Published online before print January 26, 2009, doi: 10.1161/CIRCULATIONAHA.108.789297
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(Circulation. 2009;119:699-708.)
© 2009 American Heart Association, Inc.
Molecular Cardiology |
Dual Angiogenic and Neurotrophic Effects of Bone Marrow–Derived Endothelial Progenitor Cells on Diabetic Neuropathy
From the Division of Cardiovascular Research, Caritas St. Elizabeth’s Medical Center, Tufts University School of Medicine, Boston, Mass (J.-O.J., M.-O.K., H.K., S.-W.K., M.I., J.-u.L., J.L., Y.J.C., H.-J.C., N.L., M.S., A.W., Y.-s.Y.); Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Ga (M.-O.K., H.K., M.-Y.L., S.-W.K., J.L., Y.J.C., Y.-S.Y.); Department of Internal Medicine, Seoul National University Hospital, Seoul, South Koria (H.-J.C.); Division of Cardiology, Hallym University School of Medcine, Seoul, South Korea (N.L.); and Stem Cell Research Center, 21C R&D Program of Ministry of Education, Science, and Technology, Yonsei University Medical Center, Seoul, South Korea (D.-W.K.). Dr Jeong is currently at the Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon, South Korea. Dr Cho is currently at the Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea. Dr N. Lee is currently at the Division of Cardiology, Hallym University School of Medicine, Seoul, South Korea.
Correspondence to Young-sup Yoon, MD, PhD, Division of Cardiology, Department of Medicine, Emory University School of Medicine, 1639 Pierce Dr, WMB 319, Atlanta, GA 30322. E-mail yyoon5{at}emory.edu
Received April 29, 2008; accepted November 28, 2008.
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Abstract |
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Background— Endothelial progenitor cells (EPCs) are known to promote neovascularization in ischemic diseases. Recent evidence suggested that diabetic neuropathy is causally related to impaired angiogenesis and deficient growth factors. Accordingly, we investigated whether diabetic neuropathy could be reversed by local transplantation of EPCs.
Methods and Results— We found that motor and sensory nerve conduction velocities, blood flow, and capillary density were reduced in sciatic nerves of streptozotocin-induced diabetic mice but recovered to normal levels after hind-limb injection of bone marrow–derived EPCs. Injected EPCs were preferentially and durably engrafted in the sciatic nerves. A portion of engrafted EPCs were uniquely localized in close proximity to vasa nervorum, and a smaller portion of these EPCs were colocalized with endothelial cells. Multiple angiogenic and neurotrophic factors were significantly increased in the EPC-injected nerves. These dual angiogenic and neurotrophic effects of EPCs were confirmed by higher proliferation of Schwann cells and endothelial cells cultured in EPC-conditioned media.
Conclusions— We demonstrate for the first time that bone marrow-derived EPCs could reverse various manifestations of diabetic neuropathy. These therapeutic effects were mediated by direct augmentation of neovascularization in peripheral nerves through long-term and preferential engraftment of EPCs in nerves and particularly vasa nervorum and their paracrine effects. These findings suggest that EPC transplantation could represent an innovative therapeutic option for treating diabetic neuropathy.
Key Words: angiogenesis • diabetes mellitus • progenitor cells • diabetic neuropathy
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Introduction |
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Peripheral neuropathy is the most common complication of diabetes mellitus, affecting up to 60% of diabetic patients.1 Loss of sensation in the feet, the most frequent manifestation of diabetic neuropathy (DN), frequently leads to foot ulcers and may progress into amputation of the limb.2,3 Despite a continuous increase in the incidence of diabetes mellitus and DN, current treatments have yet to effectively treat DN. Our group reported that experimental DN is characterized by reduced microcirculation in peripheral nerves caused by the destruction of the vasa nervorum and thus administration of angiogenic factors such as vascular endothelial growth factors (VEGFs), sonic hedgehog (SHh), and statin could restore neural function by augmenting angiogenesis.4–6 In addition, deficiency of neurotrophic factors is regarded as one of the most plausible mechanisms underlying DN.7 Alterations of nerve growth factor, ciliary neurotrophic factor, glial-derived neurotrophic factor, and brain-derived neurotrophic factor have been reported.8–12 However, in clinical trials, single neurotrophic cytokines turned out to be ineffective for treating DN.13 Recently, many classic angiogenic factors were shown to possess neurotrophic activities and vice versa. VEGF,14–16 SHh,17,18 insulin-like growth factor-1,19 and neurotrophins20,21 are some of the representative factors with these dual effects. Because DN lacks both angiogenic and neurotrophic factors, using a therapeutic agent that has dual angioneurotrophic activities may prove more beneficial for treating DN. In this regard, endothelial progenitor cells (EPCs) can be an optimal candidate for treating DN because they possess paracrine properties that encompass both angiogenic and neurotrophic effects. Furthermore, unlike protein or gene therapy, cell therapy may be able to provide long-term effects. EPCs are putative progenitor cells of endothelial cells, exist in peripheral blood and bone marrow (BM), and contribute to postnatal neovascularization. Growing evidence suggests that EPCs are effective in treating various cardiovascular diseases.22–25 Mechanistically, EPCs work through transdifferentiation into vasculature22,26 and paracrine effects.24,27 The paracrine effects are made possible because EPCs produce multiple biological factors such as VEGF, insulin-like growth factor-1, and fibroblast growth factor-2 (FGF-2). Accordingly, we sought to investigate whether transplantation of EPCs could attenuate or reverse DN by augmenting neovascularization and providing angiogenic and neurotrophic factors.
