Genetic Insights into Age-Related Macular Degeneration.

One of the major causes of vision impairment among elderly people in developed nations is age-related macular degeneration (AMD). The distinctive features of AMD are the accumulation of extracellular deposits called drusen and the gradual deterioration of photoreceptors and nearby tissues in the macula. AMD is a complex and multifaceted disease influenced by several factors such as aging, environmental risk factors, and a person's genetic susceptibility to the condition. The interaction among these factors leads to the initiation and advancement of AMD, where genetic predisposition plays a crucial role. With the advent of high-throughput genotyping technologies, many novel genetic loci associated with AMD have been identified, enhancing our knowledge of its genetic architecture. The common genetic variants linked to AMD are found on chromosome 1q32 (in the complement factor H gene) and 10q26 (age-related maculopathy susceptibility 2 and high-temperature requirement A serine peptidase 1 genes) loci, along with several other risk variants. This review summarizes the common genetic variants of complement pathways, lipid metabolism, and extracellular matrix proteins associated with AMD risk, highlighting the intricate pathways contributing to AMD pathogenesis. Knowledge of the genetic underpinnings of AMD will allow for the future development of personalized diagnostics and targeted therapeutic interventions, paving the way for more effective management of AMD and improved outcomes for affected individuals.

Linking Adiponectin and Its Receptors to Age-Related Macular Degeneration (AMD).

In recent years, there has been a captivating focus of interest in elucidating the intricate crosstalk between adiponectin (APN), a versatile fat-associated adipokine and ocular pathologies. Unveiling the intricate relationship between adipocytokine APN and its receptors (AdipoRs) with aging eye disorders has emerged as a fascinating frontier in medical research. This review article delves into this connection, illuminating the hidden influence of APN on retinal health. This comprehensive review critically examines the latest findings and breakthroughs that underscore the pivotal roles of APN/AdipoRs signaling in maintaining ocular homeostasis and protecting against eye ailments. Here, we meticulously explore the intriguing mechanisms by which APN protein influences retinal function and overall visual acuity. Drawing from an extensive array of cutting-edge studies, the article highlights APN's multifaceted functions, ranging from anti-inflammatory properties and oxidative stress reduction to angiogenic regulation within retinal and macula tissues. The involvement of APN/AdipoRs in mediating these effects opens up novel avenues for potential therapeutic interventions targeting prevalent aging eye conditions. Moreover, this review unravels the interplay between APN signaling pathways and age-related macular degeneration (AMD). The single-cell RNA-seq results validate the expression of both the receptor isoforms (AdipoR1/R2) in retinal cells. The transcriptomic analysis showed lower expression of AdipoR1/2 in dry AMD pathogenesis compared to healthy subjects. The inhibitory adiponectin peptide (APN1) demonstrated over 75% suppression of CNV, whereas the control peptide did not exert any inhibitory effect on choroidal neovascularization (CNV). The elucidation of these relationships fosters a deeper understanding of adipose tissue's profound influence on ocular health, presenting new prospects for personalized treatments and preventative measures. Because APN1 inhibits CNV and leakage, it can be used to treat human AMD, although the possibility to treat human AMD is in the early stage and more clinical research is needed. In conclusion, this review provides a captivating journey into the enthralling world of APN, intertwining the realms of adipose biology and ophthalmology in aging.

New Discoveries in Retinal Cell Degeneration and Retinal Diseases.

Age-related macular degeneration (AMD) has two phenotypes: dry AMD and wet AMD [...].

Emerging Role of Adiponectin/AdipoRs Signaling in Choroidal Neovascularization, Age-Related Macular Degeneration, and Diabetic Retinopathy.

