Mechanism of action of angiostatic steroids: suppression of plasminogen activator activity via stimulation of plasminogen activator inhibitor synthesis

Prevention of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) compromises quality of life. However, the available therapeutic options are limited. This has led to the identification of modifiable risk factors to prevent the development or alter the natural course and prognosis of AMD. The identification and modification of risk factors has the potential for greater public health impact on reducing morbidity from AMD. Likewise, identifying the imaging clues and genetic clues could serve as a guide to recognizing the propensity for progression to severe and end stages of the disease. Several attempts, both successful and unsuccessful, have been made for interventions that could delay the progression of AMD. Of these, pharmacological interventions have shown promising results. The Age-Related Eye Disease Study 1 and 2 have shown the beneficial role of antioxidants in a selected group of patients.

[Current treatments for corneal neovascularization]

The extension of blood vessels into the normally avascular stroma defines corneal neovascularization. Though this phenomenon, pathophysiological and clinical features are well characterized, therapeutic modalities have been hindered by a lack of safe, efficacious and non-controversial treatments. In this literature review, we focus on available therapeutic options in light of recent evidence provided by animal and clinical studies. First, this review will focus on pharmacological treatments that target angiogenesis. The low cost and market availability of bevacizumab make it the first anti-angiogenic therapy choice, and it has demonstrable efficacy in reducing corneal neovascularization when administered topically or subconjunctivally. However, novel anti-angiogenic molecules targeting the intracellular pathways of angiogenesis (siRNA, antisense oligonucleotides) provide a promising alternative. Laser therapy (direct photocoagulation or photo-dynamic therapy) and fine needle diathermy also find a place in the treatment of stabilized corneal neovascularization alone or in association with anti-angiogenic therapy. Additionally, ocular surface reconstruction using amniotic membrane graft or limbal stem cell transplantation is essential when corneal neovascularization is secondary to primary or acquired limbal deficiency.

Topical use of rapamycin in herpetic stromal keratitis

PURPOSE

To evaluate and compare the efficacy of rapamycin used topically in a mouse model of herpetic stromal keratitis.

METHODS

The corneas were infected with herpes simplex virus type-1 strain KOS. Animals were divided into: control (CG), rapamycin (RAPA), cyclosporine (CsA), and dexamethasone (DEXA). The evolution of the disease was assessed clinically and histologically.

RESULTS

On day 10 postinfection (pi), the RAPA group showed only a significantly lower angiogenic development than the CG. On day 14 pi, the treated groups had significantly lower scores for angiogenesis and necrosis than the CG. Also, on day 14 pi, the RAPA and DEXA groups showed significantly lower histopathological scores compared to the CG.

CONCLUSIONS

The topical application of 0.05% rapamycin showed greater efficacy than 0.5% cyclosporine and similar efficacy to 0.1% dexamethasone to minimize the immuno-inflammatory process. Also, rapamycin showed early inhibition of the formation of new vessels.

Surgical implantation of steroids with antiangiogenic characteristics for treating neovascular age-related macular degeneration

BACKGROUND

Neovascular age-related macular degeneration (AMD) is associated with rapid vision loss due to choroidal neovascularization (CNV), leakage, and scarring. Steroids have gained attention in their role for the treatment of neovascular AMD for their antiangiogenic and anti-inflammatory properties.

OBJECTIVES

This review aims to examine effects of steroids with antiangiogenic properties in the treatment of neovascular AMD.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 11), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to November 2012), EMBASE (January 1980 to November 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to November 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 21 November 2012.

SELECTION CRITERIA

We included randomized controlled clinical trials of intra- and peri-ocular antiangiogenic steroids in people diagnosed with neovascular AMD.

DATA COLLECTION AND ANALYSIS

Two authors independently screened abstracts and full-text articles, assessed risk of bias in the included trials, and extracted data. We did not conduct a meta-analysis.

MAIN RESULTS

We included three trials after screening a total of 1503 abstracts and 21 full-text articles. The three trials included a total of 809 participants. One trial compared different doses of acetonide anecortave acetate with placebo, a second trial compared triamcinolone acetonide versus placebo, and the third trial compared anecortave acetate against photodynamic therapy (PDT). We did not conduct a meta-analysis owing to heterogeneity of interventions and comparisons. The risk ratio for loss of 3 or more lines of vision at 12 months follow-up was 0.8 (95% confidence interval (CI) 0.45 to 1.45) with 3 mg anecortave acetate, 0.45 (95% CI = 0.21 to 0.97) with 15 mg anecortave acetate, 0.91 (0.52 to 1.58) with 30 mg anecortave acetate, 0.97 (95% CI 0.74 to 1.26) with triamcinolone acetonide, all compared to placebo and 1.08 (95% CI 0.91 to 1.29) with anecortave acetate compared with PDT.

AUTHORS' CONCLUSIONS

Based on the included trials, we found no evidence that antiangiogenic steroids prevent visual loss in patients with neovascular AMD. With the emergence of anti-vascular endothelial growth factor modalities, based on evidence summarized in this review, it is unclear what role steroids have in treating patients with neovascular AMD.

Treatments for corneal neovascularization: a review

Corneal neovascularization (CNV) may be a physiological response to various stimuli, but a chronic and persistent upregulation of neoangiogenesis can result in pathological CNV. Pathological blood vessels are immature and lack structural integrity, predisposing the cornea to lipid exudation, inflammation, and scarring. CNV can therefore become a potentially blinding condition. In this review, we frame CNV in an epidemiological perspective, consider risk factors for CNV, provide an overview of CNV pathogenesis, and consider the impact of CNV on corneal transplantation. We consider treatments that are of largely historical interest, before reviewing contemporary medical and surgical treatments. Within medical treatments, we report on steroids, nonsteroidal anti-inflammatory agents, antivascular endothelial growth factor agents, and cyclosporine. Within surgical treatments, we report on the use of lasers, photodynamic therapy, superficial keratectomy, and diathermy/cautery-based treatments.

Glucocorticoid-mediated inhibition of angiogenic changes in human endothelial cells is not caused by reductions in cell proliferation or migration

Background

Glucocorticoid-mediated inhibition of angiogenesis is important in physiology, pathophysiology and therapy. However, the mechanisms through which glucocorticoids inhibit growth of new blood vessels have not been established. This study addresses the hypothesis that physiological levels of glucocorticoids inhibit angiogenesis by directly preventing tube formation by endothelial cells.

