Cyclosporine and angiogenesis in psoriasis

Cyclooxygenase-2 in cancer and angiogenesis

Tumor angiogenesis is a process where new blood vessels are formed from preexisting ones, resulting in several pathologies. Solid tumors induce angiogenesis to obtain the required nutrients and oxygen. Otherwise, tumors do not grow beyond 2 to 3 mm in diameter. Cyclooxygenase-2, an inducible enzyme important in inflammation, catalyzes the production of prostanoids from arachidonic acid. Cyclooxygenase-2 plays an important role in several cancer types, including colorectal, gastric, prostate, breast, lung, and endometrial cancer. Besides, cyclooxygenase-2 has been implicated in the progression and angiogenesis of cancers. Cyclooxygenase-2 inhibitors have been used to block angiogenesis and tumor proliferation. In this review, the recent studies related to the role of cyclooxygenase-2 in several cancer types and tumor-induced angiogenesis were compiled.

Severe psoriasis treated with a new macrolide: everolimus

Psoriasis is an immune-mediated disease with a chronic relapsing course, and the particularly severe forms that are refractory to traditional therapies are often difficult to manage. Everolimus (Certican; Novartis, Basel, Switzerland) is a new rapamycin-derived macrolide that is used in the prophylaxis of rejection in heart and kidney transplant patients. The mechanism underlying its immunosuppressant and antiproliferative activity is different from, but complementary to, that of calcineurin inhibitors such as ciclosporin. We describe a woman with severe psoriasis treated with everolimus combined with subtherapeutic doses of ciclosporin.

Regulation by prostaglandin E2 and histamine of angiogenesis in inflammatory granulation tissue

In an air pouch-type carrageenin-induced inflammation model in rats, the selective cyclooxygenase (COX)-2 inhibitor NS-398 dose dependently inhibited the granulation tissue formation, angiogenesis and the level of vascular endothelial growth factor (VEGF) in the granulation tissue. In culture of the minced granulation tissue, PGE2 induced VEGF production in a concentration-dependent manner. Histamine also induced VEGF production in the granulation tissue in vitro. The H2 receptor antagonist cimetidine, the cAMP antagonist Rp-cAMP and the protein kinase A inhibitor H-89 suppressed the histamine-induced VEGF production in the granulation tissue. However, the H1 receptor antagonist pyrilamine maleate, the H3 receptor antagonist thioperamide, the protein kinase C inhibitors Ro 31-8425 and calphostin C or the tyrosine kinase inhibitor genistein showed no effect. Subcutaneous implantation of a cotton thread in the dorsum of histidine decarboxylase-deficient (HDC-/-) mice, but not in mast cell-deficient (WBB6F1-W/Wv) mice, induced less angiogenesis with lower levels of VEGF in the granulation tissue than in their corresponding wild-type (HDC+/+ and WBB6F1(-)+/+) mice. In HDC-/- mice, the topical injection of histamine or the H2 receptor agonist dimaprit rescued the defective angiogenesis and granulation tissue formation. In addition, cimetidine but not pyrilamine maleate and thioperamide inhibited the histamine-induced angiogenesis in the granulation tissue in HDC-/- mice. These findings suggest that PGE2 and histamine augment angiogenesis in the inflammatory granulation tissue by inducing VEGF production, and histamine induces VEGF production possibly through the H2 receptor--cAMP--protein kinase A pathway.

Inhibition by acharan sulphate of angiogenesis in experimental inflammation models

