IOVS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Espinosa-Heidmann, D. G.
Right arrow Articles by Cousins, S. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Espinosa-Heidmann, D. G.
Right arrow Articles by Cousins, S. W.
(Investigative Ophthalmology and Visual Science. 2002;43:1567-1573.)
© 2002 by The Association for Research in Vision and Ophthalmology, Inc.

Age as an Independent Risk Factor for Severity of Experimental Choroidal Neovascularization

Diego G. Espinosa-Heidmann1, Ivan Suner1, Eleut P. Hernandez1, William D. Frazier1, Karl G. Csaky2 and Scott W. Cousins1

1 From the Bascom Palmer Eye Institute, Department of Ophthalmology, The University of Miami School of Medicine, Miami, Florida; and the 2 National Eye Institute, National Institutes of Health, Bethesda, Maryland.


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
PURPOSE. For many vascular diseases, aging appears to be an independent risk factor for severity of vascular complications, and blood vessels of aged individuals often demonstrate exaggerated repair responses to injury. This study was undertaken to determine the influence of aging on the severity of neovascularization in a mouse model of laser-induced choroidal neovascularization (CNV).

METHODS. CNV was induced in young (2-month-old) and aged (16-month-old) C57BL/6 mice by making four separate choroidal burns in each eye with a diode red laser (650 nm). At 1, 2, and 4 weeks, the left eyes were removed for histopathology, and the right eyes were removed for flatmount analysis of CNV surface area, vascularity, and cellularity.

RESULTS. Aged mice demonstrated a much larger area of CNV than did young mice (3.81 ± 1.28 vs. 1.36 ± 0.99 disc areas, P < 0.001) at 2 weeks, when the lesions showed maximum growth. Aged mice also demonstrated higher ratios for vascularity and cellularity of the CNV (1.34 ± 0.06 vs. 1.03 ± 0.11, P < 0.0001 and 4.06 ± 1.19 vs. 1.91 ± 0.81, P < 0.002 at 2 weeks, respectively). Histopathology revealed that CNV in older eyes was larger, thicker, and more cellular than in young eyes.

CONCLUSIONS. In mice, age is associated with more severe CNV, defined as larger surface area, greater vascularity, and greater cellularity. Age–related systemic susceptibility factors, independent of local changes in the retina, may contribute to the greater severity of CNV in older than in younger individuals.


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 
Choroidal neovascularization (CNV) is the major vision-threatening complication associated with several common retinal degenerative or inflammatory diseases, especially age-related macular degeneration (AMD),1 2 3 4 5 pathologic myopia, angioid streaks, and ocular histoplasmosis.6 7 8 The severity of CNV (defined as size of affected area, amount of hemodynamic instability, and tendency to form large disciform scars) appears to be strongly associated with both the underlying degenerative disorder and the age of the affected individual. CNV in ocular histoplasmosis or myopia, which occurs in young individuals, tends to present as small classic CNV, shows development of minor exudation, and often evolves into relatively small fibrotic scars.9 10 11 In AMD, CNV typically grows large, is hemodynamically unstable (i.e., exudes plasma and tends to hemorrhage) and often progresses into large fibrovascular scars.

The specific biological factors that predispose to more severe CNV are unknown. Disease-specific differences in the severity of subretinal degenerative changes are often proposed as a significant factor in the severity of CNV. For instance, in ocular histoplasmosis, RPE degeneration is usually localized to small inflammatory foci, which are the site of CNV’s formation.12 13 14 15 In AMD, however, widespread RPE degeneration, deposits in Bruch membrane, and choriocapillaris damage are present. These degenerative changes may contribute significantly to the nature and severity of CNV.16 17 18

However, another possible mechanism contributing to CNV’s severity is the presence of age-related changes in systemic biology,19 20 21 22 independent of subretinal degeneration. In particular, aging individuals often demonstrate dysfunctional blood vessel repair after vascular injury, leading to increased endothelial and smooth muscle proliferation, abnormal repair of the extracellular matrix, excessive fibrosis, and even angiogenesis.23 This concept of age-related "dysfunctional response to vascular injury" is relevant in several age-related vascular diseases, such as renal glomerulosclerosis24 25 26 27 28 and coronary neointimal proliferation after angioplasty.29 30 31 32 33 34 35 The specific role of aging as a pathogenic mechanism of CNV’s formation has not been evaluated.

The purpose of this study was to examine the role of age as an independent risk factor for the severity of CNV in a mouse model of diode laser injury to the choroid. We observed that older mice demonstrated much more severe CNV, defined as larger surface area, greater vascularity, and greater cellular density. However, collagen content and morphologic features were similar.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Mice
Mice used in this study were handled in accordance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. A total of 43 female, normal C57BL/6 mice age 2 months (n = 21; weight, 18–20 g) and 16 months (n = 22; weight, 25–30 g), at the onset of the study, were purchased from the National Institute on Aging (Bethesda, MD).