Clinical Perspective p 708
In the present study, we report that BM-derived EPCs, by directly augmenting neural neovascularization, could effectively treat DN. We found for the first time that intramuscularly injected EPCs are preferentially engrafted into peripheral nerves, are specifically localized around vasa nervorum, and increase the expression of various angiogenic and neurotrophic factors.
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Methods |
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Induction of Diabetes Mellitus
All protocols were approved by St Elizabeth’s Institutional Animal Care and Use Committee. We induced diabetes mellitus in 6-week-old male C57BL/6J mice by intraperitoneal injection of streptozotocin (150 mg/kg).
Isolation of EPCs and Cell Culture
For EPC culture, the bones of 8-week-old C57BL/6J mice were excised and crushed with PBS. Mononuclear cells were fractionated by density gradient centrifugation. Isolated mononuclear cells were cultured on rat plasma vitronectin–precoated 10-cm dishes.23,24
Intramuscular Injection of Cultured EPCs
We labeled EPCs with a red fluorescent dye, CM-DiI (Invitrogen, Carlsbad, Calif), as previously described28 and injected EPCs (1x106) or the same volume of saline into the muscles percutaneously along the course of the sciatic nerve.
Laser Doppler Imaging of Vasa Nervorum Blood Flow
Perfusion of sciatic vasa nervorum was measured in each hind limb of mice with a laser Doppler perfusion imager (Moor Instruments, Millwey, Axminster, Devon, UK).4,5 After anesthesia, nerves were exposed, and flow measurements were repeated twice over the same region of interest.
Fluorescent Imaging of Blood Vessels in Sciatic Nerves and Femoral Muscles
Vascularity of sciatic nerves and femoral muscles was assessed by in situ fluorescent staining with an endothelial cell–specific marker, BS-1 lectin.4,5 After anesthesia, the hind limbs were perfused with BS-1 lectin conjugated to FITC (Vector Laboratories, Burlingame, Calif) by cardiac injection. Fifteen minutes later, the animals were killed, and the sciatic nerves and femoral muscles were harvested. After fixation, samples were either whole mounted or embedded in optical coherence tomography compound for frozen section.
Statistical Analysis
All results are presented as mean±SEM. Statistical analysis was performed by an unpaired Student t test for comparisons between 2 groups and ANOVA for >2 groups. For statistical analysis of nerve conduction velocity (NCV) measurements in Figure 1, we used a repeated-measures ANOVA. Values of P<0.05 are considered statistically significant.
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Details on the materials and methods, including the following items, can be found in the online-only Data Supplement: measurements of NCV,6,15 tail-flick testing,4,6 double-fluorescence immunohistochemistry for BrdU28 and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL),29 in vitro cell proliferation assay,6 quantitative reverse-transcription polymerase chain reaction for mRNA expression,24 and Western blot analysis.29
The authors had full access to and take full responsibility for the integrity of the data. All authors have read and agree to the manuscript as written.
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Results |
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EPC Transplantation Improves Neural Function in Diabetic Mice
To determine the impact of local transplantation of EPCs on the function of peripheral nerves in diabetes mellitus, we measured NCVs every 2 weeks for 8 weeks after treatment. At baseline, 12 weeks after induction of diabetes mellitus, both motor and sensory NCVs were slowed by
35% and 40%, respectively, in diabetic mice (injected with saline) compared with the nondiabetic mice (NDM-saline), indicating development of significant peripheral neuropathy (Figure 1A and 1B). Diabetic mice were randomly assigned to EPC (DM-EPC) or saline injection (DM-saline) groups and were injected intramuscularly around the sciatic nerves. After EPC treatment, both motor and sensory NCVs gradually recovered to normal levels over 8 weeks (Figure 1A and 1B). Statistically, a repeated-measures ANOVA demonstrated a significant difference in NCVs between the DM-EPC and DM-saline groups at baseline (P<0.05) and at 4 and 8 weeks (P<0.01). Tail-flick testing 4 weeks after treatment showed that in DM-saline mice, tail-flick temperatures were significantly increased compared with nondiabetic control mice. In contrast, in the DM-EPC mice, tail-flick temperatures were significantly decreased to the level of nondiabetic mice, indicating recovery of sensory nerve function (Figure 1C).
