<p>Sir,</p> <p>Recently, i read with interest the article of Javanmard et al., who reported that the aqueous level of vascular endothelial growth factor (VEGF) in non-proliferative diabetic retinopathy (NPDR) was not different compare to non-diabetic patients, while soluble form of VEGF receptor-1 (sVEGFR-1) was lower in NPDR than non-diabetic subjects. <sup> <xref ref-type="bibr" rid="ref1">1</xref> </sup></p> <p>Several diabetic complications are related to imbalances between angiogenic and antiangiogenic factors. <sup> <xref ref-type="bibr" rid="ref2">2</xref> </sup>Diabetic retinopathy is a microvascular diabetic complication and previous studies reported the role of angiogenic factors especially VEGF in this process. <sup> <xref ref-type="bibr" rid="ref3">3</xref> </sup>It was shown that the VEGF/sVEGFR-1 ratio is a better indicator for angiogenesis process. <sup> <xref ref-type="bibr" rid="ref4">4</xref> </sup>Although, in this study, the authors did not compare VEGF/sVEGFR-1 ratio between two groups, however, we should consider that the we cannot estimate the angiogenesis process NPDR patients solely by measurements of aqueous level of VEGF. In a recent paper, Waltenberger discussed regarding the VEGF resistance and angiogenic paradox in diabetes. <sup> <xref ref-type="bibr" rid="ref5">5</xref> </sup>He indicated that the monocyte is a suitable cellular model for VEGF resistance. Although, the angiogenic response of VEGF is elevated in diabetes mellitus, however, the response to VEGF is reduced. On the other hand, it is important to distinguish between angiogenesis and arteriogenesis which may be involved in this paradox. According to this hypothesis, it seems that during the short period, arteriogenesis is reduced in diabetes mellitus due to VEGF resistance, however, in long-period, angiogenesis increases in spite of VEGF resistance the results of high and continuous stimulation of VEGF. <sup> <xref ref-type="bibr" rid="ref5">5</xref> </sup>Increase in arteriogenesis is associated with collateral vessel formation, while, increase in angiogenesis is associated with diabetic retinopathy. <sup> <xref ref-type="bibr" rid="ref5">5</xref> </sup>, <sup> <xref ref-type="bibr" rid="ref6">6</xref> </sup>Thus, it seems that the role of VEGF and their receptors in proliferative or NPDR are more complex.</p> </sec> </body> <back> <ref-list> <ref id="ref1"> <label>1</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"> <name> <surname>Javanmard</surname> <given-names>SH</given-names> </name> <name> <surname>Hassanpour</surname> <given-names>Z</given-names> </name> <name> <surname>Abbaspoor</surname> <given-names>Z</given-names> </name> <name> <surname>Naderian</surname> <given-names>GA</given-names> </name> <name> <surname>Jahanmard</surname> <given-names>M</given-names> </name> </person-group> <article-title>Aqueous concentrations of VEGF and soluble VEGF receptor-1 in diabetic retinopathy patients</article-title> <source>J Res Med Sci</source> <year>2012</year> <volume>17</volume> <fpage>1124</fpage> <lpage>27</lpage> </nlm-citation> </ref> <ref id="ref2"> <label>2</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"> <name> <surname>Tahergorabi</surname> <given-names>Z</given-names> </name> <name> <surname>Khazaei</surname> <given-names>M</given-names> </name> </person-group> <article-title>Imbalance of angiogenesis in diabetic complications: The mechanisms</article-title> <source>Int J Prev Med</source> <year>2012</year> <volume>3</volume> <fpage>827</fpage> <lpage>38</lpage> </nlm-citation> </ref> <ref id="ref3"> <label>3</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"> <name> <surname>Gupta</surname> <given-names>N</given-names> </name> <name> <surname>Mansoor</surname> <given-names>S</given-names> </name> <name> <surname>Sharma</surname> <given-names>A</given-names> </name> <name> <surname>Sapkal</surname> <given-names>A</given-names> </name> <name> <surname>Sheth</surname> <given-names>J</given-names> </name> <name> <surname>Falatoonzadeh</surname> <given-names>P</given-names> </name> <etal /> </person-group> <article-title>Diabetic retinopathy and VEGF</article-title> <source>Open Ophthalmol J</source> <year>2013</year> <volume>7</volume> <fpage>4</fpage> <lpage>10</lpage> </nlm-citation> </ref> <ref id="ref4"> <label>4</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"> <name> <surname>Bando</surname> <given-names>H</given-names> </name> <name> <surname>Weich</surname> <given-names>HA</given-names> </name> <name> <surname>Brokelmann</surname> <given-names>M</given-names> </name> <name> <surname>Horiguchi</surname> <given-names>S</given-names> </name> <name> <surname>Funata</surname> <given-names>N</given-names> </name> <name> <surname>Ogawa</surname> <given-names>T</given-names> </name> <etal /> </person-group> <article-title>Association between intratumoral free and total VEGF, soluble VEGFR-1, VEGFR-2 and prognosis in breast cancer</article-title> <source>Br J Cancer</source> <year>2005</year> <volume>92</volume> <fpage>553</fpage> <lpage>61</lpage> </nlm-citation> </ref> <ref id="ref5"> <label>5</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"> <name> <surname>Waltenberger</surname> <given-names>J</given-names> </name> </person-group> <article-title>VEGF resistance as a molecular basis to explain the angiogenesis paradox in diabetes mellitus</article-title> <source>Biochem Soc Trans</source> <year>2009</year> <volume>37</volume> <fpage>1167</fpage> <lpage>70</lpage> </nlm-citation> </ref> <ref id="ref6"> <label>6</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"> <name> <surname>Costa</surname> <given-names>PZ</given-names> </name> <name> <surname>Soares</surname> <given-names>R</given-names> </name> </person-group> <article-title>Neovascularization in diabetes and its complications.Unraveling the angiogenic paradox</article-title> <source>Life Sci ; [Epub ahead of print]</source> <year>3; [</year> <volume></volume> <fpage></fpage> <comment>Neovascularization in diabetes and its complications Unraveling the angiogenic paradox Life Sci 2013; [Epub ahead of print]</comment> </nlm-citation> </ref> <ref id="ref7"> <label>7</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"></person-group> <article-title></article-title> <source></source> <year></year> <volume></volume> <fpage></fpage> </nlm-citation> </ref> </ref-list> </back> </article>

