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Chyła-Danił G, Sałaga-Zaleska K, Kreft E, Krzesińska A, Herman S, Kuchta A, Sakowicz-Burkiewicz M, Lenartowicz M, Jankowski M. Suramin Affects the Renal VEGF-A/VEGFR Axis in Short-Term Streptozotocin-Induced Diabetes. Pharmaceuticals (Basel) 2023; 16:ph16030470. [PMID: 36986570 PMCID: PMC10053825 DOI: 10.3390/ph16030470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/15/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Diabetic nephropathy (DN) accounts for approximately 50% of end-stage renal diseases. Vascular endothelial growth factor A (VEGF-A) is thought to be a critical mediator of vascular dysfunction in DN, but its role is unclear. The lack of pharmacological tools to modify renal concentrations further hinders the understanding of its role in DN. In this study, rats were evaluated after 3 weeks of streptozotocin-induced diabetes and two suramin treatments (10 mg/kg, ip). Vascular endothelial growth factor A expression was evaluated by western blot of glomeruli and immunofluorescence of the renal cortex. RT-PCR for receptors Vegfr1 mRNA and Vegfr2 mRNA quantitation was performed. The soluble adhesive molecules (sICAM-1, sVCAM-1) in blood were measured by ELISA and the vasoreactivity of interlobar arteries to acetylcholine was evaluated using wire myography. Suramin administration reduced the expression and intraglomerular localisation of VEGF-A. Increased VEGFR-2 expression in diabetes was reduced by suramin to non-diabetic levels. Diabetes reduced the sVCAM-1 concentrations. Suramin in diabetes restored acetylcholine relaxation properties to non-diabetic levels. In conclusion, suramin affects the renal VEGF-A/VEGF receptors axis and has a beneficial impact on endothelium-dependent relaxation of renal arteries. Thus, suramin may be used as a pharmacological agent to investigate the potential role of VEGF-A in the pathogenesis of renal vascular complications in short-term diabetes.
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Affiliation(s)
- Gabriela Chyła-Danił
- Department of Clinical Chemistry, Medical University of Gdańsk, Dębinki 7, 80-210 Gdańsk, Poland
| | - Kornelia Sałaga-Zaleska
- Department of Clinical Chemistry, Medical University of Gdańsk, Dębinki 7, 80-210 Gdańsk, Poland
| | - Ewelina Kreft
- Department of Clinical Chemistry, Medical University of Gdańsk, Dębinki 7, 80-210 Gdańsk, Poland
| | - Aleksandra Krzesińska
- Department of Clinical Chemistry, Medical University of Gdańsk, Dębinki 7, 80-210 Gdańsk, Poland
| | - Sylwia Herman
- Laboratory of Genetics and Evolutionism, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
| | - Agnieszka Kuchta
- Department of Clinical Chemistry, Medical University of Gdańsk, Dębinki 7, 80-210 Gdańsk, Poland
| | | | - Małgorzata Lenartowicz
- Laboratory of Genetics and Evolutionism, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
| | - Maciej Jankowski
- Department of Clinical Chemistry, Medical University of Gdańsk, Dębinki 7, 80-210 Gdańsk, Poland
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Rodríguez RR, González-Bulnes A, Garcia-Contreras C, Elena Rodriguez-Rodriguez A, Astiz S, Vazquez-Gomez M, Luis Pesantez J, Isabel B, Salido-Ruiz E, González J, Donate Correa J, Luis-Lima S, Porrini E. The Iberian pig fed with high-fat diet: a model of renal disease in obesity and metabolic syndrome. Int J Obes (Lond) 2019; 44:457-465. [PMID: 31636376 DOI: 10.1038/s41366-019-0434-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 05/07/2019] [Accepted: 05/28/2019] [Indexed: 11/09/2022]
Abstract
BACKGROUND The pathogenesis of renal disease in the context of overweight/obesity, metabolic syndrome, and insulin resistance is not completely understood. This may be due to the lack of a definitive animal model of disease, which limits our understanding of obesity-induced renal damage. We evaluated the changes in renal histology and lipid deposits induced by obesity in a model of insulin resistance: the Iberian swine fed with fat-enriched food. METHODS Twenty-eight female sows were randomized to standard (SD) or high-fat diet (HFD: 6.8% of saturated fat) for 100 days. Weight, adiposity, analytics, oral glucose tolerance tests, and measured renal function were determined. Renal histology and lipid deposits in renal tissue were analyzed. RESULTS Animals on HFD developed obesity, hypertension, high levels of LDL cholesterol, triglycerides, insulin resistance, and glomerular hyperfiltration. No animal developed overt diabetes. Animals on HFD showed "diabetoid changes", including mesangial expansion [21.40% ± 4 vs.13.20% ± 4.0, p < 0.0001], nodular glomerulosclerosis [7.40% ± 7, 0.75 vs. 2.40% ± 4.7, p = 0.02], and glomerulomegaly (18% vs. 10%, p = 0.010) than those on SD. Tubular atrophy, interstitial fibrosis, inflammation, arteriolar hyalinosis, or fibrointimal thickening were mild and similar between groups. Triglyceride content in renal tissue was higher in animals on HFD than in SD (15.4% ± 0.5 vs. 12.7% ± 0.7; p < 0.01). CONCLUSIONS Iberian pigs fed with fat-enriched food showed diabetoid changes and glomerulomegaly as observed in obese humans making this model suitable to study obesity-induced renal disease.