EPC Transplantation Improves Neural Vascularity in Diabetic Mice
We measured sciatic nerve blood flow in each limb using laser Doppler flow imaging at 4 weeks after treatment. Nerve blood flow was markedly decreased in DM-saline compared with NDM-saline mice (P<0.05; Figure 2A and 2B). The blood flow and the blood flow ratio between treated and nontreated limbs were significantly increased in the DM-EPC mice compared with the DM-saline mice (P<0.001; Figure 2C).
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Next, to investigate changes in functional vessels, we harvested sciatic nerves at 4 weeks after treatment after injection of BS-1 lectin into the heart. Whole-mount images of sciatic nerves showed that DM-saline mice had fewer functional vasa nervorum, which are responsible for perfusion of peripheral nerves, compared with NDM-saline mice (P<0.01) (Figure 3A and 3B, left and middle). In contrast, the vasa nervorum was visibly increased after EPC treatment (Figure 3A and 3B, middle and right). Quantitative analysis of the vessels in cross sections of sciatic nerves showed a higher number of vasa nervorum in the EPC-injected mice compared with the saline-injected mice (Figure 3C).
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Transplanted EPCs Home to Sciatic Nerves and Are Durably Engrafted
Next, we studied the engraftment and transdifferentiation characteristics of EPCs in sciatic nerves harvested at 2, 4, 8, and 12 weeks after EPC transplantation. The endothelial characteristics of cultured EPCs were confirmed by conventional EPC assay and fluorescence-activated cell sorter analyses. We found that 31% of the EPCs were positive for Tie2 expression and 91% for CD11b expression, suggesting that a majority of cultured EPCs originated from a monocyte population and that cultured EPCs possess proangiogenic/vasculogenic potential (Figure I of the online-only Data Supplement).27 To identify vasa nervorum, we injected BS-1 lectin before the mice were killed. In whole-mount preparations of sciatic nerves, we observed that intramuscularly injected EPCs, prelabeled with the red fluorescent dye DiI, homed to sciatic nerves and robustly engrafted over the study period of 12 weeks (Figure 4A and 4B). In contrast, engrafted EPCs were observed less frequently in the femoral muscles at 2 weeks, and most of the EPCs disappeared within 8 weeks (Figure 4C). These findings suggest that EPCs preferentially home to the sciatic nerve and that a large number of the engrafted EPCs migrated along the course of and abutting the vasa nervorum (Figure 5A through 5C). Immunohistochemistry and fluorescence-activated cell sorter analysis of the digested nerves at 8 weeks after treatment revealed that 90% of the engrafted EPCs exhibit CD11b and Tie2, suggestive of the phenotype of proangiogenic Tie2-expressing monocytes/macrophages (online-only Data Supplement Figure IIA and IIB).30 In cross sections, a small portion of the EPCs expressed an endothelial cell phenotype, suggesting transdifferentiation into endothelial cells (Figure 5D and 5E). These data show that locally injected EPCs have specific tissue tropism to diabetic nerves and affinity for endothelial cells within the nerves. We found that the expression of SDF-1
and MCP-1 was detected only in the nerves, not in the muscles, which suggests that these factors may play a role in recruiting EPCs to diabetic nerves (online-only Data Supplement Figure III).
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EPC Transplantation Increases Proliferation of Endothelial Cells and Schwann Cells
We also investigated the paracrine effects of EPCs. We implanted a mini-osmotic pump loaded with BrdU in the back skin immediately after treatment that released BrdU for 4 weeks.28 These sciatic nerves were harvested at 4 weeks, and double immunohistochemistry with antibodies against BrdU and a Schwann cell marker, S-100, was performed. We found >4 times as many BrdU-positive Schwann cells in the DM-EPC group as in the DM-saline group (Figure 6A and 6B). To determine whether this proproliferative effect could be mediated through the paracrine action of EPCs, we used hypoxic conditions to mimic the in vivo status of diabetic nerves that are under ischemia as a result of the loss of vasa nervorum. Schwann cells or endothelial cells (human umbilical vein endothelial cells [HUVECs]) were cultured in EPC-conditioned media, collected after EPCs had been cultivated either in normoxia or 5% hypoxia or in plain EBM-2 (Figure 6C and 6D). We found that proliferation of both Schwann cells and HUVECs grown in hypoxic EPC-conditioned media was significantly higher than controls (Schwann cells, 13.4% increase over 3% FBS, P<0.01; HUVECs, 24.4% increase over 3% FBS, P<0.01; Figure 6C and 6D). Taken together, these findings suggest that transplanted EPCs effectively induced proliferation of Schwann cells and endothelial cells through their paracrine activity.
