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A case of prohormone convertase deficiency diagnosed with type 2 diabetes. Turk Arch Pediatr 2021; 56:81-84. [PMID: 34013237 DOI: 10.14744/turkpediatriars.2020.36459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 04/05/2020] [Indexed: 12/27/2022]
Abstract
Prohormone convertase 1/3, encoded by the proprotein convertase subtilisin/kexin type 1 gene, is essential for processing prohormones; therefore, its deficiency is characterized by a deficiency of variable levels in all hormone systems. Although a case of postprandial hypoglycemia has been previously reported in the literature, prohormone convertase insufficiency with type 2 diabetes mellitus has not yet been reported. Our case, a 14-year-old girl, was referred due to excess weight gain. She was diagnosed as having type 2 diabetes mellitus based on laboratory test results. Prohormone convertase deficiency was considered due to the history of resistant diarrhea during the infancy period and her rapid weight gain. Proinsulin level was measured as >700 pmol/L(3.60-22) during diagnosis. In genetic analysis, a c.685G> T(p.V229F) homozygous mutation in the PCSK1 gene was detected and this has not been reported in relation to this disorder. In conclusion, patients with recurrent resistant diarrhea during infancy followed by rapid weight gain need to be evaluated with the diagnosis of prohormone convertase deficiency.
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Murai N, Saito N, Nii S, Nishikawa Y, Suzuki A, Kodama E, Iida T, Mikura K, Imai H, Hashizume M, Kigawa Y, Tadokoro R, Sugisawa C, Endo K, Iizaka T, Otsuka F, Ishibashi S, Nagasaka S. Postloading insulinemia is independently associated with arterial stiffness in young Japanese persons. Hypertens Res 2021; 44:1515-1523. [PMID: 34518649 PMCID: PMC8568691 DOI: 10.1038/s41440-021-00749-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 08/23/2021] [Indexed: 02/07/2023]
Abstract
Associations of arterial stiffness with glucose, insulin, and proinsulin dynamics during the oral glucose tolerance test (OGTT) remain under debate. The aim of this study was to investigate whether plasma glucose (PG), insulin, and proinsulin (Pro) contribute to arterial stiffness, measured by pulse wave velocity (PWV), in young Japanese persons. PG, immunoreactive insulin (IRI), and Pro levels were determined in 1193 young Japanese subjects (<40 years of age) with normal glucose tolerance or nondiabetic hyperglycemia before and at 30, 60, and 120 min during a 75-g OGTT. Participants were divided into two groups according to the median PWV. Background factors, PG, IRI, and Pro levels during the OGTT, and insulin sensitivity (SI) indices in each group were compared. Several multiple regression analysis models were used to evaluate factors contributing to PWV. All IRI and Pro levels before and after glucose loading and the area under the curve (AUC) values for IRI and Pro increased with higher PWV. 1/HOMA-IR and ISI-Matsuda as measures of SI decreased with higher PWV. The IRI AUC and Pro level before glucose loading (Pro0) were independently associated with PWV, in addition to male sex, heart rate, and mean blood pressure. The IRI AUC had a stronger relationship with PWV than Pro0. The IRI AUC had an independent relationship with PWV, whereas both SI indices did not. Postloading insulinemia, but not reduced SI, was independently associated with arterial stiffness in young Japanese persons.
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Affiliation(s)
- Norimitsu Murai
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Naoko Saito
- grid.410804.90000000123090000Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Sayuri Nii
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Yuto Nishikawa
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Asami Suzuki
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Eriko Kodama
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Tatsuya Iida
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Kentaro Mikura
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Hideyuki Imai
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Mai Hashizume
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Yasuyoshi Kigawa
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Rie Tadokoro
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Chiho Sugisawa
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Kei Endo
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Toru Iizaka
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Fumiko Otsuka
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan
| | - Shun Ishibashi
- grid.410804.90000000123090000Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Shoichiro Nagasaka
- grid.412808.70000 0004 1764 9041Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa Japan ,grid.410804.90000000123090000Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
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Murai N, Saito N, Kodama E, Iida T, Mikura K, Imai H, Kaji M, Hashizume M, Kigawa Y, Koizumi G, Tadokoro R, Sugisawa C, Endo K, Iizaka T, Saiki R, Otsuka F, Ishibashi S, Nagasaka S. Insulin and Proinsulin Dynamics Progressively Deteriorate From Within the Normal Range Toward Impaired Glucose Tolerance. J Endocr Soc 2020; 4:bvaa066. [PMID: 32617449 PMCID: PMC7316365 DOI: 10.1210/jendso/bvaa066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/29/2020] [Indexed: 12/14/2022] Open
Abstract
Context Slight elevations in plasma glucose (PG) manifest in advance of diabetes onset, but abnormalities in immunoreactive insulin (IRI), proinsulin (Pro), and adiponectin dynamics during this stage remain poorly understood. Objective The objective of this work is to investigate whether IRI and Pro dynamics become abnormal as glucose tolerance deteriorates from within the normal range toward impaired glucose tolerance (IGT), as well as the relationship between PG, and these dynamics and serum adiponectin levels. Design A cross-sectional study was designed. Setting This study took place at Jichi Medical University in Japan. Participants and Measurements PG, IRI, and Pro levels were determined in 1311 young Japanese individuals (age < 40 years) with normal or IGT before and at 30, 60, and 120 minutes during a 75-g oral glucose tolerance test. Participants were assigned to 4 groups according to glucose tolerance, and then background factors, adiponectin levels, insulin sensitivity (SI), and insulin secretion (β) indexes were determined. Results PG levels as well as IRI and Pro levels 60 and 120 minutes after glucose-loading increased incrementally with deteriorating glucose tolerance. All measures of β and the SI measure index of insulin sensitivity (ISI)-Matsuda decreased incrementally. Serum adiponectin levels were not significantly different among the glucose tolerance groups, but were independently and negatively correlated with fasting glucose. Conclusions Early β decreased and postloading Pro levels became excessive in a progressive manner as glucose tolerance deteriorated from within the normal range toward IGT.