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Affiliation(s)
- Rosa Rodríguez Rodríguez
- Pathology Department, Hospital Universitario de Canarias, Tenerife, Spain.,University of La Laguna, Santa Cruz de Tenerife, Spain
| | - Antonio González-Bulnes
- Comparative Physiology Group, SGIT-INIA, Madrid, Spain.,Faculty of Veterinary, Universidad Complutense de Madrid, Madrid, Spain
| | | | | | - Susana Astiz
- Comparative Physiology Group, SGIT-INIA, Madrid, Spain
| | | | | | | | - Eduardo Salido-Ruiz
- Pathology Department, Hospital Universitario de Canarias, Tenerife, Spain.,University of La Laguna, Santa Cruz de Tenerife, Spain.,Instituto Tecnologías Biomédicas (ITB), Tenerife, Spain
| | | | - Javier Donate Correa
- Nephrology Department, Research Unit Hospital Universitario de Canarias, Tenerife, Spain
| | - Sergio Luis-Lima
- Instituto Tecnologías Biomédicas (ITB), Tenerife, Spain.,Nephrology Department, Research Unit Hospital Universitario de Canarias, Tenerife, Spain
| | - Esteban Porrini
- University of La Laguna, Santa Cruz de Tenerife, Spain. .,Instituto Tecnologías Biomédicas (ITB), Tenerife, Spain. .,Nephrology Department, Research Unit Hospital Universitario de Canarias, Tenerife, Spain.
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Hozzein WN, Badr G, Badr BM, Allam A, Ghamdi AA, Al-Wadaan MA, Al-Waili NS. Bee venom improves diabetic wound healing by protecting functional macrophages from apoptosis and enhancing Nrf2, Ang-1 and Tie-2 signaling. Mol Immunol 2018; 103:322-335. [PMID: 30366166 DOI: 10.1016/j.molimm.2018.10.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 10/06/2018] [Accepted: 10/14/2018] [Indexed: 02/07/2023]
Abstract
Impaired wound healing is a serious complication of diabetes that negatively affects the patient's socioeconomic life. Multiple mechanisms contribute to impaired diabetic wound healing including deficient recruitment of wound macrophages/neutrophils and impaired neovascularization. Bee venom (BV) has been used as an anti-inflammatory agent for the treatment of several diseases. Nevertheless, the impacts of BV on the diabetic wound healing have been poorly studied. In the present study, we investigated the molecular mechanisms underlying BV treatment on diabetic wound healing in a type I diabetic mouse model. Three experimental groups were used: group 1, non-diabetic control mice; group 2, vehicle-diabetic mice; and group 3, BV-treated diabetic mice. We found that the diabetic mice exhibited impaired wound closure characterized by a significant decrease in collagen and β-defensin-2 (BD-2) expression compared to control non-diabetic mice. The impairment of diabetic wound healing is attributed to increased ROS levels and abolished antioxidant enzymes activity in the wounded tissues. Additionally, wounded tissue in diabetic mice revealed aberrantly decreased levels of Ang-1 and Nrf2 (the agonist ligands of Tie-2) followed by a marked reduction in the phosphorylation of Tie2 and downstream signaling eNOS, AKT and ERK. Impaired diabetic wound healing was also characterized by a significant reduction in activities of total antioxidant enzymes followed by a marked reduction in the levels of CCL2, CCL3 and CXCL2; which led to impaired recruitment and functions of wound macrophages/neutrophils; and significant reduction in the expression of CD31, a marker for neovascularization and angiogenesis of the injured tissue. Interestingly, BV treatment significantly enhanced wound closure in diabetic mice by increasing collagen and BD-2 expression and restoring the levels of Ang-1 and Nrf2 and hence enhancing the Tie-2 downstream signaling. Most importantly, treatment of diabetic mice with BV significantly restored the activities of wounded tissue antioxidant enzymes and the levels of chemokines, and subsequently rescued wound macrophages from mitochondrial membrane potential-induced apoptosis. Our findings reveal the immune-enhancing effects of BV for improving healing process of diabetic wounds and provide the first insight concerning the underlying molecular mechanisms.
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Affiliation(s)
- Wael N Hozzein
- Bioproducts Research Chair, Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia; Botany Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
| | - Gamal Badr
- Zoology Department, Faculty of Science, Assiut University, 71516, Assiut, Egypt; Laboratory of Immunology and Molecular Physiology, Zoology Department, Faculty of Science, Assiut University, 71516, Assiut, Egypt.
| | - Badr M Badr
- Radiation Biology Department, National Centre for Radiation Research and Technology (NCRRT), Cairo, Egypt
| | - Ahmed Allam
- Zoology Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
| | - Ahmad Al Ghamdi
- Chair of Engineer Abdullah Baqshan for Bee Research, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Mohammed A Al-Wadaan
- Bioproducts Research Chair, Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
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Obesity-related glomerulopathy: clinical and pathologic characteristics and pathogenesis. Nat Rev Nephrol 2016; 12:453-71. [PMID: 27263398 DOI: 10.1038/nrneph.2016.75] [Citation(s) in RCA: 416] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The prevalence of obesity-related glomerulopathy is increasing in parallel with the worldwide obesity epidemic. Glomerular hypertrophy and adaptive focal segmental glomerulosclerosis define the condition pathologically. The glomerulus enlarges in response to obesity-induced increases in glomerular filtration rate, renal plasma flow, filtration fraction and tubular sodium reabsorption. Normal insulin/phosphatidylinositol 3-kinase/Akt and mTOR signalling are critical for podocyte hypertrophy and adaptation. Adipokines and ectopic lipid accumulation in the kidney promote insulin resistance of podocytes and maladaptive responses to cope with the mechanical forces of renal hyperfiltration. Although most patients have stable or slowly progressive proteinuria, up to one-third develop progressive renal failure and end-stage renal disease. Renin-angiotensin-aldosterone blockade is effective in the short-term but weight loss by hypocaloric diet or bariatric surgery has induced more consistent and dramatic antiproteinuric effects and reversal of hyperfiltration. Altered fatty acid and cholesterol metabolism are increasingly recognized as key mediators of renal lipid accumulation, inflammation, oxidative stress and fibrosis. Newer therapies directed to lipid metabolism, including SREBP antagonists, PPARα agonists, FXR and TGR5 agonists, and LXR agonists, hold therapeutic promise.
