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Chen L, Hu Y, Ma Y, Wang H. Non-linear association of fasting C-peptide and uric acid levels with renal dysfunction based on restricted cubic spline in patients with type 2 diabetes: A real-world study. Front Endocrinol (Lausanne) 2023; 14:1157123. [PMID: 37033221 PMCID: PMC10076627 DOI: 10.3389/fendo.2023.1157123] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/08/2023] [Indexed: 04/11/2023] Open
Abstract
BACKGROUND Previous studies had showed divergent findings on the associations of C-peptide and/or uric acid (UA) with renal dysfunction odds in patients with type 2 diabetes mellitus (T2DM). We hypothesized that there were non-linear relationships between C-peptide, UA and renal dysfunction odds. This study aimed to further investigate the relationships of different stratification of C-peptide and UA with renal dysfunction in patients with T2DM. METHOD We conducted a cross-sectional real-world observational study of 411 patients with T2DM. The levels of fasting C-peptide, 2h postprandial C-peptide, the ratio of fasting C-peptide to 2h postprandial C-peptide (C0/C2 ratio), UA and other characteristics were recorded. Restricted cubic spline (RCS) curves was performed to evaluated the associations of stratified C-peptide and UA with renal dysfunction odds. RESULTS Fasting C-peptide, C0/C2 ratio and UA were independently and significantly associated with renal dysfunction in patients with T2DM as assessed by multivariate analyses (p < 0.05). In especial, non-linear relationships with threshold effects were observed among fasting C-peptide, UA and renal dysfunction according to RCS analyses. Compared with patients with 0.28 ≤ fasting C-peptide ≤ 0.56 nmol/L, patients with fasting C-peptide < 0.28 nmol/L (OR = 1.38, p = 0.246) or fasting C-peptide > 0.56 nmol/L (OR = 1.85, p = 0.021) had relatively higher renal dysfunction odds after adjusting for confounding factors. Similarly, compared with patients with 276 ≤ UA ≤ 409 μmol/L, patients with UA < 276 μmol/L (OR = 1.32, p = 0.262) or UA > 409 μmol/L (OR = 6.24, p < 0.001) had relatively higher odds of renal dysfunction. CONCLUSION The renal dysfunction odds in patients with T2DM was non-linearly associated with the levels of serum fasting C-peptide and UA. Fasting C-peptide and UA might have the potential role in odds stratification of renal dysfunction.
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Affiliation(s)
- Lu Chen
- Department of Clinical Laboratory, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, Zhejiang, China
| | - Yifei Hu
- Department of Clinical Laboratory, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, Zhejiang, China
| | - Yongjun Ma
- Department of Clinical Laboratory, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, Zhejiang, China
- *Correspondence: Yongjun Ma, ; Huabin Wang,
| | - Huabin Wang
- Department of Clinical Laboratory, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, Zhejiang, China
- Central Laboratory, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, Zhejiang, China
- *Correspondence: Yongjun Ma, ; Huabin Wang,
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Luo J, Jiang J, Huang H, Jiang F, Xu Z, Zhou Z, Zhu H. C-peptide ameliorates high glucose-induced podocyte dysfunction through the regulation of the Notch and TGF-β signaling pathways. Peptides 2021; 142:170557. [PMID: 33901627 DOI: 10.1016/j.peptides.2021.170557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/25/2022]
Abstract
The podocyte is one of the main components of the glomerular filtration barrier in the kidney, and its injury may contribute to proteinuria, glomerulosclerosis and eventually kidney failure. C-peptide, a cleavage product of proinsulin, shows therapeutic potential for treating diabetic nephropathy (DN). The aim of this study was to investigate the effect of C-peptide on high glucose-induced podocyte dysfunction. In the present study, we found that the protective effects of islet transplantation were superior to simple insulin therapy for the treatment of DN in streptozotocin (STZ)-treated rats. And such superiority may due to the function of C-peptide secreted at the implanted site. Based on this background, we determined that the application of C-peptide significantly prevented high glucose-induced podocyte injury by increasing the expression of nephrin and synaptopodin. Meanwhile, C-peptide suppressed high glucose-induced epithelial-mesenchymal transition (EMT) and renal fibrosis via decreasing the expression of snail, vimentin, α-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF). Moreover, the Notch and transforming growth factor-β (TGF-β) signaling pathways were activated by high glucose, and treatment with C-peptide down-regulated the expression of the Notch signaling molecules Notch 1 and Jagged 1 and the TGF-β signaling molecule TGF-β1. These findings suggested that C-peptide might serve as a novel treatment method for DN and podocyte dysfunction.
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Affiliation(s)
- Jiao Luo
- Department of Laboratory Medicine, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Jiahong Jiang
- Department of Endocrinology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325000, China
| | - Hongjian Huang
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325000, China
| | - Feifei Jiang
- Department of Endocrinology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325000, China
| | - Zeru Xu
- Department of Endocrinology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325000, China
| | - Zijun Zhou
- Department of Endocrinology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325000, China
| | - Hong Zhu
- Department of Endocrinology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325000, China.
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Biological Activity of c-Peptide in Microvascular Complications of Type 1 Diabetes-Time for Translational Studies or Back to the Basics? Int J Mol Sci 2020; 21:ijms21249723. [PMID: 33419247 PMCID: PMC7766542 DOI: 10.3390/ijms21249723] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/15/2022] Open
Abstract
People with type 1 diabetes have an increased risk of developing microvascular complications, which have a negative impact on the quality of life and reduce life expectancy. Numerous studies in animals with experimental diabetes show that c-peptide supplementation exerts beneficial effects on diabetes-induced damage in peripheral nerves and kidneys. There is substantial evidence that c-peptide counteracts the detrimental changes caused by hyperglycemia at the cellular level, such as decreased activation of endothelial nitric oxide synthase and sodium potassium ATPase, and increase in formation of pro-inflammatory molecules mediated by nuclear factor kappa-light-chain-enhancer of activated B cells: cytokines, chemokines, cell adhesion molecules, vascular endothelial growth factor, and transforming growth factor beta. However, despite positive results from cell and animal studies, no successful c-peptide replacement therapies have been developed so far. Therefore, it is important to improve our understanding of the impact of c-peptide on the pathophysiology of microvascular complications to develop novel c-peptide-based treatments. This article aims to review current knowledge on the impact of c-peptide on diabetic neuro- and nephropathy and to evaluate its potential therapeutic role.
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Ni X, Xu Z, Wang J, Zheng S, Cai Y. C-peptide and islet transplantation improve glomerular filtration barrier in diabetic nephropathy rats. Transpl Immunol 2020; 62:101322. [PMID: 32798711 DOI: 10.1016/j.trim.2020.101322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/01/2020] [Accepted: 08/11/2020] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Islet transplantation has been proved to be effective in delaying early stage of DN. This study was established to observe the mechanism of islet transplantation on early diabetic nephropathy (DN). METHOD The diabetes mellitus (DM) rat model was established by an injection of a single-dose streptozotocin. According to the treatment, the rats were randomly divided into 4 groups: the untreated DN rats (DN group); the C-peptide treated rats (CP group); the islet transplanted rats (IT group); the normal control rats (NC group). Renal function and structure of glomerular filtration barrier (GFB) were evaluated by urinalysis and histopathological examination, respectively. The renal fibrotic factors, TGF- β1 and CTGF, as well as the anti-renal fibrosis factor HGF were assessed by immunohistochemical staining and western blotting methods. RESULTS After C-peptide treatment and islet transplantation, the GFB structure was obviously improved. The blood glucose significantly decreased in the IT group. The 24h urine protein and glomerular basement membrane thickness decreased, the pathological changes of podocytes improved, TGF- β1 and CTGF decreased and HGF increased in the CP group and the IT group compared with that in the DN group (P < 0.05), especially in the IT group. CONCLUSION Islet transplantation could ameliorate the structure of GFB of early DN in a rat model, and the treatment effect was partly attributed to the restoration of C-peptide concentration. Suppressing the fibrosis system can be the potential mechanism of islet transplantation, which is independent of blood glucose control.