Laser Treatment
Mice were anesthetized with an intramuscular administration of ketamine hydrochloride (42.8 mg/kg; Fort Dodge Animal Health, Fort Dodge, IA), xylazine (8.5 mg/kg; Phoenix Scientific, Inc., St. Joseph, MO), and acepromazine (1.4 mg/kg; Phoenix Scientific, Inc.). Pupillary dilation was achieved by using 1.0% tropicamide (Alcon Laboratories, Fort Worth, TX) and 2.5% phenylephrine hydrochloride (Akorn, Buffalo Grove, IL). A diode red laser (650 nm; OcuLight SLx; Iris Medical Instruments, Inc., Mountain View, CA) was delivered to the retina through a slit lamp biomicroscope (Haag-Streit; Mason, OH) using a 22 x 22-mm coverglass (Baxter Health Care Corp., McGaw Park, IL) as a contact lens. Treatment parameters were chosen to produce a cavitation bubble in the choroid without hemorrhage. This was achieved in both young and old mice with 75-µm spot size, 150-mW intensity, and 100-ms duration. Mice with obvious media opacities (i.e., cornea and/or lens) were excluded. Four laser burns were performed in the 12, 3, 6, and 9 o’clock positions of the posterior pole around the optic nerve of both eyes of the animals. One, 2, and 4 weeks later, eyes were examined for CNV by the various methods described in the following sections.

Fluorescein Angiography and Preparation for Analysis
Sodium fluorescein (0.03 mL of 10 mg/mL; Akorn) was injected into the heart of the anesthetized mice. The angiograms were recorded using a camera (MD-R; Nikon, Garden City, NY) attached to an operating microscope (Op-Mi6; Carl Zeiss, Thornwood, NY) and a custom-made angiography machine with a power supply flash of 50 to 400 joules (Carl Zeiss). Photographs were taken at approximately 1 and 5 minutes after dye injection. Mice were then perfused through the heart with a mixture of high-molecular-weight fluorescein-isothiocyanate (FITC)-dextran (Sigma, St. Louis, MO): 2 x 106 molecular weight + 4 x 104 molecular weight in a proportion of 2:1, in lactated Ringer’s solution at a concentration of 10 mg/mL (0.6 mL of this solution was injected into each animal). The right eye was enucleated for flatmount preparation. Each animal was then perfused and fixed through the heart with formaldehyde, buffered 10% (Ricca Chemical Company, Arlington, TX). Left eyes were enucleated and stored in fixative for 24 hours.

Histology
Fixed globes from young and old mice at 1, 2, or 4 weeks after laser treatment were embedded in paraffin and processed for standard hematoxylin and eosin (H&E) staining, to assess standard morphology, or Masson’s trichrome staining, to assess collagen and matrix formation. Serial thick sections were examined from the entire retina, and a single specimen representing the largest and thickest specimen within the examined specimens was evaluated for each eye. H&E- and Masson’s trichrome–stained sections were digitized using a light microscope (Labophot; Nikon) connected to a color video camera and a frame grabber (DEI-750; Optronics, Goletta, CA). Using image analysis software (Photoshop 5.5; Adobe, San Diego, CA), the diameter and maximum thickness of CNV were calculated from H&E specimens in pixel dimensions. The relative collagen content was approximated from the Masson’s trichrome–stained specimens by determination of the ratio of the average luminosity of the blue channel from the extracellular matrix of the lesion divided by the average density of the blue channel taken from representative areas within the sclera.

Flatmount Preparation
A technique to visualize FITC-dextran–perfused vessels within CNV was modified to allow simultaneous visualization of cell nuclei within the lesion. The anterior segment and the neurosensory retina were removed. Four radial relaxing incisions were made in the remaining sclera–choroid–RPE complex. RPE was removed using microsponges (Alcon Laboratories) after placing the tissue on a glass slide with the laser spots facing upward under an operating microscope (Op-Mi6; Carl Zeiss). Cellular nuclei were stained with a mixture of 1 mg/mL digitonin (Sigma) and 0.5 mg/mL propidium iodide (PI; Sigma). Green FITC and red propidium fluorescence within the neovascular complexes was visualized under an immunofluorescence microscope (Axiophot Photomicroscope; Carl Zeiss), in which an objective of x4 and FITC filter (exciter filter: 450–490 nm; dichroic mirror: 510 nm; LP Filter: 520 nm) and PI filters were used, respectively (exciter filter: 510–561 nm; dichroic mirror: 580 nm; LP filter: 590 nm). A color video camera and a frame grabber (DEI-750; Optronics) were used to digitize the images.

Surface area of CNV was determined by using either FITC-dextran fluorescence or PI fluorescence, and outlining the margins of the lesion with the image-analysis software (Photoshop; Adobe). The area in pixels was normalized by dividing by the average area of the disc measured in 10 independent eyes. Five eyes were examined 4 hours after laser treatment, to determine the average laser spot size (0.48 disc areas). A CNV was defined as present if the surface area of an individual lesion was more than 0.50 disc areas.

An index of vascularity was approximated by calculating the ratio of the average luminosity of the green channel of FITC images from five samples within the CNV compared with five independent samples from the normal choroid away from the CNV (i.e., background luminosity). An index of cellular density was approximated by calculating the average luminosity of the red channel within the lesion divided by the average density from the normal choroid away from the CNV (i.e., background choroidal cellular density).

Statistical Analysis
Morphometric data for different lesions in each eye were averaged to provide one value per eye. The mean and SD for these measures for each group was calculated and probabilities (t-test) were determined by computer (Prism 3.0; GraphPad Software Inc., San Diego, CA). Results at P < 0.05 were considered statistically significant for all forms of statistical analysis used.