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Li F, Lei T, Xie K, Wu X, Tang C, Jiang M, Liu J, Luo E, Shen G. Effects of extremely low frequency pulsed magnetic fields on diabetic nephropathy in streptozotocin-treated rats. Biomed Eng Online 2016; 15:8. [PMID: 26786255 PMCID: PMC4717615 DOI: 10.1186/s12938-015-0121-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 12/22/2015] [Indexed: 12/31/2022] Open
Abstract
Background Extremely low frequency pulsed magnetic fields (ELFPMF) have been shown to induce Faraday currents and measurable effects on biological systems. A kind of very high frequency electromagnetic field was reported that it improved the symptoms of diabetic nephropathy (DN) which is a major complication of diabetes. However, few studies have examined the effects of ELFPMF DN at the present. The present study was designed to investigate the effects of ELFPMF on DN in streptozotocin (STZ)–induced type 1 diabetic rats. Methods Adult male SD rats were randomly divided into three weight-matched groups: Control (non-diabetic rats without DN), DN + ELFPMF (diabetic rats with DN exposed to ELFPMF, 8 h/days, 6 weeks) and DN (diabetic rats with DN exposed to sham ELFPMF). Renal morphology was examined by light and electron microscopy, vascular endothelial growth factor (VEGF)-A and connective tissue growth factor (CTGF) were measured by enzyme linked immune sorbent assay. Results After 6 weeks’ ELFPMF exposure, alterations of hyperglycemia and weight loss in STZ-treated rats with DN were not found, while both positive and negative effects of ELFPMF on the development of DN in diabetic rats were observed. The positive one was that ELFPMF exposure attenuated the pathological alterations in renal structure observed in STZ-treated rats with DN, which were demonstrated by slighter glomerular and tubule-interstitial lesions examined by light microscopy and slighter damage to glomerular basement membrane and podocyte foot processes examined by electron microscopy. And then, the negative one was that ELFPMF stimulation statistically significantly decreased renal expression of VEGF-A and statistically significantly increased renal expression of CTGF in diabetic rats with DN, which might partially aggravate the symptoms of DN. Conclusion Both positive and negative effects of ELFPMF on the development of DN in diabetic rats were observed. The positive effect induced by ELFPMF might play a dominant role in the procession of DN in diabetic rats, and it is suggested that the positive effect should be derived from the correction of pathogenic diabetes-induced mediators.
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Affiliation(s)
- Feijiang Li
- School of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.
| | - Tao Lei
- School of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.
| | - Kangning Xie
- School of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.
| | - Xiaoming Wu
- School of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.
| | - Chi Tang
- School of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.
| | - Maogang Jiang
- School of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.
| | - Juan Liu
- School of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.
| | - Erping Luo
- School of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.
| | - Guanghao Shen
- School of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.
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Nagasu H, Satoh M, Kiyokage E, Kidokoro K, Toida K, Channon KM, Kanwar YS, Sasaki T, Kashihara N. Activation of endothelial NAD(P)H oxidase accelerates early glomerular injury in diabetic mice. J Transl Med 2016; 96:25-36. [PMID: 26552047 PMCID: PMC4874489 DOI: 10.1038/labinvest.2015.128] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 09/12/2015] [Accepted: 09/18/2015] [Indexed: 11/09/2022] Open
Abstract
Increased generation of reactive oxygen species (ROS) is a common denominative pathogenic mechanism underlying vascular and renal complications in diabetes mellitus. Endothelial NAD(P)H oxidase is a major source of vascular ROS, and it has an important role in endothelial dysfunction. We hypothesized that activation of endothelial NAD(P)H oxidase initiates and worsens the progression of diabetic nephropathy, particularly in the development of albuminuria. We used transgenic mice with endothelial-targeted overexpression of the catalytic subunit of NAD(P)H oxidase, Nox2 (NOX2TG). NOX2TG mice were crossed with Akita insulin-dependent diabetic (Akita) mice that develop progressive hyperglycemia. We compared the progression of diabetic nephropathy in Akita versus NOX2TG-Akita mice. NOX2TG-Akita mice and Akita mice developed significant albuminuria above the baseline at 6 and 10 weeks of age, respectively. Compared with Akita mice, NOX2TG-Akita mice exhibited higher levels of NAD(P)H oxidase activity in glomeruli, developed glomerular endothelial perturbations, and attenuated expression of glomerular glycocalyx. Moreover, in contrast to Akita mice, the NOX2TG-Akita mice had numerous endothelial microparticles (blebs), as detected by scanning electron microscopy, and increased glomerular permeability. Furthermore, NOX2TG-Akita mice exhibited distinct phenotypic changes in glomerular mesangial cells expressing α-smooth muscle actin, and in podocytes expressing increased levels of desmin, whereas the glomeruli generated increased levels of ROS. In conclusion, activation of endothelial NAD(P)H oxidase in the presence of hyperglycemia initiated and exacerbated diabetic nephropathy characterized by the development of albuminuria. Moreover, ROS generated in the endothelium compounded glomerular dysfunctions by altering the phenotypes of mesangial cells and compromising the integrity of the podocytes.