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Affiliation(s)
- Xiaojie Ni
- Department of Transplantation, The First Affiliated Hospital, Wenzhou Medical University, Shangcai Cun, Ouhai Qu, Wenzhou Province, Zhejiang 325000, China
| | - Ziqiang Xu
- Department of Transplantation, The First Affiliated Hospital, Wenzhou Medical University, Shangcai Cun, Ouhai Qu, Wenzhou Province, Zhejiang 325000, China
| | - Jinjun Wang
- Department of Transplantation, The First Affiliated Hospital, Wenzhou Medical University, Shangcai Cun, Ouhai Qu, Wenzhou Province, Zhejiang 325000, China
| | - Shaoling Zheng
- Department of Transplantation, The First Affiliated Hospital, Wenzhou Medical University, Shangcai Cun, Ouhai Qu, Wenzhou Province, Zhejiang 325000, China
| | - Yong Cai
- Department of Transplantation, The First Affiliated Hospital, Wenzhou Medical University, Shangcai Cun, Ouhai Qu, Wenzhou Province, Zhejiang 325000, China.
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Poteryaeva ON, Usynin IF. [Molecular mechanisms of action and physiological effects of the proinsulin C-peptide (a systematic review)]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2020; 66:196-207. [PMID: 32588825 DOI: 10.18097/pbmc20206603196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The C-peptide is a fragment of proinsulin, the cleavage of which forms active insulin. In recent years, new information has appeared on the physiological effects of the C-peptide, indicating its positive effect on many organs and tissues, including the kidneys, nervous system, heart, vascular endothelium and blood microcirculation. Studies on experimental models of diabetes mellitus in animals, as well as clinical trials in patients with diabetes, have shown that the C-peptide has an important regulatory effect on the early stages of functional and structural disorders caused by this disease. The C-peptide exhibits its effects through binding to a specific receptor on the cell membrane and activation of downstream signaling pathways. Intracellular signaling involves G-proteins and Ca2+-dependent pathways, resulting in activation and increased expression of endothelial nitric oxide synthase, Na+/K+-ATPase and important transcription factors involved in apoptosis, anti-inflammatory and other intracellular defense mechanisms. This review gives an idea of the C-peptide as a bioactive endogenous peptide that has its own biological activity and therapeutic potential.
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Affiliation(s)
- O N Poteryaeva
- Institute of Biochemistry, Federal Research Center of Fundamental and Translation Medicine, Novosibirsk, Russia
| | - I F Usynin
- Institute of Biochemistry, Federal Research Center of Fundamental and Translation Medicine, Novosibirsk, Russia
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6
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Bulboacă AE, Boarescu PM, Bolboacă SD, Blidaru M, Feștilă D, Dogaru G, Nicula CA. Comparative Effect Of Curcumin Versus Liposomal Curcumin On Systemic Pro-Inflammatory Cytokines Profile, MCP-1 And RANTES In Experimental Diabetes Mellitus. Int J Nanomedicine 2019; 14:8961-8972. [PMID: 31819412 PMCID: PMC6873975 DOI: 10.2147/ijn.s226790] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 10/25/2019] [Indexed: 12/22/2022] Open
Abstract
Purpose Anti-inflammatory proprieties of curcumin were proved to be useful in various diseases, including diabetes mellitus. The aim of this study was to assess the anti-inflammatory comparative effect of curcumin solution with liposomal curcumin formula, regarding the improvement of serum levels of TNF-α (tumor necrosis factor-alpha), IL-6 (interleukin), IL-1α, IL-1β, MCP-1 (monocyte chemoattractant protein-1) and RANTES in experimental diabetes, induced by streptozotocin (STZ), in rats. Materials and methods Six groups of 7 rats were investigated regarding the effect of i.p. (intraperitoneal) administration of two concentrations of curcumin solution (CC1 and CC2) and two concentrations of liposomal curcumin (LCC1 and LCC2): group 1 – control group with i.p. administration of 1 mL saline solution, group 2 – i.p. STZ administration (60mg/kg bw, bw=body weight), group 3 – STZ+CC1 administration, group 4 – STZ+CC2 administration, group 5 – STZ+ LCC1 administration and group 6 – STZ+ LCC2 administration. The concentrations of curcumin formulas were 1 mg/0.1 kg bw for CC1 and LCC1 and 2 mg/0.1 kg bw for CC2 and LCC2, respectively. Serum levels of C-peptide (as an indicator of pancreatic function) and TNF-α, IL-6, IL-1α, IL-1β, MCP-1, and RANTES (as biomarkers for systemic inflammation) were assessed for each group. Results The plasma level of C-peptide showed significant improvements when LCC was administrated, with better results for LCC2 when compared to LCC1 (P<0.003). LCC2 pretreatment proved to be more efficient in reducing the level of TNF-α (P<0.003) and RANTES (P<0.003) than CC2 pretreatment. Upon comparing LCC2 with LCC1 formulas, the differences were significant for TNF-α (P=0.004), IL-1β (P=0.022), and RANTES (P=0.003) levels. Conclusion Liposomal curcumin in a dose of 2 mg/0.1 kg bw proved to have an optimum therapeutic effect as a pretreatment in DM induced by STZ. This result can constitute a base for clinical studies for curcumin efficiency as adjuvant therapy in type 1 DM.
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Affiliation(s)
- Adriana Elena Bulboacă
- Pathophysiology Department, Iuliu Hațieganu University of Medicine and Pharmacy Cluj-Napoca, Cluj-Napoca, Romania
| | - Paul Mihai Boarescu
- Pathophysiology Department, Iuliu Hațieganu University of Medicine and Pharmacy Cluj-Napoca, Cluj-Napoca, Romania
| | - Sorana D Bolboacă
- Department of Medical Informatics and Biostatistics, Iuliu Hațieganu University of Medicine And Pharmacy, Cluj-Napoca, Romania
| | - Mihai Blidaru
- Pathophysiology Department, Iuliu Hațieganu University of Medicine and Pharmacy Cluj-Napoca, Cluj-Napoca, Romania
| | - Dana Feștilă
- Department of Maxillofacial Surgery and Radiology, Iuliu Hațieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Gabriela Dogaru
- Department of Physical Medicine and Rehabilitation, Iuliu Hațieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Cristina Ariadna Nicula
- Department of Ophthalmology, Iuliu Haţieganu University of Medicine and Pharmacy Cluj-Napoca, Cluj-Napoca, Romania
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7
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Yang X, Luo M, Jiang Q, Wang Y. Effects of Huangkui Capsule on the Expression of SPARC in the Kidney Tissue of a Rat Model with Diabetic Nephropathy. Curr Gene Ther 2019; 19:211-215. [PMID: 31553295 DOI: 10.2174/1566523219666190925112249] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 06/03/2019] [Accepted: 06/12/2019] [Indexed: 11/22/2022]
Abstract
Objective:
The objective of the research is to investigate the effects of Huangkui capsule on
the expression of SPARC in the kidney tissues of diabetic nephropathy.