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Affiliation(s)
- Norimitsu Murai
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Naoko Saito
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Eriko Kodama
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Tatsuya Iida
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Kentaro Mikura
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Hideyuki Imai
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Mariko Kaji
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Mai Hashizume
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Yasuyoshi Kigawa
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Go Koizumi
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Rie Tadokoro
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Chiho Sugisawa
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Kei Endo
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Toru Iizaka
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Ryo Saiki
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Fumiko Otsuka
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Shun Ishibashi
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Shoichiro Nagasaka
- Division of Diabetes, Metabolism and Endocrinology, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan.,Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
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Bhat PV, Vinod V, Priyanka AN, Kamath A. Maternal serum lipid levels, oxidative stress and antioxidant activity in pre-eclampsia patients from Southwest India. Pregnancy Hypertens 2018; 15:130-133. [PMID: 30825910 DOI: 10.1016/j.preghy.2018.12.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 12/11/2018] [Accepted: 12/30/2018] [Indexed: 10/27/2022]
Abstract
OBJECTIVE A study was carried out to evaluate the effects of metabolic syndrome components and oxidative stress factors among preeclamptic women from South West India. STUDY DESIGN A case-control study was carried out by enrolling fifty pre-eclampsia cases and hundred low-risk pregnant women within the age group of 18-40 years, at 28-34 weeks of pregnancy. The fasting glucose level, fasting insulin level, insulin resistance, total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), malondialdehyde, the ferric reducing ability of plasma (FRAP assay), cardiac output and aortic wall distensibility were measured. MAIN OUTCOME MEASURES There was a significant rise in the fasting blood glucose, fasting insulin, insulin resistance levels, total cholesterol, triglycerides, LDL, and antioxidant levels in pre-eclamptic women (p < 0.001). The cardiac output and aortic wall distensibility were observed to be low in the cases. CONCLUSION We conclude that abnormal lipid metabolism and high lipid peroxide concentrations observed in pre-eclampsia may result in oxidative stress and vascular dysfunction.
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Affiliation(s)
- Parvati V Bhat
- Department of Obstetrics and Gynecology, Dr T M A Pai Hospital, MMMC, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India.
| | - Vinutha Vinod
- Dr T M A Pai Hospital, MMMC, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Alluri Naga Priyanka
- Department of Obstetrics and Gynecology, Dr T M A Pai Hospital, MMMC, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Asha Kamath
- Department of Statistics, Prasanna School of Public Health, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India.