Age-related macular degeneration (AMD), a leading cause of irreversible blindness in adults, may result in poor central vision, making it difficult to see, read, and drive. AMD is generally classified in either dry or wet types. Milder cases of dry AMD may progress to geographic atrophy (GA), leading to significant visual disability; wet, or neovascular AMD, which involves choroidal neovascularization (CNV), can lead to complete loss of central vision. Adiponectin (APN) discovery in the mid-1990's and, subsequently, its two cognate receptors (AdipoRs) in the early 2000s have led to a remarkable progress in better understanding metabolic disorders, as well as metabolism-associated ocular pathology. APN/AdipoRs signaling plays a central role in a variety of molecular and cellular physiological events, including glucose and lipid metabolism, whole-body energy regulation, immune and inflammation responses, insulin sensitivity and retinal cell biological functions. This review is an amalgamation of recent information related to APN/AdipoRs in the pathophysiology of retinal diseases and furthers its association with AMD and diabetic retinopathy. Additionally, we present our original research, where we designed control peptide and CNV inhibitory peptide from the globular region of APN to see the effect of these peptides on the mouse model of laser-induced CNV. The inhibitory peptide (APN1) inhibited CNV by more than 75% while the control peptide did not inhibit CNV.

Role of Adiponectin Peptide I (APNp1) in Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is an eye disease that can cause central vision loss, particularly in the elderly population. There are 2 classes of AMD, wet-type and dry-type. Wet-type involves excess angiogenesis around the macula, referred to as choroidal neovascularization (CNV). This can result in leaky vessels, often causing more severe vision loss than dry-type AMD. Adiponectin peptide 1 (APNp1) has been shown to slow the progression of CNV. Here, we used a mouse model and FITC-labeled APNp1 to determine if APNp1 could be delivered effectively as an eye drop. Our experiment revealed that topically applied FITC-APNp1 could reach the macula of the eye, which is crucial for treating wet-type AMD. We also tested delivery of APNp1 via injection of an adeno-associated virus (AAV) vector in a mouse model of CNV. AAV is a harmless virus easy to manipulate and is very often used for protein or peptide deliveries. Results revealed an increase in the expression of APNp1 in the retina and choroid over a 28-day period. Finally, we investigated the mechanism by which APNp1 affects CNV by examining the expression of adiponectin receptor 1 (AdipoR1) and proliferating cell nuclear antigen (PCNA) in the retinal and choroidal tissue of the mouse eyes. AdipoR1 and PCNA were overexpressed in these tissues in mice with laser-induced CNV compared to naïve mice. Based on our data shown here, we think it will enhance our understanding of APNp1 as a therapeutic agent for wet-type AMD and possible treatment alternatives that could be more beneficial for patients.

Role of thalidomide, senicapoc, and sodium butyrate in choroidal neovascularization.

Choroidal neovascularization (CNV) is the hallmark of wet age-related macular degeneration (AMD), a leading cause of irreversible blindness in the modern world. The objective for this study was to investigate the therapeutic potential of known antiangiogenic agents: thalidomide, senicapoc, and sodium butyrate. Dose-dependent effect of the agents on growth of ARPE-19 cells and human umbilical vein endothelial cells (HUVECs) was investigated with cell counting assays. Half-maximal inhibitory concentrations of thalidomide (765 µM and 1520 µM), senicapoc (50 µM and 79 µM), and sodium butyrate (933 µM and 557 µM) were determined for HUVECs and ARPE-19 cells, respectively. Immunofluorescence analysis showed decrease of VEGFA expression in both ARPE-19 cells and HUVECs after treatment only with thalidomide but not with senicapoc or sodium butyrate. Efficacy of the agents was studied in vivo with laser-induced CNV in C57BL/6 mice. Thalidomide (24 µg), senicapoc (4 µg), or sodium butyrate (100 µg) was intravitreally injected the day after CNV induction. Thalidomide, senicapoc, and sodium butyrate inhibited CNV size by 56%, 24%, and 21% respectively on day 7 post-laser. Thalidomide also reduced cobalt chloride induced increase of VEGFA mRNA in ARPE-19 (-33%) and protein in culture medium (-20%). Our results suggest that thalidomide may have more therapeutic potential than senicapoc or sodium butyrate for treatment of CNV or wet AMD.

Protective role of adiponectin against testicular impairment in high-fat diet/streptozotocin-induced type 2 diabetic mice.