Methods:
SD rats were divided into three groups: normal control group, untreated DN group and
HKC-treated DN group. The therapeutic effects and underlying molecular mechanism of HKC on DN
rats induced by streptozotocin were evaluated by the levels of serum creatinine, blood urea nitrogen,
24-hour urinary protein and the expression of SPARC. Pathological changes in kidney tissues were
observed through hematoxylin-eosin (HE) staining. Moreover, western blot and quantitative real-time
polymerase chain reaction (qRT-PCR) were applied to detect the variation of SPARC.
Results:
This study was performed to investigate the effects of HKC on DN in SD rats model and its
molecular mechanism. Our results showed that the rats treated with HKC had an improved general
state and reduced creatinine, blood urea nitrogen and 24-hour urinary protein levels. The deterioration
of renal function was delayed due to treatment with HKC. HE staining was utilized to observe that
HKC can improve histopathological findings in the kidney tissues of DN rats, including kidney fibrosis.
Results of western blot and qRT-PCR showed that HKC can inhibit the expressions of SPARC in
the rat model of DN.
Conclusion:
The present findings demonstrated that HKC inhibited SPARC level and had significant
therapeutic effects on DN.
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Affiliation(s)
- Xiaoyao Yang
- Department of Science and Education, Heilongjiang Provincial Hospital, Harbin, China
| | - Meng Luo
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Qinghua Jiang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Yiwei Wang
- Department of Science and Education, Heilongjiang Provincial Hospital, Harbin, China
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Ahmad Hajam Y, Rai S, Basheer M, Ghosh H, Singh S. Protective Role of Melatonin in Streptozotocin Induced Pancreatic Damages in Diabetic Wistar Rat. Pak J Biol Sci 2019; 21:423-431. [PMID: 30724043 DOI: 10.3923/pjbs.2018.423.431] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND AND OBJECTIVE Hyperglycemia is a representative hallmark and risk factor for diabetes and is closely linked to diabetes associated complications. The aim of the present study was to evaluate the therapeutic potential of exogenous melatonin against the streptozotocin induced pancreatic damages in rats. MATERIALS AND METHODS Streptozotocin was injected for consecutive 6 days. Diabetes was confirmed by blood glucose measurement after 72 h and on 7th day after injection. Animals having blood glucose level above 250 mg dL-1 were considered as diabetic and were administered exogenous melatonin for 4 weeks. Animals were euthanized after last dose, pancreas were dissected out, weighed and fixed in Bouin's fixative for histology and further tissues were kept at -20°C for biochemistry. RESULTS Diabetic rats displayed significant increase in lipid peroxidation, but pancreatic weight index, antioxidant system (GSH, SOD and CAT) showed decrease. Melatonin treatment to diabetic rats restored the alteration in physiological and biochemical markers. Results were supported by the histopathological observations, STZ treated pancreas showed damage in islets of langerhans, while as melatonin treated diabetic rats recovered the cellular architecture which inturn normalize the function of the pancreas. CONCLUSION Therefore, melatonin might be considered as a molecule to protect the pancreatic damages.
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Oliveira CM, Domingueti CP. The role of C-peptide in the attenuation of outcomes of diabetic kidney disease: a systematic review and meta-analysis. ACTA ACUST UNITED AC 2018; 40:375-387. [PMID: 30106427 PMCID: PMC6533998 DOI: 10.1590/2175-8239-jbn-2017-0027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 05/23/2018] [Indexed: 12/14/2022]
Abstract
Introduction: Preclinical trials have shown that C-peptide may contribute to the treatment
of diabetic kidney disease (DKD). This systematic review and meta-analysis
aimed to assess the use of C-peptide in attenuating the outcomes of DKD. Methods: Searches were made on databases PubMed, Web of Science, and Scielo for in
vivo clinical and preclinical trials written in English, Portuguese or
Spanish that looked into the use of C-peptide in the attenuation of the
outcomes of DKD. Results: Twelve papers were included in this review, one clinical and eleven
preclinical trials. In the clinical trial, DKD patients given C-peptide had
lower levels of albuminuria than the subjects in the control group, but
glomerular filtration rates were not significantly different. The main
parameters assessed in the preclinical trials were glomerular filtration
rate (six trials) and albuminuria (five trials); three trials described less
hyperfiltration and three reported lower levels of albuminuria in the groups
offered C-peptide. The meta-analysis revealed that the animals given
C-peptide had lower glomerular volumes and lower urine potassium levels than
the groups not given C-peptide. Conclusion: The results of the studies included in the systematic review diverged.
However, the meta-analysis showed that the animals given C-peptide had lower
glomerular volumes and lower urine potassium levels.
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10
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Arimura E, Okatani H, Araki T, Ushikai M, Nakakuma M, Abe M, Kawaguchi H, Izumi H, Horiuchi M. Effects of Diets with Different Proportions of Protein/Carbohydrate on Retinal Manifestations in db Mice. In Vivo 2018; 32:265-272. [PMID: 29475908 PMCID: PMC5905193 DOI: 10.21873/invivo.11233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 01/18/2023]
Abstract
BACKGROUND/AIM Diabetic nephropathy is aggravated by a higher intake of total protein. The effects of diets with different proportions of protein and carbohydrate on diabetic retinopathy in db mice, a type-2 diabetes animal model, were examined, as well as diabetic nephropathy. MATERIALS AND METHODS Control and db mice at 5 weeks of age were fed the diets (% energy of protein/carbohydrate/fat; L-diet: 12/71/17; H-diet: 24/59/17) under ad libitum conditions and pair-feeding conditions for 6 weeks, respectively. RESULTS Mice fed the H-diet showed significantly greater retinal thickness by optical coherence tomography, and lower mRNA levels of angiotensinogen. Comparing combinations of diets and genotypes, db-H mice showed significantly higher mRNA levels of angiotensin-converting enzyme, advanced glycosylation end product-specific receptor, and cluster of differentiation molecule 11b (a microglial marker) than db-L mice. CONCLUSION Dietary protein and carbohydrate proportions influenced retinal manifestations, including retinal thickness and gene expression in control and diabetic mice.
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Affiliation(s)
- Emi Arimura
- Department of Life and Environmental Science, Kagoshima Prefectural College, Kagoshima, Japan
- Department of Hygiene and Health Promotion Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Hideaki Okatani
- Drug Safety Research Laboratories, Shin Nippon Biomedical Laboratories, Ltd., Kagoshima, Japan
| | - Tomoaki Araki
- Drug Safety Research Laboratories, Shin Nippon Biomedical Laboratories, Ltd., Kagoshima, Japan
| | - Miharu Ushikai
- Department of Hygiene and Health Promotion Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Miwa Nakakuma
- Department of Life and Environmental Science, Kagoshima Prefectural College, Kagoshima, Japan
- Department of Hygiene and Health Promotion Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Masaharu Abe
- Department of Hygiene and Health Promotion Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Hiroaki Kawaguchi
- Department of Hygiene and Health Promotion Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Hiroyuki Izumi
- Drug Safety Research Laboratories, Shin Nippon Biomedical Laboratories, Ltd., Kagoshima, Japan
| | - Masahisa Horiuchi
- Department of Hygiene and Health Promotion Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
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Abstract
Kidney disease is a serious development in diabetes mellitus and poses an increasing clinical problem. Despite increasing incidence and prevalence of diabetic kidney disease, there have been no new therapies for this condition in the last 20 years. Mounting evidence supports a biological role for C-peptide, and findings from multiple studies now suggest that C-peptide may beneficially affect the disturbed metabolic and pathophysiological pathways leading to the development of diabetic nephropathy. Studies of C-peptide in animal models and in humans with type 1 diabetes all suggest a renoprotective effect for this peptide. In diabetic rodents, C-peptide reduces glomerular hyperfiltration and albuminuria. Cohort studies of diabetic patients with combined islet and kidney transplants suggest that maintained C-peptide secretion is protective of renal graft function. Further, in short-term studies of patients with type 1 diabetes, administration of C-peptide is also associated with a lowered hyperfiltration rate and reduced microalbuminuria. Thus, the available information suggests that type 1 diabetes should be regarded as a dual hormone deficiency disease and that clinical trials of C-peptide in diabetic nephropathy are both justified and urgently required.