   Results
Top
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
Comparison of fluorescein angiography between young and old mice revealed a similar frequency of fluorescein leakage in approximately 75% of the cases. Young mice revealed the typical pattern of early focal hyperfluorescence that increased in size over time. However, older mice demonstrated larger areas of early hyperfluorescence and much greater areas and intensity of late fluorescein leakage, suggesting pooling of subretinal fluid (Fig. 1) .



View larger version (106K):
[in this window]
[in a new window]
  		Figure 1. Fluorescein angiograms of eyes obtained 2 weeks after diode laser photocoagulation. Young mice showed the typical pattern of early (A) focal hyperfluorescence that increased in size over time (B). However, older mice demonstrated a larger area of early (C) hyperfluorescence and a much greater area and intensity of late (D) fluorescein leakage, suggesting pooling of subretinal fluid.

 
Histopathology confirmed that CNV in older mice had much larger diameter and thicker center (Fig. 2) , which was confirmed with quantitative analysis (Fig. 3) . Morphologic features of CNV between young and old were similar, except for the presence of prominent RPE cystlike structures underlying the CNV in the larger lesions of older mice. These pseudocystic cavities did not fill with fluorescein or FITC-dextran and were similar to those observed in the primate model.36



View larger version (109K):
[in this window]
[in a new window]
  		Figure 2. Histopathology sections confirmed that CNV lesions in younger mice (A, B) were of a smaller diameter and thickness than the lesions in older mice (C, D). Arrows demarcate the lesion’s diameter. Morphologic features of the CNV lesions in both young and old were similar, except for the presence of large RPE cystlike structures ({star}) beneath the lesions in the older mice. Stain, H&E. Magnification, (A, C) x40; (B, D) x100.

 


View larger version (16K):
[in this window]
[in a new window]
  		Figure 3. Quantitative analysis of histopathology sections confirming thicker (A) and larger diameter (B) of CNV lesions in old mice.

 
Flatmount analysis better demonstrated the increased size, vascularity, and cellularity in CNV from old mice (Fig. 4) . CNV (defined as surface area >0.5 disc areas) was observed in 68 (94%) of 72 lesions in 2-month-old mice and in all 76 (100%) the lesions induced in 16-month-old animals. CNV in young mice reached maximum size within 14 days and showed four small, discrete circular lesions with poorly defined margins by FITC. In contrast, CNV in older mice were much larger, with irregular borders and extensions. CNV from different laser spots often became confluent. The margins of the lesion outlined by PI fluorescence (i.e., cell nuclei) was slightly larger than the margins by FITC, suggesting the presence of more avascular cellular growth at the margins of the CNV in older mice. Quantitative analysis of the surface area of CNV over time confirmed that older mice had significantly larger areas of CNV (Figs. 5A 5B) .



View larger version (77K):
[in this window]
[in a new window]
  		Figure 4. Flatmount preparation provided better visualization of the increased size, vascularity, and cellularity in CNV in old mice. CNV in young mice reached maximum size within 14 days and by FITC (A) were seen as four small discrete circular lesions with poorly defined margins (dotted circles). In contrast, CNV in older (C) mice were much larger, with irregular borders and extensions shown by FITC. CNV from different laser spots often became confluent (dotted lines). The margins of the lesions when outlined by PI staining (i.e., cell nuclei) were slightly larger than shown by FITC in both young (B) and old (D), suggesting a more avascular margin of cellular growth in CNV of older mice. Circled D, optic disc.

 


View larger version (33K):
[in this window]
[in a new window]
  		Figure 5. Quantitative analysis of flatmounted specimens, confirming that older mice had significantly larger CNV lesions when measured by both FITC (A) and PI (B). The relative vascularity of the lesions was measured by calculating the ratio of FITC fluorescence in the lesion compared with the background choroid. The data showed a significantly greater luminosity index in the older mice (C). Cellular density of CNV was measured by calculating the ratio of fluorescent luminosity from the PI nuclear staining in the lesion compared with the background choroid. This cellularity index also was significantly greater in the older mice (D).

 
The relative vascularity of CNV in young and old mice was calculated by measuring the ratio of FITC fluorescence in the lesion compared with that in the background choroid. The data showed a significantly greater luminosity index in the older mice (Fig. 5C) .

We also evaluated the cell density in CNV by measuring the ratio of fluorescent luminosity from the PI nuclear staining in the lesion compared with that in the background choroid. This cellularity index also was significantly greater in the older mice at all time points (Fig. 5D) .

Finally, we measured the amount of extracellular matrixdeposition, by using Masson’s trichrome stain. Qualitative assessment indicated that, as expected, a greater matrix area was present in the larger CNV of older mice (Fig. 6) . However, no statistically significant difference was found in the relative density of matrix deposition evaluated by relative Masson’s trichrome uptake within the CNV (Fig. 7) , suggesting that there is no major difference in the relative collagen concentration per unit area of extracellular matrix.



View larger version (53K):
[in this window]
[in a new window]
  		Figure 6. Masson’s trichrome–stained sections demonstrating extracellular matrix deposition. Qualitative analysis showed that there was less extracellular matrix deposition in young (A) than in old (B) mice.

 


View larger version (23K):
[in this window]
[in a new window]
  		Figure 7. No statistical difference was found in the relative density of matrix deposition evaluated by relative Masson’s trichrome uptake within CNV. This suggests that there is no major difference in the relative collagen concentration per unit area of extracellular matrix at the different time points studied after diode laser photocoagulation.