Methodology/Principal Findings

Cultured human umbilical vein (HUVEC) and aortic (HAoEC) endothelial cells were used to determine the influence of glucocorticoids on tube-like structure (TLS) formation, and on cellular proliferation (5-bromo-2′-deoxyuridine (BrdU) incorporation), viability (ATP production) and migration (Boyden chambers). Dexamethasone or cortisol (at physiological concentrations) inhibited both basal and prostaglandin F_2α (PGF_2α)-induced and vascular endothelial growth factor (VEGF) stimulated TLS formation in endothelial cells (ECs) cultured on Matrigel, effects which were blocked with the glucocorticoid receptor antagonist RU38486. Glucocorticoids had no effect on EC viability, migration or proliferation. Time-lapse imaging showed that cortisol blocked VEGF-stimulated cytoskeletal reorganisation and initialisation of tube formation. Real time PCR suggested that increased expression of thrombospodin-1 contributed to glucocorticoid-mediated inhibition of TLS formation.

Conclusions/Significance

We conclude that glucocorticoids interact directly with glucocorticoid receptors on vascular ECs to inhibit TLS formation. This action, which was conserved in ECs from two distinct vascular territories, was due to alterations in cell morphology rather than inhibition of EC viability, migration or proliferation and may be mediated in part by induction of thrombospodin-1. These findings provide important insights into the anti-angiogenic action of endogenous glucocorticoids in health and disease.

Levonorgestrel-releasing intrauterine system (Mirena) and Depot medroxyprogesterone acetate (Depoprovera) as long-term maintenance therapy for patients with moderate and severe endometriosis: a randomised controlled trial

BACKGROUND

Progestogen therapy has been found to be useful in controlling endometriosis. For patients after conservative surgery, long-term medical maintenance therapy should be sought to prevent recurrence and control symptoms. Levonorgestrel-releasing intrauterine system (LNG-IUS) may be a useful form of prolonged progestogen therapy for endometriosis.

AIMS

To evaluate and compare the efficacy and safety of LNG-IUS to depot medroxyprogesterone acetate (MPA) for patients with moderate or severe endometriosis following conservative surgery, in terms of symptoms control, recurrence prevention and patients' acceptance.

METHODS

A total of 30 patients after conservative surgery for endometriosis underwent randomisation. Of these patients, 15 received LNG-IUS and 15 had three-monthly depot MPA for three years. Their symptom control, recurrence, compliance and change in bone mineral density (BMD) were compared. The data were analysed using student's t-test and chi-square test.

RESULTS

Symptoms and recurrence were controlled by both therapies. The compliance was better in LNG-IUS Group with 13 patients staying on their therapy versus seven patients in Depot MPA Group. LNG-IUS users had a significantly better change in BMD (+0.023, +0.071 g/cm(2)) than Depot MPA users (-0.030, -0.017 g/cm(2)) in both hip and lumbar regions.

CONCLUSIONS

Levonorgestrel-releasing intrauterine system was effective in symptom control and prevention of recurrence. LNG-IUS users showed a better compliance. After three years, bone gain was noted with LNG-IUS, but bone loss with depot MPA.

A Novel Chemical Delivery System Comprising an Ocular Sustained Release Formulation of a 3α, 17α, 21-trihydroxy-5β-pregnan-20-one-BIS-5-Flourouracil Codrug

Directly compressed sustained release pellets were prepared from material consisting of a molecule of 3alpha, 17alpha, 21-trihydroxy-5beta-pregnan-20-one (trihydroxy steroid, THS) covalently linked via carbonate moieties to two molecules of 5-flourouracil (5FU) to form a novel THS-BIS-5FU codrug for the treatment of angiogenesis. Dissolution and drug release was tested in vitro in 0.1M phosphate buffer (pH 7.4), human serum, and vitreous humor. The results suggest that neat THS-BIS-5FU codrug pellets are useful for sustained release ocular delivery of the parent compounds, and that the unique physicochemical properties of the codrug allow slow dissolution and rapid release of the two parent drugs. This codrug formulation is regarded as a "chemical delivery" system that involves dissolution of the codrug as the rate-limiting step followed by rapid hydrolysis of the carbonate ester linkages to release the parent drugs via sustained delivery.

Evaluating systemic prednisone therapy for proliferating haemangioma in infancy

In this study, we reviewed the history of 38 children with proliferating haemangiomas treated with systemic corticosteroids at our institution between 2000 and 2002. Prednisone was administered at an initial dose of 2 mg/kg per day for 2 weeks followed by a dose of 1 mg/kg per day for another 2-4 weeks and consecutive slow tapering over an additional 4-5 months. For 93% of the children, this protocol was successful in reducing the size of the haemangioma by more than 25% after 2 weeks of treatment. Side effects were moderate and reversible after cessation of therapy.

Anecortave acetate in the treatment of age-related macular degeneration

RETAANE 15mg (anecortave acetate suspension) is under investigation to treat exudative age-related macular degeneration (AMD), the single largest cause of blindness in the Western world, affecting over 15 million people in the USA. RETAANE suspension is a unique synthetic cortisene and has antiangiogenic properties that were established in multiple experimental models of angiogenesis. The molecule acts at multiple sites of the angiogenic cascade. Clinical trials in patients with exudative AMD have demonstrated the excellent safety record of both the drug anecortave acetate and the posterior juxtascleral depot (PJD) administration procedure. A pivotal study comparing RETAANE suspension with placebo showed a significantly higher chance of maintaining vision in the treatment (73%) as compared with placebo (47%). Another study compared RETAANE suspension with Visudyne photodynamic therapy, revealing no statistically significant differences between the two treatments over 24 months. AMD is a multi-faceted disease and therefore a molecule such as RETAANE suspension with a unique mechanism of action, demonstrated clinical efficacy, and retreatment every six months is an important potential treatment option which should be further investigated both as a monotherapy or in combination with other treatment strategies.

Surgical implantation of steroids with antiangiogenic characteristics for treating neovascular age-related macular degeneration

BACKGROUND

Neovascular age-related macular degeneration (AMD) is associated with rapid vision loss due to choroidal neovascularization (CNV), leakage, and scarring. Steroids have gained attention in their role for the treatment of neovascular AMD for their antiangiogenic and anti-inflammatory properties.

OBJECTIVES

This review aims to examine effects of steroids with antiangiogenic properties in the treatment of neovascular AMD.

