Fasting Serum C-peptide Research Articles

Association of xanthine oxidoreductase inhibitor use with insulin secretory capacity in patients with type 2 diabetes.

Xanthine oxidoreductase (XOR) inhibitor treatment, which reduces reactive oxygen species (ROS) production and increases adenosine triphosphate (ATP) synthesis, has been reported to improve glycemic control. The possible protective effects of XOR inhibitor treatment on insulin secretory capacity were investigated in patients with type 2 diabetes. This retrospective cross-sectional study included 428 patients with type 2 diabetes. Insulin secretory capacity was assessed based on fasting serum C-peptide concentration (CPR) and C-peptide index (CPI) in all subjects, while insulin resistance in non-insulin users (n = 312) was determined using the homeostasis model assessment of insulin resistance (HOMA-IR) index. Median values for CPR and CPI in all subjects were 2.4 ng/mL and 1.5, respectively, while that for HOMA-IR in non-insulin users was 3.2. The XOR inhibitor users (n = 72) had significantly (P < 0.001) higher CPR and CPI levels than non-users (n = 356). Multivariable regression analyses showed XOR inhibitor use was positively associated with CPR (β = 0.153, P = 0.001) and CPI (β = 0.144, P = 0.001). Similar results were observed in propensity score analyses. In subgroup analyses of patients with a preserved estimated glomerular filtration rate (≥60 mL/min/1.73 m2) and non-insulin users, these associations remained significant. Furthermore, the associations were significant in patients with lower (≤6.0 mg/dL) but not with higher (>6.0 mg/dL) uric acid levels (P for interaction <0.05). On the other hand, XOR inhibitor use showed no significant association with HOMA-IR. The results of XOR inhibitor treatment, especially a sufficient reduction in serum uric acid level, may provide protective effects on insulin secretory capacity in patients with type 2 diabetes.

Evaluation of Fasting Glucose-Insulin-C-Peptide-Derived Metabolic Indices for Identifying Metabolic Syndrome in Young, Healthy Adults.

Metabolic syndrome (MetS) is a condition defined by a cluster of symptoms, including excessive adipose tissue, impaired glucose homeostasis, dyslipidemia, and high blood pressure (BP). We aimed to evaluate the correlation between the MetS criteria (IDF) and fasting glucose-insulin-C-peptide-derived indices in a cohort of 128 healthy young adults who were 20-35 years old at the time of this study. We measured fasting serum glucose, insulin, C-peptide (CP), HDL-cholesterol, triglycerides, and hsCRP; HOMA-IR INS, HOMA-IR CP1, HOMA-IR CP2, HOMA-BETA, HOMA-BETA CP, QUICKI, disposition index (DI), CP index (CPI), and 20/C-peptide*glucose. Significant correlations were found between BMI and all HOMA indices, QUICKI, and CPI; waist circumferences and HOMA-IR INS, HOMA-BETA, and QUICKI (for both sexes); glucose and HOMA-IR INS/CP1/CP2, HOMA-BETA CP, DI, and QUICKI; HDL-cholesterol and HOMA-IR INS, HOMA-BETA, and QUICKI for males and females only with QUICKI; triglycerides and HOMA-IR INS, HOMA-BETA, and QUICKI; systolic BP and HOMA-IR INS, HOMA-BETA; diastolic BP and DI. The cut-off values for HOMA-IR INS, HOMA-BETA, and QUICKI in the combined group (females + males) were 1.855, 82.250, 0.355; 2.115, 106.370, 0.345 for males; 1.805, 71.305, 0.355 for females. A stronger correlation was found between males' indices and hsCRP. In conclusion, CP-derived indices do not add significant information, and the male sex is more predisposed to MetS.

Associations between time in range and insulin secretory capacity in Japanese patients with type 2 diabetes

Impaired insulin secretory capacity is associated with high glycemic variability in patients with type 2 diabetes (T2DM). However, there are no existing reports on the association between insulin secretory capacity and time in range (TIR). This retrospective study involved 330 T2DM admitted for diabetes education who underwent intermittently scanned continuous glucose monitoring (isCGM) and had their fasting serum C-peptide immunoreactivity (S-CPR) measured within 5 days of admission. The baseline characteristics were as follows: age, 60.2 years; glycated hemoglobin (HbA1c), 9.2%; S-CPR, 2.2 ng/mL; S-CPR index (S-CPR [ng/mL]/fasting plasma glucose [mg/dL] × 100), 1.6; and TIR, 60.3%. TIR correlated significantly with the S-CPR index, which was confirmed by multivariate analysis that included various factors such as HbA1c. Receiver operating characteristic (ROC) analysis showed that 1.88 was the optimal S-CPR index level to predict TIR ≥ 70%. In addition to HbA1c and biguanide use, the S-CPR index was a significant factor associated with TIR > 70%. S-CPR index values of ≥ 1.88 also correlated significantly with TIR > 70%. In conclusion, insulin secretory capacity is associated with TIR in Japanese T2DM, suggesting that the S-CPR index might be a potentially useful biomarker insulin secretory capacity, in association with TIR.Trial registration UMIN0000254333.

Maternal fasting serum C-peptide concentrations in the first and second trimesters and subsequent risk of gestational diabetes mellitus: A nested case-control study among Chinese women

ObjectiveTo examine the association of serum connecting peptide (C-peptide) concentrations with gestational diabetes mellitus (GDM) risk among Chinese women. MethodsA nested case-control study was conducted on 436 reproductive-aged women, involving 218 GDM cases and 218 controls matched at 1:1 by maternal age, in Beijing, China between January 2016 and December 2017. Fasting serum C-peptide were successively determined at 10–14 and 15–20 weeks of gestation. Restricted cubic spline and logistic regression analyses were utilized, and receiver operating characteristic (ROC) curves were generated to evaluate the predictive capacity of C-peptide for GDM. ResultsFasting serum C-peptide concentrations exhibited a significant decrease from the initial to the subsequent trimester in females with normal glucose tolerance (NGT). For each 1 log ng/mL increase of fasting serum C-peptide during the first and second trimesters, GDM risk increased by 2.38-fold [odds ratio (OR): 2.38, 95% confidence intervals (95%CI): 1.33–4.40] and 3.07-fold (OR: 3.07, 95%CI: 1.49–6.62), respectively. The areas under the ROC curves for the first- and second-trimester C-peptide were 80.4% and 82.4%. ConclusionOur findings revealed a positive correlation between fasting serum C-peptide during the first and second trimesters and the risk of GDM or its subtypes, underscoring the potential of C-peptide as a predictor for GDM development.

Production of alginate macrocapsule device for long-term normoglycaemia in the treatment of type 1 diabetes mellitus with pancreatic cell sheet engineering

Type 1 diabetes-mellitus (T1DM) is characterized by damage of beta cells in pancreatic islets. Cell-sheet engineering, one of the newest therapeutic approaches, has also been used to create functional islet systems by creating islet/beta cell-sheets and transferring these systems to areas that require minimally invasive intervention, such as extrahepatic areas. Since islets, beta cells, and pancreas transplants are allogeneic, immune problems such as tissue rejection occur after treatment, and patients become insulin dependent again. In this study, we aimed to design the most suitable cell-sheet treatment method and macrocapsule-device that could provide long-term normoglycemia in rats. Firstly, mesenchymal stem cells (MSCs) and beta cells were co-cultured in a temperature-responsive culture dish to obtain a cell-sheet and then the cell-sheets macroencapsulated using different concentrations of alginate. The mechanical properties and pore sizes of the macrocapsule-device were characterized. The viability and activity of cell-sheets in the macrocapsule were evaluated in vitro and in vivo. Fasting blood glucose levels, body weight, and serum insulin & C-peptide levels were evaluated after transplantation in diabetic-rats. After the transplantation, the blood glucose level at 225 mg dl–1 on the 10th day dropped to 168 mg dl–1 on the 15th day, and remained at the normoglycemic level for 210 days. In this study, an alginate macrocapsule-device was successfully developed to protect cell-sheets from immune attacks after transplantation. The results of our study provide the basis for future animal and human studies in which this method can be used to provide long-term cellular therapy in T1DM patients.

New diagnostic criteria (2023) for slowly progressive type 1 diabetes (SPIDDM): Report from Committee on Type 1 Diabetes of the Japan Diabetes Society (English version).

The diagnostic criteria for slowly progressive type 1 diabetes (slowly progressive insulin-dependent diabetes mellitus; SPIDDM) have been revised by the Committee on Type 1 Diabetes of the Japan Diabetes Society. All of the following three criteria must be met for 'a definitive diagnosis of SPIDDM': (1) presence of anti-islet autoantibodies at some point in time during the disease course; (2) absence of ketosis or ketoacidosis at the diagnosis of diabetes with no requirement for insulin treatment to correct hyperglycemia immediately after diagnosis in principle; and (3) gradual decrease of insulin secretion over time, with insulin treatment required at more than 3 months after diagnosis, and the presence of severe endogenous insulin deficiency (fasting serum C-peptide immunoreactivity <0.6 ng/mL) at the last observed point in time. When a patient fulfills only (1) and (2), but not (3), he/she is diagnosed with 'SPIDDM (probable)' becausethe diabetes is non-insulin-dependent type.

FRI626 Association Between Fasting Serum C-peptide Values And The Presence Of Chronic Kidney Disease In Patients With Type 2 Diabetes Mellitus

Abstract Disclosure: L. Leyva Figueroa: None. F.J. Gomez-Perez: None. F. Gonzalez-Valdivia: None. D. Cuevas-Ramos: None. Background: High C-peptide levels have been associated with microvascular complications, although there is controversial evidence in patients with T2DM. Objective: To correlate fasting serum C-peptide values in patients with T2DM with diabetic nephropathy. Hypothesis: In patients with type 2 diabetes mellitus there is a positive correlation of minimum r=0.3 between fasting C-peptide, albumin/creatinine ratio (ACR) and glomerular filtration rate (eGFR). Research Question: Is there a significant and independent correlation between fasting C-peptide values, ACR, and eGFR in patients with type 2 diabetes mellitus? Methods: Retrospective, cross-sectional, observational, real-world study, in 551 type 2 diabetic patients. Data was collected from the electronic clinical records. Microalbuminuria was defined as an ACR equal or greater than 30, and eGFR was calculated by CKD-EPI 2021. Fasting C-peptide was measured by immunochemiluminescence. Continuous variables were expressed as means +/− standard deviation, while categorical variables will be expressed as percentages. We used one-way ANOVA to compare continuous variables between groups, and Chi-square test to compare categorical variables. Multivariate logistic regression analysis was used to analyze the independent relationship between C-peptide quartiles, eGFR, and ACR, adjusted for weight, insulin, and disease duration. Results: 551 patients were evaluated (63% were women), with mean age of 62 ±11 years old, and a HbA1c of 8.4%. Median (interquartile range) of disease duration was 20 years (12-25), with a C-peptide median level of 1.6 (0.9-2.4 ng/ml), with no significant difference by gender. A statistically significant direct relationship was found between a higher C-peptide quartile and higher ACR (F=9.8, p= 0.03). A significant correlation was also found between C-peptide and ACR (r=0.16, p&amp;lt;0.001), and also with eGFR (r=−0.11, p=0.01). Using a multivariate regression analysis we identified an independent association between C-peptide and ACR (beta=44.7, CI95%, 16-73, p=0.002), and also with eGFR (beta −2.7, CI95% −4.7 to −0.6, p=0.01). Conclusions: A significant and independent association was found between C-peptide levels and kidney function and albuminuria. Future studies may confirm that C-peptide can stand as an early marker for diabetic nephropathy. Presentation: Friday, June 16, 2023

Association of common variants of TCF7L2 and PCSK2 with gestational diabetes mellitus in West Bengal, India

The genetic etiology of gestational diabetes mellitus (GDM) was suggested to overlap with type-2 diabetes(T2D). Transcription factor 7-like 2 (TCF7L2) and Proprotein Convertase Subtilisin/Kexin type 2 (PCSK2) are T2D susceptibility genes of the insulin synthesis/processing pathway. We analyzed associations of TCF7L2 and PCSK2 variants with GDM risk and evaluated their potential impact on impaired insulin processing in an eastern Indian population. The study included 114 GDM (case) and 228 non-GDM pregnant women (control). rs7903146, rs4132670, rs12255372 of TCF7L2, and rs2269023 of PCSK2 were genotyped by PCR-RFLP, and genotype distributions were compared between case and control. Fasting serum proinsulin and C-peptide levels were measured by ELISA and the Proinsulin/C-peptide ratio was considered an indicator of proinsulin conversion. Significantly higher frequency of risk allele (T) of rs12255372 (p = 0.02, OR = 2.0, 95%CI = 1.11–3.64) and rs4132670 (p = 0.002, OR = 2.26, 95%CI = 1.32–3.87) of TCF7L2 was found in GDM cases than non-GDM controls; TT genotype was associated with significantly increased disease risk. In rs7903146 (TCF7L2) and rs2269023 (PCSK2), although the frequency of risk allele (T) was not significantly higher in cases than controls, an association of TT for both variants remained significant with higher GDM risk in the recessive model. Increased serum pro-insulin and proinsulin:c-peptide ratio was found in GDM than non-GDM women and the phenomenon showed significant association with careers of risk alleles for TCF7L2 variants. In conclusion, TCF7L2 and PCSK2 variants are related to GDM risk in the studied population and hence may serve as potential biomarkers for assessing the disease risk. TCF7L2 variants contribute to impaired insulin processing.

Assessment Of Serum Vitamin D Level In Children With Type 1 Diabetes Mellitus: A Cross-Sectional Study.

To estimate vitamin D levelsin children with type 1 diabetes, and to evaluate itsrole in the pathogenesis and progress of the disease. The cross-sectional study was conducted at the Paediatric Department of Kafrelsheikh University Hospital, Egypt, from November 2019 to August 2021, and comprised children of either gender aged 3-18 years who were either inpatients or visiting the paediatric outpatient clinic. The subjects were enrolled into 3 groups. Those with newly diagnosed type 1 diabetes were in group A, those with established type 1 diabetes were in group B, and healthy children matched for age and gender and randomly selected were in the control group C. Glycated haemoglobin, serum fasting C-peptide, and serum vitamin D levels were evaluated using quantitative colorimetric determination, an automated analyser, and enzyme-linked immunosorbent assay, respectively. Data was analysed using SPSS 25. Of the 80 subjects, 30(37.5%) were in group A; 17(56.7%) boys and 13(43.3%) girls with mean age 7.77±2.95 years. In group B, there were 30(37.5%) subjects; 14(46.7%) boys and 16(53.3%) girls with mean age 9.6±3.62 years. There were 20(25%) subjects in group C; 10(50%) boys and as many girls with mean age 8.38±2.68 years (p>0.05). Glycated haemoglobin,serum fasting C-peptide and serum vitamin D wassignificantly different between the control group and the treatment groups (p<0.05). Between the treatment groups, group B had better markers than group A (p<0.05). Serum vitamin D deficiency may play a role in the pathogenesis and insulin sensitivity in cases of type 1 diabetes.

Pretransplant C-peptide Levels and Pancreas Transplant Outcomes: Risk and Reward.

We read with interest the report by Parajuli et al1, chronicling the University of Wisconsin experience in simultaneous pancreas-kidney transplantation (SPKT) according to the pretransplant fasting serum C-peptide levels. The authors demonstrated that higher pretransplant C-peptide levels predicted the risk of a composite outcome (combination of pancreas graft failure according to the United Network for Organ Sharing definition and pancreas graft dysfunction defined as initiation of any antidiabetic agent) posttransplant in patients with a type 2 diabetes phenotype.1,2 Recipients were categorized into 3 groups based on pretransplant fasting serum C-peptide levels: low (≤2 ng/mL, n = 14), medium (>2–8 ng/mL, n = 47), and high (>8 ng/mL, n = 15). The uncensored composite outcome of pancreas graft failure or dysfunction occurred in 0% in the low, 23% in the medium, and 33% of patients in the high C-peptide groups, respectively, suggesting that higher levels of pretransplant C-peptide are associated with inferior posttransplant outcomes. These findings confirm our recent report based on a case-controlled, single-center, retrospective study of 46 SPKT patients with pretransplant fasting serum C-peptide levels ≥2.0 ng/mL compared with 46 control patients (C-peptide level <0.5 ng/mL) matched for recipient age, gender, race, and transplant date.3 In our study, we likewise reported inferior mid-term outcomes in the group with higher pretransplant C-peptide levels. In our overall SPKT experience, we have 205 patients with a minimum of 5-y follow-up. Using the above C-peptide categories as per the Wisconsin study, we identified 166 patients in the low, 32 patients in the medium, and 7 patients in the high C-peptide groups. Five-y actual (uncensored) patient and graft survival rates were as follows: patient (91% low versus 93.8% medium versus 85.7% high) and kidney (80.7% versus 71.9% versus 71.4%), respectively. Using the composite end point of pancreas graft failure or dysfunction, pancreas outcomes were 25.3% low versus 34.4% medium versus 71.4% high C-peptide (P = 0.10). Similar to the Wisconsin study, we are limited by the small sample size in the high pretransplant C-peptide group but the findings indicate a trend toward a greater need for supplemental antidiabetic therapy in patients with higher pretransplant C-peptide levels. Unfortunately, what is missing from these studies is a better characterization of patients with partial pancreas allograft function (dysfunction) who continue to be free from wide glycemic excursions and do not experience hypoglycemia (despite the need for antidiabetic therapy) because of preserved counterregulatory function of the pancreas allograft.4 In our experience, we identified posttransplant weight gain, insulin resistance, and rejection as potential mitigating factors to explain these inferior outcomes. Consequently, we recommend greater emphasis on weight management strategies, behavioral modification, nutritional counseling, structured physical training programs, timely adjustments in (and use of less diabetogenic) immunosuppression, more intense long-term monitoring by the transplant center, and increased use of novel antidiabetic agents such as Glucagon-like peptide 1 receptor agonists and Sodium-glucose cotransporter-2 inhibitors when indicated in this unique population. We congratulate the authors on this excellent study and agree that these findings should not be an impetus to limit access to pancreas transplantation but rather help guide clinical decision-making and optimize posttransplant management.

Analyze of the correlation and corresponding value of serum C-peptide and insulin in adult population

Objective: To investigate the correlation between serum C-peptide and in adult population, and establish the corresponding insulin values of serum C-peptide levels. Methods: Cross-sectional study. The clinical data of the adults who underwent physical examination in the Second Medical Center of PLA General Hospital from January 2017 to December 2021 were retrospectively included. The participants were divided into type 2 diabetes group, prediabetes group and normal plasma glucose group according to the diagnostic criteria for diabetes. The correlation between serum C-peptide and insulin was explored by Pearson correlation analysis, linear regression analysis, and nonlinear regression analysis, and the corresponding insulin values of serum C-peptide were established. Results: A total of 48 008 adults were enrolled, including 31 633 males (65.9%) and 16 375 females (34.1%), aged (50.1±9.9) years (18-89 years). There were 8 160 subjects (17.0%) with type 2 diabetes, 13 263 subjects (27.6%) with prediabetes, and 26 585 subjects (55.4%) with normal plasma glucose. The serum fasting C-peptide (FCP, M(Q1, Q3)] of the three groups were 2.76(2.18, 3.47), 2.54(1.99, 3.21) and 2.18(1.71, 2.79)μg/L, respectively. The fasting insulin [FINS, M(Q1,Q3)] of the three groups were 10.98(7.57, 16.09), 10.06(6.95, 14.47) and 8.43(5.86,12.12)mU/L, respectively. FCP was positively correlated with FINS (r=0.82), and 2 h postprandial C-peptide (2 h CP) was positively correlated with 2 h postprandial insulin (2 h INS) (r=0.84) (both P<0.001). FCP was linearly associated with FINS (R2=0.68), and 2 h CP was linearly associated with 2 h INS (R2=0.71) (both P<0.001). There was a power function correlation between FCP and FINS (R2=0.74), and 2 h CP and 2 h INS (R2=0.78) (both P<0.001). The results of the statistical analysis were similar in various glucose metabolism subgroups. Since the fitting degree of the power function model was higher than that of the linear model, the power function model was the best model. The power function equation was FINS=2.96×FCP1.32, and 2 h INS=1.64×(2 h CP)1.60, respectively. Multivariate linear regression analysis demonstrated that FCP was a related factor of FINS (R2=0.70, P<0.001) and 2 h CP was a related factor of 2 h INS (R2=0.73, P<0.001), after adjusting for related confounders. Conclusions: There was a power function correlation between FCP and FINS, 2 h CP and 2 h INS in adult population. The insulin values corresponding to C-peptide levels were established in the study.

Residual β-cell function in Brazilian Type 1 diabetes after 3 years of diagnosis: prevalence and association with low presence of nephropathy

BackgroundPersistence of β cell-function in Type 1 diabetes (T1D) is associated with glycaemia stability and lower prevalence of microvascular complications. We aimed to assess the prevalence of residual C- peptide secretion in long-term Brazilian childhood onset T1D receiving usual diabetes care and its association to clinical, metabolic variables and microvascular complications.MethodsA cross-sectional observational study with 138 T1D adults with ≥ 3 years from the diagnosis by routine diabetes care. Clinical, metabolic variables and microvascular complications were compared between positive ultra-sensitive fasting serum C-peptide (FCP +) and negative (FCP-) participants.ResultsT1D studied had ≥ 3 yrs. of diagnosis and 60% had FCP > 1.15 pmol/L. FCP + T1D were older at diagnosis (10 vs 8 y.o; p = 0.03) and had less duration of diabetes (11 vs 15 y.o; p = 0.002). There was no association between the FCP + and other clinical and metabolic variable but there was inversely association with microalbuminuria (28.6% vs 13.4%, p = 0.03), regardless of HbA1c. FCP > 47 pmol/L were associated with nephropathy protection but were not related to others microvascular complications.ConclusionResidual insulin secretion is present in 60% of T1D with ≥ 3 years of diagnosis in routine diabetes care. FCP + was positively associated with age of diagnosis and negatively with duration of disease and microalbuminuria, regardless of HbA1c.

Association of serum magnesium with insulin resistance in patients with metabolic syndrome

Background: Metabolic syndrome (MS) consists of a constellation of metabolic abnormalities that confer an increased risk of cardiovascular disease. Low magnesium level is an important pathogenic factor in most of the disorders of MS and also contributes to increased cardiovascular risk. Aims and Objectives: The aim of the study was to find the association of serum magnesium with insulin resistance in patients with MS. Materials and Methods: A cross-sectional comparative study was conducted in a tertiary care center in Kerala after obtaining clearance from the Institutional Ethics Committee. Thirty subjects with MS who satisfied at least 3 features of national cholesterol education program adult treatment panel III criteria in the age group of 45–65 years were selected and 30 normal subjects after proper exclusion and obtaining written informed consent. Serum magnesium levels and fasting C-peptide levels were measured. Insulin resistance was calculated from fasting serum C-peptide and fasting plasma glucose value using homeostasis model assessment. Results: The mean values of magnesium levels were significantly lower, and insulin resistance was higher in patients with MS when compared to normal subjects. The correlation of serum magnesium levels with insulin resistance was negative and significant. Conclusion: The present study shows that hypomagnesemia can result in insulin resistance. Magnesium supplementation can reduce insulin resistance and improve glycemic controls and reduce cardiovascular risk.

Clinical characteristics and efficacy of pioglitazone in a Japanese patient with familial partial lipodystrophy due to peroxisome proliferator-activated receptor γ gene mutation.

Familial partial lipodystrophy (FPLD) 3 is a rare genetic disorder caused by peroxisome proliferator-activated receptor γ gene (PPARG) mutations. Most cases have been reported in Western patients. Here, we describe a first pedigree of FPLD 3 in Japanese. The proband was a 51-year-old woman. She was diagnosed with fatty liver at age 32 years, dyslipidemia at age 37 years, and diabetes mellitus at age 41 years. Her body mass index was 18.5 kg/m2, and body fat percentage was 19.2%. On physical examination, she had less subcutaneous fat in the upper limbs than in other sites. On magnetic resonance imaging, atrophy of subcutaneous adipose tissue was seen in the upper limbs and lower legs. Fasting serum C-peptide immunoreactivity was high (3.4 ng/mL), and the plasma glucose disappearance rate was low (2.07%/min) on an insulin tolerance test, both suggesting apparent insulin resistance. The serum total adiponectin level was low (2.3 μg/mL). Mild fatty liver was seen on abdominal computed tomography. On genetic analysis, a P495L mutation in PPARG was identified. The same mutation was also seen in her father, who had non-obese diabetes mellitus, and FPLD 3 was diagnosed. Modest increases in body fat and serum total adiponectin were seen with pioglitazone treatment. Attention should be paid to avoid overlooking lipodystrophy syndromes even in non-obese diabetic patients if they show features of insulin resistance.

Fasting and meal-stimulated serum C-peptide in long-standing type 1 diabetes mellitus.

This study aims to evaluate the stability of C-peptide over time and to compare fasting C-peptide and C-peptide response after mixed-meal tolerance test (MMTT) at T90 or T120 with C-peptide area under the curve (AUC) in long-standing type 1 diabetes. We included 607 type 1 diabetes individuals with diabetes duration >5 years. C-peptide concentrations (ultrasensitive assay) were collected in the fasting state, and in a subpopulation after MMTT (T0, just prior to, T30-T60-T90-T120, 30-120 min after ingestion of mixed-meal) (n=168). Fasting C-peptide concentrations (in n=535) at Year 0 and Year 1 were compared. The clinical determinants associated with residual C-peptide secretion and the correspondence of C-peptide at MMTT T90 / T120 and total AUC were assessed. A total of 153 participants (25%) had detectable fasting serum C-peptide (i.e ≥ 3.8pmol/L). Fasting C-peptide was significantly lower at Year 1 (p < 0.001, effect size=-0.16). Participants with higher fasting C-peptide had a higher age at diagnosis and shorter disease duration and were less frequently insulin pump users. Overall, 109 of 168 (65%) participants had both non-detectable fasting and post-meal serum C-peptide concentrations. The T90 and T120 C-peptide values at MMTT were concordant with total AUC. In 17 (10%) individuals, C-peptide was only detectable at MMTT and not in the fasting state. Stimulated C-peptide was detectable in an additional 10% of individuals compared with fasting in individuals with >5 years of diabetes duration. T90 and T120 MMTT measurements showed good concordance with the MMTT total AUC. Overall, there was a decrease of C-peptide at 1-year follow-up.

Application of urine C-peptide creatinine ratio in type 2 diabetic patients with different levels of renal function.

This study aims to investigate the effect of single urine C peptide/creatinine (UCPCR) in assessing the islet β Cell function of type 2 diabetes mellitus (T2DM) patients with different renal function. A total of 85 T2DM patients were recruited in this study, all the patients were assigned to one group with estimated glomerular filtration rate (eGFR)≤60 ml·min-1·1.73 m-2 and another group complicated with eGFR>60 ml·min-1·1.73 m-2. Serum creatinine, urine creatinine, serum fasting C-peptide (FCP), fasting blood glucose (FBG), glycosylated hemoglobin (HbA1C) and 24-hour urinary C-peptide (24hUCP) were measured. The modified homeostasis model assessment-islet β cell function [HOMA-islet (CP-DM)], the modified homeostasis model assessment-insulin resistance [HOMA-IR(CP)] and UCPCR were calculated. When compared with group eGFR ≤60 ml·min-1·1.73 m-2, the levels of UCPCR, FCP, the modified HOMA-IR(CP) and HOMA-islet (CP-DM) were promoted and the concentrations of HbA1C, FPG, creatinine were decreased in the patients of eGFR>60 ml·min-1·1.73 m-2 (P<0.05); FCP was uncorrelated with 24hUCP while associated with UCPCR in the patients of eGFR ≤ 60 ml·min-1·1.73 m-2; UCPCR was positively correlated with FCP and HOMA-IR(CP) in the T2DM patients with different levels of renal function; the cut-off (UCPCR ≤ 1.13 nmol/g) had 88.37% sensitivity and 95.24% specificity [95% confidence interval (CI):0.919-0.997] for identifying severe insulin deficiency in T2DM patients[area under the curve (AUC) 0.978]. UCPCR can be used to evaluate islets β Cell function in T2DM patients with different renal function status.

Preserved C-peptide secretion is associated with higher time in range (TIR) on intermittently scanned continuous glucose monitoring in Chinese adults with type 1 diabetes.

To explore the relationship between C-peptide secretion and time in range (TIR) in adult patients with type 1 diabetes. From December 2018 to December 2020, 76 type 1 diabetes participants were enrolled from the Department of Endocrinology and Metabolism of Peking University People's Hospital. All participants wore intermittently scanned continuous glucose monitoring (isCGM), and insulin dosage was adjusted according to standardized clinical procedures. Subjects were divided into low C-peptide group (<10 pmol/L) and preserved C-peptide group (10-200 pmol/L) based on fasting serum C-peptide levels. Differences of TIR, metrics related to glucose variability and hypoglycemic events were compared. A total of 94,846 isCGM values obtained from 39 male and 37 female participants were analyzed. Individuals with preserved C-peptide secretion had shorter diabetes duration (2.0 (0.5, 10.0) vs 10.0 (3.0, 18.3) years, P = 0.002). TIR was higher in the individuals with preserved C-peptide than those with decreased C-peptide (67.1% (54.2, 75.8) vs 45.5% (33.9, 56.1), P < 0.001), and time above range was significantly lower in those with preserved C-peptide (28.0% (15.6, 42.4) vs 49.4% (39.1, 64.2), P < 0.001). Preserved C-peptide was associated with lower glucose variability, as defined by s.d. (3.0 mmol/L (2.6, 3.4) vs 3.8 mmol/L (3.2, 4.3), P < 0.001) and interquartile range (4.3 mmol/L (3.1, 4.8) vs 5.3 mmol/L (4.5, 6.3), P < 0.001). Metrics related to hypoglycemia were not different between the two groups. Preserved C-peptide secretion was associated with higher TIR and lower glucose variability in Chinese type 1 diabetes adults.

Assessment Of Some Amino Acids, Metal And Biomarkers In Diabetic Patients With Type2 DM In Thi-Qar Governorate, South Of Iraq

The study was designed to investigate the levels of l-arginine, l-carnitine, zinc, magnesium and chromium in patients with type2 diabetes. 100 samples of peoples with type 2 diabetes aged )17-65( years were used, divided into (50 males and 50 females), and the data was compared with 100 healthy subjects (50 males and 50 females) as a control group. Also, biochemical parameters of fasting blood glucose, serum insulin, serum c-peptide and cumulative hemoglobin HbA1c% were measured for both patients and control groups. The results indicate that diabetic patients have lowered levels of l-arginine and l-carnitine (88.03± 4.45b, 38.79± 4.18b) sequentially, and zinc, magnesium and chromium (0.54± 0.08b, 1.58± 0.10b, 0.12± 0.02b) sequentially in blood compared with the healthy subjects of control group where the levels of l-arginine, l-carnitine, zinc, magnesium and chromium (107.59± 9.75a, 56.48± 4.08a, 0.90± 0.12a, 1.99± 0.20a, 0.22 ± 0.04a) sequentially, Also there was elevated of levels of fasting blood glucose, serum insulin, serum c-peptide and HbA1c% in diabetic patients (206.85± 33.34a, 27.48± 5.78a, 4.45± 0.81a, 9.09± 1.52a) sequentially compared with the control groups (87.04 ± 9.37b, 16.48 ± 3.64b, 2.66 ± 0.73b, 3.83 ± 0.96b) sequentially.

Fasting Serum C-Peptide Level May not be Low in Young-Onset Diabetes

Background: Diabetes mellitus (DM) is one of the growing health problems among the young population. Secretory defect of insulin is an important cause, and it can be assessed by measuring fasting serum C-peptide level. Aim: The aim of this article is to assess fasting serum C-peptide in young-onset DM individuals. Materials and Methods: This case–control study was conducted in the Department of Endocrinology, Bangabandhu Sheikh Mujib Medical University (BSMMU) from March 2015 to February 2017. For this purpose, 40 individuals with DM (irrespective of DM type; age range: 11–29 years) were enrolled as case and an equal number of young healthy individuals as control. Demographic profiles, clinical profiles, and serum C-peptide were recorded in a standard and pre-tested structured datasheet. C-peptide was measured by the chemiluminescent immunometric assay. Results: Median fasting C-peptide was 2.67 [interquartile range (IQR) 1.06–4.07, range 0.12–20.0] ng/mL in diabetes individuals, whereas it was 2.19 (IQR 1.36–2.94, range 0.44–9.85) ng/mL in the control group; the difference was insignificant (P = 0.331). Waist circumference (WC) was significantly higher in the young diabetes group in comparison to that of control subjects and so were the plasma glucose values and diastolic blood pressure (P &lt; 0.05 for all). Diabetic participants with low C-peptide group had significantly lower body mass index (BMI) and WC and higher fasting plasma glucose (FPG) and HbA1c in comparison to others (P &lt; 0.05 for all); whereas the high C-peptide group had opposite body indices (higher BMI and WC) and glycemic parameters (lower FPG and HbA1c) (P &lt; 0.05 for all). The classic hyperglycemic symptoms were more common in the low C-peptide group (P = 0.029). In participants with diabetes, C-peptide positively correlated with BMI and WC, whereas it showed a negative correlation with age (P &lt; 0.05 for all). In the control group, C-peptide positively correlated with WC only (P = 0.018). Conclusion: The level of fasting serum C-peptide in diabetic subjects was similar to healthy controls, and it was higher in those subjects who had higher BMI, WC, and lower age.

Implications of increased circulating macrophage inhibitory protein-5 in patients with type 2 diabetes mellitus

BackgroundType 2 diabetes mellitus (T2DM) which is regarded as an inflammatory disease is associated with several chemokines, although the association with macrophage inhibitory protein-5 (MIP-5) which has a chemotaxis for many immune cells has not been reported. This study was designed to determine the circulating level of MIP-5 as well as clinical significance in T2DM patients. MethodsMIP-5 was measured in sera of 156 T2DM patients and 20 healthy controls (HCs). The association of serum MIP-5 with various clinical and laboratory characteristics of T2DM was analyzed. ResultsSerum MIP-5 levels were significantly elevated in T2DM patients compared with HCs (P < 0.001). The univariate analyses revealed that increased serum MIP-5 was associated with age, disease duration, fasting serum insulin and C-peptide, serum urea, creatinine, urinary albumin-to-creatinine ratio (uACR), estimated glomerular filtration rate (eGFR), hypertension, coronary artery disease (CAD), peripheral neuropathy (PN), peripheral artery disease (PAD), diabetic ketosis (DK), diabetic kidney disease (DKD) and Repaglinide medication (all P < 0.05). The multivariate linear regression analysis showed that CAD (P = 0.046), eGFR (P < 0.001) and uACR (P = 0.004) remained significantly associated with serum MIP-5, but other variables did not. The multivariate logistic regression analysis showed that increased MIP-5 was independently associated with increased risk of DKD development (OR, 95 %CI, 1.044, 1.003–1.086, P = 0.034), but not with CAD in T2DM patients (OR, 95 %CI, 1.029, 0.990–1.069, P = 0.144). The correlations among MIP-5, eGFR and uACR were compared between patients with and without DKD. Serum MIP-5 correlated negatively with eGFR, but did not with uACR, in T2DM patient both with and without DKD. uACR correlated negatively with eGFR in T2DM patients without DKD, but did not in those with DKD. ConclusionThe present study indicates that circulating MIP-5 is increased in T2DM patients and associated closely with DKD risk and renal decline. Therefore, circulating MIP-5 may be a novel and potential biomarker for T2DM and DKD.