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Affiliation(s)
- N J Brunskill
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
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12
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C-peptide as a Therapy for Kidney Disease: A Systematic Review and Meta-Analysis. PLoS One 2015; 10:e0127439. [PMID: 25993479 PMCID: PMC4439165 DOI: 10.1371/journal.pone.0127439] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 04/14/2015] [Indexed: 12/19/2022] Open
Abstract
C-peptide has intrinsic biological activity and may be renoprotective. We conducted a systematic review to determine whether C-peptide had a beneficial effect on renal outcomes. MEDLINE, EMBASE, and the Cochrane Central Databases were searched for human and animal studies in which C-peptide was administered and renal endpoints were subsequently measured. We identified 4 human trials involving 74 patients as well as 18 animal studies involving 35 separate experiments with a total of 641 animals. In humans, the renal effects of exogenously delivered C-peptide were only studied in type 1 diabetics with either normal renal function or incipient nephropathy. Pooled analysis showed no difference in GFR (mean difference, -1.36 mL/min/1.73 m2, p = 0.72) in patients receiving C-peptide compared to a control group, but two studies reported a reduction in glomerular hyperfiltration (p<0.05). Reduction in albuminuria was also reported in the C-peptide group (p<0.05). In diabetic rodent models, C-peptide led to a reduction in GFR (mean difference, -0.62 mL/min, p<0.00001) reflecting a partial reduction in glomerular hyperfiltration. C-peptide also reduced proteinuria (mean difference, -186.25 mg/day, p = 0.05), glomerular volume (p<0.00001), and mesangial matrix area (p<0.00001) in diabetic animals without affecting blood pressure or plasma glucose. Most studies were relatively short-term in duration, ranging from 1 hour to 3 months. Human studies of sufficient sample size and duration are needed to determine if the beneficial effects of C-peptide seen in animal models translate into improved long-term clinical outcomes for patients with chronic kidney disease. (PROSPERO CRD42014007472)
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C-peptide ameliorates renal injury in type 2 diabetic rats through protein kinase A-mediated inhibition of fibronectin synthesis. Biochem Biophys Res Commun 2015; 458:674-680. [DOI: 10.1016/j.bbrc.2015.02.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 02/04/2015] [Indexed: 12/16/2022]
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Wahren J, Larsson C. C-peptide: new findings and therapeutic possibilities. Diabetes Res Clin Pract 2015; 107:309-19. [PMID: 25648391 DOI: 10.1016/j.diabres.2015.01.016] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 01/15/2015] [Indexed: 12/18/2022]
Abstract
Much new information on C-peptide physiology has appeared during the past 20 years. It has been shown that C-peptide binds specifically to cell membranes, elicits intracellular signaling via G-protein and Ca2+ -dependent pathways, resulting in activation and increased expression of endothelial nitric oxide synthase, Na+, K+ -ATPase and several transcription factors of importance for anti-inflammatory, anti-oxidant and cell protective mechanisms. Studies in animal models of diabetes and early clinical trials in patients with type 1 diabetes demonstrate that C-peptide in replacement doses elicits beneficial effects on early stages of diabetes-induced functional and structural abnormalities of the peripheral nerves, the kidneys and the retina. Much remains to be learned about C-peptide's mechanism of action and long-term clinical trials in type 1 diabetes subjects will be required to determine C-peptide's clinical utility. Nevertheless, even a cautious evaluation of the available evidence presents the picture of a bioactive endogenous peptide with therapeutic potential.
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Affiliation(s)
- John Wahren
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Cebix AB, Stockholm, Sweden.
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Ghorbani A, Shafiee-Nick R. Pathological consequences of C-peptide deficiency in insulin-dependent diabetes mellitus. World J Diabetes 2015; 6:145-150. [PMID: 25685285 PMCID: PMC4317306 DOI: 10.4239/wjd.v6.i1.145] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 11/03/2014] [Accepted: 12/17/2014] [Indexed: 02/05/2023] Open
Abstract
Diabetes is associated with several complications such as retinopathy, nephropathy, neuropathy and cardiovascular diseases. Currently, insulin is the main used medication for management of insulin-dependent diabetes mellitus (type-1 diabetes). In this metabolic syndrome, in addition to decrease of endogenous insulin, the plasma level of connecting peptide (C-peptide) is also reduced due to beta cell destruction. Studies in the past decade have shown that C-peptide is much more than a byproduct of insulin biosynthesis and possess different biological activities. Therefore, it may be possible that C-peptide deficiency be involved, at least in part, in the development of different complications of diabetes. It has been shown that a small level of remaining C-peptide is associated with significant metabolic benefit. The purpose of this review is to describe beneficial effects of C-peptide replacement on pathological features associated with insulin-dependent diabetes. Also, experimental and clinical findings on the effects of C-peptide on whole-body glucose utilization, adipose tissue metabolism and tissues blood flow are summarized and discussed. The hypoglycemic, antilipolytic and vasodilator effects of C-peptide suggest that it may contribute to fine-tuning of the tissues metabolism under different physiologic or pathologic conditions. Therefore, C-peptide replacement together with the classic insulin therapy may prevent, retard, or ameliorate diabetic complications in patients with type-1 diabetes.
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Maezawa Y, Takemoto M, Yokote K. Cell biology of diabetic nephropathy: Roles of endothelial cells, tubulointerstitial cells and podocytes. J Diabetes Investig 2014; 6:3-15. [PMID: 25621126 PMCID: PMC4296695 DOI: 10.1111/jdi.12255] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 05/15/2014] [Indexed: 02/06/2023] Open
Abstract
Diabetic nephropathy is the major cause of end-stage renal failure throughout the world in both developed and developing countries. Diabetes affects all cell types of the kidney, including endothelial cells, tubulointerstitial cells, podocytes and mesangial cells. During the past decade, the importance of podocyte injury in the formation and progression of diabetic nephropathy has been established and emphasized. However, recent findings provide additional perspectives on pathogenesis of diabetic nephropathy. Glomerular endothelial damage is already present in the normoalbuminuric stage of the disease when podocyte injury starts. Genetic targeting of mice that cause endothelial injury leads to accelerated diabetic nephropathy. Tubulointerstitial damage, previously considered to be a secondary effect of glomerular protein leakage, was shown to have a primary significance in the progression of diabetic nephropathy. Emerging evidence suggests that the glomerular filtration barrier and tubulointerstitial compartment is a composite, dynamic entity where any injury of one cell type spreads to other cell types, and leads to the dysfunction of the whole apparatus. Accumulation of novel knowledge would provide a better understanding of the pathogenesis of diabetic nephropathy, and might lead to a development of a new therapeutic strategy for the disease.