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Affiliation(s)
- Hajime Nagasu
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Minoru Satoh
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Emi Kiyokage
- Department of Anatomy, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Kengo Kidokoro
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Kazunori Toida
- Department of Anatomy, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Keith M Channon
- Department of Cardiovascular Medicine, University of Oxford, Oxford, UK
| | - Yashpal S Kanwar
- Department of Pathology and Medicine, Northwestern University, Chicago, IL, USA
| | - Tamaki Sasaki
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Naoki Kashihara
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan
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Hale LJ, Hurcombe J, Lay A, Santamaría B, Valverde AM, Saleem MA, Mathieson PW, Welsh GI, Coward RJ. Insulin directly stimulates VEGF-A production in the glomerular podocyte. Am J Physiol Renal Physiol 2013; 305:F182-8. [PMID: 23698113 DOI: 10.1152/ajprenal.00548.2012] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Podocytes are critically important for maintaining the integrity of the glomerular filtration barrier and preventing albuminuria. Recently, it has become clear that to achieve this, they need to be insulin sensitive and produce an optimal amount of VEGF-A. In other tissues, insulin has been shown to regulate VEGF-A release, but this has not been previously examined in the podocyte. Using in vitro and in vivo approaches, in the present study, we now show that insulin regulates VEGF-A in the podocyte in both mice and humans via the insulin receptor (IR). Insulin directly increased VEGF-A mRNA levels and protein production in conditionally immortalized wild-type human and murine podocytes. Furthermore, when podocytes were rendered insulin resistant in vitro (using stable short hairpin RNA knockdown of the IR) or in vivo (using transgenic podocyte-specific IR knockout mice), podocyte VEGF-A production was impaired. Importantly, in vivo, this occurs before the development of any podocyte damage due to podocyte insulin resistance. Modulation of VEGF-A by insulin in the podocyte may be another important factor in the development of glomerular disease associated with conditions in which insulin signaling to the podocyte is deranged.
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Affiliation(s)
- L J Hale
- Academic and Children's Renal Unit, University of Bristol, Learning and Research building, Southmead Hospital, Bristol, United Kingdom
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8
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Leong-Poi H. Contrast ultrasound and targeted microbubbles: diagnostic and therapeutic applications in progressive diabetic nephropathy. Semin Nephrol 2013; 32:494-504. [PMID: 23062991 DOI: 10.1016/j.semnephrol.2012.07.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Diabetic nephropathy remains one of the most common causes for end-stage renal disease worldwide. Although therapies aimed at optimizing glycemic control and systemic blood pressure have benefit, the reduction in progressive nephropathy remains modest at best. Thus, research continues to focus on newer therapies to address the unmet needs for additional renal protective strategies. The ability to noninvasively image the molecular and cellular processes that underlie diabetic nephropathy would be useful in risk stratifying patients with diabetes, and more importantly would aid in the evaluation of novel therapies to prevent and treat nephropathy. In addition, the development of ultrasound technologies that allow targeted gene delivery using high-power ultrasound and DNA-bearing microbubbles may have applicability for gene therapy to prevent diabetic nephropathy. This review highlights contrast-enhanced ultrasound imaging techniques for the evaluation of renal pathologies, including perfusion and molecular imaging techniques, and ultrasound-mediated gene delivery for therapeutic applications in diabetic nephropathy, that have potential for translation to clinical practice.
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Affiliation(s)
- Howard Leong-Poi
- Division of Cardiology, Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
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Roy H, Bhardwaj S, Babu M, Lähteenvuo JE, Ylä-Herttuala S. VEGF-DdeltaNdeltaC mediated angiogenesis in skeletal muscles of diabetic WHHL rabbits. Eur J Clin Invest 2010; 40:422-32. [PMID: 20534064 DOI: 10.1111/j.1365-2362.2010.02285.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Arterial occlusive disease is often associated with diabetes mellitus and hypercholesterolaemia which may reduce angiogenic potential of several growth factors. Accordingly, the usefulness of therapeutic angiogenesis in the presence of diabetes and hypercholesterolaemia has remained unclear. We evaluated angiogenic effects of the mature form of vascular endothelial growth factor-D (VEGF-D(deltaNdeltaC)) in skeletal muscles in the presence of severe diabetes and hypercholesterolaemia. METHODS Intra muscular injections of adenoviruses encoding human VEGF-D(deltaNdeltaC) (AdVEGF-D(deltaNdeltaC)) were given in the hind limbs of a group of diabetic hypercholesterolaemic rabbits and adenoviruses encoding LacZ (AdLacZ) were used as a control. All animals were killed 6 days after the gene transfer. RESULTS Capillary count, capillary area, capillary permeability and perfusion were significantly higher in the AdVEGF-D(deltaNdeltaC) transduced muscles compared with the AdLacZ controls. Expressions of endothelial nitric oxide synthase (eNOS) and VEGF receptor(R)-2 were also significantly increased in the VEGF-D(deltaNdeltaC) transduced muscles, along with an increased expression of angiopoietins (Angs) and neuropilin-2 (NP-2). Furthermore, VEGF-D(deltaNdeltaC) gene transfer to the skeletal muscles increased localized recruitment of cells with endothelial progenitor-like characteristics. CONCLUSIONS VEGF-D(deltaNdeltaC) gene transfer can induce efficient angiogenesis in the presence of severe diabetes and hypercholesterolaemia by upregulating eNOS and VEGFR-2 expression. VEGF-D(deltaNdeltaC) appears to be a promising agent for inducing therapeutic angiogenesis even in cases with severe diabetes and hypercholesterolaemia.
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Affiliation(s)
- Himadri Roy
- Department of Molecular Medicine and Biotechnology, A. I. Virtanen Institute for Molecular Sciences
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10
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Patel J, Gudehithlu KP, Dunea G, Arruda JAL, Singh AK. Foreign body-induced granulation tissue is a source of adult stem cells. Transl Res 2010; 155:191-9. [PMID: 20303468 DOI: 10.1016/j.trsl.2009.08.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 08/20/2009] [Accepted: 08/23/2009] [Indexed: 12/19/2022]
Abstract
In the current study, we have cultured and propagated the cells obtained from the granulation tissue that forms around perforated polyvinyl tubes placed in the subcutaneous space of normal rats. We found that these cells (called granulation tissue-derived stem cells [GTSCs]) expressed markers of embryonic pluripotent cells (Oct-4 and Nanog) and of adult stem cells (CXCR4 and Thy1.1) as well as produced high levels of vascular endothelial growth factor (VEGF) for up to 10 passages. By fluorescence-activated cell-sorting (FACS) analysis, GTSCs were positive for stem-cell surface markers CD90, CD59, and CD44 and were negative for CD45, which suggests that they were of mesenchymal origin and not of hematopoietic lineage. When incubated in specific differentiation medium, these cells transformed into adipogenic, osteogenic, and chondrogenic lineages, which shows that they were multipotent. Furthermore, after systemic injection, these cells were found in the vicinity of an injured site created in the liver but not in normal areas of the liver, which indicates their propensity to seek and engraft to an injured area in the body. We conclude that granulation tissue induced by a large foreign body is a convenient source of adult stem cells that can be maintained in culture and can be used to repair and regenerate injured tissue.