1. The effects of acharan sulphate, a glycosaminoglycan isolated from the giant African snail Achatina fulica, on angiogenesis in the granulation tissue were analysed using an air pouch-type carrageenin-induced inflammation model in rats and a cotton thread-induced inflammation model in mice. 2. In the carrageenin-induced inflammation model in rats, intra-pouch injections of acharan sulphate (5 and 50 micro g) inhibited the pouch fluid accumulation and the granulation tissue formation as well as the angiogenesis in the granulation tissue at day 6 in a dose-dependent manner. 3. The inhibitory effects of acharan sulphate at 50 micro g on the pouch fluid accumulation and the leucocyte infiltration into the pouch fluid was not so effective as that of the cyclo-oxygenase inhibitor indomethacin at 100 micro g, but the inhibitory effects of acharan sulphate at 50 micro g on the granulation tissue formation and angiogenesis in the granulation tissue were almost the same as those of indomethacin at 100 micro g. 4. Acharan sulphate did not affect levels of vascular endothelial growth factor (VEGF) in the granulation tissue and in the pouch fluid at day 6, but indomethacin significantly lowered them. 5. In the cotton thread-induced inflammation model in mice, injections of acharan sulphate (10 micro g) at the site of the cotton thread implantation inhibited the granulation tissue formation and angiogenesis as indomethacin (20 micro g) did. Acharan sulphate (10 micro g) did not affect levels of VEGF in the cotton thread-induced granulation tissue at day 5, but indomethacin (20 micro g) significantly lowered them. 6. In culture of human vascular endothelial cells, acharan sulphate at 10 and 100 micro g ml(-1) inhibited VEGF-induced capillary tube formation. 7. These findings suggest that the inhibitory effect of acharan sulphate on angiogenesis in carrageenin- and cotton thread-induced granulation tissues is not due to the inhibition of VEGF protein induction, but is due to the inhibition of VEGF-induced vascular tube formation.

Defective angiogenesis in the inflammatory granulation tissue in histidine decarboxylase-deficient mice but not in mast cell-deficient mice

We have analyzed the role of histamine in the angiogenesis of the granulation tissue in histidine decarboxylase-deficient (HDC(-/-)) mice, mast cell-deficient mice (WBB6F1-W/W(V)), and their corresponding wild-type mice (HDC(+/+) and WBB6F(1)(+/+)). In HDC(+/+) mice, subcutaneous implantation of a cotton thread in the dorsum induced granulation tissue formation with angiogenesis, while the topical injection of anti-vascular endothelial growth factor (VEGF) IgG strongly suppressed them. In HDC(-/-) mice which showed lower VEGF levels in the granulation tissue, there was notably less angiogenesis and granulation tissue formation than in HDC(+/+) mice. The topical injection of histamine or the H(2) agonist dimaprit rescued the defective angiogenesis and granulation tissue formation in HDC(-/-) mice. There was no significant difference in the granulation tissue formation and angiogenesis between WBB6F1-W/W(V) and WBB6F1(+/+) mice. In addition, macrophages in the granulation tissue were found to express HDC. Our findings indicate that histamine derived from non-mast cells plays a significant role in the angiogenesis of the inflammatory granulation tissue.

Antiangiogenic properties of a novel shark cartilage extract: potential role in the treatment of psoriasis

BACKGROUND

A number of inflammatory and immune diseases are associated with vascular changes. Psoriasis, as an example, is a common inflammatory skin disease with dilation of capillaries as an early histological change. In more developed psoriatic lesions there is proliferation of blood vessels and neovascularization. The use of agents that target these vascular changes represents a novel therapeutic strategy in the treatment of inflammatory diseases. Since cartilage is an avascular tissue, it has been hypothesized that there may be factors found in cartilage that inhibit blood vessel formation.

OBJECTIVE

The objectives of this study were 1) to determine whether extracts of cartilage could inhibit angiogenesis, and 2) since altered angiogenesis is associated with certain diseases, including psoriasis, to examine whether inhibition of angiogenesis could potentially contribute to the treatment of psoriasis.

METHODS

Extracts of shark cartilage were prepared by homogenization and ultrafiltration to derive the active agent termed AE -941. This agent was tested for antiangiogenesis activity using the embryonic vascularization test, which is a modification of the ex vivo chick embryo culture (CAM). Since one of the first steps in angiogenesis is degradation by metalloproteinases of the basement membrane of capillaries, AE -941 was tested for collagenase activity using a fluorogenic peptide substrate. Anti-inflammatory properties were tested using a cutaneous irritation model in humans.

RESULTS

A dose dependent inhibition in embryonic neovascularization as well as in collagenase activity by AE -941 was demonstrated. When test compounds were applied on the forearms of test subjects, AE -941 was shown to have anti-inflammatory properties. Anecdotal data suggested that topical AE -941 had a beneficial effect in psoriasis.

CONCLUSION

Our results show that AE -941 has anti-angiogenic and anti-inflammatory properties. Antiangiogenesis agents such as AE -941 provide an entirely new class of agents to treat cutaneous and systemic diseases associated with altered vascularity.