JRMS

J Res Med Sci

Journal of Research in Medical Sciences

1735-1995 1735-7136

Medknow Publications Pvt Ltd

India

JRMS-18-536

24250710

Letter to Editor

Diabetic retinopathy and vascular endothelial growth factor

Khazaei

Majid

Department of Physiology, Isfahan University of Medical Sciences, Isfahan, Iran

Address for correspondence:Majid Khazaei, Department of Physiology, Hezar Jarib Ave, Isfahan University of Medical Sciences, Isfahan, Iran khazaei@med.mui.ac.ir

June 2013

18 6 536 536

2013

This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

<p>Sir,</p> <p>Recently, i read with interest the article of Javanmard et al., who reported that the aqueous level of vascular endothelial growth factor (VEGF) in non-proliferative diabetic retinopathy (NPDR) was not different compare to non-diabetic patients, while soluble form of VEGF receptor-1 (sVEGFR-1) was lower in NPDR than non-diabetic subjects. <sup> <xref ref-type="bibr" rid="ref1">1</xref> </sup></p> <p>Several diabetic complications are related to imbalances between angiogenic and antiangiogenic factors. <sup> <xref ref-type="bibr" rid="ref2">2</xref> </sup>Diabetic retinopathy is a microvascular diabetic complication and previous studies reported the role of angiogenic factors especially VEGF in this process. <sup> <xref ref-type="bibr" rid="ref3">3</xref> </sup>It was shown that the VEGF/sVEGFR-1 ratio is a better indicator for angiogenesis process. <sup> <xref ref-type="bibr" rid="ref4">4</xref> </sup>Although, in this study, the authors did not compare VEGF/sVEGFR-1 ratio between two groups, however, we should consider that the we cannot estimate the angiogenesis process NPDR patients solely by measurements of aqueous level of VEGF. In a recent paper, Waltenberger discussed regarding the VEGF resistance and angiogenic paradox in diabetes. <sup> <xref ref-type="bibr" rid="ref5">5</xref> </sup>He indicated that the monocyte is a suitable cellular model for VEGF resistance. Although, the angiogenic response of VEGF is elevated in diabetes mellitus, however, the response to VEGF is reduced. On the other hand, it is important to distinguish between angiogenesis and arteriogenesis which may be involved in this paradox. According to this hypothesis, it seems that during the short period, arteriogenesis is reduced in diabetes mellitus due to VEGF resistance, however, in long-period, angiogenesis increases in spite of VEGF resistance the results of high and continuous stimulation of VEGF. <sup> <xref ref-type="bibr" rid="ref5">5</xref> </sup>Increase in arteriogenesis is associated with collateral vessel formation, while, increase in angiogenesis is associated with diabetic retinopathy. <sup> <xref ref-type="bibr" rid="ref5">5</xref> </sup>, <sup> <xref ref-type="bibr" rid="ref6">6</xref> </sup>Thus, it seems that the role of VEGF and their receptors in proliferative or NPDR are more complex.</p> </sec> </body> <back> <ref-list> <ref id="ref1"> <label>1</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"> <name> <surname>Javanmard</surname> <given-names>SH</given-names> </name> <name> <surname>Hassanpour</surname> <given-names>Z</given-names> </name> <name> <surname>Abbaspoor</surname> <given-names>Z</given-names> </name> <name> <surname>Naderian</surname> <given-names>GA</given-names> </name> <name> <surname>Jahanmard</surname> <given-names>M</given-names> </name> </person-group> <article-title>Aqueous concentrations of VEGF and soluble VEGF receptor-1 in diabetic