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EPC Transplantation Decreases Apoptosis in Endothelial Cells and Schwann Cells in Diabetic Nerves
We further asked whether EPC transplantation can affect ongoing apoptosis in diabetic nerves. We performed TUNEL assay on sciatic nerves obtained 1 week after cell transplantation. The number of TUNEL-positive cells was 4-fold higher in the nerves of DM-saline mice than in NDM-saline mice (P<0.05; Figure 7A and 7B), but this number was reduced by 50% in the DM-EPC mice (P<0.001 versus DM-saline; Figure 7B). Qualitatively, concomitant staining with TUNEL and either ILB4 or S100 revealed that apoptosis occurred in both endothelial cells and Schwann cells (Figure 7C and 7D).
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EPC Transplantation Increases Multiple Angiogenic, Antiapoptotic, and Neurotrophic Factors
Next, to determine whether paracrine factors secreted by EPCs could mediate the proproliferative and antiapoptotic effects of EPCs, we examined the levels of angiogenic and neurotrophic factors in sciatic nerves at 4 weeks after EPC transplantation. Quantitative reverse-transcription polymerase chain reaction revealed that mRNA expression levels of angiogenic and neurotrophic factors were higher in the EPC-injected group than in the saline-injected group (VEGF-A, 3.4±1.2-fold; FGF-2, 1.5±0.3-fold; and Gli 1, 2.6±0.8-fold, all P<0.05; brain-derived neurotrophic factor, 5.9±1.2-fold; SHh, 2.4±0.4-fold; and SDF-1, 1.9±0.1-fold, all P<0.001; Figure 8A through 8G). The levels of nerve growth factor, angiopoietin 1, epidermal growth factor, and hepatocyte growth factor were too low to be detected (data not shown). Western blot analysis further demonstrated that the protein levels of VEGF, FGF-2, and Gli 1 were significantly increased in the EPC group compared with the saline group (VEGF A, 2.2±0.5-fold; FGF-2, 1.6±0.2-fold; and Gli 1, 1.9±0.3-fold, all P<0.05). These findings suggest that intramuscular injection of EPCs upregulated multiple angiogenic and neurotrophic factors at the mRNA and protein levels (Figure 8H and 8I).
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Discussion |
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In this study, we have found that local transplantation of BM-derived EPCs improved various manifestations of experimental DN through direct effects on peripheral nerves. Some of the most salient findings of the present study are as follows. First, local transplantation of BM-derived EPCs restored neurophysiological deficits in DN. Second, EPC treatment increased neural vascularity functionally and histologically. Third, intramuscularly injected EPCs preferentially homed to sciatic nerves, characteristically localized in close proximity to vasa nervorum, and transdifferentiated into endothelial cells, albeit infrequently. Fourth, a large number of engrafted EPCs survived in peripheral nerves for >12 weeks and induced prolonged expression of angiogenic and neurotrophic factors. Fifth, EPC transplantation increased proliferation and decreased apoptosis of endothelial and Schwann cells.
It is our hypothesis that microvascular insufficiency in nerves plays a major role in the development and progression of DN and therefore that therapeutic intervention by EPC transplantation can reverse or attenuate DN by inducing neovascularization and supplying angioneurotrophic cytokines. The coincidence of restoration of vasa nervorum accompanied by functional nerve recovery has been documented in DN with distinct angiogenic agents.4–6 Again, this study provides strong evidence that the development of and recovery from DN are pathophysiologically associated with loss and gain, respectively, of vasa nervorum.
The most notable finding of the present study is the direct effect of EPCs on peripheral nerves. BS-1 lectin perfusion experiments clearly demonstrate for the first time that EPC transplantation increases capillary density and blood flow in nerves, suggesting that EPCs induce genuine neovascularization in nerves. Mechanistically, because transdifferentiation of EPCs into endothelial cells was observed only infrequently, our results suggest a greater contribution by angiogenesis than vasculogenesis to this process. This neural angiogenesis appears to be made possible through upregulation of various angiogenic factors in nerves after EPC transplantation. In fact, this is the first evidence documenting upregulation of multiple paracrine or humoral factors in peripheral nerves after treatment with stem/progenitor cells. In this study, factors such as VEGF-A,4,15 FGF-2,31 brain-derived neurotrophic factor,32 SHh,5,18 and SDF-1,33,34 which are known to function as both angiogenic and neurotrophic factors, were highly expressed in EPC-transplanted nerves. These upregulated factors could have provided additional benefits for the recovery of neural function by promoting proliferation and inhibiting apoptosis of Schwann cells. In addition, these humoral effects might be contributed not only by the injected EPCs but also by the recovering nerves after EPC treatment.24 This is the first report showing such dual angiogenic and neurotrophic effects of EPCs. This upregulation of various classes of biologically important factors may be one of the greatest benefits of stem cell therapy over any single protein or gene therapy, enabling the concerted efforts of multiple neuroangiogenic cytokines necessary for neurovascular recovery.