 

   Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
We evaluated the severity of CNV induced by laser injury to the choroid in young and old mice. We found that CNV in older mice were larger, thicker, more cellular, and probably more vascularized than CNV in younger mice. However, we did not observe a difference in frequency of fluorescein leakage or in relative extracellular matrix concentration. Nevertheless, the amount of leakage and amount of matrix was probably greater in older mice, because of the increased size of the CNV.

The effect of aging on the formation of pathologic or physiologic neovascularization in nonocular tissues is controversial, and only a few studies have addressed the question. Some studies have suggested the existence of impaired angiogenesis in aging animals, especially in models based on postischemic neovascularization. For example, studies investigating neovascularization after hindlimb ischemia have concluded that aging impairs physiologic neovascularization.37 Also, partial impairment in border zone angiogenesis was observed more often in older than in younger patients with stroke.38 Proposed mechanisms have included the age-related loss of expression of angiogenic growth factors, loss of the proliferative capacity of aging endothelial cells, or loss of the expression of endothelial enzymes responsible for digesting the extracellular matrix.39 40 41 42 43 44 45

Other studies, however, suggest that increased neovascular responses occur in older animals, especially those using models of vascular injury. In fact, abnormal vascular repair after blood vessel injury in aged individuals has been demonstrated in several nonocular vascular beds. Aortic injury in rats resulted in increased neointimal proliferation of vascular smooth muscle cells in aged rats when compared with younger animals.46 47 Aging also increases susceptibility to injury-induced nephropathy in animals, resulting in progressive glomerular basement membrane thickening and blood vessel proliferation.48 49 In addition, aging appears to be associated with increased vasoproliferation in a mouse model for neurodegeneration.50 51 52 Proposed age-related biological changes that might influence excessive vascular repair in aging include loss of soluble growth inhibitors from the blood (i.e., sex hormones),53 54 55 56 increase in soluble growth stimulants (i.e., cholesterol and lipids),57 58 59 60 changes in immune function (i.e., low-grade inflammation)19 20 21 22 or changes in the circulating vascular progenitors cells responsible for regenerating injured vessels (i.e., increase in the number of circulating vascular progenitors).61 62 63

Our experiments were designed to evaluate the impact of aging on the severity of CNV. Although we cannot rule out the contribution of age-related changes in the biology of the choriocapillaris or Bruch membrane in older mice, we believe that the best explanation for our data is the presence of age-related dysregulation in choroidal vascular repair after laser injury, resulting in the abnormal regulation of CNV growth and development in older mice. The present study does not address the mechanisms regulating the severity of CNV, although we are currently evaluating the contribution of inflammatory stimuli. Furthermore, the effect of age must be confirmed in another CNV model based on angiogenic factor overexpression,64 rather than laser injury.

These results also indicate that it is feasible to measure different parameters of CNV to assess severity. Although plasma exudation and hemorrhage are considered to be complications that most acutely cause loss of vision in humans, the presence of CNV in the absence of leakage (i.e., after successful photodynamic therapy) is still associated with chronic progressive loss of vision.65 66 67 68 For example, even in the absence of active leakage, CNV may be associated with abnormal overlying RPE,69 70 71 cells within CNV may produce cytotoxins injurious to photoreceptors,72 73 74 75 76 or CNV may disrupt transport between retina and choroid. Thus, it is possible that measurement of cell density, matrix deposition, and other parameters may be useful markers to evaluate long-term complications of CNV.


   Footnotes
 
Presented at the annual meeting of the Association for Research in Vision and Ophthalmology, Fort Lauderdale, Florida, May 2001.

Supported by National Eye Institute and National Institute of Allergy and Infectious diseases Grant EY/AI-13318.

Submitted for publication October 4, 2001; accepted December 21, 2001.

Commercial relationships policy: N.

The publication costs of this article were defrayed in part by page charge payment. This article must therefore be marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