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Affiliation(s)
- Jilpa Patel
- Department of Medicine, Hektoen Institute of Medicine, Chicago, IL 60612, USA.
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11
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Lagranha CJ, Fiorino P, Casarini DE, Schaan BD, Irigoyen MC. [Molecular bases of diabetic nephropathy]. ACTA ACUST UNITED AC 2009; 51:901-12. [PMID: 17934656 DOI: 10.1590/s0004-27302007000600003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Accepted: 05/14/2007] [Indexed: 11/22/2022]
Abstract
The determinant of the diabetic nephropathy is hyperglycemia, but hypertension and other genetic factors are also involved. Glomerulus is the focus of the injury, where mesangial cell proliferation and extracellular matrix occur because of the increase of the intra- and extracellular glucose concentration and overexpression of GLUT1. Sequentially, there are increases in the flow by the poliol pathway, oxidative stress, increased intracellular production of advanced glycation end products (AGEs), activation of the PKC pathway, increase of the activity of the hexosamine pathway, and activation of TGF-beta1. High glucose concentrations also increase angiotensin II (AII) levels. Therefore, glucose and AII exert similar effects in inducing extracellular matrix formation in the mesangial cells, using similar transductional signal, which increases TGF-beta1 levels. In this review we focus in the effect of glucose and AII in the mesangial cells in causing the events related to the genesis of diabetic nephropathy. The alterations in the signal pathways discussed in this review give support to the observational studies and clinical assays, where metabolic and antihypertensive controls obtained with angiotensin-converting inhibitors have shown important and additive effect in the prevention of the beginning and progression of diabetic nephropathy. New therapeutic strategies directed to the described intracellular events may give future additional benefits.
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Affiliation(s)
- Claudia J Lagranha
- Laboratório de Hipertensão Experimental, Unidade de Hipertensão, Instituto do Coração, HC-FMUSP, São Paulo
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12
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Abstract
The field of vascular endothelial growth factor (VEGF) has recently witnessed a surge of research into its role in diabetic kidney disease. Based on its credentials as a potent inducer of vasopermeability and angiogenesis, podocyte-derived VEGF is believed to participate in the glomerular capillary hyperpermeability of macromolecules that potentially underlies the pathogenesis of diabetic albuminuria. The evidence for VEGF's role is relatively straightforward in animal models of diabetes, establishing that VEGF is upregulated in the diabetic kidney, that VEGF alone reproduces some aspects of diabetic glomerulopathy, and that antagonism of VEGF attenuates diabetic albuminuria and other associated features of the podocytopathy. However, the promise shown in the animal studies has not carried over as convincingly into the realm of human studies, as some investigators find a negative or no relationship between VEGF and diabetic nephropathy, whereas others find a positive correlation between the two. If VEGF does play a role in diabetic renal disease, its observed effects and known mechanisms seem to point squarely at the podocyte as a central target of the maladaptive VEGF overactivity.
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Affiliation(s)
- Sheldon Chen
- Department of Internal Medicine, American University of Beirut, Beirut, Lebanon
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Yang Z, Mo X, Gong Q, Pan Q, Yang X, Cai W, Li C, Ma JX, He Y, Gao G. Critical effect of VEGF in the process of endothelial cell apoptosis induced by high glucose. Apoptosis 2008; 13:1331-43. [DOI: 10.1007/s10495-008-0257-y] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Chen JX, Stinnett A. Disruption of Ang-1/Tie-2 signaling contributes to the impaired myocardial vascular maturation and angiogenesis in type II diabetic mice. Arterioscler Thromb Vasc Biol 2008; 28:1606-13. [PMID: 18556567 DOI: 10.1161/atvbaha.108.169235] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Microvascular insufficiency represents a major cause of end-organ failure among diabetics. The current studies were undertaken to determine whether dysregulation of the angiopoietins/Tie-2 system would result in an impairment of smooth muscle cell (SMC) recruitment and vascular maturation, which contributes to impaired angiogenesis in diabetes. METHODS AND RESULTS Tie-2 expression was significantly attenuated, whereas angiopoietin-2 (Ang-2) was increased in db/db mice subjected to myocardial ischemia. Our morphological analysis showed that the number of SMC coverage area per neovessel was significantly reduced in db/db mice. This was accompanied by a significant reduction of myocardial capillary density and arteriole formation. Interestingly, Angiopoietin-1(Ang-1)-induced SMC recruitment and vessel outgrowth were severely impaired in db/db mice. Our in vitro studies further demonstrated that exposure of mouse heart endothelial cells to high glucose resulted in a significant upregulation of Ang-2 and a downregulation of Tie-2 expression. These alterations led to a significant impairment of Ang-1-induced Akt and eNOS phosphorylation, along with a remarkable impairment of Ang-1-induced endothelial cell migration and endothelial cell spheroid sprouting. Ang-1 gene transfer restored Tie-2 expression and rescued these abnormalities in diabetes. CONCLUSIONS Our findings underscore the important role of Ang-1-Tie-2 signaling in the diabetes-induced impairment of vascular maturation and angiogenesis.