One prior study showed that cord blood–derived EPCs were effective for treating DN.35 Although this study reported a therapeutic potential of cord blood cells, mechanistically, a wide difference exists between that study and the present one. The study by Naruse et al,35 which used umbilical cord blood–derived EPCs, suggested that the therapeutic effects might be due to increased differentiation of EPCs into endothelial cells in hind-limb muscles, which then led to an increase in sciatic nerve blood flow. However, that study did not investigate the fate or engraftment characteristics of the EPCs in tissues, nor did it address the mechanisms by which transplanted EPCs increase neovascularization in muscles or nerve. In fact, more studies argue against the transdifferentiation of EPCs as a major mechanism underlying therapeutic effects.24,27 In contrast, our study clearly provided 2 important mechanistic insights. First, intramuscularly injected EPCs exert therapeutic effects through direct modulation of nerves, not through muscular neovascularization. Second, the dominant mechanism is humoral or paracrine effects, not transdifferentiation. Histological examination of our samples revealed that in hind-limb muscles the number of engrafted EPCs was much smaller, and a majority of EPCs disappeared within 8 weeks; in the sciatic nerves, however, EPCs robustly survived for >12 weeks. Interestingly, the study by Naruse et al35 showed that capillary density, which had decreased in hind-limb muscles of diabetic rats at 12 weeks of diabetes mellitus, was significantly increased after cord blood EPC treatment. In contrast, our data suggested that blood flow and capillary density were decreased mildly but not statistically significantly in hind-limb muscles. This discrepancy might have been due to the difference in animal species or genetic backgrounds of mice20 used for a diabetic model: Naruse et al used nude rats, whereas we used C57BL6/J mice. Nude rats exhibit more severe impairment in angiogenesis because they lack T cells36; this blunted angiogenic response in the nude rat might have caused the significantly reduced vascularity seen in the hind-limb muscle in diabetic nude rat. Thus, we have concerns that using human cord blood EPCs in nude rats might not have properly addressed the mechanisms involving the therapeutic effects of EPCs resulting from xenogenic mismatch and the choice of an angiogenically impaired animal model. In contrast, the present study, by using syngeneic mice for both donors and recipients, avoided such potential confounding factors.
We made 3 novel observations on the fate of EPCs in tissues. One of the most striking findings was that EPCs homed to peripheral nerves far more preferentially than to muscles (Figure 5). This scale of close interaction between any BM cells and steady-state tissues was not previously reported either with or without diabetes mellitus. SDF-1 and MCP-1 produced by diabetic nerves seemed to be able to attract injected EPCs. Another notable finding was the durable engraftment of BM-derived EPCs into diabetic nerves. After reports on the short-lasting engraftment of transplanted BM cells in a myocardial infarction model,37,38 the notion has been widely accepted that engrafted adult stem/progenitor cells disappear within a couple of weeks. However, the present study disclosed that a large number of BM-derived progenitor cells could survive for a prolonged period of time, 12 weeks, in nerves. These data indicate that the engraftment characteristics of progenitor cells may depend more on the recipient environment than on the transplanted cells themselves. However, a limitation of this study is that although we detected long-term EPC engraftment, the 12-week time frame is much shorter than the clinical course of this disease. The last intriguing finding is that the engrafted EPCs were localized in close proximity to the vasa nervorum. To the best of our knowledge, such a significant magnitude of tropism of BM-derived cells to blood vessels has not been reported in any other tissues, either in normal or in diseased states. These unique characteristics of BM-derived EPCs, ie, peripheral neurotropism, sustained engraftment, and vascular localization of EPCs, could have caused robust and prolonged paracrine or humoral effects and led to the reversal of functional and histological impairment of peripheral nerves in diabetes mellitus.