SEARCH STRATEGY

We searched for trials in CENTRAL, MEDLINE, EMBASE, and LILACS on 2 October 2006.

SELECTION CRITERIA

We included randomised controlled clinical trials of intra- and peri-ocular steroids in people diagnosed with neovascular AMD.

DATA COLLECTION AND ANALYSIS

Review authors extracted the data and assessed trial quality independently. We did not pool data since the included studies evaluated difference comparisons.

MAIN RESULTS

We report the risk of losing three or more lines vision at 12 months - "vision loss". One trial (139 people randomized) reported that a single dose of intravitreal triamcinolone (n = 75) (4 mg) had no significant effect on the risk of vision loss compared to placebo (n = 76). (Risk ratio vision loss 0.97, 95% confidence interval (CI) 0.74 to 1.26). Eyes treated with triamcinolone were more likely to develop cataracts and experience increased intraocular pressure (IOP) compared to untreated eyes. One trial (128 people randomized) reported the effects of anecortave acetate (3 mg (n = 32), 15 mg (n = 33) or 30 mg (n = 33) single dose with retreatment every six months if indicated) compared to placebo (n = 30). Risk ratio vision loss 0.80 (95% CI 0.45 to 1.45) in the 3 mg group, 0.45 (95% CI 0.21 to 0.97) in the 15 mg group and 0.91 (95% CI 0.52 to 1.58) in the 30 mg group. Side effects were similar in all treatment groups with the anecortave group having a slightly higher incidence of foreign body sensation compared to placebo. There was a high loss to follow-up. The final analysis may have been subject to selection bias as participants who were not selected for retreatment, possibly with worsening disease, were excluded. There was also a possibility of type I error due to multiple statistical comparisons. The sample size was estimated on the basis of a single 2-way comparison but three 2-way comparisons were analysed and presented. One trial reported that anecortave acetate (n = 263) (15 mg administered at beginning of study and six months) gave similar results to photodynamic therapy (n = 267) (risk ratio vision loss 1.08, 95% CI 0.91 to 1.29).

AUTHORS' CONCLUSIONS

Overall there is weak evidence as to the benefits and harms of steroids with antiangiogenic properties for treating neovascular AMD with only three published trials of variable quality. Intravitreal triamcinolone injection for neovascular AMD does not appear to prevent severe vision loss and is associated with increased IOP and higher risk of cataract formation. Anecortave acetate 15 mg may have a mild benefit in stabilizing vision, but further better quality evidence is needed. The role of steroids in combination with other treatment modalities is yet to be determined.

The role of progestins in treating the pain of endometriosis

Progestins, synthetic progestational agents, have been used in the management of symptomatic endometriosis both as primary therapy and as an adjunct to surgical resection. A variety of oral agents have been employed in this regard with investigators demonstrating differing degrees of benefit. Unfortunately, due to the lack of large-scale, appropriately controlled, randomized trials, or dose-ranging studies, no single agent can be demonstrated to be truly efficacious. The lack of a standardized instrument to evaluate painful symptoms makes comparative analysis more difficult. Injectable administration of long-acting depot medroxyprogesterone acetate preparations intramuscularly or subcutaneously has been investigated in three randomized trials. The lower dose subcutaneous injection holds promise with an apparent reduction in side effects. Issues of reversible bone mineral density loss, breakthrough bleeding, and return of menses have not been completely resolved. Selective progesterone receptor modulators represent an intriguing alternative. These orally administered agents have been shown in preliminary investigations to be not only efficacious in reducing symptoms but also associated with minimal side effects. Further investigation of these agents is clearly required.

POSTERIOR JUXTASCLERAL INJECTION OF ANECORTAVE ACETATE

PURPOSE

To confirm juxtascleral delivery of anecortave acetate in rabbit eyes by ocular imaging techniques and to determine drug localization and distribution as a function of time after injection.

METHODS

Four female New Zealand white rabbits (weight, 2.5-3.0 kg) received a single juxtascleral posterior sub-Tenon capsule injection of 0.5 mL or 1 mL of 30 mg/mL anecortave acetate. Rabbit eyes were imaged with ultrasonography and magnetic resonance imaging (MRI) before injection, immediately after injection, and at 2 hours, 1 week, and 4 weeks after injection. Rabbit eyes were also imaged with b-mode ultrasonography during the juxtascleral injections.

RESULTS

Ultrasonography and MRI demonstrated that juxtascleral posterior sub-Tenon capsule injection of anecortave acetate effectively delivered the drug in direct apposition to the posterior pole of the rabbit eye. The drug remained in the juxtascleral site for at least 5 weeks. The drug was visualized clearly by MRI immediately after injection, decreasing in intensity thereafter. Cannula insertion and the drug delivery process were clearly visualized by real-time ultrasound analysis. Immediately after drug injection, ultrasonography indirectly localized anecortave acetate localization as an echolucent zone posterior to the scleral surface. At the later time points, however, the juxtascleral location of the drug was verified with ultrasonography as a relatively echogenic focus in the same location.

CONCLUSIONS

Juxtascleral administration of anecortave acetate via a posterior sub-Tenon capsule approach effectively delivered the drug to the desired position in direct apposition to the globe posteriorly. MRI and ultrasonography both demonstrated that anecortave acetate remained localized to this location for at least 5 weeks after initial injection.

Decreased suppression of interleukin-6 after treatment with medroxyprogesterone acetate and danazol in endometrial stromal cells of women with adenomyosis

OBJECTIVE

To examine changes in local cytokine production in the eutopic endometrium of adenomyosis after treatment with medroxyprogesterone acetate (MPA) and danazol.

DESIGN

Prospective cohort study.

SETTING

Tertiary university hospital.

PATIENT(S)

Twenty-four women with adenomyosis (study group) and 22 women without adenomyosis (control group).

INTERVENTION(S)

Eutopic endometrium was separated into single endometrial stromal cells (ESCs), and was cultured in vitro alone, with MPA (10(-7) M), or with danazol (10(-7) M) for 8 days.

MAIN OUTCOME MEASURE(S)

Messenger RNA expression of interleukin (IL)-6, IL-8, and tumor necrosis factor-alpha in ESCs, and their concentrations in the supernatants of ESCs.