retinopathy patients</article-title> <source>J Res Med Sci</source> <year>2012</year> <volume>17</volume> <fpage>1124</fpage> <lpage>27</lpage> </nlm-citation> </ref> <ref id="ref2"> <label>2</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"> <name> <surname>Tahergorabi</surname> <given-names>Z</given-names> </name> <name> <surname>Khazaei</surname> <given-names>M</given-names> </name> </person-group> <article-title>Imbalance of angiogenesis in diabetic complications: The mechanisms</article-title> <source>Int J Prev Med</source> <year>2012</year> <volume>3</volume> <fpage>827</fpage> <lpage>38</lpage> </nlm-citation> </ref> <ref id="ref3"> <label>3</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"> <name> <surname>Gupta</surname> <given-names>N</given-names> </name> <name> <surname>Mansoor</surname> <given-names>S</given-names> </name> <name> <surname>Sharma</surname> <given-names>A</given-names> </name> <name> <surname>Sapkal</surname> <given-names>A</given-names> </name> <name> <surname>Sheth</surname> <given-names>J</given-names> </name> <name> <surname>Falatoonzadeh</surname> <given-names>P</given-names> </name> <etal /> </person-group> <article-title>Diabetic retinopathy and VEGF</article-title> <source>Open Ophthalmol J</source> <year>2013</year> <volume>7</volume> <fpage>4</fpage> <lpage>10</lpage> </nlm-citation> </ref> <ref id="ref4"> <label>4</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"> <name> <surname>Bando</surname> <given-names>H</given-names> </name> <name> <surname>Weich</surname> <given-names>HA</given-names> </name> <name> <surname>Brokelmann</surname> <given-names>M</given-names> </name> <name> <surname>Horiguchi</surname> <given-names>S</given-names> </name> <name> <surname>Funata</surname> <given-names>N</given-names> </name> <name> <surname>Ogawa</surname> <given-names>T</given-names> </name> <etal /> </person-group> <article-title>Association between intratumoral free and total VEGF, soluble VEGFR-1, VEGFR-2 and prognosis in breast cancer</article-title> <source>Br J Cancer</source> <year>2005</year> <volume>92</volume> <fpage>553</fpage> <lpage>61</lpage> </nlm-citation> </ref> <ref id="ref5"> <label>5</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"> <name> <surname>Waltenberger</surname> <given-names>J</given-names> </name> </person-group> <article-title>VEGF resistance as a molecular basis to explain the angiogenesis paradox in diabetes mellitus</article-title> <source>Biochem Soc Trans</source> <year>2009</year> <volume>37</volume> <fpage>1167</fpage> <lpage>70</lpage> </nlm-citation> </ref> <ref id="ref6"> <label>6</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"> <name> <surname>Costa</surname> <given-names>PZ</given-names> </name> <name> <surname>Soares</surname> <given-names>R</given-names> </name> </person-group> <article-title>Neovascularization in diabetes and its complications.Unraveling the angiogenic paradox</article-title> <source>Life Sci ; [Epub ahead of print]</source> <year>3; [</year> <volume></volume> <fpage></fpage> <comment>Neovascularization in diabetes and its complications Unraveling the angiogenic paradox Life Sci 2013; [Epub ahead of print]</comment> </nlm-citation> </ref> <ref id="ref7"> <label>7</label> <nlm-citation citation-type="journal"> <person-group person-group-type="author"></person-group> <article-title></article-title> <source></source> <year></year> <volume></volume> <fpage></fpage> </nlm-citation> </ref> </ref-list> </back> </article>