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Affiliation(s)
- Yoshiro Maezawa
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine Chiba, Japan ; Division of Diabetes, Metabolism and Endocrinology, Chiba University Hospital Chiba, Japan
| | - Minoru Takemoto
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine Chiba, Japan ; Division of Diabetes, Metabolism and Endocrinology, Chiba University Hospital Chiba, Japan
| | - Koutaro Yokote
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine Chiba, Japan ; Division of Diabetes, Metabolism and Endocrinology, Chiba University Hospital Chiba, Japan
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Effects of Chinese Medicine Tong xinluo on Diabetic Nephropathy via Inhibiting TGF- β 1-Induced Epithelial-to-Mesenchymal Transition. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:123497. [PMID: 24864150 PMCID: PMC4016864 DOI: 10.1155/2014/123497] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 03/18/2014] [Accepted: 03/22/2014] [Indexed: 12/31/2022]
Abstract
Diabetic nephropathy (DN) is a major cause of chronic kidney failure and characterized by interstitial and glomeruli fibrosis. Epithelial-to-mesenchymal transition (EMT) plays an important role in the pathogenesis of DN. Tong xinluo (TXL), a Chinese herbal compound, has been used in China with established therapeutic efficacy in patients with DN. To investigate the molecular mechanism of TXL improving DN, KK-Ay mice were selected as models for the evaluation of pathogenesis and treatment in DN. In vitro, TGF-β1 was used to induce EMT. Western blot (WB), immunofluorescence staining, and real-time polymerase chain reaction (RT-PCR) were applied to detect the changes of EMT markers in vivo and in vitro, respectively. Results showed the expressions of TGF-β1 and its downstream proteins smad3/p-smad3 were greatly reduced in TXL group; meantime, TXL restored the expression of smad7. As a result, the expressions of collagen IV (Col IV) and fibronectin (FN) were significantly decreased in TXL group. In vivo, 24 h-UAER (24-hour urine albumin excretion ratio) and BUN (blood urea nitrogen) were decreased and Ccr (creatinine clearance ratio) was increased in TXL group compared with DN group. In summary, the present study demonstrates that TXL successfully inhibits TGF-β1-induced epithelial-to-mesenchymal transition in DN, which may account for the therapeutic efficacy in TXL-mediated renoprotection.
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Usarek M, Jagielski AK, Krempa P, Dylewska A, Kiersztan A, Drozak J, Girstun A, Derlacz RA, Bryla J. Proinsulin C-peptide potentiates the inhibitory action of insulin on glucose synthesis in primary cultured rabbit kidney-cortex tubules: Metabolic studies. Biochem Cell Biol 2014; 92:1-8. [DOI: 10.1139/bcb-2013-0074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Effects of equimolar concentrations of proinsulin C-peptide and insulin on glucose synthesis were studied in primary cultures of rabbit kidney-cortex tubules grown in the presence of alanine, glycerol, and octanoate. The rhodamine-labeled C-peptide entered renal tubular cells and localized in nuclei, both in the presence and absence of insulin; preincubations with the unlabeled compound inhibited internalization. C-peptide did not affect glucose formation when added alone but potentiated the inhibitory action of insulin by about 20% due to a decrease in flux through glucose-6-phosphate isomerase (GPI) and (or) glucose-6-phosphatase (G6Pase). GPI inhibition was caused by: (i) increased intracellular contents of fructose-1,6-bisphosphate and fructose-1-phosphate, inhibitors of the enzyme and (ii) reduced level of the phosphorylated GPI, which exhibits higher enzymatic activity in the presence of casein kinase 2. A decrease in flux through G6Pase, due to diminished import of G6P by G6P-transporter from the cytoplasm into endoplasmic reticulum lumen, is also suggested. The data show for the first time that in the presence of insulin and C-peptide, both GPI and G6P-ase may act as regulatory enzymes of renal gluconeogenic pathway.
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Affiliation(s)
- Michal Usarek
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Adam Konrad Jagielski
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Paulina Krempa
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Anna Dylewska
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Anna Kiersztan
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Jakub Drozak
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Agnieszka Girstun
- Department of Molecular Biology, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Rafal Andrzej Derlacz
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Jadwiga Bryla
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
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Flynn ER, Lee J, Hutchens ZM, Chade AR, Maric-Bilkan C. C-peptide preserves the renal microvascular architecture in the streptozotocin-induced diabetic rat. J Diabetes Complications 2013; 27:538-47. [PMID: 23994433 PMCID: PMC3818424 DOI: 10.1016/j.jdiacomp.2013.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 07/12/2013] [Accepted: 07/17/2013] [Indexed: 12/11/2022]
Abstract
AIMS C-peptide is renoprotective in type 1 diabetes, however, the mechanisms of its actions are not completely understood. We hypothesized that C-peptide attenuates diabetes-associated renal microvascular injury. METHOD After 4 or 8weeks of streptozotocin (STZ)-induced diabetes, rats received either vehicle or C-peptide in the presence of low or high doses of insulin. Urine albumin excretion (UAE) was measured prior to initiation of treatment (baseline) and 2 or 4weeks after treatment (sacrifice). Glomerular hypertrophy, glomerular filtration rate (GFR) and renal microvascular density, quantified ex vivo by 3D micro-CT reconstruction, were measured at sacrifice. RESULTS In rats receiving low doses of insulin, treatment with C-peptide reduced HbA1c levels by 24%. In these rats, the 107% increase in UAE rate from baseline to sacrifice in vehicle-treated rats was largely prevented with C-peptide. C-peptide also reduced diabetes-associated glomerular hyperfiltration by 30%, glomerular hypertrophy by 22% and increased the density of microvessels between 0 and 500μm in diameter by an average of 31% compared with vehicle-treated groups. Similar renoprotective effects of C-peptide were observed in rats treated with higher doses of daily insulin, despite no differences in HbA1c levels. CONCLUSIONS The study suggests that C-peptide is renoprotective by preserving the integrity of the renal microvasculature irrespective of glucose regulation.
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Affiliation(s)
- Elizabeth R. Flynn
- The Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS
| | - Jonathan Lee
- The Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS
| | - Zachary M. Hutchens
- The Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS
| | - Alejandro R. Chade
- The Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS
- Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson, MS
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS
- Department of Radiology, University of Mississippi Medical Center, Jackson, MS
| | - Christine Maric-Bilkan
- The Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS
- Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson, MS
- Correspondence to: Christine Maric-Bilkan, Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216-4505, Phone: 601-984-1818, Fax: 601-984-1817,
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Giebink AW, Vogel PA, Medawala W, Spence DM. C-peptide-stimulated nitric oxide production in a cultured pulmonary artery endothelium is erythrocyte mediated and requires Zn(2+). Diabetes Metab Res Rev 2013; 29:44-52. [PMID: 23007928 DOI: 10.1002/dmrr.2359] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 08/23/2012] [Indexed: 12/13/2022]
Abstract
BACKGROUND C-peptide has been shown to stimulate the production of nitric oxide (NO) in aortic endothelial cells via activation of endothelial nitric oxide synthase (eNOS) through an increased calcium influx. Here, results obtained using cultured bovine pulmonary artery endothelial cells (bPAECs) suggest that C-peptide does not induce eNOS activation directly in cultured pulmonary artery endothelium. However, C-peptide has been shown to stimulate the release of ATP from erythrocytes, a well-documented stimulus of eNOS activity in the pulmonary endothelium. Therefore, studies were performed to examine if C-peptide can indirectly stimulate NO production in a cultured pulmonary endothelium that is erythrocyte mediated. METHODS NO production and free intracellular calcium changes were monitored in immobilized bPAECs using specific intracellular fluorescent probes after stimulation with adenosine triphosphate (ATP), calcium ionophore A23187, or C-peptide. A microfluidic device enabled immobilized bPAECs to interact with flowing erythrocytes in the presence and absence of C-peptide to determine the role of the erythrocyte in C-peptide-stimulated NO production in cultured bPAECs. RESULTS ATP and the calcium ionophore stimulate significant increases in both intracellular NO production and influx of free calcium in cultured bPAECs. In contrast, C-peptide, ranging from physiological to above physiological concentrations, was unable to stimulate NO production or calcium influx in the bPAECs. However, when erythrocytes were pre-incubated with a mixture containing physiological concentrations of C-peptide with Zn(2+) and haemodynamically pumped beneath bPAECs cultured on a microfluidic device, an 88.6 ± 7.5% increase in endothelial NO production was observed. CONCLUSIONS C-peptide does not affect NO production in bPAECs directly but can impact NO production through an erythrocyte-mediated mechanism. Furthermore, in the absence of Zn(2+), C-peptide does not stimulate this NO production directly or indirectly. These results suggest that C-peptide, in the presence of Zn(2+), may be a determinant in purinergic receptor signalling via its ability to stimulate the release of ATP from erythrocytes.