RESULT(S)

A significant decrease of IL-6 concentration in the supernatant, measured by ELISA, was found with time of ESCs cultured with MPA and danazol in the control group, but not in adenomyosis. The IL-6 mRNA in ESCs determined by real-time quantitative polymerase chain, as well as its concentration in the supernatant, was much higher in adenomyosis than that in the control group after treatment with MPA and danazol for 8 days.

CONCLUSION(S)

Medroxyprogesterone acetate and danazol appeared to have a decreased effect on the suppression of IL-6 liberated by ESCs in adenomyosis. This aberrant secretion of IL-6 might play a role in the formation of ectopic endometrial implants in adenomyosis.

Emerging drugs in endometriosis

Endometriosis is a common, estrogen-dependent, gynaecological disease, defined as the presence of endometrial-like tissue outside the uterus. Although several medications are used for treatment of the disease, they are associated with high recurrence rates, considerable side effects and limited duration of application. Due to these limitations and to the impact of endometriosis on the quality of life of affected women, their environment and the society, there is a great need for new drugs able to abolish endometriosis and its symptoms. Studies in recent years investigating the (patho)physiological mechanisms involved in disease aetiology have fostered the development of novel therapeutic concepts for endometriosis, by targeting the hypothalamic-pituitary-gonadal axis, by selective modulation of estrogenic and progestogenic pathways, by inhibiting angiogenesis or by interfering with inflammatory and immunological factors. This article presents a brief summary of the currently available medications and an overview regarding the development of some of the most interesting and/or most promising novel drug candidates for endometriosis.

Targeting angiogenesis, the underlying disorder in neovascular age-related macular degeneration

Angiogenesis has a causal role in many diseases, including neovascular age-related macular degeneration (AMD). Identification of key regulators of angiogenesis, including vascular endothelial growth factor (VEGF), fibroblast growth factor 2, pigment epithelium-derived growth factor, angiopoietins and extracellular matrix molecules, has facilitated the development of novel therapeutic agents that target the underlying pathological angiogenic process. Among these, VEGF serves as a "master switch" for many ocular neovascular conditions through its promotion of endothelial cell proliferation and survival, vascular permeability and ocular inflammation. Two anti-VEGF agents are now clinically available: bevacizumab, an antibody for metastatic colorectal cancer, and pegaptanib sodium, an aptamer for neovascular AMD. Unlike bevacizumab, which binds all VEGF isoforms, pegaptanib targets only VEGF165, the isoform responsible for pathological ocular neovascularization and thus an ideal target for treatment of AMD. Although other therapies targeting angiogenesis in AMD are in clinical development, to date, pegaptanib is the only therapy approved by the Food and Drug Administration of the United States for the treatment of all neovascular AMD and represents a valuable addition to the hitherto limited options available for patients.

Promising new treatments for neovascular age-related macular degeneration

Angiogenesis, the growth of new blood vessels from existing blood vessels, is responsible for vision loss in a variety of ophthalmic diseases. In neovascular age-related macular degeneration (AMD), the leading cause for legal blindness in many industrialised countries, abnormal blood vessels grow in the macula and cause blindness. There are a number of factors important in the angiogenic cascade but VEGF-A has been implicated in recent years as the major factor responsible for neovascular and exudative diseases of the eye. Numerous antiangiogenic drugs are in development but anti-VEGF drugs have shown great promise in treating neovascular AMD and other ocular diseases, and many of these drugs have been adopted from oncology where antiangiogenic therapy is gaining wide acceptance. For the first time in neovascular AMD, anti-VEGF drugs have brought the hope of vision improvement to a significant proportion of patients. This review provides an overview on angiogenic mechanisms, potential antiangiogenic treatment strategies and different antiangiogenic drugs with special focus on neovascular AMD.

Evaluation of O(3alpha)-, O(21)-di-(N(1)-methyloxycarbonyl-2, 4-dioxo-5-fluoropyrimidinyl) 17alpha-hydroxy-5beta-pregnan-20-one as a novel potential antiangiogenic codrug

Intraocular neovascularization is a complication in a variety of eye diseases, and is a leading cause of visual loss. The purpose of this study was to design and synthesize three novel codrugs of the antiangiostatic steroid, 3alpha, 17alpha, 21-trihydroxy-5beta-pregnan-20-one (trihydroxy steroid, THS) with the cytotoxic agent 5-fluorouracil (5FU) which incorporates either one or two molecules of 5FU attached through carbonate ester linkages at positions O(3), and/or O(21) of the THS molecule. Furthermore, a kinetic study of the O(3alpha)-, O(21)-di-(N(1)-methyloxycarbonyl-2, 4-dioxo-5-fluoropyrimidinyL) 17alpha-hydroxy-5beta-pregnan-20-one (THS-BIS-5FU) codrug was carried out. The overall goal of this codrug strategy was to improve sustained drug delivery of both compounds by overcoming their individual solubility problems, and to thus enhance their bioavailability. The codrug was found to be optimal with superior angiostatic activity using the CAM assay compared to the activity of the parent compounds alone. In the hydrolysis studies 5FU was released at a faster rate than THS with an unknown intermediate observed by HPLC, a rationale and proposed structure and mechanism of the unknown THS derivative is provided.

Anecortave acetate

This manuscript reviews the pharmacotherapeutics of the novel, angiostatic cortisene, anecortave acetate suspension, for the treatment of age-related macular degeneration. The chemistry, pharmacokinetics and pharmacodynamics of anecortave acetate are discussed, and the results of the multi-centre, randomised, controlled clinical trials for the treatment of subfoveal choroidal neovascularisation in age-related macular degeneration summarised. It also discusses ongoing clinical trials involving anecortave acetate for dry and wet age-related macular degeneration.