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Affiliation(s)
- Jian-Xiong Chen
- Department of Pediatrics, Division of Neonatology, Vanderbilt University Medical Center, MRB IV-1125, Nashville, TN 37232-2650, USA.
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15
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Stromal cells cultured from omentum express pluripotent markers, produce high amounts of VEGF, and engraft to injured sites. Cell Tissue Res 2008; 332:81-8. [PMID: 18196277 DOI: 10.1007/s00441-007-0560-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Accepted: 11/20/2007] [Indexed: 01/06/2023]
Abstract
When rat omentum becomes activated by intraperitoneal injection of inert polydextran particles, these particles are rapidly surrounded by cells that express markers of adult stem cells (SDF-1alpha, CXCR4, WT-1) and of embryonic pluripotent cells (Oct-4, Nanog, SSEA-1). We have cultured such cells, because they may offer a convenient source of adult stem cells, and have found that they retain stem cell markers and produce high levels of vascular endothelial growth factor for up to ten passages. After systemic or local injection of these cultured cells into rats with acute injury of various organs, the cells specifically engraft at the injured sites. Thus, our experiments show that omental stromal cells can be cultured from activated omentum, and that these cells exhibit stem cell properties enabling them to be used for repair and possibly for the regeneration of damaged tissues.
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16
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Yao D, Taguchi T, Matsumura T, Pestell R, Edelstein D, Giardino I, Suske G, Rabbani N, Thornalley PJ, Sarthy VP, Hammes HP, Brownlee M. High glucose increases angiopoietin-2 transcription in microvascular endothelial cells through methylglyoxal modification of mSin3A. J Biol Chem 2007; 282:31038-45. [PMID: 17670746 DOI: 10.1074/jbc.m704703200] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Methylglyoxal is a highly reactive dicarbonyl degradation product formed from triose phosphates during glycolysis. Methylglyoxal forms stable adducts primarily with arginine residues of intracellular proteins. The biologic role of this covalent modification in regulating cell function is not known. Here we report that in mouse kidney endothelial cells, high glucose causes increased methylglyoxal modification of the corepressor mSin3A. Methylglyoxal modification of mSin3A results in increased recruitment of O-GlcNAc-transferase, with consequent increased modification of Sp3 by O-linked N-acetylglucosamine. This modification of Sp3 causes decreased binding to a glucose-responsive GC-box in the angiopoietin-2 (Ang-2) promoter, resulting in increased Ang-2 expression. Increased Ang-2 expression induced by high glucose increased expression of intracellular adhesion molecule 1 and vascular cell adhesion molecule 1 in cells and in kidneys from diabetic mice and sensitized microvascular endothelial cells to the proinflammatory effects of tumor necrosis factor alpha. This novel mechanism for regulating gene expression may play a role in the pathobiology of diabetic vascular disease.
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Affiliation(s)
- Dachun Yao
- Juvenile Diabetes Research Foundation International Center for Diabetic Complications Research, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Abstract
Angiogenesis, the formation of new blood vessels from pre-existing vasculature, plays a key role in both physiologic and pathologic events, including wound healing, cancer, and diabetes. Neovascularization has been implicated in the genesis of diverse diabetic complications such as retinopathy, impaired wound healing, neuropathy, and, most recently, diabetic nephropathy. Diabetic nephropathy is one of the major microvascular-associated complications in diabetes and is the leading cause of end-stage renal disease worldwide. In this review we describe the major factors involved in the pathologic glomerular microvascular alterations in response to hyperglycemia and the possible use of anti-angiogenic therapies for the treatment of diabetic nephropathy.
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Affiliation(s)
- Roy Zent
- Department of Research Medicine, Veterans Affairs Hospital, Nashville, TN, USA
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18
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Sun H, Zheng JM, Chen S, Zeng CH, Liu ZH, Li LS. Enhanced Expression of ANGPTL2 in the Microvascular Lesions of Diabetic Glomerulopathy. ACTA ACUST UNITED AC 2007; 105:e117-23. [PMID: 17347581 DOI: 10.1159/000100493] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Accepted: 12/14/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND Diabetic nephropathy (DN) is one of the most important microvascular complications of diabetes mellitus. However, the underlying mechanisms remain unclear. We studied the expression characteristics of angiopoietin-like 2 (ANGPTL2), a novel DN-associated growth factor identified in our previous gene chip screening. METHODS Glomeruli were microdissected from renal biopsies from 24 patients with DN and 8 donor controls. The expression of ANGPTL2 was assessed by RT-PCR and immunohistochemistry, and then correlated with clinical and pathological indices of glomerular injury. RESULTS Consistent with the results of the gene chip experiment, abundant expression of ANGPTL2 was found more frequently in diabetic glomeruli as compared to donor controls (95 vs. 38%, chi(2) = 15.9, p < 0.01). ANGPTL2 mRNA upregulation was more prominent in glomeruli with less microaneurysm (22 vs. 66%, p < 0.05), inflammatory influx (6 vs. 50%, p < 0.05) or endothelial foam cell formation (11 vs. 53%, p < 0.05). Immunostaining revealed an upregulation of ANGPTL2 protein in hypertrophied diabetic glomeruli, mainly distributed in podocytes, which were supposed to be the origin of ANGPTL2. CONCLUSION The upregulation of ANGPTL2 in diabetic glomerulopathy shows a close relationship to abnormal microvasculature and endothelial inflammation. ANGPTL2 may play an important role in the pathogenesis of diabetic glomerulopathy.