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Affiliation(s)
- Adam W Giebink
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
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Arimura E, Horiuchi M, Kawaguchi H, Miyoshi N, Aoyama K, Takeuchi T. Low-protein diet improves blood and urinary glucose levels and renal manifestations of diabetes in C57BLKS-db/db mice. Eur J Nutr 2012; 52:813-24. [PMID: 22692501 DOI: 10.1007/s00394-012-0387-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 05/22/2012] [Indexed: 12/17/2022]
Abstract
PURPOSE Dietary protein content is related clinically to the development of diabetic nephropathy. Here, we investigated how dietary protein content (12-24 % energy) within the range used by humans affected renal manifestations including the expressions of genes involved in the renin-angiotensin (RA) system in control and diabetic mice. Moreover, we examined the effects of dietary protein content on HbA1c and urinary glucose. METHODS Control (CT) and leptin receptor-deficient obese (db) mice, 5 weeks old, were fed the diets below. Under ad libitum conditions, mice were fed 12, 18, and 24 % energy from protein (L-, M-, and H-diets) for 8 weeks. Under pair-feeding conditions, db mice were supplied H-diet (db-Hp) to the equivalent energy to that consumed by db-L mice. Renal manifestations and values related to glucose and insulin were examined biochemically and pathologically. RESULTS Under ad libitum conditions, db mice consumed food and water dose dependently of the dietary protein content, although they were consumed similarly by CT mice. CT-L mice showed lower urinary albumin and kidney weight, in association with lower mRNA levels of angiotensinogen and renin, than CT-H mice. Under pair-feeding conditions, db-L mice showed a lower ratio of kidney/body weight, HbA1(C), and urinary glucose, and a higher β-cell distribution rate in the pancreas than db-Hp mice. CONCLUSIONS Low-protein intake in the range used by humans may relieve renal manifestations through the suppressed expression of genes in the renal RA system of CT mice. On the other hand, in db mice, low-protein intake improved hyperglycemia and the renal manifestations of diabetes.
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Affiliation(s)
- Emi Arimura
- Department of Life and Environmental Science, Kagoshima Prefectural College, Kagoshima, Japan
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Affiliation(s)
- John Wahren
- Department of Molecular Medicine and Surgery, Karolinska Institutet,Stockholm, Sweden.
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Lindahl E, Nordquist L, Müller P, El Agha E, Friederich M, Dahlman-Wright K, Palm F, Jörnvall H. Early transcriptional regulation by C-peptide in freshly isolated rat proximal tubular cells. Diabetes Metab Res Rev 2011; 27:697-704. [PMID: 21618400 DOI: 10.1002/dmrr.1220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 03/06/2011] [Accepted: 05/17/2011] [Indexed: 12/17/2022]
Abstract
BACKGROUND Clinical studies have shown that proinsulin C-peptide exerts renoprotective effects in type 1 diabetes, although the underlying mechanisms are poorly understood. As C-peptide has been shown to induce several intracellular events and to localize to nuclei, we aimed to determine whether gene transcription is affected in proximal tubular kidney cells, and if so, whether the genes with altered transcription include those related to protective mechanisms. METHODS The effect of C-peptide incubation (2 h) on gene expression was investigated in freshly isolated proximal tubular cells from streptozotocin-diabetic Sprague-Dawley rats using global gene expression profiling and real-time quantitative polymerase chain reaction. Protein expression was assayed using western blotting. Different bioinformatic strategies were employed. RESULTS Gene transcription profiling demonstrated differential transcription of 492 genes (p < 0.01) after 2 h of C-peptide exposure, with the majority of these genes repressed (83%). Real-time quantitative polymerase chain reaction validation supported a trend of several G protein-coupled receptors being activated, and certain transcription factors being repressed. Also, C-peptide repressed the transcription of genes associated with the pathways of circulatory and inflammatory diseases. CONCLUSION This study shows that C-peptide exerts early effects on gene transcription in proximal tubular cells. The findings also bring further knowledge to the renoprotective mechanisms of C-peptide in type 1 diabetes, and support a transcriptional activity for C-peptide. It is suggested that C-peptide may play a regulatory role in the gene expression of proximal tubular cells.
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Affiliation(s)
- Emma Lindahl
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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E6AP is required for replicative and oncogene-induced senescence in mouse embryo fibroblasts. Oncogene 2011; 31:2199-209. [DOI: 10.1038/onc.2011.402] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Nordquist L, Palm F, Andresen BT. Renal and vascular benefits of C-peptide: Molecular mechanisms of C-peptide action. Biologics 2011; 2:441-52. [PMID: 19707375 PMCID: PMC2721399 DOI: 10.2147/btt.s3221] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
C-peptide has long been thought to be an inert byproduct of insulin production, but it has become apparent, and accepted, that C-peptide has important biological properties. C-peptide displays beneficial effects in many tissues affected by diabetic complications, such as increased peripheral blood flow and protection from renal damage. However, the mechanisms mediating these effects remain unclear. C-peptide interacts with cellular membranes at unidentified sites distinctive of the insulin family of receptors, and signals to multiple targets known to play a role in diabetes and diabetic complications, such as Na+/K+-ATPase and NOS. In general, the physiological and molecular effects of C-peptide resemble insulin, but C-peptide also possesses traits separate from those of insulin. These basic studies have been confirmed in human studies, suggesting that C-peptide may lend itself to clinical applications. However, the molecular and physiological properties of C-peptide are not completely elucidated, and large clinical studies have not begun. In order to further these goals, we critically summarize the current state of knowledge regarding C-peptide’s renal and vascular effects and the molecular signaling of C-peptide.
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Affiliation(s)
- Lina Nordquist
- Department of Medical Cell Biology, Division of Integrative Physiology, Uppsala University, Uppsala, Sweden
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Affiliation(s)
- Patrizia Luppi
- Division of Immunogenetics, Department of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Rangos Research Center, 530 45th Street, Pittsburgh, PA 15201, USA
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Sun W, Gao X, Zhao X, Cui D, Xia Q. Beneficial effects of C-peptide on renal morphology in diabetic rats. Acta Biochim Biophys Sin (Shanghai) 2010; 42:893-9. [PMID: 21106770 DOI: 10.1093/abbs/gmq100] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The study was undertaken to examine the effects of C-peptide on glomerular volume (V(GLOM)), mesangial matrix synthesis, and degradation in streptozotocin (STZ)-diabetic rats with poor or moderate glycemic control. Series 1 (poor glycemic control) included groups of healthy rats, hyperglycemic rats, diabetic insulin-treated rats and diabetic C-peptide-treated rats. Series 2 (moderate glycemic control) included groups of healthy rats, diabetic insulin-treated rats, diabetic insulin- and C-peptide-treated rats. After 8 weeks, the left kidney was excised for evaluation of V(GLOM) and mesangial matrix area via light microscopy. Mesangial cells were cultured for 48 h and type IV collagen expression and matrix metalloproteinase (MMP)-2 expression were measured by ELISA and RT-PCR. The results indicated that in Series 1, C-peptide administration suppressed the diabetes-induced increase in the V(GLOM) and the mesangial matrix area. In Series 2, C-peptide administration resulted in a similar decrease in the V(GLOM) and a greater decrease in the mesangial matrix area when compared with insulin therapy alone. Moreover, C-peptide (300 nM) completely inhibited the glucose-induced increase of the collagen IV mRNA expression and protein concentration in mesangial cells cultured in 30 mM glucose medium. MMP-2 mRNA expression was not influenced by C-peptide. In conclusion, C-peptide administration to STZ-diabetic rats for 8 weeks results in the inhibition of diabetes-induced expansion of the mesangial matrix. This effect is independent of the level of glycemic control and results from the inhibition of diabetes-induced excessive formation of mesangial type IV collagen.