Corresponding author: Scott W. Cousins, Bascom Palmer Eye Institute, William L. McKnight Vision Research Center, 1638 NW 10th Avenue, Miami, FL 33136; scousins{at}med.miami.edu.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. Ferris, FL. (1983) Senile macular degeneration: review of epidemiologic features Am J Epidemiol 118,132-151[Free Full Text]
  2. Young, RW. (1987) Pathophysiology of aged-related macular degeneration Surv Ophthalmol 31,291-306[Medline][Order article via Infotrieve]
  3. Starr, CE, Guyer, DR, Yannuzzi, LA. (1998) Aged-related macular degeneration Postgrad Med 103,153-164
  4. O’Shea, JG. (1996) Age-related macular degeneration: a leading cause of blindness Med J Aust 165,561-564[Medline][Order article via Infotrieve]
  5. Snow, KK, Seddon, JM. (1999) Do age-related macular degeneration and cardiovascular disease share common antecedents? Ophthalmic Epidemiol 6,125-143[Medline][Order article via Infotrieve]
  6. Hotchkiss, ML, Fine, SL. (1981) Pathologic myopia and choroidal neovascularization Am J Ophthalmol 91,177-183[Medline][Order article via Infotrieve]
  7. Cohen, SY, Laroche, A, Leguen, Y, Soubrane, G, Coscas, GJ. (1996) Etiology of choroidal neovascularization in young patients Ophthalmology 103,1241-1244[Medline][Order article via Infotrieve]
  8. Sickenberg, M, Schmidt-Erfurth, U, Miller, JW, et al (2000) A preliminary study of photodynamic therapy using verteporfin for choroidal neovascularization in pathologic myopia, ocular histoplasmosis syndrome, angioid streaks, and idiopathic causes Arch Ophthalmol 117,327-336
  9. Fried, M, Siebert, A, Meyer-Schwickerath, G, Wessing, A. (1980) Natural history of Fuchs’ spot: a long-term follow-up study Doc Ophthalmol Proc Series 28,215-221
  10. Avila, MP, Weiter, JJ, Jalkh, AE, Trempe, CL, Pruett, RC, Schepens, CL. (1984) Natural history of choroidal neovascularization in degenerative myopia Ophthalmology 91,1573-1581[Medline][Order article via Infotrieve]
  11. . Macular Photocoagulation Study Group (1996) Five-year follow eyes of individuals with ocular histoplasmosis and unilateral extrafoveal or juxtafoveal choroidal neovascularization Arch Ophthalmol 114,677-688[Abstract/Free Full Text]
  12. Smith, RE, Dunn, S, Jester, JV. (1984) Natural history of experimental histoplasmic choroiditis in the primate Invest Ophthalmol Vis Sci 25,810-819[Abstract/Free Full Text]
  13. Jester, JV, Smith, RE. (1985) Subretinal neovascularization after experimental ocular histoplasmosis in a subhuman primate Am J Ophthalmol 100,252-258[Medline][Order article via Infotrieve]
  14. Anderson, A, Clifford, W, Palvolgyi, I, Rife, L, Taylor, C, Smith, R. (1992) Immunopathology of chronic experimental histoplasmic choroiditis in the primate Invest Ophthalmol Vis Sci 33,1637-1641[Abstract/Free Full Text]
  15. Palvolgyi, I, Anderson, A, Rife, L, Taylor, C, Smith, R. (1993) Immunopathology of reactivation of experimental ocular histoplasmosis Exp Eye Res 57,169-175[Medline][Order article via Infotrieve]
  16. Bressler, NM, Bressler, SB, Fine, SL. (1988) Aged-related macular degeneration Surv Ophthalmol 32,375-413[Medline][Order article via Infotrieve]
  17. Bressler, SB, Maguire, MG, Bressler, NM, Fine, SL. (1990) Relationship of drusen and abnormalities of the retinal pigment epithelium to the prognosis of neovascular macular degeneration Arch Ophthalmol 108,1442-1447[Abstract/Free Full Text]
  18. Bressler, NM, Silva, JC, Bressler, SB, Fine, SL, Green, WR. (1994) Clinicopathologic correlation of drusen and retinal pigment epithelial abnormalities in age-related macular degeneration Retina 14,130-142[Medline][Order article via Infotrieve]
  19. Franceschi, C, Bonafè, M, Valensin, S, et al (2000) Inflamm-aging Ann N Y Acad Sci 900,244-254
  20. Kirwood, TBL, Franceschi, C. (1992) Is aging as complex as it would appear Ann N Y Acad Sci 663,412-417[Medline][Order article via Infotrieve]
  21. Franceschi, C, Valensin, S, Fagnoni, F, Barbi, C, Bonafè, M. (1999) Biomarkers of immunosenescence within an evolutionary perspective: the challenge of heterogeneity and the role of antigenic load Exp Gerontol 34,911-921[Medline][Order article via Infotrieve]
  22. Franceschi, C, Bonafè, M, Valensin, S. (2000) Human immunosenescence: the prevailing of innate immunity, the failing of clonotypic immunity, and the filling of immunological space Vaccine 18,1717-1720[Medline][Order article via Infotrieve]
  23. Bilato, C, Crow, MT. (1996) Atherosclerosis and the vascular biology of aging Aging Clin Exp Res 8,221-234
  24. Neugarten, J, Gallo, G, Silbiger, S, Kasiske, B. (1999) Glomerulosclerosis in aging humans is not influenced by gender Am J Kidney Dis 34,884-888[Medline][Order article via Infotrieve]
  25. Ungar, A, Castellani, S, Di Sergio, CD, et al (2000) Changes in renal autacoids and hemodynamics associated with aging and isolated systolic hypertension Prostaglandins Other Lipid Mediat 62,117-133[Medline][Order article via Infotrieve]
  26. Johnson, RJ. (1997) What mediates progressive glomerulosclerosis? The glomerular endothelium comes of age Am J Pathol 151,1179-1181[Medline][Order article via Infotrieve]