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Affiliation(s)
- Hua Sun
- Nanjing University, School of Medicine, Research Institute of Nephrology, Jinling Hospital, Nanjing, China
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19
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Litbarg NO, Gudehithlu KP, Sethupathi P, Arruda JAL, Dunea G, Singh AK. Activated omentum becomes rich in factors that promote healing and tissue regeneration. Cell Tissue Res 2007; 328:487-97. [PMID: 17468892 DOI: 10.1007/s00441-006-0356-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Accepted: 10/20/2006] [Indexed: 02/06/2023]
Abstract
In order to study the mechanism by which an omental pedicle promotes healing when applied to an injured site, we injected a foreign body into the abdominal cavity to activate the omentum. One week after the injection, we isolated the omentum and measured blood vessel density, blood content, growth and angiogenesis factors (VEGF and others), chemotactic factors (SDF-1 alpha), and progenitor cells (CXCR-4, WT-1). We found that the native omentum, which consisted mostly of adipose tissue, expanded the mass of its non-adipose part (milky spots) 15- to 20-fold. VEGF and other growth factors increased by two- to four-fold, blood vessel density by three-fold, and blood content by two-fold. The activated omentum also showed increases in SDF-1 alpha, CXCR-4, and WT-1 cells (factors and cells positively associated with tissue regeneration). Thus, we propose that an omentum activated by a foreign body (or by injury) greatly expands its milky-spot tissue and becomes rich in growth factors and progenitor cells that facilitate the healing and regeneration of injured tissue.
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Affiliation(s)
- Natalia O Litbarg
- Department of Medicine, Stroger Hospital of Cook County, Chicago, IL 60612, USA
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20
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Baelde HJ, Eikmans M, Lappin DWP, Doran PP, Hohenadel D, Brinkkoetter PT, van der Woude FJ, Waldherr R, Rabelink TJ, de Heer E, Bruijn JA. Reduction of VEGF-A and CTGF expression in diabetic nephropathy is associated with podocyte loss. Kidney Int 2007; 71:637-45. [PMID: 17264876 DOI: 10.1038/sj.ki.5002101] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Micro-vascular and renal complications in diabetic patients are a considerable clinical challenge. In a previous study, we found a significant decrease in vascular endothelial growth factor A (VEGF-A) mRNA levels in glomeruli from patients with diabetic nephropathy (DN). We now set out to investigate the relationship between reduced VEGF-A and connective tissue growth factor (CTGF) expression levels, the number of podocytes, and the extent of interstitial fibrosis. Laser capture microdissection was applied to obtain glomerular RNA from 28 patients with DN and 22 controls. mRNA levels of VEGF-A, CTGF, nephrin, podocin, and Wilms tumor1 (WT1) were measured using real-time polymerase chain reaction. Protein expression was evaluated using immuno-stainings for VEGF-A and CTGF, as well as markers for podocytes (WT1) and endothelial cells (CD31). We found a significant decrease in glomerular mRNA levels for VEGF-A (2.5 times), CTGF (1.6), nephrin (2.8), podocin (3.3), and WT1 (1.7) in patients with DN. There was a significant correlation between expression of podocyte markers and VEGF-A mRNA levels, and an inverse correlation between podocin message and the extent of interstitial fibrosis. CD31-positive area was significantly decreased (3.2 times) in patients with DN. Reduction of angiogenic factors correlated with the extent of interstitial fibrosis. This downregulation was related to a reduction of podocytes in DN. The results may suggest that downregulation of VEGF-A and CTGF in DN is a result of podocyte loss.
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Affiliation(s)
- H J Baelde
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
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Lu Y, Deng A, Yang X, Liu J, Zhu Z. A potential pathological role of angiopoietins expression in glomeruli during progressive glomerulisclerosis related to podocyte injury. ACTA ACUST UNITED AC 2006; 26:294-7. [PMID: 16961273 DOI: 10.1007/bf02829555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A potential pathological role of angiopoietins (Ang) in glomeruli following podocyte injury-induced progressive glomerulosclerosis was explored. Eighty male Wistar rats were randomly allocated into sham operation group (Sham, n = 25), Uninephrectomy group (UPHT, n = 25) and Uninephrectomy+Daunorubicin group (DRB, n = 30). In DRB group, daunorubicin (5 mg/kg) was injected via tail vein on the 7th and 14th day after uninephrectomy. At week 1, 2, 4, 6 and 8 respectively following establishment of the animal model, 5 rats in Sham group and UPHT group, and 6 in DRB group were taken respectively for determining 24-h urinary protein excretion rate (24hUPER), blood urea nitrogen (BUN) and serum creatinine (Scr). The sections of kidneys were examined by an electric microscope, PAS staining, immunohistochemical staining and in situ hybridization histochemistry. The results showed that 24hUPER, BUN and Scr in DRB group were more than those in Sham group and UPHT group at the same time points, and there was a trend towards an increase on level of GSI in DRB group from week 2 to week 8. Electric microscopy revealed that podocyte injury presented in DRB group. The expression of Ang1 mRNA and protein in glomeruli of DRB group was decreased, while the expression of Ang2 protein in glomeruli of DRB group increased. Meanwhile, the expression of Ang1 mRNA had a negative correlation with the expression of Ang2 mRNA, and the expression of Ang1 protein had a positive correlation with the expression of Ang1 mRNA, and had a negative correlation with 24hUPER, BUN, Scr, glomerular sclerotic index (GSI), the expression of Ang2 protein and CoIV protein. The expression of Ang2 protein had a positive correlation with the expression of Ang2 mRNA, and had a positive correlation with 24hUPER, BUN, Scr, GSI, the expression of CoIV protein. It was concluded that podocyte injury might lead to an alteration in the expression of Ang1 and Ang2 within glomeruli. Ang2 may get rid of inhibition from Ang1 for downregulation of the Ang1 expression, which facilitate upregulation of the Ang2 expression in glomeruli to promote progressive glomerulosclerosis in the rats.