Suppression of Laser-Induced Choroidal Neovascularization by Subconjunctival Injection of 9.ALPHA.-Fluoromedroxyprogesterone Acetate (FMPA), an Anti-angiogenic Agent, in Rats

9alpha-Fluoromedroxyprogesterone acetate (FMPA) is a synthetic analog of medroxyprogesterone acetate (MPA). FMPA exhibited more potent anti-tumor and anti-angiogenic activities in some assay systems than the parent agent, MPA. Exudative age-related macular degeneration (AMD) is characterized by choroidal neovascularization (CNV). Anecortave acetate, an angiostatic steroid, is clinically efficacious in patients with exudative AMD. Betamethasone is an anti-angiogenic steroid. Therefore, we examined the effects of FMPA, anecortave acetate and betamethasone on laser-induced CNV in rats. Anecortave acetate and betamethasone were included as positive controls. Crypton laser was applied to the fundus in Brown Norway rats. Laser photocoagulations were performed in each eye between the major retinal vessels of the superior retina. Subconjunctival injection of FMPA, anecortave acetate or betamethasone was performed once just after the photocoagulation (on day 0). The incidence of CNV formation was evaluated by fluorescein angiography (FAG) on day 14. On the next day, examination of the retinal function was performed by electro retinogram (ERG). Subconjunctival injection of FMPA at doses of 300, 1000 and 3000 microg/eye dose-dependently inhibited the incidence of CNV formation. Significant differences were observed at doses of 1000 and 3000 microg/eye of FMPA as compared with the control group. Anecortave acetate and betamethasone significantly inhibited the incidence of CNV formation. FMPA at the doses used in this study did not affect the retinal function in rats, as determined by ERG. FMPA appeared to be effective in a rat model of CNV, so it was demonstrated that FMPA might be useful in the treatment of AMD.

Factor XIII (FXIII) and angiogenesis

Factor XIII is a plasma transglutaminase that participates in the final stage of the coagulation cascade. Thrombin-activated FXIII (FXIIIa) catalyzes the formation of covalent cross-links between gamma-glutamyl and epsilon-lysyl residues on adjacent fibrin chains in polymerized fibrin to yield the mature clot. In addition to its role in hemostasis, FXIII is known to participate in wound healing and embryo implantation, which are processes involving angiogenesis. In this review, we discuss the role of FXIII in angiogenesis and the molecular mechanisms underlying its proangiogenic effects. The FXIII role in tissue repair and remodeling may at least in part be attributed to its pro-angiogenic activity.

Advances in the management of endometriosis: an update for clinicians

Endometriosis is a chronic and recurrent disease characterized by the presence and proliferation of endometrial tissue outside the uterine cavity, which occurs in approximately 10% of women of reproductive age. In this estrogen-dependent disorder, lesions become inactive and gradually undergo regression during states of ovarian down-regulation, such as amenorrhoea or menopause. The impact of endometriosis includes impaired fertility potential, as well as symptoms of dysmenorrhoea, dyspareunia and chronic non-menstrual pain, all of which adversely affect quality of life. Management of endometriosis focuses on pain relief and includes medical and surgical treatment. Pharmacologic therapies currently in use include combination oral contraceptives (COCs), danazol, GnRH analogues and progestins. Although some agents show efficacy in relieving pain, all differ in their side effects, making it difficult to achieve a balance between efficacy and safety. Efficacy has been demonstrated with danazol or GnRH analogues; however, treatment is limited to 6 months because of significant metabolic side effects. Alternatives for longer-term management of symptoms include add-back therapy with GnRH analogues, COCs or progestins. Newer options for treatment of endometriosis include depot medroxyprogesterone acetate subcutaneous injection, as well as several agents under investigation that may prove to have therapeutic potential.

Inhibitory effect of triamcinolone acetonide on corneal neovascularization

BACKGROUND

Corneal neovascularization (NV) plays an important role in the pathogenesis of corneal disorders. Recently, triamcinolone acetonide (TA) has been reported as a potential treatment for ocular angiogenesis. However, there are no reports on the inhibitory effect of TA on the corneal NV.

METHODS

Triamcinolone acetonide (2 mg) was administered to four rabbits' eyes by a subconjunctival injection immediately after a basic fibroblast growth factor (bFGF)-pellet was placed into the cornea. As a control, four eyes received an injection of distilled water. Four weeks later, the inhibition of corneal NV was evaluated as the percentage ratio of the vessel invasion area to the area that was sandwiched between the pellet and the limbus cornea. To identify the characteristic appearance of new corneal vessels, the control cornea was examined by using the antibody of vascular endothelial growth factor (VEGF). To confirm TA concentration in TA-treated corneas, the TA level was measured using high-performance liquid chromatography.

RESULTS

Neovascularization from the limbus to the pellet was detected in control eyes 4 weeks after the bFGF pellet implantation. TA-treated eyes demonstrated the inhibition of the neovascular response to the pellet. The severity of NV as compared between control and TA-treated eyes was statistically significant (P<0.05). Morphologically, new vessel growth was shown in the control cornea, and endothelial cells of new vessels were positively stained with the antibody of VEGF. TA concentration in TA-treated corneas at 2 weeks showed 63.5+/-42.8 microg/g (n=4, mean +/- SD), while TA was not detected in control and TA-treated corneas at 4 weeks. The level of TA was effectively maintained for at least 2 weeks after the subconjunctival injection.

CONCLUSION

We have demonstrated that subconjunctival TA administration inhibited rabbit corneal NV. This agent may prove useful in the treatment of corneal angiogenic disorders.

SUPPRESSION OF LASER-INDUCED CHOROIDAL NEOVASCULARIZATION BY POSTERIOR SUB-TENON ADMINISTRATION OF TRIAMCINOLONE ACETONIDE

PURPOSE

To evaluate the inhibitory effect of triamcinolone acetonide (TA) on choroidal neovascularization (CNV) by posterior sub-Tenon administration using a laser-induced CNV model in the rat.

METHODS

Experimental CNV was induced by laser photocoagulation in Brown-Norway male rats. Experimental eyes received posterior sub-Tenon administration of either 2 mg (n = 10) or 0.5 mg (n = 8) of TA. Control eyes (n = 10) received posterior sub-Tenon administration of isotonic sodium chloride solution. Two weeks after treatment, CNV was evaluated by fluorescein angiography and histopathological examination. Concentrations of TA in the vitreous, retina, and choroid were determined by high-performance liquid chromatography at 3 and 7 days after posterior sub-Tenon administration.

RESULTS

The eyes treated with 2 mg of TA showed statistically significant inhibition of fluorescein leakage by fluorescein angiography, as compared with control eyes and eyes treated with 0.5 mg of TA (P < 0.01). The thickness of CNV membranes in eyes treated with 2 mg of TA also decreased statistically significantly, as compared with control eyes (P < 0.01). TA was detected in the vitreous, retina, and choroid 3 days after administration and in the choroid 7 days after administration.

CONCLUSIONS

Posterior sub-Tenon administration of TA may be useful to treat CNV.