  27. Magil, A, Cohen, A. (1989) Monocytes and focal glomerulosclerosis Lab Invest 61,404-409[Medline][Order article via Infotrieve]
  28. Johnson, RJ. (1994) The glomerular response to injury: progression or resolution? Kidney Int 45,1769-1782[Medline][Order article via Infotrieve]
  29. Nilson, J. (1986) Growth factors and the pathogenesis of atherosclerosis Atherosclerosis 62,185-199[Medline][Order article via Infotrieve]
  30. Hazzard, WR. (1989) Atherosclerosis and aging: a scenario in flux Am J Cardiol 63,20H-24H[Medline][Order article via Infotrieve]
  31. Brindle, NPJ. (1993) Growth factors in endothelial regeneration Cardiovasc Res 27,1162-1172
  32. Newby, AC, George, SJ. (1993) Proposed roles for growth factors in mediating smooth muscle proliferation in vascular pathologies Cardiovasc Res 27,1173-1183[Free Full Text]
  33. Van Belle, E, Bauters, C, Asahara, T, Isner, JM. (1998) Endothelial regrowth after arterial injury: from vascular repair to therapeutics Cardiovasc Res 38,54-68[Free Full Text]
  34. Bauters, C, Six, I, Van Belle, E. (1999) Growth factors and endothelial dysfunction Drugs 58,13-18
  35. Owens, GK. (1995) Regulation of differentiation of vascular smooth muscle cells Physiol Rev 75,487-517[Abstract/Free Full Text]
  36. Miller, H, Miller, B, Ryan, SJ. (1986) The role of retinal pigment epithelium in the involution of subretinal neovascularization Invest Ophthalmol Vis Sci 27,1644-1652[Abstract/Free Full Text]
  37. Rivard, A, Fabre, JE, Silver, M, et al (1999) Age-dependent impairment of angiogenesis Circulation 99,111-120[Abstract/Free Full Text]
  38. Szpak, GM, Lechowicz, W, Lewandowska, E, Bertrand, E, Wierzba-Bobrowicz, T, Dymecki, J. (1999) Border zone neovascularization in cerebral ischemic infarct Folia Neuropathol 37,264-268[Medline][Order article via Infotrieve]
  39. Reed, MJ, Corsa, A, Pendergrass, W, Penn, P, Sage, EH, Abrass, B. (1998) Neovascularization in aged mice: delayed angiogenesis is coincident with decreased levels of transforming growth factor ß and type I Collagen Am J Pathol 152,113-123[Abstract]
  40. Rivard, A, Berthou-Soulie, L, Principe, N, et al (2000) Age-dependent defect in vascular endothelial growth factor expression is associated with reduced hypoxia-inducible factor 1 activity J Biol Chem 275,29643-29647[Abstract/Free Full Text]
  41. Swift, ME, Kleinman, HK, DiPietro, LA. (1999) Impaired wound repair and delayed angiogenesis in aged mice Lab Invest 79,1479-1487[Medline][Order article via Infotrieve]
  42. Breitschopf, K, Zeiher, AM, Dimmeler, S. (2001) Pro-atherogenic factors induce telomerase inactivation in endothelial cells through an Akt-dependent mechanism FEBS Lett 493,21-25[Medline][Order article via Infotrieve]
  43. Reed, MJ, Corsa, AC, Kudravi, SA, McCormick, RS, Arthur, WT. (2000) A deficit in collagenase activity contributes to impaired migration of aged microvascular endothelial cells J Cell Biochem 77,116-126[Medline][Order article via Infotrieve]
  44. Marinho, A, Soares, R, Ferro, J, Lacerda, M, Schmitt, C. (1997) Angiogenesis in breast cancer is related to age but not to other prognostic parameters Pathol Res Pract 193,267-273[Medline][Order article via Infotrieve]
  45. Ashcroft, GS, Horan, MA, Ferguson, WJ. (1997) Aging is associated with reduced deposition of specific extracellular matrix components, an upregulation of angiogenesis, and an altered inflammatory response in a murine incisional wound healing model J Invest Derm 108,430-437[Medline][Order article via Infotrieve]
  46. Stemerman, MB, Weinstein, R, Rowe, JW, Maciag, T, Fuhro, R, Gardner, R. (1982) Vascular smooth muscle cell growth kinetics in vivo in aged rats Proc Natl Acad Sci 79,3863-3866[Abstract/Free Full Text]
  47. Hairiri, RJ, Alonso, DR, Hajjar, DP, Coletti, D, Weksler, ME. (1986) Aging and arteriosclerosis. I: development of myointimal hyperplasia after endothelial injury J Exp Med 164,1171-1178[Abstract/Free Full Text]
  48. Abrass, CK. (2000) The nature of chronic progressive nephropathy in aging rats Adv Ren Replace Ther 7,4-10[Medline][Order article via Infotrieve]
  49. Razzaque, MS, Shimokawa, I, Nazneen, A, Higami, Y, Taguchi, T. (1998) Age-related nephropathy in the Fischer 344 rat is associated with overexpression of collagens and collagen-binding heat shock protein 47 Cell Tissue Res 293,471-478[Medline][Order article via Infotrieve]
  50. Campbell, IL, Abraham, CR, Masliah, E, et al (1993) Neurologic disease induced in transgenic mice by cerebral overexpression of interleukin 6 Proc Natl Acad Sci USA 90,10061-10065[Abstract/Free Full Text]
  51. Fee, D, Grzybicki, D, Dobbs, M, et al (2000) Interleukin 6 promotes vasculogenesis of murine brain microvessel endothelial cells Cytokine 12,655-665[Medline][Order article via Infotrieve]
  52. Kalaria, RN. (1996) Cerebral vessels in ageing and Alzheimer’s disease Pharmacol Ther 72,193-214[Medline][Order article via Infotrieve]
  53. Chen, SJ, Li, H, Durand, J, Oparil, S, Chen, YF. (1996) Estrogen reduces myointimal proliferation after balloon injury of rat carotid artery Circulation 93,577-584[Abstract/Free Full Text]