Because advanced DN, which is a likely candidate for cell therapy, is frequently combined with and presents by diabetic foot ulcers and/or limb ischemia and because EPCs are also known to be effective for treating diabetic wounds or lower-limb ischemia, a therapeutic approach of using EPCs in advanced DN can be clinically relevant and valuable. Practically, because the safety of autologous BM-derived EPCs or similar progenitor cells has been documented by a number of clinical trials,25,39 it would be possible to advance this strategy into a pilot clinical trial. The effectiveness of the patient’s own diabetic EPCs versus healthy EPCs needs to be evaluated because of a potential concern about the negative effects of diabetes mellitus on EPCs. Taken together, these findings suggest that cell therapy with BM-derived EPCs may represent an innovative therapeutic option for treating DN.
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Acknowledgments |
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We are grateful to Sunkhoon Lee, PhD, and Bongwon Park, MS, for their help in statistical analysis.
Sources of Funding
This work was supported in part by National Institutes of Health grants (HL079137, HL084471), a Juvenile Diabetic Research Foundation Innovation grant (5-2007-951), and a grant (SC4071) from Stem Cell Research Center of the 21st Century Frontier Research Program funded by the Ministry of Science and Technology, Republic of Korea.
Disclosures
None.
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References |
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1. Leinninger GM, Vincent AM, Feldman EL. The role of growth factors in diabetic peripheral neuropathy. J Peripher Nerv Syst. 2004; 9: 26–53.[CrossRef][Medline] [Order article via Infotrieve]
2. Tomlinson DR, Fernyhough P, Diemel LT. Role of neurotrophins in diabetic neuropathy and treatment with nerve growth factors. Diabetes. 1997; 46 (suppl 2): S43–S49.[Medline] [Order article via Infotrieve]
3. Reiber GE, Boyko EJ, Smith DG. Lower extremity foot ulcers and amputations in diabetes. In: Harris MI, Cowie CC, Stern MP, Boyko EJ, Reiber GE, Bennett PH, eds. Diabetes in America. 2 ed. Washington, DC: National Institute of Diabetes and Digestive and Kidney Diseases; 1995: 409–427.
4. Schratzberger P, Walter DH, Rittig K, Bahlmann FH, Pola R, Curry C, Silver M, Krainin JG, Weinberg DH, Ropper AH, Isner JM. Reversal of experimental diabetic neuropathy by VEGF gene transfer. J Clin Invest. 2001; 107: 1083–1092.[Medline] [Order article via Infotrieve]
5. Kusano KF, Allendoerfer KL, Munger W, Pola R, Bosch-Marce M, Kirchmair R, Yoon YS, Curry C, Silver M, Kearney M, Asahara T, Losordo DW. Sonic hedgehog induces arteriogenesis in diabetic vasa nervorum and restores function in diabetic neuropathy. Arterioscler Thromb Vasc Biol. 2004; 24: 2102–2107.
6. Ii M, Nishimura H, Kusano KF, Qin G, Yoon Y-s, Wecker A, Asahara T, Losordo DW. Neuronal nitric oxide synthase mediates statin-induced restoration of vasa nervorum and reversal of diabetic neuropathy. Circulation. 2005; 112: 93–102.
7. Leinninger GM, Vincent AM, Feldman EL. The role of growth factors in diabetic peripheral neuropathy. J Peripher Nerv Syst. 2004; 9: 26–53.[CrossRef][Medline] [Order article via Infotrieve]
8. Apfel SC. Neurotrophic factors in the therapy of diabetic neuropathy. Am J Med. 1999; 107: 34S–42S.[Medline] [Order article via Infotrieve]
9. Grandis M, Nobbio L, Abbruzzese M, Banchi L, Minuto F, Barreca A, Garrone S, Mancardi GL, Schenone A. Insulin treatment enhances expression of IGF-I in sural nerves of diabetic patients. Muscle Nerve. 2001; 24: 622–629.[CrossRef][Medline] [Order article via Infotrieve]
10. Mizisin AP, Vu Y, Shuff M, Calcutt NA. Ciliary neurotrophic factor improves nerve conduction and ameliorates regeneration deficits in diabetic rats. Diabetes. 2004; 53: 1807–1812.
11. Anitha M, Gondha C, Sutliff R, Parsadanian A, Mwangi S, Sitaraman SV, Srinivasan S. GDNF rescues hyperglycemia-induced diabetic enteric neuropathy through activation of the PI3K/Akt pathway. J Clin Invest. 2006; 116: 344–356.[CrossRef][Medline] [Order article via Infotrieve]
12. Wellmer A, Misra VP, Sharief MK, Kopelman PG, Anand P. A double-blind placebo-controlled clinical trial of recombinant human brain-derived neurotrophic factor (rhBDNF) in diabetic polyneuropathy. J Peripher Nerv Syst. 2001; 6: 204–210.[CrossRef][Medline] [Order article via Infotrieve]
13. Pittenger G, Vinik A. Nerve growth factor and diabetic neuropathy. Exp Diabesity Res. 2003; 4: 271–285.[Medline] [Order article via Infotrieve]
14. Simovic D, Isner JM, Ropper AH, Pieczek A, Weinberg DH. Improvement in chronic ischemic neuropathy after intramuscular phVEGF165 gene transfer in patients with critical limb ischemia. Arch Neurol. 2001; 58: 761–768.