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Schmid V, Wagner R, Sailer C, Fritsche L, Kantartzis K, Peter A, Heni M, Häring HU, Stefan N, Fritsche A. Non-alcoholic fatty liver disease and impaired proinsulin conversion as newly identified predictors of the long-term non-response to a lifestyle intervention for diabetes prevention: results from the TULIP study. Diabetologia 2017; 60:2341-2351. [PMID: 28840257 DOI: 10.1007/s00125-017-4407-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 07/11/2017] [Indexed: 02/08/2023]
Abstract
AIMS/HYPOTHESIS Lifestyle intervention is effective to prevent type 2 diabetes. However, a considerable long-term non-response occurs to a standard lifestyle intervention. We investigated which risk phenotypes at baseline and their changes during the lifestyle intervention predict long-term glycaemic non-response to the intervention. METHODS Of 300 participants at high risk for type 2 diabetes who participated in a 24 month lifestyle intervention with diet modification and increased physical activity, 190 participants could be re-examined after 8.7 ± 1.6 years. All individuals underwent a five-point 75 g OGTT and measurements of body fat compartments and liver fat content with MRI and spectroscopy at baseline, 9 and 24 months during the lifestyle intervention, and at long-term follow-up. Fasting proinsulin to insulin conversion (PI/I ratio) and insulin sensitivity and secretion were calculated from the OGTT. Non-response to lifestyle intervention was defined as no decrease in glycaemia, i.e. no decrease in AUC for glucose at 0-120 min during OGTT (AUCglucose0-120 min). RESULTS Before the lifestyle intervention, 56% of participants had normal glucose regulation and 44% individuals had impaired fasting glucose and/or impaired glucose tolerance. At long-term follow-up, 11% had developed diabetes. Multivariable regression analysis with adjustment for age, sex, BMI and change in BMI during the lifestyle intervention revealed that baseline insulin secretion and insulin sensitivity, as well as change in insulin sensitivity during the lifestyle intervention, predicted long-term glycaemic control after 9 years. In addition, increased hepatic lipid content as well as impaired fasting proinsulin conversion at baseline were newly detected phenotypes that independently predicted long-term glycaemic control. CONCLUSIONS/INTERPRETATION Increased hepatic lipid content and impaired proinsulin conversion are new predictors, independent of change in body weight, for non-response to lifestyle intervention in addition to the confirmed factors, impaired insulin secretion and insulin sensitivity.
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Affiliation(s)
- Vera Schmid
- Department of Internal Medicine IV, University Hospital of Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany
- International Research Training Group 1302, University of Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany
| | - Robert Wagner
- Department of Internal Medicine IV, University Hospital of Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany
- German Centre for Diabetes Research (DZD), Tübingen, Germany
| | - Corinna Sailer
- Department of Internal Medicine IV, University Hospital of Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany
- German Centre for Diabetes Research (DZD), Tübingen, Germany
| | - Louise Fritsche
- Department of Internal Medicine IV, University Hospital of Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany
- German Centre for Diabetes Research (DZD), Tübingen, Germany
| | - Konstantinos Kantartzis
- Department of Internal Medicine IV, University Hospital of Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany
- German Centre for Diabetes Research (DZD), Tübingen, Germany
| | - Andreas Peter
- Department of Internal Medicine IV, University Hospital of Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany
- German Centre for Diabetes Research (DZD), Tübingen, Germany
| | - Martin Heni
- Department of Internal Medicine IV, University Hospital of Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany
- German Centre for Diabetes Research (DZD), Tübingen, Germany
| | - Hans-Ulrich Häring
- Department of Internal Medicine IV, University Hospital of Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany
- German Centre for Diabetes Research (DZD), Tübingen, Germany
| | - Norbert Stefan
- Department of Internal Medicine IV, University Hospital of Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany
- German Centre for Diabetes Research (DZD), Tübingen, Germany
| | - Andreas Fritsche
- Department of Internal Medicine IV, University Hospital of Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany.
- Institute for Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany.
- German Centre for Diabetes Research (DZD), Tübingen, Germany.
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6
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The progress of luminescent assay in clinical diagnosis and treatment of diabetes mellitus. J Electroanal Chem (Lausanne) 2016. [DOI: 10.1016/j.jelechem.2016.07.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Pfützner A, Hermanns I, Ramljak S, Demircik F, Pfützner AH, Kann PH, Weber MM. Elevated Intact Proinsulin Levels During an Oral Glucose Challenge Indicate Progressive ß-Cell Dysfunction and May Be Predictive for Development of Type 2 Diabetes. J Diabetes Sci Technol 2015; 9:1307-12. [PMID: 26420624 PMCID: PMC4667304 DOI: 10.1177/1932296815607862] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Elevated fasting intact proinsulin is a biomarker of late-stage ß-cell-dysfunction associated with clinically relevant insulin resistance. In this pilot investigation, we explored the potential value of measuring intact proinsulin as a functional predictor of ß-cell exhaustion during an oral glucose tolerance test (OGTT). METHODS The study was performed with 31 participants, 11 of whom were healthy subjects (7 female, age: 59 ± 20 years), 10 had impaired glucose tolerance (IGT, 6 female, 62 ± 10 years), and 10 had known type 2 diabetes (T2DM, 5 female, 53 ± 11 years, HbA1c: 7.0 ± 0.6%, disease duration: 8 ± 5 years). During OGTT, blood was drawn after 0 hours, 1 hour, and 2 hours for determination of glucose and intact proinsulin. Five years later, patients were again contacted to assess their diabetes status and the association to the previous OGTT results was analyzed. RESULTS The OGTT (0 hours/1 hour/2 hours) results were as follows: healthy subjects: glucose: 94 ± 8 mg/dL/140 ± 29 mg/dL/90 ± 24 mg/dL, intact proinsulin: 3 ± 2 pmol/L/10 ± 7 pmol/L/10 ± 5 pmol/L); IGT: glucose: 102 ± 9 mg/dL/158 ± 57 mg/dL/149 ± 34 mg/dL, intact proinsulin: 7 ± 4 pmol/L/23 ± 8 pmol/L/28 ± 6 pmol/L; T2DM: glucose: 121 ± 20 mg/dL/230 ± 51 mg/dL/213 ± 34 mg/dL; intact proinsulin: 7 ± 7 pmol/L/26 ± 9 pmol/L/27 ± 10 pmol/L). Five years later, all of the IGT and 2 of the healthy subjects had developed T2DM and one had devloped IGT. All of them had elevated 2-hour proinsulin values in the initial OGTT, while patients with normal intact proinsulin results did not develop diabetes. CONCLUSIONS Elevated 2-hour intact proinsulin levels during OGTT were predictive for later type 2 diabetes development. Further studies need to confirm our findings in larger populations.
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Affiliation(s)
- Andreas Pfützner
- Pfützner Science & Health Institute, Diabetes Center and Practice, Mainz, Germany
| | - Iris Hermanns
- University Hospital Mainz, Center of Thrombosis and Homeostasis, Mainz, Germany
| | - Sanja Ramljak
- Pfützner Science & Health Institute, Diabetes Center and Practice, Mainz, Germany
| | - Filiz Demircik
- Pfützner Science & Health Institute, Diabetes Center and Practice, Mainz, Germany
| | | | - Peter H Kann
- Universitäty Hospital, Department of Endocrinology & Diabetes, Marburg, Germany
| | - Matthias M Weber
- University-Hospital, Department of Endocrinology & Diabetes, Mainz, Germany
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Imai S, Takahashi T, Naito S, Yamauchi A, Okada C, Notsu Y, Sakikawa I, Hatanaka M, Iwasaki T, Morita A, Fujii I, Yamane S. Development of a novel immunoassay specific for mouse intact proinsulin. Anal Biochem 2015; 484:91-8. [DOI: 10.1016/j.ab.2015.05.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 05/13/2015] [Accepted: 05/18/2015] [Indexed: 11/16/2022]
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9
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Katsuta H, Ozawa S, Suzuki K, Takahashi K, Tanaka T, Sumitani Y, Nishida S, Kondo T, Hosaka T, Inukai K, Ishida H. The association between impaired proinsulin processing and type 2 diabetes mellitus in non-obese Japanese individuals. Endocr J 2015; 62:485-92. [PMID: 25892189 DOI: 10.1507/endocrj.ej14-0611] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We aimed to examine the association between impaired proinsulin processing in pancreatic beta cells and type 2 diabetes mellitus in non-obese Japanese patients. Participants were divided into groups for normal glucose tolerance, prediabetes, and type 2 diabetes based on the oral glucose tolerance test (OGTT). Activities of prohormone convertase (PC) 1/3 and PC2 in fasting states were estimated. Multiple regression analysis was undertaken to ascertain if alteration of the activities of these enzymes contributes to the development of impaired glucose tolerance by comparison with HOMA-β and the oral disposition index (DI(O)). Overall, 452 subjects were included. PC1/3 activity tended to decrease in type 2 diabetes compared with normal glucose tolerance. PC2 activity showed no difference among the three groups. Decreased estimated PC1/3 activity was significantly associated with type 2 diabetes after adjustment for sex, age, creatinine, triglycerides, HOMA-β and DI(O). Odds ratios (95% CI) of PC1/3, HOMA-β, and DI(O) were 2.16 (1.12-4.19), 3.44 (1.82-6.52) and 14.60 (7.87-27.11), respectively. Furthermore, decreased PC1/3(≤1.7) combined with decreased HOMA-β (≤30) had a sensitivity of 73% and specificity of 62%. Decreased PC1/3 activity may be a useful measurement of beta-cell function alongside decreased HOMA-β or DI(O). A combined decrease in estimated fasting PC1/3 activity and HOMA-β measurement led to suspicion of type 2 diabetes in the non-obese Japanese population studied.
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Affiliation(s)
- Hidenori Katsuta
- Third Department of Internal Medicine, Division of Diabetes, Endocrinology and Metabolism, Kyorin University School of Medicine, Tokyo 181-8611, Japan
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Ozawa S, Katsuta H, Suzuki K, Takahashi K, Tanaka T, Sumitani Y, Nishida S, Yoshimoto K, Ishida H. Estimated proinsulin processing activity of prohormone convertase (PC) 1/3 rather than PC2 is decreased in pancreatic β-cells of type 2 diabetic patients. Endocr J 2014; 61:607-14. [PMID: 24705588 DOI: 10.1507/endocrj.ej13-0506] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Type 2 diabetic (T2D) patients exhibit fasting relative hyperproinsulinemia owing to pancreatic β-cell dysfunction. To clarify the mechanism underlying this hyperproinsulinemic state, we evaluated the activities of the endopeptidases prohormone convertase (PC) 1/3 and PC2 in T2D patients. Fasting blood levels of intact proinsulin (IPI), total proinsulin (t-PI) and C-peptide were measured simultaneously, and intravenous glucagon loading was performed to investigate the dynamics of circulating proinsulin-related molecules released from pancreatic β-cells in 12 healthy volunteers and 18 T2D patients. Taking advantage of the 95% cross-reactivity between proinsulin and des-31,32-proinsulin (des-31,32-PI) with the human proinsulin radioimmunoassay kit used in this study, we estimated PC1/3 and PC2 activities using the following formulas: des-31,32-PI = (t-PI-IPI)/0.95; PC1/3 activity = des-31,32-PI/IPI; and PC2 activity = C-peptide/des-31,32-PI. C-peptide responses to glucagon were slightly lower among T2D patients. IPI and the IPI/C-peptide ratio were significantly higher in T2D patients (p<0.05 and p<0.01, respectively). There was no difference in des-31,32-PI levels or PC2 activity between the two groups. However, PC1/3 activity was significantly lower in T2D patients than in the control group (p<0.01). We propose that decreased activity of PC1/3 rather than PC2 in pancreatic β-cells is involved in the impaired proinsulin processing, resulting in elevated IPI levels in T2D patients.
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Affiliation(s)
- Sachihiko Ozawa
- Third Department of Internal Medicine, Division of Diabetes, Endocrinology and Metabolism, Kyorin University School of Medicine, Tokyo 181-8611, Japan
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Chevenne D, Deghmoun S, Coric L, Nicolas M, Lévy-Marchal C. Evaluation of an ELISA assay for total proinsulin and establishment of reference values during an oral glucose tolerance test in a healthy population. Clin Biochem 2011; 44:1349-51. [PMID: 21889934 DOI: 10.1016/j.clinbiochem.2011.08.1129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 07/18/2011] [Accepted: 08/14/2011] [Indexed: 10/17/2022]
Abstract
OBJECTIVES Assessment of the analytical performance of the Total Proinsulin ELISA Kit (Millipore) and determination of reference values. DESIGN AND METHODS Imprecision, specificity, antibodies interference and reference values in normoglycaemic non-obese adults were determined. RESULTS The inter-assay CV is <6.9%, the limits of detection and quantification are 0.2 and 0.6 pmol/L. Molar cross-reactivity of split proinsulins varies from 103 to 92.5%. The interference of anti-(pro)insulin antibodies can be eliminated with the use of polyethylene glycol. The reference values are 2.7-14.2 pmol/L at fasting, 8.5-56.5 pmol/L at T30 min and 11.9-70.5 pmol/L at T120 min during an OGTT. CONCLUSION The reference values established for this kit, which showed good analytical performances, allow for a better assessment of pathologies associated with increased proinsulinaemia.
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Affiliation(s)
- Didier Chevenne
- Hôpital Robert Debré, laboratoire de biochimie-hormonologie, 48 bd Sérurier, 75019-Paris, France.
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12
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Pfützner A, Forst T. Elevated intact proinsulin levels are indicative of Beta-cell dysfunction, insulin resistance, and cardiovascular risk: impact of the antidiabetic agent pioglitazone. J Diabetes Sci Technol 2011; 5:784-93. [PMID: 21722594 PMCID: PMC3192645 DOI: 10.1177/193229681100500333] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Insulin resistance (IR) and deterioration of beta-cell secretion are main features in the development of type 2 diabetes, which is reflected in increasing serum intact proinsulin levels in later disease stage. Introduction of stable assays that are able to distinguish between intact proinsulin and its specific and unspecific cleavage products has resulted in the finding that serum intact proinsulin values can serve as a direct marker for beta-cell dysfunction, are a highly specific indicator of IR, and can predict cardiovascular risk. METHOD Determination of fasting intact proinsulin may be used to monitor and optimize antidiabetic therapeutic approaches. Our study group has been involved in a variety of clinical studies investigating drug effects on beta-cell secretory capacity, IR, and intact proinsulin levels. One focus was on the impact of insulin-sensitizing therapy with pioglitazone on the pancreatic beta-cell load. RESULTS Treatment with pioglitazone resulted in significant decreases in elevated proinsulin levels in type 2 diabetes patients. This effect was independent from glycemic control. CONCLUSIONS Measurement of fasting intact proinsulin values allows a staging of beta-cell dysfunction and evaluation of IR, thus providing an interesting diagnostic tool for both selection of appropriate therapy and monitoring of treatment success.
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Affiliation(s)
- Andreas Pfützner
- IKFE, Institute for Clinical Research and Development, Mainz, Germany.
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Engel A, Helfrich J, Manderscheid N, Musholt PB, Forst T, Pfützner A, Dahmen N. Investigation of insulin resistance in narcoleptic patients: dependent or independent of body mass index? Neuropsychiatr Dis Treat 2011; 7:351-6. [PMID: 21822386 PMCID: PMC3148926 DOI: 10.2147/ndt.s18455] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Narcolepsy is a severe sleep-wake cycle disorder resulting in most cases from a lack of orexin, the energy balance-regulating hormone. Narcoleptic patients have been reported to suffer from an excess morbidity of Type 2 diabetes, even after correction for their often elevated body mass index. METHODS To explore whether narcolepsy is specifically associated with a propensity to develop insulin resistance, we measured fasting glucose, insulin, and intact proinsulin levels in 43 narcoleptic patients and 47 controls matched for body mass index and age. The proinsulin-to-insulin ratio was calculated. Insulin resistance was determined using the homeostatic model assessment method. RESULTS Narcoleptic patients did not show elevated insulin resistance parameters. CONCLUSION In contrast with earlier reports, we found no evidence that narcolepsy specifically elevates the risk of insulin resistance (and consequently of type 2 diabetes) independently of body mass index.
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Affiliation(s)
- Alice Engel
- Department of Psychiatry, University of Mainz, Germany
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14
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Saisho Y, Maruyama T, Hirose H, Saruta T. Relationship between proinsulin-to-insulin ratio and advanced glycation endproducts in Japanese type 2 diabetic subjects. Diabetes Res Clin Pract 2007; 78:182-8. [PMID: 17467843 DOI: 10.1016/j.diabres.2007.03.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Revised: 01/26/2007] [Accepted: 03/12/2007] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Type 2 diabetes (T2DM) is characterized by increased proinsulin-to-insulin ratio (P/I ratio), increased glycation and oxidative stress, and beta-cell dysfunction. Previous reports implicated that increased P/I ratio, glycation and oxidative stress constitute markers of beta-cell dysfunction in T2DM. However, its clinical relevance remains to be elucidated. Therefore, in the present study we investigated the relationship between the P/I ratio, glycation and oxidative stress markers in patients with T2DM, using newly developed intact chemiluminescent immunoassay for proinsulin. METHODS Fasting intact proinsulin, insulin, advanced glycation endproducts (AGEs), pentosidine, lipid peroxide and urine 8-isoprostane as well as other metabolic parameters were measured in 64 T2DM subjects. RESULTS Using univariate analysis, P/I ratio showed significant positive correlations with plasma glucose (r=0.465), HbA1c (r=0.434) and AGEs (r=0.282), and significant negative correlations with insulin (r=-0.330) and HOMA-beta (r=-0.520) even after adjustment for age, sex, duration of diabetes, family history of diabetes, use of sulfonylureas, smoking and body mass index. Additionally, stepwise multiple regression analysis revealed that HOMA-beta, HbA1c and AGEs were independently and significantly correlated with P/I ratio. CONCLUSION These findings suggest that not only hyperglycemia per se but also glycation is involved in beta-cell dysfunction in T2DM subjects.
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Affiliation(s)
- Yoshifumi Saisho
- Department of Internal Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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15
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Pfützner A, Lorra B, Abdollahnia MR, Kann PH, Mathieu D, Pehnert C, Oligschleger C, Kaiser M, Forst T. The switch from sulfonylurea to preprandial short- acting insulin analog substitution has an immediate and comprehensive beta-cell protective effect in patients with type 2 diabetes mellitus. Diabetes Technol Ther 2006; 8:375-84. [PMID: 16800759 DOI: 10.1089/dia.2006.8.375] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Supplementary insulin therapy provides assistance to meal-time insulin secretion in patients with type 2 diabetes and may have protective effects on beta-cell function. METHODS This study explored the immediate effect of supplementary insulin therapy on beta- cell function in patients with glimepiride monotherapy (five women, 15 men; 61.8 +/- 6.4 years old; body mass index, 31.1 +/- 4.4 kg/m(2); hemoglobin A1c, 7.0 +/- 1.3%). After 1 week of continued glimiperide therapy, the patients were randomized either to continue with their oral treatment or to switch to a fixed-dose supplementary insulin therapy (8 U of insulin aspart subcutaneously before each meal) for another week. Oral glucose tolerance tests (OGTTs) after drug uptake were performed at days 7 and 14, with measurement of glucose, insulin, C-peptide, intact and total proinsulin, glucagon, lactate, free fatty acids, and adiponectin. RESULTS Significant reductions from baseline were seen in the supplementary insulin therapy group for the fasting values of insulin (from 13.1 +/- 5.1 microU/mL to 10.6 +/- 5.2 microU/mL, P < 0.01), intact proinsulin (from 18.3 +/- 11.2 pmol/L to 10.3 +/- 4.6 pmol/L, P micro 0.05), total proinsulin (from 43.3 +/- 22.7 pmol/L to 29.7 +/- 14.5 pmol/L, P < 0.01), split proinsulin (from 24.9 +/- 13.8 pmol/L to 19.4 +/- 10.8 pmol/L, P micro 0.01), and the degree of beta-cell dysfunction (P < 0.05). Also, lower values for intact and total proinsulin and split proinsulin in the OGTT were observed in this group during the OGTT at the end point, while no changes at all occurred in the glimepiride group. CONCLUSIONS A fixed low-dose preprandial insulin aspart therapy resulted in an overall beta-cell protection with an improved fasting beta-cell secretion profile already within 1 week. Our study indicates that supplementary insulin therapy might be a reasonable alternative to bedtime basal insulin injections for initiation of insulin therapy in patients with type 2 diabetes.
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Affiliation(s)
- Andreas Pfützner
- IKFE, Institute for Clinical Research and Development, Mainz, Germany.
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16
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Pfützner A, Standl E, Strotmann HJ, Schulze J, Hohberg C, Lübben G, Pahler S, Schöndorf T, Forst T. Association of high-sensitive C-reactive protein with advanced stage β-cell dysfunction and insulin resistance in patients with type 2 diabetes mellitus. Clin Chem Lab Med 2006; 44:556-60. [PMID: 16681424 DOI: 10.1515/cclm.2006.108] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
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Affiliation(s)
- Andreas Pfützner
- Institute for Clinical Research and Development, IKFE GmbH, Parcusstrasse 8, 55116 Mainz, Germany.
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17
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Pfützner A, Standl E, Hohberg C, Konrad T, Strotmann HJ, Lübben G, Langenfeld MR, Schulze J, Forst T. IRIS II study: intact proinsulin is confirmed as a highly specific indicator for insulin resistance in a large cross-sectional study design. Diabetes Technol Ther 2005; 7:478-86. [PMID: 15929679 DOI: 10.1089/dia.2005.7.478] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND The cross-sectional IRIS-II study tried to assess the prevalence of insulin resistance and macrovascular disease in orally treated patients with Type 2 diabetes. METHODS In total, 4,270 patients were enrolled into the study (2,146 male, 2,124 female; mean +/- SD age 63.9 +/- 11.1 years; body mass index 30.1 +/- 5.5 kg/m2; duration of disease 5.4 +/- 5.6 years; hemoglobin A1c 6.8 +/- 1.3%). The study consisted of a single morning visit with completion of a standardized questionnaire and collection of a fasting blood sample. RESULTS The mean intact proinsulin value was 11.4 +/- 12.4 pmol/L (normal range < 10 pmol/L). Homeostasis model assessment resulted in 1,147 insulin-sensitive patients (26.9%) and 3,123 patients (73.1%) with insulin resistance. Of the latter patients 1,465 (34.3% of all patients) had also elevated intact proinsulin values, while 1,658 (38.8%) had no proinsulin elevation. In contrast, 1,042 (24.4%) of the insulin-sensitive patients had normal intact proinsulin, and only 105 (2.4%) had elevated intact proinsulin concentrations (chi2 test P < 0.0001). A specificity of 93.2% (sensitivity 46.9%) was calculated for elevated intact proinsulin as an indirect marker for insulin resistance. Of the 1,451 patients treated with sulfonylurea 52% had elevated intact proinsulin values and increased prevalence of cardiovascular complications (odds ratio 1.45). CONCLUSION Type 2 patients with elevated fasting intact proinsulin values can be regarded as being insulin resistant. The results confirm that fasting intact proinsulin is a suitable measure for beta-cell dysfunction and insulin resistance in type 2 diabetes and may be used to support therapeutic decisions.
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Langenfeld MR, Forst T, Standl E, Strotmann HJ, Lübben G, Pahler S, Kann P, Pfützner A. IRIS II Study: Sensitivity and specificity of intact proinsulin, adiponectin, and the proinsulin/adiponectin ratio as markers for insulin resistance. Diabetes Technol Ther 2004; 6:836-43. [PMID: 15684637 DOI: 10.1089/dia.2004.6.836] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE This study was performed to compare the specificity and sensitivity of intact proinsulin, adiponectin, and their ratio (proinsulin/adiponectin) in the prediction of insulin resistance as assessed by the homeostasis model assessment (HOMA) score (> or =2 = resistant). RESEARCH DESIGN AND METHODS Using a cross-sectional approach, 500 orally treated patients with type 2 diabetes (272 women, 238 men; mean +/- SD age, 64.8 +/- 11.6 years; hemoglobin A1c, 7.0 +/- 1.5%; disease duration, 5.8 +/- 6.1 years) were investigated. Various cutoffs for body mass index-adjusted adiponectin and proinsulin/adiponectin were compared with the established cutoff value of 10 pmol/L for fasting proinsulin. RESULTS Fasting proinsulin correlated more closely with the HOMA score (r = 0.560, P < 0.001) than fasting adiponectin (r = -0.204, P < 0.001) or proinsulin/adiponectin (r = 0.355, P < 0.001). For proinsulin, specificity and sensitivity for insulin resistance in correlation to the HOMA score results were 96% and 70%, respectively. At a comparable specificity level to proinsulin, adiponectin did not reach a comparable sensitivity (14%), while the proinsulin/adiponectin ratio almost reached the same sensitivity (65%). Overall, patients with elevated proinsulin had a higher prevalence of micro- and macrovascular disease [odds ratio 1.47 (adiponectin, 1.08; proinsulin/ adiponectin, 1.48) and 1.34 (adiponectin, 1.32; proinsulin/adiponectin, 1.27), respectively]. CONCLUSIONS Elevation of fasting intact proinsulin seems to be the more specific marker for insulin resistance and increased cardiovascular risk than suppression of fasting adiponectin. Formation of the ratio does not lead to a further increase in the predictive value.
