Plasma Copeptin and Risk of Lower-Extremity Amputation in Type 1 and Type 2 Diabetes

The incidence of lower extremity amputation and its associated risk factors in patients with diabetic foot ulcers: A meta-analysis

This study analysed the incidence of lower extremity amputation and its associated risk factors in patients with diabetic foot ulcers. This study systematically searched both Chinese and English databases, including CNKI, Wanfang, VIP, PubMed, EMBASE and Web of Science, to identify cohort studies related to lower extremity amputation and associated risk factors in patients with diabetic foot ulcers up to October 2023. The patients were stratified based on whether they underwent lower extremity amputation, and relevant data, including basic information, patient characteristics, complications, comorbidities and pertinent laboratory test data, were extracted from the included studies. The literature quality assessment in this study utilized the Newcastle-Ottawa Scale to screen for high-quality literature, resulting in the inclusion of 16 cohort studies, all of which were of at least moderate quality. Meta-analysis of outcome indicators was conducted using the Stata 14.0 software. The results indicate that the overall amputation rate of lower extremities in patients with diabetic foot ulcers is 31% (0.25, 0.38). Among the 16 variables evaluated, gender (male), smoking history, body mass index (BMI), hypertension, cardiovascular disease, kidney disease, white blood cell count, haemoglobin and albumin levels were found to be correlated with the occurrence of lower extremity amputation in patients with diabetic foot ulcers. However, no significant correlation was observed between age, diabetes type, duration of diabetes, stroke, glycosylated haemoglobin, creatinine and total cholesterol levels and lower extremity amputation in patients with diabetic foot ulcers. This meta-analysis indicates that the overall amputation rate in patients with diabetic foot ulcers is 31%. Factors such as gender (male), smoking history, high BMI, hypertension, cardiovascular disease, kidney disease, white blood cell count, haemoglobin and albumin levels are identified as significant risk factors for lower extremity amputation in diabetic foot ulcer patients. These findings suggest that attention should be focused on these risk factors in patients with diabetic foot ulcers to reduce the risk of lower extremity amputation. Therefore, preventive and intervention measures targeting these risk factors are of significant importance in clinical practice. (Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier [CRD42024497538]).

Sodium-glucose co-transporter 2 inhibitor use in patients with diabetes mellitus undergoing endovascular therapy for symptomatic peripheral artery disease

BACKGROUND

This study aimed to reveal the prevalence of sodium-glucose co-transporter 2 (SGLT2) inhibitor treatment and its association with restenosis risk in patients with diabetes mellitus undergoing endovascular therapy for symptomatic peripheral artery disease.

METHODS

We used the database of a multicenter prospective study registering patients with symptomatic peripheral artery disease undergoing femoropopliteal drug-coated balloon treatment in Japan. The current analysis included 1058 patients with diabetes mellitus free from end-stage renal disease. The association of clinical characteristics with SGLT2 inhibitor use was investigated using the logistic regression model. The propensity score matching was adopted to compare the primary patency, i.e., freedom from restenosis, after endovascular therapy between patients treated with and without a SGLT2 inhibitor.

RESULTS

The proportion of SGLT2 inhibitor treatment at revascularization was 14.8% (95% confidence interval, 12.8-17.1%). Younger age, increased body mass index, and increased hemoglobin A1c levels were independently associated with SGLT2 inhibitor use (all P < 0.05). The proportion of SGLT2 inhibitor reached 38.2% (95% confidence interval, 25.4-52.3%) in patients with the three associated factors. The propensity score-matching analysis demonstrated that primary patency was not different between patients treated with a SGLT2 inhibitor and those without it (72.0% [95% confidence interval, 64.1-80.9%] versus 67.8% [62.7-73.3%] at 2 years; P = 0.45).

CONCLUSIONS

SGLT2 inhibitors were not rarely used in patients with diabetes mellitus who underwent femoropopliteal endovascular therapy using a drug coated balloon for symptomatic peripheral artery disease in real-world settings. SGLT2 inhibitor treatment was not associated with an increased risk of restenosis.