  54. Krasinski, K, Spyridopoulos, I, Asahara, T, Van der Zee, R, Isner, JM, Losordo, DW. (1997) Estradiol accelerates functional endothelial recovery after arterial injury Circulation 95,1768-1772[Abstract/Free Full Text]
  55. White, CR, Shelton, J, Shi-Juan, BS, et al (1997) Estrogen receptor endothelial cell function in an experimental model of vascular injury Circulation 96,1624-1630[Abstract/Free Full Text]
  56. Selzman, CH, Whitehill, TA, Shames, BD, Pulido, EJ, Cain, BC, Harken, AH. (1998) The biology of estrogen-mediated repair of cardiovascular surgery Ann Thorac Surg 65,868-874[Abstract/Free Full Text]
  57. Yui, S, Mizuno, D, Yamazaki, M. (1985) Induction of macrophage growth by the lipid moiety of lipoprotein and its augmentation by denaturation of the lipoproteins J Leukoc Biol 38,697-707[Abstract]
  58. Chen, JK, Hoshi, H, McClure, DB, McKeehan, WL. (1986) Role of lipoproteins in growth of human adult arterial endothelial and smooth muscle cells in low lipoprotein-deficient serum J Cell Physiol 129,207-209[Medline][Order article via Infotrieve]
  59. Chatterjee, S. (1992) Role of oxidized human plasma low density lipoprotein in atherosclerosis: effects on smooth muscle cell proliferation Mol Cell Biochem 111,143-147[Medline][Order article via Infotrieve]
  60. Björkerud, S, Björkerud, B. (1994) Lipoproteins are major and primary mitogens and growth promoters for human arterial smooth muscle cells and lung fibroblasts in vitro Arterioscler Thromb 14,288-298[Abstract/Free Full Text]
  61. Bertolini, F, Mancuso, P, Gobbi, A, Pruneri, G. (2000) The thin red line: angiogenesis in normal and malignant hematopoiesis Exp Hematol 28,993-1000[Medline][Order article via Infotrieve]
  62. Asahara, T, Masuda, H, Takahashi, T, et al (1999) Bone marrow origin of endothelial progenitor cells responsible for postnatal vasculogenesis in physiological and pathological neovascularization Circ Res 85,221-228[Abstract/Free Full Text]
  63. Shi, Q, Rafii, S, Hong-De Wu, M, et al (1998) Evidence for circulating bone marrow-derived endothelial cells Blood 92,362-367[Abstract/Free Full Text]
  64. Baffi, J, Byrnes, G, Chan, CC, Csaky, KG. (2000) Choroidal neovascularization in the rat induced by adenovirus mediated expression of vascular endothelial growth factor Invest Ophthalmol Vis Sci 41,3582-3589[Abstract/Free Full Text]
  65. Miller, JW, Schmidt-Erfurth, U, Sickenberg, M, et al (1999) Photodynamic therapy with verteporfin for choroidal neovascularization caused by age-related macular degeneration: results of a single treatment in phase 1 and 2 study Arch Ophthalmol 117,1161-1173[Abstract/Free Full Text]
  66. Schmidt-Erfurth, U, Miller, JW, Sickenberg, M, et al (1999) Photodynamic therapy with verteporfin for choroidal neovascularization caused by age-related macular degeneration: results of retreatments in a phase 1 and 2 study Arch Ophthalmol 117,1177-1187[Abstract/Free Full Text]
  67. . TAP tudy group (1999) Photodynamic therapy with verteporfin for choroidal neovascularization caused by age-related macular degeneration: one-year results of 2 randomized clinical trials-TAP report 1 Arch Ophthalmol 117,1329-1345[Abstract/Free Full Text]
  68. Schmidt-Erfurth, U, Hasan, T. (2000) Mechanisms of action of photodynamic therapy with verteporfin for the treatment of age-related macular degeneration Surv Ophthalmol 45,195-214[Medline][Order article via Infotrieve]
  69. Green, WR, McDonnell, PJ, Yeo, JH. (1985) Pathologic features of senile macular degeneration Ophthalmology 92,615-627[Medline][Order article via Infotrieve]
  70. Hsu, HT, Goodnight, R, Ryan, SJ. (1989) Subretinal choroidal neovascularization as a response to penetrating retinal injury in the pigmented rabbit Jpn J Ophthalmol 33,358-366[Medline][Order article via Infotrieve]
  71. Zarbin, MA. (1998) Age-related macular degeneration: review of pathogenesis Eur J Ophthalmol 8,199-206[Medline][Order article via Infotrieve]
  72. Oh, H, Takagi, H, Takagi, C., Suzuma,, et al (1999) The potential angiogenic role of macrophages in the formation of choroidal neovascular membranes Invest Ophthalmol Vis Sci 40,1891-1898[Abstract/Free Full Text]
  73. Cuthbertson, RA, Lang, RA, Coghlan, JP. (1990) Macrophage products IL-1{alpha}, TNF{alpha} and bFGF may mediate multiple cytopathic effects in the developing eyes of GM-CSF transgenic mice Exp Eye Res 51,335-344[Medline][Order article via Infotrieve]
  74. Hollborn, M, Kohen, L, Wiedemann,, Enzmann, V. (2001) The influence of pro-inflammatory cytokines on human retinal pigment epithelium cell receptors Graefes Arch Clin Exp Ophthalmol 239,294-301[Medline][Order article via Infotrieve]
  75. Platts, KE, Benson, MT, Rennie, IG, Sharrard, M, Rees, RC. (1995) Cytokine modulation of adhesion molecule expression on human retinal pigment epithelial cells Invest Ophthalmol Vis Sci 36,2262-2269[Abstract/Free Full Text]
  76. Rao, NA, Wu, GS. (2000) Free radical mediated photoreceptor damage in uveitis Prog Retinal Eye Res 19,1-41[Medline][Order article via Infotrieve]