Type 2 diabetes (T2D) is the most common endocrine and metabolic disorder, leading to reproductive impairments and infertility in male. Our recent study showed crucial role of adiponectin in the regulation of testicular functions, and the circulating level of adiponectin declines in diabetes. The current study thus aimed to examine the efficacy of adiponectin in improving testicular dysfunction in high-fat diet/streptozotocin-induced T2D mice. T2D was induced in pre-pubertal mice fed with high-fat diet for ∼10 weeks followed by a single dose of streptozotocin. T2D mice showed presence of increased body mass, hyperglycemia, hyperinsulinemia, insulin resistance, increased oxidative stress, and declined serum testosterone compared to vehicle-treated control mice. The spermatogenic, steroidogenic, metabolic, and antioxidative parameters were evaluated in T2D mice treated with adiponectin for both two and four weeks. The exogenous administration of adiponectin to T2D mice showed enhanced serum testosterone and expression of testicular steroidogenic markers proteins, insulin receptor and GLUT8 proteins, increase in intra-testicular concentrations of glucose and lactate and activity of LDH and antioxidant enzymes compared to the levels in untreated T2D mice. This suggests that treatment of adiponectin effectively improves testicular functions by increasing expression of insulin receptor-mediated increased transport of energy substrate (glucose and lactate) and a marked reduction in oxidative stress are the possible mechanism by which adiponectin effectively improves testicular function in T2D mice.

Inhibitory role of transforming growth factor ß2 in experimental autoimmune anterior uveitis.

PURPOSE: Experimental autoimmune anterior uveitis (EAAU) is a clinically relevant animal model for human idiopathic anterior uveitis (IAU). The role of the immunomodulator transforming growth factor ß2 (TGF-ß2) in EAAU pathology is unknown. In this study, we investigated the regulatory role of TGF-ß2 in EAAU. METHODS: EAAU was induced in male Lewis rats by footpad injection of melanin-associated antigen (MAA). TGF-ß2 was administered intravenously (iv) in MAA-sensitized rats during the induction of EAAU, or after the clinical onset of uveitis. MAA-sensitized rats injected similarly with an equal volume of PBS served as control. Animals were examined daily between days 7 and 30 post-injection for the clinical signs of uveitis using slit lamp biomicroscopy. Animals were sacrificed at various time points and eyes were harvested for histological analysis to assess the course and severity of inflammation. For histopathological analysis, paraffin sections of harvested eyes were stained with hematoxylin and eosin. Popliteal lymph nodes (LNs) were used for CD4+CD25+FoxP3+ T regulatory (Tregs) population analysis and for CD4+ T cell proliferation assay. RESULTS: Administration of recombinant TGF-ß2 during the early stages of EAAU prevented the induction of uveitis. Compared to PBS, the presence of TGF-ß2 in the cell culture significantly (p < 0.05) inhibited the proliferation of CD4+ T cells in response to MAA. In MAA-sensitized Lewis rats, iv treatment with recombinant TGF-ß2 resulted in significantly (p < 0.05) increased percentage of Tregs compared to animals treated similarly with PBS. Thus, TGF-ß2 inhibited the induction of EAAU by inhibiting CD4+ T cell proliferation and increasing the number of Tregs. Injection of TGF-ß2 in rats with active EAAU resulted in diminished disease activity. Unfortunately, this treatment did not lead to the early resolution of EAAU. CONCLUSIONS: TGF-ß2 plays a critical role in regulation of intraocular inflammation in EAAU. Findings reported in this study improve our understanding of immunopathology of IAU and suggest that recombinant TGF-ß2 may be a promising therapeutic agent for human IAU.

Direct actions of adiponectin on changes in reproductive, metabolic, and anti-oxidative enzymes status in the testis of adult mice.

Obesity is a major health problem that is linked to decreased sperm count. It is hypothesized that an obesity-associated reduction in adiponectin secretion may be responsible for impairment of spermatogenesis. Therefore, the aim of the study was to evaluate the direct role of adiponectin in spermatogenesis and steroid synthesis in adult mice. This study showed that adiponectin receptors (AdipoR1 and AdipoR2) were localized in Leydig cells and seminiferous tubules in the testis of adult mice. The result of the in vitro study showed the direct action of adiponectin on spermatogenesis by stimulating cell proliferation (PCNA) and survival (Bcl2) and by suppressing cell apoptosis. Treatment of testis with adiponectin also enhanced transport of the energetic substrates glucose and lactate to protect cells from undergoing apoptosis. Adiponectin treatment further showed a significant reduction in oxidative stress and nitric oxide. Our findings suggest that adiponectin effectively facilitates cell survival and proliferation, as well as protects from apoptosis. Thus, adiponectin treatment may be responsible for enhancing sperm counts. Interestingly, this study showed the stimulatory effect of adiponectin in spermatogenesis but showed an inhibitory effect on testosterone and estradiol synthesis in the testes. Based on the present study, it is hypothesized that systemic adiponectin treatment may be a promising therapeutic strategy for the improvement of spermatogenesis and sperm count.

Role of adiponectin as a modulator of testicular function during aging in mice.

The mechanisms by which testicular functions decline with aging remain largely speculative. Our recent finding showed the importance of adiponectin in the regulation of testicular functions, whereas its concentration declines during male infertility. Thus, the aim of present study was to explore the potential role of adiponectin during aging. The changes in adiponectin, adiponectin-receptors, and insulin receptor proteins expression in the testis were evaluated and compared with the testicular parameters, mass, and testosterone level in the mice from early post-natal to late senescence period. Further, the current study has examined the effect of exogenous adiponectin treatment on testicular functions in aged mice. The results showed a significant decline in adiponectin/adiponectin-receptors expression simultaneously with a significant decline in testicular mass, insulin receptor expression and testosterone synthesis in the testis of aged mice. Exogenous treatment of adiponectin to aged mice resulted in marked improvements in testicular mass, histological features (cells proliferation), insulin receptor expression, testicular glucose uptake, anti-oxidative enzymes activity and testosterone synthesis as compared with the control. Based on these findings, it may be concluded that a marked decline in adiponectin synthesis and action results in decreased insulin sensitivity (development of insulin resistance) and increased oxidative stress which consequently suppresses testicular functions during aging. This study further showed that treatment with adiponectin ameliorates reduced testicular functions by enhanced expression of insulin receptor in the testis of senescent mice. It is thus hypothesized that systemic adiponectin treatment could be a promising therapeutic strategy for improvement of testosterone production and sperm counts during aging.

Adiponectin and Chemerin: Contrary Adipokines in Regulating Reproduction and Metabolic Disorders.

Metabolic disorders such as obesity and type 2 diabetes are one of the most familiar risk factors in the present time among every age-group. It is associated with altered levels of adipokines such as adiponectin, chemerin, leptin, resistin, visfatin, and so on. Adiponectin is one of the adipocyte-specific protein with novel applications pertaining to metabolism by promoting insulin sensitivity and regulating glucose and fatty acid catabolism, while chemerin is considered as an inhibitor of insulin signaling and glucose catabolism. Other than these established functions, both the adipokines are intimately involved in coordinating reproductive activities, but they exhibit contrary functions. This review is an amalgamation of recent information related to adiponectin and chemerin in male and female reproduction and further its association with metabolism-related reproductive disorders. The direct effect of adiponectin and chemerin on various reproductive parameters has been investigated, but there was a rampant failure to account for in vivo data which gives a broad outlook on the regulatory mechanism of both adiponectin and chemerin related to male and female reproductive functions. Adiponectin is known to promote gonadal activities, while chemerin exerts antigonadal actions. Recent research suggests that high chemerin/low adiponectin ratio plays a vital role in causing dyslipidemia and metabolic syndrome in patients. The dysregulated ratio of adiponectin to chemerin during various metabolic disorders makes it really worthy in relation to an application for therapeutics. Still, a lot regarding both the adipokines has to be explored and brought forward in order to deal with therapeutics of metabolism-related reproductive disorders.

Systemic adiponectin treatment reverses polycystic ovary syndrome-like features in an animal model.

The present study examined the efficacy of adiponectin for regulating the reproductive, metabolic and fertility status of mice with polycystic ovary syndrome (PCOS). PCOS was induced in prepubertal (21- to 22-day-old) mice using dehydroepiandrosterone (6mg 100g-1day-1 for 25days), after which mice were administered either a low or high dose of adiponectin (5 or 15µgmL-1, s.c., respectively). PCOS mice exhibited typical features, including the presence of numerous cystic follicles, increased circulating androgens, increased body mass, altered steroidogenesis, decreased insulin receptor expression and increased serum triglycerides, serum glucose, Toll-like receptor (TLR)-4 (a marker of inflammation) and vascular endothelial growth factor (VEGF; a marker of angiogenesis). These parameters were significantly correlated with a reduction in adiponectin in PCOS mice compared with vehicle-treated control mice. Exogenous adiponectin treatment of PCOS mice restored body mass and circulating androgen, triglyceride and glucose levels. Adiponectin also restored ovarian expression of steroidogenic markers (LH receptors, steroidogenic acute regulatory protein and 3ß-hydroxysteroid dehydrogenase), insulin receptor, TLR-4 and VEGF levels in control mice. Adiponectin restored ovulation in PCOS mice, as indicated by the presence of a corpus luteum and attainment of pregnancy. These findings suggest that adiponectin effectively facilitates fertility in anovulatory PCOS. We hypothesise that systemic adiponectin treatment may be a promising therapeutic strategy for the management of PCOS.

Direct action of adiponectin ameliorates increased androgen synthesis and reduces insulin receptor expression in the polycystic ovary.

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder of reproductive age females, leading to infertility. Despite extensive research, the exact pathophysiology and treatment are lacking. The aim of the current study was to evaluate the direct role of adiponectin either alone or together with luteinizing hormone (LH) on sex hormone synthesis and changes in insulin receptor (IR) in the ovary of dehydroepiandrosterone (DHEA)-treated PCOS-mice. Immunohistochemical study showed decreased expression of adiponectin receptor (AdipoR1) in PCOS-ovary which correlated with increased synthesis of androgen and decreased expression of IR. The treatment with adiponectin with or without LH to PCOS-ovary in vitro caused significant decline in androgen synthesis and increase in IR. This study showed the direct role of adiponectin in ameliorating hyperandrogenism and reducing IR in the ovary of PCOS-mice. Thus adiponectin treatment may be a novel therapeutic strategy for combating PCOS.

The Complement Regulatory Protein CD46 Deficient Mouse Spontaneously Develops Dry-Type Age-Related Macular Degeneration-Like Phenotype.

In the mouse, membrane cofactor protein (CD46), a key regulator of the alternative pathway of the complement system, is only expressed in the eye and on the inner acrosomal membrane of spermatozoa. We noted that although Cd46(-/-) mice have normal systemic alternative pathway activating ability, lack of CD46 leads to dysregulated complement activation in the eye, as evidenced by increased deposition of C5b-9 in the retinal pigment epithelium (RPE) and choroid. A knockout of CD46 induced the following cardinal features of human dry age-related macular degeneration (AMD) in 12-month-old male and female mice: accumulation of autofluorescent material in and hypertrophy of the RPE, dense deposits in and thickening of Bruch's membrane, loss of photoreceptors, cells in subretinal space, and a reduction of choroidal vessels. Collectively, our results demonstrate spontaneous age-related degenerative changes in the retina, RPE, and choroid of Cd46(-/-) mice that are consistent with human dry AMD. These findings provide the exciting possibility of using Cd46(-/-) mice as a convenient and reliable animal model for dry AMD. Having such a relatively straight-forward model for dry AMD should provide valuable insights into pathogenesis and a test model system for novel drug targets. More important, tissue-specific expression of CD46 gives the Cd46(-/-) mouse model of dry AMD a unique advantage over other mouse models using knockout strains.

Effect of aspirin on models of retinal pigment epithelium pathology.

BACKGROUND: To characterize the effect of aspirin (ASA) in mouse models of choroidal neovascularization (CNV) and retinal degeneration. METHODS: In vivo: Male C57BL/6 mice were given ASA in food or regular rodent diet. CNV was induced by argon laser photocoagulation. Subretinal injections of polyethylene glycol 400 (PEG-400) were administered to induce retinal degeneration. CNV size, laser spot area and mean intensity of VEGF in the laser injured zones were measured. In the PEG injected eyes the thickness of retinal pigment epithelium (RPE) and choroid was measured. In vitro: Human ARPE-19 cells were treated with 0.5 or 2.0 mM/L of ASA for 72 h. ELISA was used to measure the concentration of VEGF and CCL-2 in the supernatants. Additionally, damaged RPE monolayer was treated with ASA (0.5 or 2.0 mM/L) and vehicle separately. Size of damaged area was measured. ELISA was used to measure secretion of VEGF-A and CCL-2 by damaged cells after 24 h. RESULTS: No statistically significant effect of ASA on CNV size, laser spot size or VEGF expression was noted in CNV model. In the PEG model, ASA did not have any effect on RPE and choroid thickness; however, a significant increase in RPE atrophy was observed (P = 0.02 + 38%). In addition, ASA had a significant effect on the ability of the RPE cells to regenerate and become confluent after mechanical damage. CONCLUSIONS: ASA at doses consumed clinically for various medical causes may not worsen CNV in human subjects. However, ASA may increase RPE atrophy when consumed over long periods of time.

Relationship between the complement system, risk factors and prediction models in age-related macular degeneration.

Studies performed over the past decade in humans and experimental animals have been a major source of information and improved our understanding of how dysregulation of the complement system contributes to age-related macular degeneration (AMD) pathology. Drusen, the hall-mark of dry-type AMD are reported to be the by-product of complement mediated inflammatory processes. In wet AMD, unregulated complement activation results in increased production of angiogenic growth factors leading to choroidal neovascularization both in humans and in animal models. In this review article we have linked the complement system with modifiable and non-modifiable AMD risk factors as well as with prediction models of AMD. Understanding the association between the complement system, risk factors and prediction models will help improve our understanding of AMD pathology and management of this disease.

Polyethylene glycol induced mouse model of retinal degeneration.

Age-related macular degeneration (AMD) is a leading cause of irreversible blindness. This study was done to characterize dry AMD-like changes in mouse retinal pigment epithelium (RPE) and retina after polyethylene glycol (PEG) treatment. We injected male C57BL/6 mice subretinally with PBS, 0.025, 0.25, 0.5 and 1.0 mg of PEG-400 and the animals were sacrificed on day 5. Eyes were harvested and processed for histological analysis. In all other experiments 0.5 mg PEG was injected and animals were sacrificed on days 1, 3, 5 or 14. Paraffin, 5 µm and plastic, 1 µm and 80 nm sections were used for further analysis. Subretinal injection of 0.5 mg PEG induced a 32% reduction of outer nuclear layer (ONL) thickness, 61% decrease of photoreceptor outer and inner segment length, 49% decrease of nuclear density in the ONL and 31% increase of RPE cell density by day 5 after injection. The maximum level of TUNEL positive nuclei in the ONL (6.8 + 1.99%) was detected at day 5 after PEG injection and co-localized with Casp3act. Histological signs of apoptosis were observed in the ONL by light or electron microscopy. Degeneration of RPE cells was found in PEG injected eyes. Gene expression data identified several genes reported to be involved in human AMD. C3, Cfi, Serping1, Mmp9, Htra1 and Lpl were up-regulated in PEG injected eyes compared to PBS controls. PEG leads to morphological and gene expression changes in RPE and retina consistent with dry AMD. This model will be useful to investigate dry AMD pathogenesis and treatment.

Complement regulatory protein CD46 protects against choroidal neovascularization in mice.

Dysregulation of the complement system is increasingly recognized as a contributing factor in age-related macular degeneration. Although the complement regulator CD46 is expressed ubiquitously in humans, in mouse it was previously thought to be expressed only on spermatozoa. We detected CD46 mRNA and protein in the posterior ocular segment (neuronal retina, retinal pigment epithelium, and choroid) of wild-type (WT) C57BL/6J mice. Cd46(-/-) knockout mice exhibited increased levels of the membrane attack complex and of vascular endothelial growth factor (VEGF) in the retina and choroid. The Cd46(-/-) mice were also more susceptible to laser-induced choroidal neovascularization (CNV). In Cd46(-/-) mice, 19% of laser spots were positive for CNV at day 2 after treatment, but no positive spots were detected in WT mice. At day 3, 42% of laser spots were positive in Cd46(-/-) mice, but only 11% in WT mice. A fully developed CNV complex was noted in both Cd46(-/-) and WT mice at day 7; however, lesion size was significantly (P < 0.05) increased in Cd46(-/-) mice. Our findings provide evidence for expression of CD46 in the mouse eye and a role for CD46 in protection against laser-induced CNV. We propose that the Cd46(-/-) mouse has a greater susceptibility to experimental CNV because of insufficient complement inhibition, which leads to increased membrane attack complex deposition and VEGF expression.

Inhibitory role of adiponectin peptide I on rat choroidal neovascularization.

Age-related macular degeneration (AMD) is a leading cause of central blindness in the elderly population. The wet type of AMD is characterized by extensive growth of new vessels. One of the effective strategies to treat wet AMD is to limit the choroidal neovascularization (CNV). We studied the effects of adiponectin peptide I (APNpI) on new vessel growth in laser-induced rat model of wet AMD and on rat choroidal endothelial cell (CEC) culture. CNV size and vessel density were investigated by microscopy. Immunohistochemical staining (IHC) for von Willebrand Factor (vWF), APN, APN receptors 1 (AdipoR1), 2 (AdipoR2), VEGF, VEGF receptor 2 (VEGF-R2), proliferating cell nuclear antigen (PCNA) was performed in CNV area. The mRNA expression of VEGF and VEGF-R2 in RPE-choroid was investigated by RT-PCR and real-time PCR. APNpI inhibited area of CNV by 4 fold, number of vWF positive vessels by 99% and area of subretinal tissue by 40%. The expression of VEGF and VEGF-R2 at mRNA and protein levels decreased after APNpI treatment in vivo. Proliferative index (PCNA) was 5 folds less in laser spots of APNpI treated rats compared to controls. In conclusion, APNpI inhibited formation of new vessels in rat model of CNV by decreasing VEGF, VEGF-R2 expression and cell proliferation. Thus, APNpI may have potential therapeutic use for AMD treatment since it significantly inhibited CNV.

The effect of nicotine on anti-vascular endothelial growth factor therapy in a mouse model of neovascular age-related macular degeneration.

PURPOSE: The purpose of this article is to evaluate the effect of nicotine on anti-vascular endothelial growth factor therapy in the treatment of neovascular age-related macular degeneration. METHODS: One group of mice received nicotine in drinking water and the other group received water only. Choroidal neovascularization (CNV) was induced with a laser. Nicotinic acetylcholine receptor-α7 (nAChRα7) expression was evaluated by immunohistochemistry. Bevacizumab or adiponectin peptide II (APNpII) was injected intravitreally on Day 7 postlaser, and the effects were evaluated on Days 14 and 21. α-Bungarotoxin was injected intraperitoneally on Days 2 to 5, and its effect was evaluated on Day 14. RESULTS: Expression of nAChRα7 was 2 to 7 times higher between Days 3 and 7 postlaser compared with naive mice. In water-fed mice, APNpII, bevacizumab, and α-bungarotoxin significantly reduced CNV size. In nicotine-fed mice, treatment with APNpII or bevacizumab did not significantly reduce CNV size, whereas α-bungarotoxin did have an effect. Comparing water- and nicotine-fed mice, CNV size was 61% to 86% smaller in water-fed mice except for the α-bungarotoxin group, where there was no difference. Platelet-derived growth factor and vascular endothelial growth factor expression was 1.5- to 2.5-fold higher at Day 14 in nicotine-treated mice. CONCLUSION: Nicotine significantly blocks the effect of anti-vascular endothelial growth factor therapy in the treatment of laser-induced neovascular age-related macular degeneration. nAChRα7 is significantly upregulated during the formation of CNV, and treatment with an nAChRα7 antagonist decreases CNV size irrespective of nicotine administration.