AL-3789: a novel ophthalmic angiostatic steroid

Ocular neovascular diseases are a leading cause of blindness in the world. Research is beginning to unravel the complex mechanisms involved in the pathogenesis of ocular neovascular diseases, but currently there are very few methods for the effective treatment of these blinding disorders. AL-3789 (Alcon Laboratories) is an angiostatic steroid which shows significant activity in inhibiting new blood vessel formation in a wide variety of models of neovascularisation, including neovascularisation in ocular tissues. This angiostatic steroid has broad angiostatic activity and is effective in a number of different animal species and tissues, regardless of the angiogenic stimulus. AL-3789 is devoid of conventional steroid hormone activity and does not appear to have any other pharmacological side-effects at the doses and routes of administration tested. In preclinical safety studies, AL-3789 has no apparent ocular or systemic toxicity when dosed chronically by topical ocular, or by systemic administration and therefore it appears to be a relatively safe compound.

Liposome-encapsulated prednisolone phosphate inhibits growth of established tumors in mice

Glucocorticoids can inhibit solid tumor growth possibly due to an inhibitory effect on angiogenesis. The antitumor effects of the free drugs have only been observed using treatment schedules based on high and frequent dosing for prolonged periods of time. As long-circulating liposomes accumulate at sites of malignancy, we investigated the tumor-inhibiting potential of liposome-encapsulated prednisolone phosphate. Liposomal prednisolone phosphate could inhibit tumor growth dose-dependently, with 80% to 90% tumor growth inhibition of subcutaneous B16.F10 melanoma and C26 colon carcinoma murine tumor models at 20 mg/kg by single or weekly doses. Prednisolone phosphate in the free form was completely ineffective at this low-frequency treatment schedule, even when administered at a dose of 50 mg/kg. In vitro studies did not show an inhibitory effect of prednisolone (phosphate) on tumor cell, nor on endothelial cell proliferation. Histologic evaluation revealed that liposomal prednisolone phosphate-treated tumors contained a center with areas of picnotic/necrotic cells, which were not apparent in untreated tumors or tumors treated with the free drug. In conclusion, the present study shows potent antitumor effects of liposomal formulations of glucocorticoids in a low dose and low-frequency schedule, offering promise for liposomal glucocorticoids as novel antitumor agents.

Risk of venous thromboembolism in pediatric patients with brain tumors

BACKGROUND

Venous thromboembolism (VTE) is a common event in adults with malignant brain tumors approaching 24% throughout the course of the disease. The high morbidity and mortality of this complication yielded several protocols for prevention of the disease in adults undergoing neurosurgery for brain tumors and possible primary prevention afterwards. We investigated the incidence and complications of VTE in pediatric neuro-oncology patients.

PROCEDURE

We analyzed, retrospectively, the files of all consecutive patients under the age of 18 years who were hospitalized for the treatment of brain tumors between the years 1990 and 2003 in two leading, closely related, Israeli neuro-oncology centers.

RESULTS

A total of 462 children were analyzed. Three hundred eighty-four patients underwent surgery and 78 were treated medically. Only three (0.64%) of the patients developed clinical episodes of VTE that were treated conservatively. Two of these patients developed intracranial bleeding while on secondary prevention for the disease.

CONCLUSIONS

Although this study has considerable limitations in terms of retrospective design, heterogeneous group of patients and diagnoses, the changing awareness for thrombosis over the last 14 years and the inclusion of symptomatic VTE events only, our surprising data suggest that, as opposed to adults, the risk of clinically significant VTE in children with brain tumors may be exceedingly low. These findings set the stage for future forthcoming evaluations in view of the prospective studies that were done in adults and the possible significant implications for the prevention and possible etiologies of the disease.

Should Progestins Be Blamed for the Failure of Hormone Replacement Therapy to Reduce Cardiovascular Events in Randomized Controlled Trials?

Many observational studies and experimental and animal studies have demonstrated that estrogen replacement therapy (ERT) or hormone replacement therapy (HRT) (estrogen plus progestin) significantly reduces the risk of coronary heart disease. Nonetheless, recent randomized controlled trials demonstrated some trends toward an increased risk of cardiovascular events rather than a reduction of risk. Recently, both the HRT and ERT arms of the Women’s Health Initiative (WHI) study were terminated early because of an increased/no incidence of invasive breast cancer, increased incidence of stroke, and increased trend/no protective effects of cardiovascular disease. We discuss the controversial effects of HRT and ERT on cardiovascular system and provide a hypothesis that the failure of HRT and ERT in reducing the risk of cardiovascular events in postmenopausal women might be because of the stage of their atherosclerosis at the time of initiation of HRT or ERT.

Periocular hemangiomas: what every physician should know

Hemangiomas are the most common benign tumor of infancy. Most hemangiomas remain asymptomatic and can be managed by close observation; however, immediate treatment is indicated for hemangiomas that may cause significant complications. Periocular hemangiomas warrant close evaluation and early, active treatment of those with the potential to threaten or permanently compromise vision. Herein we review the clinical features of periocular hemangiomas, differential diagnosis, possible ophthalmologic complications and sequelae, and therapeutic modalities.

Tumor angiogenesis of non-small cell lung cancer

Lung cancer is one of the commonest causes of cancer death in developed countries. Recent evidence suggests that angoigenesis is related to poor prognosis in many solid tumors including non-small cell lung cancer (NSCLC). Angiogenesis is regulated by a complex interaction among growth factors and cytokines and influenced by proteolytic enzymes such as plasminogen activators and matrix metalloproteases, expression of adhesion molecules, and distribution of extracellular matrices. Fibroblasts, macrophages, mast cells, and endothelial cells themselves also affect angiogenesis. This review concentrates on angiogenic growth factors including vascular endothelial growth factor, angiopoietins, platelet derived endothelial growth factor, and basic fibroblast growth factor, proteases, adhesion molecules including vascular endothelial cadherin and integrins, osteopontin, and mast cell products in tumor angiogenesis of NSCLC.

Effects of rhizoxin, a microbial angiogenesis inhibitor, on angiogenic endothelial cell functions

Our previous study revealed that rhizoxin ([1S-[1R*,3R*,5S*,8R*(1R*,2S*,3E,5E,7E),10R*,11S*,13S*,14E,16S*,17S*]]-10-hydroxy-8-[2-methoxy-1,3,7-trimethyl-8-(2-methyl-4-oxazolyl)-3,5,7-octatrienyl]-11,16-dimethyl-4,7,12,18-tetraoxatetracyclo[15.3.1.03,5.011,13]heneicos-14-ene-6,19-dione) has a potent inhibitory effect on in vivo angiogenesis. However, little is known regarding the mechanism by which rhizoxin exhibits antiangiogenic activity. In this study, we examined its effects on the functions of endothelial cells associated with neovascular formation in vivo, using cultured vascular endothelial cells. Rhizoxin concentration-dependently inhibited the proliferation of bovine carotid artery endothelial cells, human umbilical vein endothelial cells and human dermal microvascular endothelial cells, the IC(50) values being 7, 5 and 0.4 nM, respectively. In addition, it reduced the extracellular plasminogen activator level in bovine vascular endothelial cells in the low nM range, and suppressed the migration of human dermal microvascular endothelial cells in the pM range. Furthermore, it blocked the tubular morphogenesis of human umbilical vein endothelial cells and human dermal microvascular endothelial cells on Matrigel in a concentration-dependent manner; the IC(50) values being 40 and 130 pM, respectively. These results suggest that rhizoxin exhibits antiangiogenic activity through the combined inhibition of some functions of endothelial cells responsible for induction of in vivo angiogenesis.

Angiostatin binds to tyrosine kinase substrate annexin II through the lysine-binding domain in endothelial cells

Angiostatin(AS), an internal fragment of plasminogen, is one of the most potent specific inhibitors of angiogenesis. Angiostatin treatment has resulted in the complete regression of human tumors implanted subcutaneously into nude mice and has great therapeutic value (O'Reilly et al., Nat. Med. 2, 689-692, 1996). Despite promising therapeutic value in the treatment of cancer, the mechanism of its action is still unknown. We found that angiostatin binds to a 35-kDa protein in bovine aortic endothelial (BAE) cells (Sharma et al., Proc. Am. Assoc. Cancer Res. 42, 568, A3050, 2002). In an attempt to begin to understand angiostatin's mechanism of action, we have purified and characterized this 35-kDa protein from BAE cells. Internal peptide sequence analysis of purified protein demonstrated (SLYYIQQDTK, SYSPYDMLESIK, and ALLYLXGGDD) 100% sequence identity with tyrosine kinase substrate annexin II. Solid phase binding analysis suggests that angiostatin specifically bound to purified annexin II immobilized on 96-well plastic plates. Hundred-fold molar excess of unlabeled AS and anti-annexin II antibody inhibited bindings 85 and 55%, respectively, suggesting specific interaction. Annexin II is a predominant receptor for angiostatin, since neutralizing the angiostatin by soluble receptor (annexin II) effectively blocks angiostatin's anti-EC activity. Similarly, saturating the annexin II receptor by plasminogen in endothelial cells also blocks angiostatin's activity. Both angiostatin and plasminogen bind to purified annexin II in BAE cells saturably with apparent K(d) values of 101 and 164 nM, respectively, for purified annexin II and K(d) values of 83 and 125 nM, respectively, for BAE cells. Anti-annexin II monoclonal antibody inhibited angiostatin and plasminogen binding to endothelial cells by 68 and 62%, respectively, supporting our in vitro studies that annexin II is a receptor for angiostatin. Angiostatin-binding protein/annexin II specifically expressed in endothelial cells but not in fibroblasts suggests its EC-specific function. Epsilon-aminocaproic acid, a lys analogue, effectively blocks angiostatin and annexin II interaction, indicating that the lysine-binding domain of AS is required for binding to annexin II. These results suggest that the antiangiogenic action of angiostatin may be mediated via interaction with annexin II. Identification of annexin II as a receptor for angiostatin provides further evidence that clotting and fibrinolytic pathways are directly involved in the angiogenic process.

Mechanisms and future directions for angiogenesis-based cancer therapies

Targeting angiogenesis represents a new strategy for the development of anticancer therapies. New targets derived from proliferating endothelial cells may be useful in developing anticancer drugs that prolong or stabilize the progression of tumors with minimal systemic toxicities. These drugs may also be used as novel imaging and radiommunotherapeutic agents in cancer therapy. In this review, the mechanisms and control of angiogenesis are discussed. Genetic and proteomic approaches to defining new potential targets on tumor vasculature are then summarized, followed by discussion of possible antiangiogenic treatments that may be derived from these targets and current clinical trials. Such strategies involve the use of endogenous antiangiogenic agents, chemotherapy, gene therapy, antiangiogenic radioligands, immunotherapy, and endothelial cell-based therapies. The potential biologic end points, toxicities, and resistance mechanisms to antiangiogenic agents must be considered as these therapies enter clinical trials.

Characterization of rat aortic fragment within collagen gel as an angiogenesis model; capillary morphology may reflect the action mechanisms of angiogenesis inhibitors

A fragment of rat thoracic aorta within type I collagen gel was employed as a model of angiogenesis, including the processes of cell migration, proliferation and capillary tube formation. Endogenous angiogenic factors in this model were studied. Expressions of vascular endothelial growth factor (VEGF) and its receptor, and proteolytic enzyme activities (matrix metalloprotease-2; MMP-2 and plasminogen activator; PA) increased during angiogenesis. The angiogenesis was inhibited by VEGF receptor kinase inhibitor and MMP inhibitor, confirming that these endogenous factors played an important role in angiogenesis. Interestingly, these inhibitors induced different capillary morphologies, including differences of cell migration and sprouting. Furthermore, dexamethasone (a down-regulator of MMP and PA) and TNP-470 (an endothelial cell growth inhibitor) induced another capillary morphology. The results suggest that the capillary structure in this model is dramatically influenced by the inhibition of angiogenic signalling and extracellular matrix (ECM) degradation. We also found that a novel angiogenesis inhibitor, the microbial metabolite luminacin, which was recently identified by us (Wakabayashi et al., J. Antiobiot., 53, 591-596 (2000)), induced a different morphology compared with other inhibitors examined, suggesting that it has a unique mechanism of action. Our results indicate that this rat aorta model should be useful for screening novel angiogenesis inhibitors.

Inhibitory effect on expression of angiogenic factors by antiangiogenic agents in renal cell carcinoma

Since it has been widely recognised that renal cell carcinoma is refractory to standard therapies such as chemotherapy and radiotherapy, a new modality of treatment is needed. One of the potential alternative therapies for renal cell carcinoma may be inhibition of angiogenesis. In this study, we analysed the inhibitory effects of several potential agents on expression of angiogenic factors such as vascular endothelial growth factor and basic fibroblast growth factor, which are the main mediators in angiogenesis of renal cell carcinoma. We used medroxyprogesterone acetate, interferon-alpha, interferon-gamma, minocycline hydrochrolide and genistein, which are known to be antiangiogeneic. Northern blot analyses revealed that, among the five agents examined, genistein had a strong inhibitory effect on expression of vascular endothelial growth factor mRNA and basic fibroblast growth factor mRNA. Medroxyprogesterone acetate and interferon-alpha did not significantly decrease the level of either vascular endothelial growth factor mRNA or basic fibroblast growth factor mRNA. Interferon-gamma and minocycline had mild inhibitory effects on vascular endothelial growth factor mRNA and basic fibroblast growth factor mRNA expression. Genistein also inhibited both vascular endothelial growth factor mRNA and basic fibroblast growth factor mRNA expression after treatment with epidermal growth factor and hypoxia. These findings suggest that one of the mechanisms of the inhibition of angiogenesis by genistein is suppression of the expression of the angiogenic factors vascular endothelial growth factor and basic fibroblast growth factor in renal cell carcinoma.

Use of the progestin challenge test in nonhuman primates (Macaca fascicularis)

OBJECTIVE

To determine whether the progestin challenge test (PCT) would provide a reliable, noninvasive indicator of endometrial stimulation in nonhuman primates. DESIGN; Randomized, 2x2, crossover study. SETTING; Nonhuman primates (Macaca fascicularis) in an academic research environment.

PATIENT(S)

Adult, surgically postmenopausal, female cynomolgous macaques (n = 27) were studied.

INTERVENTION(S)

Females were randomly assigned to receive estradiol (n = 14; 0.028 mg/kg body weight) or vehicle (n = 13) daily. All animals were administered two PCTs in a crossover study design using two doses (0.28 mg/kg or 0.56 mg/kg body weight) of medroxyprogesterone acetate (MPA).

MAIN OUTCOME MEASURE(S)

Incidence and severity of withdrawal bleeding and serum estradiol (E(2)) and progesterone (P(4)) levels were evaluated.

RESULT(S)

Estradiol treatment resulted in endometrial "withdrawal" bleeding in all but one instance. Females receiving daily doses of E(2) exhibited a significantly greater (P<.01) incidence, severity, and duration of withdrawal bleeding compared to control animals. Of the five positive responses observed in the control females, four occurred when the higher dose of MPA was administered.

CONCLUSION(S)

These results indicate that the PCT is a useful, noninvasive method for determining the presence of endometrial stimulation in nonhuman primates.

Vascularization pattern of C6 glioma is modified with medroxyprogesterone acetate and ibuprofen in Wistar rat brain

Beneficial effects of medroxyprogesterone acetate (MPA) in cancer therapy is partly mediated via its antiangiogenic activity. The same is true for the antitumoral action of non-steroidal antiinflammatory drugs. We have studied two liposoluble drugs, MPA and the analgesic ibuprofen, on glioma vascularization in vivo. In this study we have shown that, until the sacrifice at 27. day after tumor inoculation in the right hemisphere, MPA had a slight though insignificant activity to reduce the fatality of C6 glioma, growing in right cerebral hemisphere of male Wistar rats. But ibuprofen both alone or with MPA had no effect on survival with gavage application of a 30 mg/kg/day dosing regime. On histological analysis, intra- and peritumoral vessels were counted. Progesterone seemed to lower intratumoral, but to increase peritumoral vessels, especially glomeruloids, around the tumor mass. Coadministration of ibuprofen acted to suppress the peritumoral vessel increase, and to enhance lymphomonocytic infiltration around tumor vessels.

Thromboembolism in brain tumors

Venous thromboembolism commonly affects patients receiving treatment for primary and secondary cerebral tumors. We review the recent literature on the molecular mechanisms underlying this hypercoagulable state and clinical studies of antithrombotic prophylaxis and therapy in this population. A computerized search of the MEDLINE database for articles from 1966 to the present day. Keywords/search terms used were glioma, astrocytoma, glioblastoma multiforme, cerebral tumor, primary brain tumour, secondary brain tumour, venous thromboembolism, thromboprophylaxis, heparin, warfarin, anticoagulants, and caval filters. Although neurological deficit has been identified as an independent risk factor for thrombosis it is also clear that malignant brain tumors induce changes in the makeup of circulating blood, making it more likely to clot. Concern for the perceived risk of perioperative intracranial bleeding with antithrombotic prophylaxis appears not to be justified by the available evidence. Prospective assessment of low molecular weight heparins for prophylaxis and treatment of established thrombosis is required. Antithrombotic therapy may also offer advantages over intracaval devices in prevention of secondary pulmonary embolism in patients with brain tumors.

Matrix metalloproteinases: pro- and anti-angiogenic activities

Matrix metalloproteinases (MMP) are a family of structurally related proteinases most widely recognized for their ability to degrade extracellular matrix, although recent investigations have demonstrated other biologic functions for these enzymes. MMP are typically not constitutively expressed, but are regulated by: (1) cytokines, growth factors, and cell-cell and cell-matrix interactions that control gene expression; (2) activation of their proenzyme form; and (3) the presence of MMP inhibitors [tissue inhibitors of metalloproteinases, (TIMP)]. MMP have important roles in normal processes including development, wound healing, mammary gland, and uterine involution, but are also involved in angiogenesis, tumor growth, and metastasis. Angiogenesis, characteristically defined as the establishment of new vessels from pre-existing vasculature, is required for biologic processes such as wound healing and pathologic processes such as arthritis, tumor growth, and metastasis. Blocking of MMP activity has been studied for potential therapeutic efficacy in controlling such pathologic processes. Synthetic MMP inhibitors, most notably the hydroxymates, have been engineered for this purpose and are presently in clinical trial. These inhibitors may have broad versus specific MMP inhibitory activity. As increased non-matrix degrading capabilities of MMP are recognized, however, i.e., cytokine activation, processing of proteins to molecules of distinct biologic function, it becomes less clear whether the nonselective inhibition of MMP activity for all pathologic processes involving MMP is appropriate. This review focuses upon the contribution of MMP to the process of tumor invasion and angiogenesis, and discusses the design and use of MMP inhibitors as therapeutic agents in these processes.