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Affiliation(s)
- Wei Sun
- Department of Endocrinology, Zhongshan Hospital, Fudan University, Shanghai, China
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Sen U, Munjal C, Qipshidze N, Abe O, Gargoum R, Tyagi SC. Hydrogen sulfide regulates homocysteine-mediated glomerulosclerosis. Am J Nephrol 2010; 31:442-55. [PMID: 20395677 DOI: 10.1159/000296717] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 03/08/2010] [Indexed: 12/19/2022]
Abstract
BACKGROUND/AIMS In this study we tested the hypothesis that H(2)S regulates collagen deposition, matrix metalloproteinases (MMP) and inflammatory molecules during hyperhomocysteinemia (HHcy) resulting in attenuation of glomerulosclerosis and improved renal function. MATERIALS AND METHODS A genetic model of HHcy, cystathionine beta-synthase heterozygous (CBS+/-) and wild-type (WT) 2-kidney (2K) mice were used in this study and supplemented with or without NaHS (30 micromol/l, H(2)S donor) in drinking water for 8 weeks. To expedite the renal damage associated with HHcy, uninephrectomized (1K) mice of similar groups were also used. RESULTS Results demonstrated that NAD(P)H oxidase (p47(phox)subunit) and blood pressure were upregulated in WT 1K, CBS+/- 2K and CBS+/- 1K mice with downregulation of H(2)S production and reduced glomerular filtration rate. These changes were normalized with H(2)S supplementation. Both pro- and active MMP-2 and -9 and collagen protein expressions and glomerular depositions were also upregulated in WT 1K, CBS+/- 2K and CBS+/- 1K mice. Increased expressions of inflammatory molecules, intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1, as well as increased macrophage infiltration, were detected in WT 1K, CBS+/- 2K and CBS+/- 1K mice. These changes were ameliorated with H(2)S supplementation. CONCLUSION Together, these results suggest that increased oxidative stress and decreased H(2)S in HHcy causes matrix remodeling and inflammation resulting in glomerulosclerosis and reduced renal function.
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Affiliation(s)
- Utpal Sen
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202, USA. u0sen001 @ louisville.edu
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Hills CE, Willars GB, Brunskill NJ. Proinsulin C-peptide antagonizes the profibrotic effects of TGF-beta1 via up-regulation of retinoic acid and HGF-related signaling pathways. Mol Endocrinol 2010; 24:822-31. [PMID: 20197308 PMCID: PMC5417534 DOI: 10.1210/me.2009-0391] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 01/21/2010] [Indexed: 12/13/2022] Open
Abstract
Novel signaling roles for C-peptide have recently been discovered with evidence that it can ameliorate complications of type 1 diabetes. Here we sought to identify new pathways regulated by C-peptide of relevance to the pathophysiology of diabetic nephropathy. Microarray analysis was performed to identify genes regulated by either C-peptide and/or TGF-beta1 in a human proximal tubular cell line, HK-2. Expression of retinoic acid receptor beta (RARbeta), hepatocyte growth factor (HGF), cellular retinoic acid-binding protein II (CRABPII), vimentin, E-cadherin, Snail, and beta-catenin was assessed by immunoblotting. The cellular localization of vimentin and beta-catenin was determined by immunocytochemistry. Changes in cell morphology were assessed by phase contrast microscopy. Gene expression profiling demonstrated differential expression of 953 and 1458 genes after C-peptide exposure for 18 h or 48 h, respectively. From these, members of the antifibrotic retinoic acid (RA)- and HGF-signaling pathways were selected. Immunoblotting demonstrated that C-peptide increased RARbeta, CRABPII, and HGF. We confirmed a role for RA in reversal of TGF-beta1-induced changes associated with epithelial-mesenchymal transition, including expression changes in Snail, E-cadherin, vimetin, and redistribution of beta-catenin. Importantly, these TGF-beta1-induced changes were inhibited by C-peptide. Further, effects of TGF-beta1 on Snail and E-cadherin expression were blocked by HGF, and inhibitory effects of C-peptide were removed by blockade of HGF activity. This study identifies a novel role for HGF as an effector of C-peptide, possibly via an RA-signaling pathway, highlighting C-peptide as a potential therapy for diabetic nephropathy.
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Affiliation(s)
- Claire E Hills
- Department of Infection, Immunity and Inflammation, University of Leicester, College of Medicine Biological Sciences and Psychology, Leicester, United Kingdom
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Abstract
Proinsulin C-peptide has been found to exert beneficial effects in many tissues affected by diabetic microvascular complications, including the kidneys. Glomerular hyperfiltration and microalbuminuria are early markers of diabetic nephropathy. C-peptide at physiological concentrations effectively reduces diabetes-induced glomerular hyperfiltration via constriction of the afferent arteriole, dilation of the efferent arteriole, and inhibition of tubular reabsorption in experimental models of type 1 diabetes. The glomerular hypertrophy and mesangial matrix expansion seen in early diabetes can be reduced or prevented by C-peptide administration, possibly via interference with TGF-beta1 and TNFalpha signaling. Several of C-peptide's reno-protective effects have been confirmed in human studies; reduced glomerular hyperfiltration and diminished urinary albumin excretion have been documented in type 1 diabetes patients receiving replacement doses of C-peptide for periods of up to 3 months. In this review, we critically summarize the current state of knowledge regarding C-peptide's renal effects, and discuss possible mechanisms of its beneficial effects in diabetic nephropathy.
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Affiliation(s)
- Lina Nordquist
- Department of Medical Cell Biology, Division of Integrative Physiology, Uppsala University, 75123 Uppsala, Sweden
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Nordquist L, Johansson M. Proinsulin C-peptide: friend or foe in the development of diabetes-associated complications? Vasc Health Risk Manag 2009; 4:1283-8. [PMID: 19337542 PMCID: PMC2663462 DOI: 10.2147/vhrm.s3955] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The proinsulin connecting peptide, C-peptide, is a cleavage product of insulin synthesis that is co-secreted with insulin by pancreatic β-cells following glucose stimulation. Recombinant insulin, used in the treatment of diabetes, lacks C-peptide and preclinical and clinical studies suggest that lack of C-peptide may exacerbate diabetes-associated complications. In accordance with this, several studies suggest that C-peptide has beneficial effects in a number of diabetes-associated complications. C-peptide has been shown to prevent diabetic neuropathy by improving endoneural blood flow, preventing neuronal apoptosis and by preventing axonal swelling. In the vascular system, C-peptide has been shown to prevent vascular dysfunction in diabetic rats, and to possess anti-proliferative effects on vascular smooth muscle cells, which may prevent atherosclerosis. However, C-peptide depositions have been found in arteriosclerotic lesions of patients with hyperinsulinemic diabetes and C-peptide has been shown to induce pro-inflammatory mediators, such as nuclear factor kappa B, inducible nitric oxide synthase, and cyclooxygenase-2, indicating that C-peptide treatment could be associated with side-effects that may accelerate the development of diabetes-associated complications. This review provides a brief summary of recent research in the field and discusses potential beneficial and detrimental effects of C-peptide supplementation.
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Affiliation(s)
- Lina Nordquist
- Department of Medical Cell Biology, Division of Integrative Physiology, Uppsala University, Uppsala, Sweden.
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Abstract
In recent years, accumulating evidence indicates a biological function for proinsulin C-peptide. These results challenge the traditional view that C-peptide is essentially inert and only useful as a surrogate marker of insulin release. Accordingly, it is now clear that C-peptide binds with high affinity to cell membranes, probably to a pertussis-toxin-sensitive G-protein-coupled receptor. Subsequently, multiple signalling pathways are potently and dose-dependently activated in multiple cell types by C-peptide with the resulting activation of gene transcription and altered cell phenotype. In diabetic animals and Type 1 diabetic patients, short-term studies indicate that C-peptide also enhances glucose disposal and metabolic control. Furthermore, results derived from animal models and clinical studies in Type 1 diabetic patients suggest a salutary effect of C-peptide in the prevention and amelioration of diabetic nephropathy and neuropathy. Therefore a picture of Type 1 diabetes as a dual-hormone-deficiency disease is developing, suggesting that the replacement of C-peptide alongside insulin should be considered in its management.
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Hills CE, Al-Rasheed N, Al-Rasheed N, Willars GB, Brunskill NJ. C-peptide reverses TGF-beta1-induced changes in renal proximal tubular cells: implications for treatment of diabetic nephropathy. Am J Physiol Renal Physiol 2008; 296:F614-21. [PMID: 19091788 DOI: 10.1152/ajprenal.90500.2008] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The crucial pathology underlying progressive chronic kidney disease in diabetes is tubulointerstitial fibrosis. Central to this process is epithelial-mesenchymal transformation (EMT) of proximal tubular epithelial cells driven by maladaptive transforming growth factor-beta1 (TGF-beta1) signaling. Novel signaling roles for C-peptide have recently been discovered with evidence emerging that C-peptide may mitigate microvascular complications of diabetes. We studied the potential for C-peptide to interrupt injurious TGF-beta1 signaling pathways and thus block development of EMT in HK2 human kidney proximal tubular cells. Cells were incubated with TGF-beta1 either alone or with C-peptide in low or high glucose. Changes in cell morphology, TGF-beta1 receptor expression, vimentin, E-cadherin, and phosphorylated Smads were assessed. Luciferase reporters were used to assess Smad activity. The cytoskeleton was visualized by TRITC-phalloidin staining. The typical TGF-beta1-stimulated, EMT-associated morphological alterations of proximal tubular cells, including increased vimentin expression, decreased E-cadherin expression, and cytoskeletal rearrangements, were prevented by C-peptide treatment. C-peptide also blocked TGF-beta1-induced upregulation of expression of both type I and type II TGF-beta1 receptors and attenuated TGF-beta1-mediated Smad phosphorylation and Smad transcriptional activity. These effects of C-peptide were inhibited by pertussis toxin. The results demonstrate that C-peptide almost completely reversed the morphological changes in PT cells induced by TGF-beta1 and suggest a role or C-peptide as a renoprotective agent in diabetic nephropathy.
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Affiliation(s)
- Claire E Hills
- Department of Infection, Immunity and Inflammation, University of Leicester School of Medicine, Leicester, United Kingdom
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Honjo S, Yokote K, Fujimoto M, Takemoto M, Kobayashi K, Maezawa Y, Shimoyama T, Satoh S, Koshizaka M, Takada A, Irisuna H, Saito Y. Clinical Outcome and Mechanism of Soft Tissue Calcification in Werner Syndrome. Rejuvenation Res 2008; 11:809-19. [DOI: 10.1089/rej.2007.0649] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Satoshi Honjo
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Koutaro Yokote
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Masaki Fujimoto
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Minoru Takemoto
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Kazuki Kobayashi
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Yoshiro Maezawa
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Tatsushi Shimoyama
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Seiya Satoh
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Masaya Koshizaka
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Aki Takada
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Hiroki Irisuna
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Yasushi Saito
- Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
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C-Peptide effects on renal physiology and diabetes. EXPERIMENTAL DIABETES RESEARCH 2008; 2008:281536. [PMID: 18509500 PMCID: PMC2396455 DOI: 10.1155/2008/281536] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Accepted: 04/10/2008] [Indexed: 02/07/2023]
Abstract
The C-peptide of proinsulin is important for the biosynthesis of insulin and has for a long time been considered to be biologically inert. Animal studies have shown that some of the renal effects of the C-peptide may in part be explained by its ability to stimulate the Na,K-ATPase activity. Precisely, the C-peptide reduces diabetes-induced glomerular hyperfiltration both in animals and humans, therefore, resulting in regression of fibrosis. The tubular function is also concerned as diabetic animals supplemented with C-peptide exhibit better renal function resulting in reduced urinary sodium waste and protein excretion together with the reduction of the diabetes-induced glomerular hyperfiltration. The tubular effectors of C-peptide were considered to be tubule transporters, but recent studies have shown that biochemical pathways involving cellular kinases and inflammatory pathways may also be important. The matter theory concerning the C-peptide effects is a metabolic one involving the effects of the C-peptide on lipidic metabolic status.This review concentrates on the most convincing data which indicate that the C-peptide is a biologically active hormone for renal physiology.
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Choi MS, Jung UJ, Yeo J, Kim MJ, Lee MK. Genistein and daidzein prevent diabetes onset by elevating insulin level and altering hepatic gluconeogenic and lipogenic enzyme activities in non-obese diabetic (NOD) mice. Diabetes Metab Res Rev 2008; 24:74-81. [PMID: 17932873 DOI: 10.1002/dmrr.780] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Non-obese diabetic (NOD) mice are regarded as being excellent animal models of human type 1 diabetes or insulin dependent diabetes (IDDM). This study investigated the beneficial effects of genistein and daidzein on IDDM, an autoimmune disease. METHODS Female NOD mice were divided into control, genistein (0.02%, w/w) and daidzein (0.02%, w/w) groups. Blood glucose level, plasma biomarkers, hepatic glucose and lipid regulating enzyme activities and pancreas immunohistochemistry analysis were examined after a 9-week experimental period. RESULTS Blood glucose levels of genistein and daidzein groups were 40 and 36% of control value at the end of study (9th week). The genistein and daidzein supplements increased insulin/glucagon ratio and C-peptide level with preservation of insulin staining beta-cell of pancreas in the NOD mice. In the liver, genistein and daidzein supplements resulted in lowering glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK) activities, while increasing two lipogenic enzymes activities, malic enzyme and glucose-6-phosphate dehydrogenase (G6PD), compared to the control group. Significantly, genistein and daidzein supplementation lowered the activities of fatty acid beta-oxidation and carnitine palmitoyltransferase (CPT) in these mice. Genistein and daidzein also improved plasma triglyceride and free fatty acid (FFA) concentrations compared to the control group. CONCLUSIONS These results suggest that genistein and daidzein play important roles in regulation of glucose homeostasis in type 1 diabetic mice by down-regulating G6Pase, PEPCK, fatty acid beta-oxidation and CPT activities, while up-regulating malic enzyme and G6PD activities in liver with preservation of pancreatic beta-cells. The supplementation of genistein and daidzein are seemingly helpful for preventing IDDM onset.
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Affiliation(s)
- M S Choi
- Department of Food Science and Nutrition, Kyungpook National University, Daegu, 702-701, Republic of Korea
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