15. Schratzberger P, Schratzberger G, Silver M, Curry C, Kearney M, Magner M, Alroy J, Adelman LS, Weinberg DH, Ropper AH, Isner JI. Favorable impact of VEGF gene transfer on ischemic peripheral neuropathy. Nat Med. 2000; 6: 405–413.[CrossRef][Medline] [Order article via Infotrieve]
16. Carmeliet P, Storkebaum E. Vascular and neuronal effects of VEGF in the nervous system: implications for neurological disorders. Semin Cell Dev Biol. 2002; 13: 39–53.[CrossRef][Medline] [Order article via Infotrieve]
17. Pola R, Ling LE, Silver M, Corbley MJ, Kearney M, Blake Pepinsky R, Shapiro R, Taylor FR, Baker DP, Asahara T, Isner JM. The morphogen sonic hedgehog is an indirect angiogenic agent upregulating two families of angiogenic growth factors. Nat Med. 2001; 7: 706–711.[CrossRef][Medline] [Order article via Infotrieve]
18. Calcutt NA, Allendoerfer KL, Mizisin AP, Middlemas A, Freshwater JD, Burgers M, Ranciato R, Delcroix J-D, Taylor FR, Shapiro R, Strauch K, Dudek H, Engber TM, Galdes A, Rubin LL, Tomlinson DR. Therapeutic efficacy of sonic hedgehog protein in experimental diabetic neuropathy. J Clin Invest. 2003; 111: 507–514.[CrossRef][Medline] [Order article via Infotrieve]
19. Zhuang HX, Snyder CK, Pu SF, Ishii DN. Insulin-like growth factors reverse or arrest diabetic neuropathy: effects on hyperalgesia and impaired nerve regeneration in rats. Exp Neurol. 1996; 140: 198–205.[CrossRef][Medline] [Order article via Infotrieve]
20. Emanueli C, Salis MB, Pinna A, Graiani G, Manni L, Madeddu P. Nerve growth factor promotes angiogenesis and arteriogenesis in ischemic hindlimbs. Circulation. 2002; 106: 2257–2262.
21. Graiani G, Emanueli C, Desortes E, Van Linthout S, Pinna A, Figueroa CD, Manni L, Madeddu P. Nerve growth factor promotes reparative angiogenesis and inhibits endothelial apoptosis in cutaneous wounds of type 1 diabetic mice. Diabetologia. 2004; 47: 1047–1054.[Medline] [Order article via Infotrieve]
22. Kalka C, Masuda H, Takahashi T, Kalka-Moll WM, Silver M, Kearney M, Li T, Isner JM, Asahara T. Transplantation of ex vivo expanded endothelial progenitor cells for therapeutic neovascularization. Proc Natl Acad Sci U S A. 2000; 97: 3422–3427.
23. Kawamoto A, Gwon HC, Iwaguro H, Yamaguchi JI, Uchida S, Masuda H, Silver M, Ma H, Kearney M, Isner JM, Asahara T. Therapeutic potential of ex vivo expanded endothelial progenitor cells for myocardial ischemia. Circulation. 2001; 103: 634–637.
24. Cho HJ, Lee N, Lee JY, Choi YJ, Ii M, Wecker A, Jeong JO, Curry C, Qin G, Yoon YS. Role of host tissues for sustained humoral effects after endothelial progenitor cell transplantation into the ischemic heart. J Exp Med. 2007; 204: 3257–3269.
25. Schachinger V, Erbs S, Elsasser A, Haberbosch W, Hambrecht R, Holschermann H, Yu J, Corti R, Mathey DG, Hamm CW, Suselbeck T, Assmus B, Tonn T, Dimmeler S, Zeiher AM. Intracoronary bone marrow-derived progenitor cells in acute myocardial infarction. N Engl J Med. 2006; 355: 1210–1221.
26. Murohara T, Ikeda H, Duan J, Shintani S, Sasaki K, Eguchi H, Onitsuka I, Matsui K, Imaizumi T. Transplanted cord blood-derived endothelial precursor cells augment postnatal neovascularization. J Clin Invest. 2000; 105: 1527–1536.[Medline] [Order article via Infotrieve]
27. Rehman J, Li J, Orschell CM, March KL. Peripheral blood "endothelial progenitor cells" are derived from monocyte/macrophages and secrete angiogenic growth factors. Circulation. 2003; 107: 1164–1169.