This article has been cited by other articles:


Home page
 IOVSHome page
B. Rohrer, Q. Long, B. Coughlin, R. B. Wilson, Y. Huang, F. Qiao, P. H. Tang, K. Kunchithapautham, G. S. Gilkeson, and S. Tomlinson
A Targeted Inhibitor of the Alternative Complement Pathway Reduces Angiogenesis in a Mouse Model of Age-Related Macular Degeneration
Invest. Ophthalmol. Vis. Sci., July 1, 2009; 50(7): 3056 - 3064.
[Abstract] [Full Text] [PDF]

Home page
 FASEB J.Home page
A. G. Marneros, H. She, H. Zambarakji, H. Hashizume, E. J. Connolly, I. Kim, E. S. Gragoudas, J. W. Miller, and B. R. Olsen
Endogenous endostatin inhibits choroidal neovascularization
FASEB J, December 1, 2007; 21(14): 3809 - 3818.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
M. E. Marin-Castano, G. E. Striker, O. Alcazar, P. Catanuto, D. G. Espinosa-Heidmann, and S. W. Cousins
Repetitive Nonlethal Oxidant Injury to Retinal Pigment Epithelium Decreased Extracellular Matrix Turnover In Vitro and Induced Sub-RPE Deposits In Vivo.
Invest. Ophthalmol. Vis. Sci., September 1, 2006; 47(9): 4098 - 4112.
[Abstract] [Full Text] [PDF]

Home page
 Journals of Gerontology Series A: Biological Sciences and Medical SciencesHome page
B. Sung, S. Park, B. P. Yu, and H. Y. Chung
Modulation of PPAR in Aging, Inflammation, and Calorie Restriction
J. Gerontol. A Biol. Sci. Med. Sci., October 1, 2004; 59(10): B997 - B1006.
[Abstract] [Full Text] [PDF]

Home page
 Arch OphthalmolHome page
W.-Y. Shen, S. Y. Lee, I. Yeo, C.-M. Lai, R. Mathur, D. Tan, I. J. Constable, and P. E. Rakoczy
Predilection of the Macular Region to High Incidence of Choroidal Neovascularization After Intense Laser Photocoagulation in the Monkey
Arch Ophthalmol, March 1, 2004; 122(3): 353 - 360.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
I. J. Suner, D. G. Espinosa-Heidmann, M. E. Marin-Castano, E. P. Hernandez, S. Pereira-Simon, and S. W. Cousins
Nicotine Increases Size and Severity of Experimental Choroidal Neovascularization
Invest. Ophthalmol. Vis. Sci., January 1, 2004; 45(1): 311 - 317.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
D. G. Espinosa-Heidmann, A. Caicedo, E. P. Hernandez, K. G. Csaky, and S. W. Cousins
Bone Marrow-Derived Progenitor Cells Contribute to Experimental Choroidal Neovascularization
Invest. Ophthalmol. Vis. Sci., November 1, 2003; 44(11): 4914 - 4919.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
E. Sakurai, A. Anand, B. K. Ambati, N. van Rooijen, and J. Ambati
Macrophage Depletion Inhibits Experimental Choroidal Neovascularization
Invest. Ophthalmol. Vis. Sci., August 1, 2003; 44(8): 3578 - 3585.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
D. G. Espinosa-Heidmann, I. J. Suner, E. P. Hernandez, D. Monroy, K. G. Csaky, and S. W. Cousins
Macrophage Depletion Diminishes Lesion Size and Severity in Experimental Choroidal Neovascularization
Invest. Ophthalmol. Vis. Sci., August 1, 2003; 44(8): 3586 - 3592.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
E. Sakurai, H. Taguchi, A. Anand, B. K. Ambati, E. S. Gragoudas, J. W. Miller, A. P. Adamis, and J. Ambati
Targeted Disruption of the CD18 or ICAM-1 Gene Inhibits Choroidal Neovascularization
Invest. Ophthalmol. Vis. Sci., June 1, 2003; 44(6): 2743 - 2749.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
V. Lambert, C. Munaut, P. Carmeliet, R. D. Gerard, P. J. Declerck, A. Gils, C. Claes, J.-M. Foidart, A. Noel, and J.-M. Rakic
Dose-Dependent Modulation of Choroidal Neovascularization by Plasminogen Activator Inhibitor Type I: Implications for Clinical Trials
Invest. Ophthalmol. Vis. Sci., June 1, 2003; 44(6): 2791 - 2797.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Espinosa-Heidmann, D. G.
Right arrow Articles by Cousins, S. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Espinosa-Heidmann, D. G.
Right arrow Articles by Cousins, S. W.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS