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1.
Nutr Metab Insights ; 16: 11786388221141174, 2023.
Article in English | MEDLINE | ID: mdl-36686368

ABSTRACT

Background: We conducted a prospective placebo-controlled double-blind randomized Study to assess the impact of a single dose of a nutritional Supplement (AB001) on alcohol absorption in healthy subjects. Other objectives were the impact on breath alcohol content, cognitive function 1 hour after alcohol uptake and tolerability. Method: A total of 24 healthy volunteers were enrolled into the study (12 male, 12 female, age: 28.3 ± 10.8 years, BMI: 23.5 ± 5.7 kg/m²). On the experimental day, they ingested a light breakfast together with a single dose (2 capsules) of AB001 (or placebo) and drank 2 moderate glasses of spirit (a total of 0.6 g/kg body weight). Breath alcohol tests and blood draws for determination of blood alcohol levels were performed for up to 6 hours. After crossover, the experiment was repeated in the following week. Areas under the curves were calculated to determine alcohol absorption rates. Results: There was a significant reduction of blood alcohol by 10.1% (P < .001) with AB001, when compared to placebo. There was a less pronounced but also significant reduction of alcohol in the breath test by 7.2% (P < .05). No difference in the cognitive function test between AB001 and placebo could be observed 60 minutes after alcohol ingestion (22.6 ± 8.0 seconds vs 23.0 ± 11.2 seconds, n.s.). The supplement uptake was well tolerated and there were no adverse events related to the study intervention. Conclusion: Uptake of a single dose of AB001 shortly before drinking alcohol significantly reduced plasma alcohol and breath alcohol concentrations, but the effect was less pronounced compared to chronic uptake as shown previously.

2.
J Diabetes Sci Technol ; 14(3): 575-581, 2020 05.
Article in English | MEDLINE | ID: mdl-31640424

ABSTRACT

BACKGROUND: The pain associated with pricking the fingertip for blood glucose self-testing is considered to be a major burden in diabetes treatment. This study was performed to evaluate the system accuracy of the invasive TensorTip Combo Glucometer (CoG) device component in accordance with ISO15197:2015 requirements and to explore the accuracy of the noninvasive tissue glucose prediction component. METHODS: One hundred samples were obtained from people with type 1 and type 2 diabetes and healthy volunteers (43 females, 57 males; age: 53 ± 16 years), with glucose distribution as requested by the ISO standard. Three strip lots were tested twice by healthcare professionals in comparison to YSI 2300 Stat Plus reference method followed by a noninvasive tissue glucose reading (NI-CoG). Mean Absolute (Relative) Difference (MARD) was calculated and a consensus error grid (CEG) analysis was performed. RESULTS: The ISO system accuracy criteria were met with the invasive strip technology by 586/600 of the data points (97.1%) and for each strip lot separately. All invasive results (100%) were within CEG-zone A and total MARD was calculated to be 7.1%. With the noninvasive reading, 99% of raw data points were in A + B (91.1% and 7.8%), and the total MARD was calculated to be 18.1%. DISCUSSION: The invasive component of the CoG device was shown to be in full compliance with the current ISO15197 criteria. Good results were also obtained with the NI-CoG tissue glucose prediction. This noninvasive technology would potentially be suitable for frequent pain-free glucose monitoring in many people with diabetes.


Subject(s)
Blood Glucose Self-Monitoring/instrumentation , Blood Glucose/analysis , Diabetes Mellitus, Type 1/diagnosis , Diabetes Mellitus, Type 2/diagnosis , Reagent Strips , Adult , Aged , Biomarkers/blood , Case-Control Studies , Cross-Sectional Studies , Diabetes Mellitus, Type 1/blood , Diabetes Mellitus, Type 2/blood , Equipment Design , Female , Humans , Male , Middle Aged , Predictive Value of Tests , Reproducibility of Results
3.
J Diabetes Sci Technol ; 13(3): 507-513, 2019 05.
Article in English | MEDLINE | ID: mdl-30974985

ABSTRACT

BACKGROUND: In recent randomized clinical trials, an unusual reporting pattern of glycemic data and hypoglycemic events potentially related to an internet enabled blood glucose meter (MyGlucoHealth, BGM) was observed. Therefore, this clinical study was conducted to evaluate the system accuracy of the BGM in accordance with the ISO15197:2015 guidelines with additional data collection. METHODS: To investigate system accuracy, 10 of 3088 devices and 6 of 23 strip lots, used in the trials, were selected by a randomization procedure and a standard repeatability assessment. YSI 2300 STAT Plus was used as the standard reference method. The samples were distributed as per the ISO15197:2015 recommendations with 20 additional samples in the hypoglycemic range. Each sample was tested with 6 devices and 6 strip lots with double determinations. RESULTS: Overall, 121 subjects with blood glucose values 26-423 mg/dL were analyzed, resulting in 1452 data points. In all, 186/1452 readings (12.8%) did not meet the ISO acceptance criteria. Data evaluated according to the FDA guidelines showed that 336/1452 (23.1%) readings did not meet the acceptance criteria. A clear bias toward elevated values was observed for BG <100 mg/dL (MARD: 11.0%). CONCLUSIONS: The results show that the BGM, although approved according to standard regulatory guidelines, did not meet the level of analytical accuracy required for clinical treatment decisions according to ISO 15197:2015 and FDA requirements. In general, caution should be exercised before selection of BGMs for patients and in clinical trials.


Subject(s)
Blood Glucose/analysis , Diabetes Mellitus/blood , Hypoglycemia/diagnosis , Internet Access , Randomized Controlled Trials as Topic , Wireless Technology/instrumentation , Blood Glucose Self-Monitoring/instrumentation , Blood Glucose Self-Monitoring/standards , Clinical Trials as Topic , Data Collection/instrumentation , Data Collection/standards , Endocrinology/instrumentation , Endocrinology/methods , Endocrinology/standards , Equipment Design/standards , Equipment Failure Analysis , Female , Humans , Hypoglycemia/blood , Hypoglycemia/epidemiology , Male , Middle Aged , Practice Guidelines as Topic , Randomized Controlled Trials as Topic/standards , Randomized Controlled Trials as Topic/statistics & numerical data , Reproducibility of Results , Sensitivity and Specificity , Wireless Technology/standards
4.
J Diabetes Sci Technol ; 13(3): 514-521, 2019 05.
Article in English | MEDLINE | ID: mdl-30974988

ABSTRACT

BACKGROUND: In recent clinical trials, use of the MyGlucoHealth blood glucose meter (BGM) and electronic diary was associated with an unusual reporting pattern of glycemic data and hypoglycemic events. Therefore, the performance of representative BGMs used by the patients was investigated to assess repeatability, linearity, and hematocrit interference in accordance with regulatory guidelines. METHOD: Ten devices and 6 strip lots were selected using standard randomization and repeatability procedures. Venous heparinized blood was drawn from healthy subjects, immediately aliquoted and adjusted to 5 target blood glucose (BG) ranges for the repeatability and 11 BG concentrations for the linearity tests. For the hematocrit interference test, each sample within 5 target BG ranges was split into 5 aliquots and adjusted to hematocrit levels across the acceptance range. YSI 2300 STAT Plus was used as the laboratory reference method in all experiments. RESULTS: Measurement repeatability or precision was acceptable across the target BG ranges for all devices and strip lots with coefficient of variation (CV) between 3.4-9.7% (mean: 5.7%). Linearity was shown by a correlation coefficient of .991; however, a positive bias was seen for BG <100 mg/dL (86% measurements did not meet ISO15197:2015 acceptance criteria). Significant hematocrit interference (up to 20%) was observed for BG >100 mg/dL (ISO15197:2015 acceptance criteria: ±10%), while the results were acceptable for BG <100 mg/dL. CONCLUSIONS: The BGM met repeatability requirements but demonstrated a significant measurement bias in the low BG range. In addition, it failed the ISO15197:2015 criteria for hematocrit interference.


Subject(s)
Blood Glucose/analysis , Clinical Laboratory Techniques , Diabetes Mellitus/blood , Equipment and Supplies/standards , Internet Access , Artifacts , Blood Glucose Self-Monitoring/instrumentation , Blood Glucose Self-Monitoring/standards , Clinical Laboratory Techniques/methods , Equipment Design , Equipment Failure Analysis , Hematocrit/instrumentation , Hematocrit/methods , Hematocrit/standards , Humans , Linear Models , Reagent Strips/standards , Reproducibility of Results
5.
J Diabetes Sci Technol ; 12(6): 1178-1183, 2018 11.
Article in English | MEDLINE | ID: mdl-29451016

ABSTRACT

BACKGROUND: Frequent blood glucose readings are the most cumbersome aspect of diabetes treatment for many patients. The noninvasive TensorTip Combo Glucometer (CoG) component employs dedicated mathematical algorithms to analyze the collected signal and to predict tissue glucose at the fingertip. This study presents the performance of the CoG (the invasive and the noninvasive components) during a standardized meal experiment. METHODS: Each of the 36 participants (18 females and males each, age: 49 ± 18 years, 14 healthy subjects, 6 type 1 and 16 type 2 patients) received a device for conducting calibration at home. Thereafter, they ingested a standardized meal. Blood glucose was assessed from capillary blood samples by means of the (non)invasive device, YSI Stat 2300 plus, Contour Next at time points -30, 0, 15, 30, 45, 60, 75, 90, 120, 150, and 180 minutes. Statistical analysis was performed by consensus error grid (CEG) and calculation of mean absolute relative difference (MARD) in comparison to YSI. RESULTS: For the noninvasive (NI) CoG technology, 100% of the data pairs were found in CEG zones A (96.6%) and B (3.4%); 100% were seen in zone A for the invasive component and Contour Next. MARD was calculated to be 4.2% for Contour Next, 9.2% for the invasive component, and 14.4% for the NI component. CONCLUSIONS: After appropriate individual calibration of the NI technology, both the NI and the invasive CoG components reliably tracked tissue and blood glucose values, respectively. This may enable patients with diabetes to monitor their glucose levels frequently, reliably, and most of all pain-free.


Subject(s)
Blood Glucose/analysis , Diabetes Mellitus, Type 1/blood , Diabetes Mellitus, Type 2/blood , Eating/physiology , Meals , Adult , Aged , Blood Glucose Self-Monitoring/instrumentation , Blood Glucose Self-Monitoring/methods , Female , Humans , Male , Middle Aged , Monitoring, Physiologic/instrumentation , Monitoring, Physiologic/methods , Postprandial Period , Reference Standards , Young Adult
6.
J Diabetes Sci Technol ; 11(3): 577-583, 2017 05.
Article in English | MEDLINE | ID: mdl-28745092

ABSTRACT

The pentose xylose is enriched in edible algae, and is increasingly used as a slowly metabolized carbohydrate in functional food. It is known to interfere with glucose-dehydrogenase-based (GDH) blood glucose measurement systems for patients self-testing. The aim of our study was to investigate the extent of xylose interference in commercially available blood glucose meters. A heparinized whole blood sample was manipulated to contain 3 different glucose concentrations (50-80 mg/dL, 130-160 mg/dL, and 250-300 mg/dL) and 4 different xylose concentrations (0 mg/dL, 25 mg/dL, 50 mg/dL, and 100 mg/dL). Each sample was measured 3 times with 2 different strip lots per test meter (AccuChek Aviva, AccuChek Connect, Contour Next, FreeStyle Freedom Lite, FreeStyle Insulinx, MyStar Extra, OneTouch Verio IQ, and Wellion Calla, reference: YSI GlucoStat analyzer). For analysis, we calculated the xylose capture rate, that is, the xylose amount wrongly displayed as glucose. No xylose interference was seen with 4 meters: AccuChek Aviva (mean capture rate 0%), AccuChek Connect (-2%), MyStar Extra (10%), and Wellion Calla (8%). In contrast, substantial interference was observed with Contour Next (100%), FreeStyle Freedom Lite (104%), FreeStyle Insulinx (120%), and OneTouch Verio IQ (162%). We observed xylose interference in several GDH-based meters. This may become important with increased use of xylose in dietary and functional food products, in particular in products designed for weight loss. Our findings may affect the meter selection for patients who are consuming such food products as part of their lifestyle treatment regimen.


Subject(s)
Blood Glucose Self-Monitoring , Blood Glucose/analysis , Xylose , Glucose 1-Dehydrogenase , Humans
7.
J Diabetes Sci Technol ; 11(2): 278-283, 2017 03.
Article in English | MEDLINE | ID: mdl-27559030

ABSTRACT

BACKGROUND: Intact proinsulin is a biomarker for pancreatic ß-cell dysfunction. In large prospective studies in nondiabetic subjects, elevated intact proinsulin predicted development of type 2 diabetes and/or macrovascular events up to 7 years in advance. This study was performed to evaluate a new semiquantitative lateral flow-based point-of-care rapid test (POCT) for elevated intact proinsulin (cutoff: 15 pmol/L). The test requires 10 µL of capillary whole blood, with visual readout after 5 minutes. It is best applied at 2 hours after a glucose challenge or a meal. METHODS: POCT results were obtained by health care professionals from 60 patients and healthy subject (33 female, 27 male, 28 type 2 diabetes, age: 53.6 ± 12.3 years). An additional venous blood sample was obtained from all participants for measurement of intact proinsulin by means of a quantitative ELISA reference method (TecoMedical, Sissach, Switzerland). RESULTS: Elevated intact proinsulin levels (>15 pmol/L) were determined by the reference method in 26 participants, of whom 22 were also positive with the POCT (sensitivity: 85%). All 34 subjects with low intact proinsulin levels were tested negative by the POCT (specificity: 100%). CONCLUSIONS: The test successfully detected elevated postprandial intact proinsulin levels in 85% of the tested subjects and no false positive test result occurred. This POCT can therefore serve as a simple screening tool for identification of patients with prevalent ß-cell dysfunction, who are at high risk for development of type 2 diabetes and/or macrovascular events within the next 5-7 years.


Subject(s)
Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/diagnosis , Early Diagnosis , Point-of-Care Testing , Proinsulin/blood , Adult , Aged , Biomarkers/analysis , Female , Humans , Immunoassay , Male , Middle Aged , Sensitivity and Specificity
9.
J Diabetes Sci Technol ; 9(6): 1307-12, 2015 Sep 29.
Article in English | MEDLINE | ID: mdl-26420624

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.


Subject(s)
Diabetes Mellitus, Type 2/diagnosis , Glucose Metabolism Disorders/diagnosis , Glucose Tolerance Test , Insulin-Secreting Cells/metabolism , Proinsulin/blood , Adult , Aged , Biomarkers/blood , Case-Control Studies , Diabetes Mellitus, Type 2/blood , Disease Progression , Female , Follow-Up Studies , Glucose Metabolism Disorders/blood , Glycated Hemoglobin/metabolism , Humans , Male , Middle Aged , Pilot Projects , Predictive Value of Tests , Risk Factors , Time Factors , Up-Regulation
10.
J Diabetes Sci Technol ; 9(2): 262-7, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25549636

ABSTRACT

In previous studies, meters employing dynamic electrochemistry (DE), have been shown to correct for hematocrit (HCT) interference. This laboratory investigation assessed the HCT stability of MyStar Extra (Sanofi) in comparison to 7 competitive devices (Accu-Chek Aviva Nano & Accu-Chek Performa, Roche Diagnostics; Contour XT and Contour Link, Bayer; FreeStyle Freedom Lite, Abbott; MyLife Pura, Ypsomed; OneTouch Verio Pro, LifeScan). Venous heparinized blood was freshly drawn, immediately aliquoted, and manipulated to contain 3 different blood glucose concentrations (50-80 mg/dL, 150-180 mg/dL, and 350-400 mg/dL) and 5 different HCT levels (20-25%, 30-35%, 40-45%, 50-55%, and 60-65%). After careful oxygenation to normal blood oxygen pressure, each of the 15 different samples was measured 8 times with 2 devices and 2 strip lots of each meter (32 measurements/meter/sample). YSI Stat 2300 served as laboratory reference method. Next to determination of the mean absolute relative deviation (MARD), stability to HCT influence was assumed, when less than 10% difference occurred between the highest and lowest mean glucose deviations in relation to HCT over all tested glucose ranges (HIF: hematocrit interference factor). Four of the devices showed stable performance: Contour XT (MARD: 1.3%/HIF: 6.1%), MyStar Extra (4.7%/7.1%), OneTouch Verio Pro (4.5%/7.3%), and Contour Link (6.3%/9.3%). The 4 other meters were influenced by HCT (Accu-Chek Performa: 4.7%/20.9%, Accu-Chek Aviva Nano: 4.5%/22.4%, FreeStyle Freedom Lite: 4.8%/24.5%; MyLife Pura: 6.4%/28.7%). In this study, all meters showed a good accuracy, but only 50% of them, including MyStar Extra, were shown to reliably correct for potential hematocrit influence on the meter results.


Subject(s)
Blood Glucose Self-Monitoring/instrumentation , Blood Glucose/analysis , Electrochemistry/instrumentation , Hematocrit , Humans
11.
J Diabetes Sci Technol ; 5(1): 158-65, 2011 Jan 01.
Article in English | MEDLINE | ID: mdl-21303639

ABSTRACT

BACKGROUND: Daily routine for insulin-treated patients with diabetes mellitus requires correct performance of self-monitoring of blood glucose and insulin injections several times a day. Dexterity skills may play an important role in the performance efficacy of these procedures. METHODS: We collected data of insulin-treated (>10 years) patients with different age ranges [healthy controls, 14 female/11 male, age (mean ± standard deviation) 55 ± 7 years; type 1 diabetes mellitus (T1DM) patients, 12/13, 45 ± 9 years, disease duration 23.9 ± 6.5 years; T2DM patients, 8/17, 64 ± 6 years, 16.2 ± 6.9 years; T2DM patients (>70 years of age), 9/16, 75 ± 4 years, 19.7 ± 7.0 years]. After assessment of neuropathy (temperature, pain, and vibration perception), the patients participated in two dexterity test batteries [Jebsen-Taylor hand-function test (JHFT) and motoric performance series (MPS)]. RESULTS: Patients with type 2 diabetes showed disturbed vibration perception as compared to the other groups. The dexterity results were influenced by age to a large extent. Older T2DM patients performed worst in the majority of the subtests (e.g., JHFT, writing nondominant hand: control, 40.8 ± 11.7 s; T1DM, 46.3 ± 50.9 s, not significant versus control; old T2DM, 68.1 ± 29.5 s, p < .05; young T2DM, 52.5 ± 26.2 s, p < .05). Patients with type 1 diabetes showed similar JHFT and MPS results than the 10-year-older control subjects and performed outside of the age-dependent normal reference range. CONCLUSIONS: Manual skills and dexterity differed between the groups, and age-corrected reduced skills were common in both T1DM and T2DM patients in this study. Our findings underline the importance of considering dexterity and manual skills when designing medical devices for patients with diabetes mellitus.


Subject(s)
Blood Glucose/analysis , Diabetes Mellitus, Type 1/drug therapy , Diabetes Mellitus, Type 2/drug therapy , Insulin Infusion Systems , Insulin/administration & dosage , Motor Skills/physiology , Adult , Aged , Blood Glucose Self-Monitoring/methods , Clinical Competence , Cross-Sectional Studies , Diabetes Mellitus, Type 1/blood , Diabetes Mellitus, Type 2/blood , Efficiency/physiology , Female , Humans , Hypoglycemic Agents/administration & dosage , Injections , Insulin Infusion Systems/statistics & numerical data , Male , Middle Aged , Psychomotor Performance
12.
Clin Ther ; 30(12): 2252-62, 2008 Dec.
Article in English | MEDLINE | ID: mdl-19167585

ABSTRACT

BACKGROUND: Because the use of insulin therapy can place a substantial burden on patients with diabetes, insulin administration should be as simple as possible. OBJECTIVES: The primary aim of this trial was to compare the use of 2 insulin delivery devices-one prefilled (NovoMix 30 FlexPen [FP]; Novo Nordisk, Copenhagen, Denmark) and the other reusable (HumaPen Luxura [HL]; Eli Lilly and Company, Indianapolis, Indiana)-in patients with type 2 diabetes in terms of intuitiveness and training time. A secondary aim was to evaluate the ease of use and overall acceptance of the 2 devices. METHODS: This was a randomized, open-label, comparative, crossover handling study in adult patients with type 2 diabetes who had been treated with oral antidiabetic drugs for >or=2 years and had no previous experience with insulin injection devices. Patients were randomly allocated to the intuitiveness group (no instruction in the use of the devices provided) or the instruction group (instruction provided). The time taken to deliver an injection into a cushion was measured for each device in both groups. Patients answered questionnaires concerning the intuitiveness and ease of use of the 2 devices, their trust and confidence in the devices to deliver the insulin dose, and their overall pen preference. RESULTS: Sixty-one patients were enrolled in the study (70.5% male; mean [SD] age, 61.80 [7.60] years), 30 in the intuitiveness group and 31 in the instruction group. When all handling steps for the HL device were included, the mean (SD) injection time was significantly shorter for the FP device compared with the HL device in the intuitiveness group (1.21 [1.04] vs 1.74 [0.79] minutes, respectively; P = 0.035). The outcome was similar in the instruction group (0.71 [0.29] vs 1.09 [0.49] minutes; P < 0.001). When the time for cartridge insertion in the HL device was excluded, there was no significant difference in injection time for the respective devices in either group (intuitiveness group: 1.21 [1.04] and 1.07 [0.91] minutes; instruction group: 0.63 [0.35] and 0.71 [0.29] minutes). Twenty-two patients preferred the FP device in terms of ease of learning, compared with 8 patients preferring the HL device (P = 0.007). CONCLUSIONS: In this study, when all handling steps were included, the FP device was associated with significantly greater intuitiveness and a shorter injection time compared with the HL device. Further research is needed to determine whether these differences between devices are clinically meaningful.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Drug Delivery Systems/methods , Health Knowledge, Attitudes, Practice , Insulin/administration & dosage , Aged , Cross-Over Studies , Disposable Equipment , Drug Delivery Systems/instrumentation , Drug Packaging , Female , Humans , Hypoglycemic Agents/administration & dosage , Hypoglycemic Agents/therapeutic use , Insulin/therapeutic use , Male , Middle Aged , Patient Acceptance of Health Care/psychology , Patient Acceptance of Health Care/statistics & numerical data , Patient Compliance/psychology , Patient Education as Topic , Surveys and Questionnaires , Time Factors
13.
Clin Lab ; 50(9-10): 567-73, 2004.
Article in English | MEDLINE | ID: mdl-15481632

ABSTRACT

Proinsulin, the precursor of insulin during physiological insulin production, has been demonstrated in the past to stimulate PAI-1 secretion and consecutively block fibrinolysis. Therefore, proinsulin is contributing as an independent factor to the increased cardiovascular risk of patients with type 2 diabetes. However, development of insulin resistance in the course of type 2 diabetes leads to increased insulin demands and finally to an impairment of beta-cell function in later disease stages. Appearance of intact proinsulin in the peripheral blood has been shown to be a good laboratory marker for this phenomenon since it indicates an exhaustion of the cleavage capacity of the intracellular processing enzymes. However, the close relation of the two pathophysiological entities also makes it a very specific marker for insulin resistance per se. During the past years, new immunoassays have been developed that are able to distinguish between intact proinsulin and its specific and unspecific cleavage products. Use of these assays in recent epidemiological and intervention studies has helped to get a better understanding about beta-cell dysfunction and its relation to insulin resistance and cardiovascular risk. In a large cross-sectional study with 4270 orally treated patients, elevation of fasting intact proinsulin was very closely related to insulin resistance, as assessed by iv glucose tolerance test in a subgroup, and by HOMA analysis in the entire patient population. Effective treatment of insulin resistance (e.g. with thiazolidindiones) led to a decrease in elevated proinsulin levels and to a decrease of the cardiovascular risk profile, while the levels remained high during sulfonylurea therapy. These results suggest to reconsider intact and total proinsulin as valuable diagnostic tools in diagnosis and treatment of type 2 diabetes. Based on the published data of the new specific immunoassays, patients with elevated intact proinsulin levels (> 10 pmol/L) should be regarded and treated as being insulin-resistant, while elevation of total proinsulin (>45 pmol/l) may help to identify the high cardiovascular risk patients. Both assays can thus be used to assess beta-cell function, to facilitate the selection of the most promising therapy, and may also serve to monitor treatment success in the further course of the disease.


Subject(s)
Diabetes Mellitus, Type 2 , Insulin Resistance , Proinsulin/physiology , Biomarkers/blood , Diabetes Mellitus, Type 2/diagnosis , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/physiopathology , Humans , Immunoassay , Proinsulin/blood
14.
Diabetes Technol Ther ; 6(3): 405-12, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15198846

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.


Subject(s)
Diabetes Mellitus, Type 2/diagnosis , Diabetes Mellitus, Type 2/therapy , Proinsulin/blood , Diabetes Mellitus, Type 2/blood , Humans , Insulin Resistance , Islets of Langerhans/metabolism , Proinsulin/metabolism
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