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Affiliation(s)
- Yuanhang Lu
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
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Lu YH, Deng AG, Li N, Song MN, Yang X, Liu JS. Changes in angiopoietin expression in glomeruli involved in glomerulosclerosis in rats with daunorubicin-induced nephrosis. Acta Pharmacol Sin 2006; 27:579-87. [PMID: 16626513 DOI: 10.1111/j.1745-7254.2006.00289.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
AIM To study the potential pathological role of endogenous angiopoietins in daunorubicin-induced progressive glomerulosclerosis in rats. METHODS Seventy male Wistar rats were allocated randomly into a daunorubicin group (DRB; n=40) or a control group (n=30). The rats in the DRB group were injected with DRB (15 mg/kg), in their tails. Subsequently, at intervals of 1, 2, 4, 6, 8, and 12 weeks, 5 male Wistar rats in each group were chosen randomly for 24 h urinary protein quantitative measurements (24 h UPQM), and determination of plasma tumor necrosis factor alpha (TNF-alpha), angiopoietin-1 (Ang1), and angiopoietin-2 (Ang2) levels. Kidney sections were examined by electron microscopy, Periodic Acid Schiff (PAS) staining, immunohistochemical staining and in situ hybridization histochemistry. RESULTS As glomerulosclerosis progressed in the DRB group, expression of Ang1 mRNA and protein in glomeruli decreased and expression of TNF-alpha protein, Ang2 mRNA and protein in glomeruli increased. Expression of Ang1 mRNA and protein in glomeruli were negatively correlated with 24 h UPQM, Fn protein expression, and mean area of extracellular matrix (MAECM). In comparison, expression of Ang2 mRNA and protein in glomeruli were positively correlated with 24 h UPQM, Fn protein expression and MAECM; furthermore, there was a positive correlation between plasma Ang2 and 24 h UPQM. Plasma TNF-alpha and expression of TNF-alpha in glomeruli were positively correlated with expression of Ang2 mRNA and protein in glomeruli. There was a negative correlation between Ang1 protein expression and Ang2 protein expression in glomeruli. CONCLUSION During DRB-induced glomerulosclerosis, podocyte injury led to a shift in the balance of Ang1 and Ang2 in glomeruli. Increased TNF-alpha in plasma and glomeruli may upregulate Ang2 expression in glomeruli. Elevated Ang2 in both plasma and glomeruli may mediate protein permeability through the glomerular filtration barrier. Moreover, local expression of Ang2 may facilitate the progress of glomerulosclerosis by upregulating a component expression of extracellular matrix.
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Affiliation(s)
- Yuan-Hang Lu
- Department of Nephrology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
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Rincon-Choles H, Vasylyeva TL, Pergola PE, Bhandari B, Bhandari K, Zhang JH, Wang W, Gorin Y, Barnes JL, Abboud HE. ZO-1 expression and phosphorylation in diabetic nephropathy. Diabetes 2006; 55:894-900. [PMID: 16567508 DOI: 10.2337/diabetes.55.04.06.db05-0355] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cellular mechanisms responsible for the loss of capillary wall permselectivity in diabetic nephropathy are not well characterized. ZO-1 is a junctional protein involved in the assembly and proper function of a number of tight junctions and is also expressed at the junction of podocytes with the slit diaphragm. We investigated the effect of diabetes and high glucose concentration on the expression of ZO-1 in animal models of both type 1 and 2 diabetes and in rat glomerular epithelial cells. In diabetic animals, immunohistochemistry and Western blotting showed decreased expression of ZO-1 in glomeruli. Immunogold electron microscopy revealed redistribution of ZO-1 from the podocyte membrane to the cytoplasm in the diabetic animals. Exposure of rat glomerular epithelial cells to high glucose resulted in a decrease in the intensity of ZO-1 staining and redistribution of ZO-1 from the membrane to the cytoplasm, changes that are attenuated by blockade of the angiotensin II type 1 receptor. ZO-1 protein expression and serine and tyrosine phosphorylation of ZO-1 were also decreased in cells exposed to high glucose. These findings suggest that alterations in the content and localization of ZO-1 may be relevant to the pathogenesis of proteinuria in diabetes.
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Gudehithlu KP, Ahmed N, Wu H, Litbarg NO, Garber SL, Arruda JAL, Dunea G, Singh AK. Antagonism of vascular endothelial growth factor results in microvessel attrition and disorganization of wound tissue. ACTA ACUST UNITED AC 2005; 145:194-203. [PMID: 15962838 DOI: 10.1016/j.lab.2005.02.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Vascular endothelial growth factor (VEGF) is a potent growth factor that is indispensable for the development of blood vessels in the fetus and for wound healing in adults. VEGF likely plays a role in maintaining the blood vessels once they have been formed. It is not clear, however, whether a low tissue VEGF (caused either by disease or by systemic administration of VEGF antagonists) can cause abnormalities in preexisting blood vessels, especially of wound tissue that requires high local levels of VEGF for healing. The present study investigated the effect of VEGF antagonism on blood vessels of foreign-body granulomas (a model of wound-healing tissue). Granulomas were induced by implanting perforated polyvinyl tubes into the subcutaneous tissue of rats and allowed to develop for 14 days, at which time the implanted tubes were completely encapsulated by the subcutaneous tissue. The encapsulated granulomas consisted of 3 distinct histological layers, of which the middle layer was well perfused by a rich supply of microvessels. Morphologically, the granuloma remained "stable" after developing for 14 days. At 1 week, VEGF levels in the granuloma fluid, which is in equilibrium with the interstitial fluid, were 25 times higher than in the plasma. VEGF levels in the granuloma fluid continued to increase for up to 3 weeks, reflecting the high dependence of the wound tissue on ambient VEGF levels. After injection of the VEGF receptor antagonist in the fully formed granuloma, the preexisting blood vessels in the middle layer regressed and underwent apoptosis, accompanied by expansion of the extracellular matrix (predominately collagen I) into areas normally devoid of matrix. We conclude that wound tissue is sensitive to ambient VEGF levels, and that a low VEGF condition resulting from VEGF receptor antagonism can disrupt the healing of wound tissue.
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