, HDMECs and dermal fibroblasts, which share related extracellular secretions. Taken together, these results indicate that cultured epithelial autografts can be redesigned to include both epithelial and dermal elements, and advances the acellular`sandwich' ECM scaffold as a possible structural replacement for the lamina densa and lamina lucida, damaged or completely missing in some wounds and burns.

This paper sets out to demonstrate that scraping of the flat dorsal surface of human dermis with a scalpel blade and cell plating without centrifugation can lead to the recognition and identification of the individual packing micro pattern of dermal reticular fibroblasts at confluence. The characteristic alignment of papillary and reticular fibroblasts at right angles to each other led to the positive identification of reticular fibroblasts. A non-enzymatic means of sub-culturing (passaging), which yields fully functional, healthy cells with normal, phenotypic morphology is also described. Implications for published subcutaneous wound healing studies are discussed as well as the confluent reticular fibroblast configuration, interpreted as an anatomic site identity code, which may be the address of a specific fibroblast gene pattern expression.

Prostacyclin analogues have been reported to inhibit the expression of tissue factor procoagulant activity in human monocytes, primarily by elevating intracellular levels of adenosine 3',5'-cyclic monophosphate (cAMP). The present studies have investigated whether prostacyclins can also inhibit tissue factor expression in endothelial cells. Iloprost, carbacyclin, and ciprostene had no effect on human umbilical vein endothelial tissue factor activity induced by lipopolysaccharide (LPS), tumor necrosis factor-alpha (TNF-alpha), or interleukin-1 beta (IL-1 beta). Iloprost failed to elevate intracellular levels of cAMP, even when combined with a phosphodiesterase inhibitor. In contrast, forskolin increased endothelial cAMP and inhibited tissue factor expression. Conditioned medium from LPS-challenged monocytic THP-1 cells, which contained both TNF-alpha and IL-1 beta, induced endothelial cell procoagulant activity to levels 20-fold higher than those achieved in response to LPS alone. Iloprost abolished LPS-induced TNF-alpha secretion by THP-1 cells and inhibited IL-1 beta secretion by 45%. In keeping with this, iloprost reduced levels of TNF-alpha and IL-1 beta mRNA in LPS-challenged cells. Treatment of THP-1 cells with iloprost strongly inhibited the ability of conditioned medium to induce endothelial tissue factor expression, an effect that was mimicked by treating the medium with blocking antibodies to the cytokines. We conclude that although prostacyclin analogues do not directly suppress endothelial tissue factor expression due to their failure to elevate cAMP, they may do so indirectly by inhibiting the amplification produced by monocyte-derived cytokines.

The human dermis presents an ongoing problem for regenerative medicine. Current medical management uses various acellular dermal matrices on wound sites. The challenge for scientists is to examine, then to question accepted conventional wisdom and to present new concepts. In this paper, Autologous Cell Therapy will be described by using cell culture of autologous dermal fibroblasts and their extracellular matrix as a foundation for rebuilding the dermis in conditioned wound beds * . This proposal seems to create a conflict with the medical approach to keeping a wound bed "moist".

Skin grafts have remained relatively unchanged since their introduction as a medical treatment for burns/wounds. This paper seeks to open an academic discussion as to whether their use-by date has now been passed. A skin graft substitute is described in a paradigm using fine leaf gelatine sheets which inherently possess several distinct advantages including, discarding the harvest of autologous tissue from patient donor sites. A clinical study will be needed to determine its suitability taken together with the understanding that experimental animal studies may not provide unequivocal answers to its in situ modus operandi.

Regenerative medicine has brought about refreshing new thinking about age old problems. However, some problems remain mostly untouched and are not being addressed. A point in question is the track of scar tissue left behind post-operatively, which reveals the surgeon's line of invasive incision. This confers on the patient an adverse psychological reminder and burden for the rest of his/her life. Most patients cannot afford corrective plastic surgery to ameliorate this skin defect. This paper seeks to ask whether biomedical scientists could play a role in arriving at a more pleasing cosmetic result, using a simple cell culture procedure of isolating un-manipulated autologous primary epidermal and dermal cells from a small skin tissue segment in close proximity to the surgeon's incision line.

This paper in a medical sense can be described as a case report. The diabetic foot wounds of a relative, over 70 years of age, with Type I diabetes were so grievous and the medical treatment was so protracted that success could not be assured. There was a danger of amputation. The one outstanding feature was that the private application of an antifungal spray, between the toes of both feet without prescribed oral mycologic agents, seemed to make an inexplicable difference to the final outcome. In addition, a viewpoint drawn was that the efficacy of antibiotic therapies may be compromised by the presence of invisible fungal etiology.