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Pfützner A, Pfützner AH, Larbig M, Forst T. Role of intact proinsulin in diagnosis and treatment of type 2 diabetes mellitus. Diabetes Technol Ther 2004; 6:405-12. [PMID: 15198846 DOI: 10.1089/152091504774198124] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Insulin resistance in patients with type 2 diabetes is associated with an increased risk of cardiovascular events. While this can be partly explained by an impairment of direct insulin action on the endothelial cell, an independent contribution can be assigned also to the secretory dysfunction of the beta-cell. If the demand for insulin triggered by insulin resistance is arriving at a certain threshold, an insufficiency of the cleavage capacity of beta-cell carboxypeptidase H leads to an increased secretion of intact proinsulin in addition to the desired insulin molecule. Proinsulin, however, has been demonstrated to be an independent cardiovascular risk factor by stimulating plasminogen activator inhibitor-1 secretion and blocking fibrinolysis. A recently introduced intact proinsulin assay is able to distinguish between intact proinsulin and its specific and non-specific cleavage products. This assay allows for a pathophysiological staging of type 2 diabetes based on beta-cell secretion. It could be confirmed by a large epidemiological study (IRIS-2, 4,265 patients) that intact proinsulin is a highly specific marker for insulin resistance. It could also be shown in other studies that successful resistance treatment with insulin or glitazones led to a decrease in elevated proinsulin levels and, thus, to a decrease of cardiovascular risk, while the levels remained high during sulfonylurea therapy. Therefore, patients with increased fasting intact proinsulin values should be treated with a therapy focusing on insulin resistance. Assessment of beta-cell function by determination of intact proinsulin may facilitate the selection of the most promising therapy and may also serve to monitor treatment success in the further course of the disease.
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Affiliation(s)
- Andreas Pfützner
- Institute for Clinical Research and Development, Mainz, Germany.
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Pfützner A, Kunt T, Hohberg C, Mondok A, Pahler S, Konrad T, Lübben G, Forst T. Fasting intact proinsulin is a highly specific predictor of insulin resistance in type 2 diabetes. Diabetes Care 2004; 27:682-7. [PMID: 14988285 DOI: 10.2337/diacare.27.3.682] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE In later stages of type 2 diabetes, proinsulin and proinsulin-like molecules are secreted in increasing amounts with insulin. A recently introduced chemiluminescence assay is able to detect the uncleaved "intact" proinsulin and differentiate it from proinsulin-like molecules. This investigation explored the predictive value of intact proinsulin as an insulin resistance marker. RESEARCH DESIGN AND METHODS In total, 48 patients with type 2 diabetes (20 women and 28 men, aged 60 +/- 9 years [means +/- SD], diabetes duration 5.1 +/- 3.8 years, BMI 31.2 +/- 4.8 kg/m2, and HbA1c 6.9 +/- 1.2%) were studied by means of an intravenous glucose tolerance test and determination of fasting values of intact proinsulin, insulin, resistin, adiponectin, and glucose. Insulin resistance was determined by means of minimal model analysis (MMA) (as the gold standard) and homeostatis model assessment (HOMA). RESULTS There was a significant correlation between intact proinsulin values and insulin resistance (MMA P<0.05 and HOMA P<0.01). Elevation of intact proinsulin values above the reference range (>10 pmol/l) showed a very high specificity (MMA 100% and HOMA 92.9%) and a moderate sensitivity (MMA 48.6% and HOMA 47.1%) as marker for insulin resistance. Adiponectin values were slightly lower in the insulin resistant group, but no correlation to insulin resistance could be detected for resistin in the cross-sectional design. CONCLUSIONS Elevated intact proinsulin seems to indicate an advanced stage of beta-cell exhaustion and is a highly specific marker for insulin resistance. It might be used as arbitrary marker for the therapeutic decision between secretagogue, sensitizer, or insulin therapy in type 2 diabetes.
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Affiliation(s)
- Andreas Pfützner
- Institute for Clinical Research and Development, Mainz, Germany.
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