28. Yoon YS, Wecker A, Heyd L, Park JS, Tkebuchava T, Kusano K, Hanley A, Scadova H, Qin G, Cha DH, Johnson KL, Aikawa R, Asahara T, Losordo DW. Clonally expanded novel multipotent stem cells from human bone marrow regenerate myocardium after myocardial infarction. J Clin Invest. 2005; 115: 326–338.[CrossRef][Medline] [Order article via Infotrieve]
29. Yoon YS, Uchida S, Masuo O, Cejna M, Park JS, Gwon HC, Kirchmair R, Bahlman F, Walter D, Curry C, Hanley A, Isner JM, Losordo DW. Progressive attenuation of myocardial vascular endothelial growth factor expression is a seminal event in diabetic cardiomyopathy: restoration of microvascular homeostasis and recovery of cardiac function in diabetic cardiomyopathy after replenishment of local vascular endothelial growth factor. Circulation. 2005; 111: 2073–2085.
30. De Palma M, Venneri MA, Galli R, Sergi Sergi L, Politi LS, Sampaolesi M, Naldini L. Tie2 identifies a hematopoietic lineage of proangiogenic monocytes required for tumor vessel formation and a mesenchymal population of pericyte progenitors. Cancer Cell. 2005; 8: 211–226.[CrossRef][Medline] [Order article via Infotrieve]
31. Abe K, Saito H. Neurotrophic effect of basic fibroblast growth factor is mediated by the p42/p44 mitogen-activated protein kinase cascade in cultured rat cortical neurons. Brain Res Dev Brain Res. 2000; 122: 81–85.[CrossRef][Medline] [Order article via Infotrieve]
32. Kermani P, Rafii D, Jin DK, Whitlock P, Schaffer W, Chiang A, Vincent L, Friedrich M, Shido K, Hackett NR, Crystal RG, Rafii S, Hempstead BL. Neurotrophins promote revascularization by local recruitment of TrkB+ endothelial cells and systemic mobilization of hematopoietic progenitors. J Clin Invest. 2005; 115: 653–663.[CrossRef][Medline] [Order article via Infotrieve]
33. Chalasani SH, Baribaud F, Coughlan CM, Sunshine MJ, Lee VM, Doms RW, Littman DR, Raper JA. The chemokine stromal cell-derived factor-1 promotes the survival of embryonic retinal ganglion cells. J Neurosci. 2003; 23: 4601–4612.
34. Mirshahi F, Pourtau J, Li H, Muraine M, Trochon V, Legrand E, Vannier J, Soria J, Vasse M, Soria C. SDF-1 activity on microvascular endothelial cells: consequences on angiogenesis in in vitro and in vivo models. Thromb Res. 2000; 99: 587–594.[CrossRef][Medline] [Order article via Infotrieve]
35. Naruse K, Hamada Y, Nakashima E, Kato K, Mizubayashi R, Kamiya H, Yuzawa Y, Matsuo S, Murohara T, Matsubara T, Oiso Y, Nakamura J. Therapeutic neovascularization using cord blood-derived endothelial progenitor cells for diabetic neuropathy. Diabetes. 2005; 54: 1823–1828.
36. Hur J, Yang HM, Yoon CH, Lee CS, Park KW, Kim JH, Kim TY, Kim JY, Kang HJ, Chae IH, Oh BH, Park YB, Kim HS. Identification of a novel role of T cells in postnatal vasculogenesis: characterization of endothelial progenitor cell colonies. Circulation. 2007; 116: 1671–1682.
37. Balsam LB, Wagers AJ, Christensen JL, Kofidis T, Weissman IL, Robbins RC. Haematopoietic stem cells adopt mature haematopoietic fates in ischaemic myocardium. Nature. 2004; 428: 668–673.[CrossRef][Medline] [Order article via Infotrieve]
38. Muller-Ehmsen J, Krausgrill B, Burst V, Schenk K, Neisen UC, Fries JW, Fleischmann BK, Hescheler J, Schwinger RH. Effective engraftment but poor mid-term persistence of mononuclear and mesenchymal bone marrow cells in acute and chronic rat myocardial infarction. J Mol Cell Cardiol. 2006; 41: 876–884.[CrossRef][Medline] [Order article via Infotrieve]
39. Abdel-Latif A, Bolli R, Tleyjeh IM, Montori VM, Perin EC, Hornung CA, Zuba-Surma EK, Al-Mallah M, Dawn B. Adult bone marrow-derived cells for cardiac repair: a systematic review and meta-analysis. Arch Intern Med. 2007; 167: 989–997.
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Footnotes |
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*Drs Jeong and Kim contributed equally to this work.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/cgi/content/full/CIRCULATIONAHA.108. 789297/DC1.
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