Risk of amputation under diuretics in patients with or at risk of lower extremity arterial disease: A systematic review and meta-analysis

BACKGROUND

Recently, increased risk of amputation under sodium glucose cotransporter-2 inhibitors has been debated. Similar concerns have been raised with other "traditional" diuretics, more particularly in patients with or at risk of lower extremity arterial disease (LEAD).

AIM

To collect all available data on any potential risk of amputation associated with diuretics in patients with or at risk of LEAD. Additionally, we looked for other limb-related events in these patients.

METHODS

We searched in PubMed, Embase and Scopus databases up to February 2021 for references, using peripheral or lower extremity arterial disease, diuretics and amputation keywords, excluding case reports, experimental animal studies and non-English reports.

RESULTS

Among the 1376 hits identified in the databases, six studies were finally included in this review, including one cross-sectional and five longitudinal studies (total of 47,612 participants). One study was limited to thiazide diuretics, one focused on loop diuretics and the remainder mixed all diuretics. All studies reported a significant association between diuretic use and amputation risk in patients with or at high risk of LEAD. Despite some limitations in several studies, the meta-analysis showed an increased risk of amputation associated with diuretics (odds ratio: 1.75, 95% confidence interval: 1.53-1.99; P<0.001). Beyond amputation, patients with or at risk of LEAD under diuretics appeared to be at increased risk of other lower limb events, mostly in the presence of other comorbidities, including diabetes.

CONCLUSIONS

Although the amount of data in the literature is scarce, this first systematic review and meta-analysis favours an increased risk of amputation in patients with or at risk of LEAD under diuretics. Further prospective studies must be conducted to provide a better understanding of the mechanisms. Meanwhile, the use of diuretics in these patients should be parsimonious, considering alternatives whenever possible.

Copeptin as a Biomarker of Microcirculation Alterations in Systemic Sclerosis

Background

Systemic sclerosis is a connective tissue disease characterized by vasculopathy and progressive fibrosis, leading to multiorgan dysfunction. Given the complex and not fully elucidated pathogenesis, biomarkers of rapid disease progression and therapeutic response are lacking. Copeptin, which reflects vasopressin activity in serum, is used in diagnosing or prognosing different cardiometabolic conditions.

Objective

The aim of study was to investigate the concentration of copeptin in patients with systemic sclerosis and correlate it with specific clinical symptoms.

Patients and Methods

Serum copeptin was measured in patients with systemic sclerosis (34 women and 3 men; mean age 57.6 years) and in healthy individuals (n=30) using commercially available ELISA kits. According to the criteria of LeRoy our systemic sclerosis cohort consisted of 17 patients with limited cutaneous systemic sclerosis (45.9%) and 20 diffuse cutaneous systemic sclerosis patients (54.1%). According to the criteria of LeRoy our systemic sclerosis cohort consisted of 17 patients with limited cutaneous systemic sclerosis (45.9%) and 20 diffuse cutaneous systemic sclerosis patients (54.1%). The median duration of the disease was 10 [4-14] years.

Results

We found significantly higher copeptin concentration in patients with systemic sclerosis (4.21 pmol/L [3.04-5.42]) in comparison to control group (3.40 pmol/L [2.38-3.76], p<0.01). Copeptin significantly correlated with Raynaud's condition score (r=0.801, p<0.05). Patients with "late" capillaroscopic patterns had higher copeptin concentrations (5.37 pmol/L [4.29-8.06]) than patients with "early" (2.43 pmol/L [2.25-3.20], p<0.05) and "active" patterns (3.93 pmol/L [2.92-5.16], p<0.05]). Copeptin was found to be significantly higher in SSc patients with DUs (5.71 pmol/L [IQR 4.85-8.06]) when compared to SSc patients without DUs (3.31 pmol/L, [2.28-4.30], p<0.05). Additionally, copeptin concentration had good diagnostic accuracy in discriminating between patients with and without digital ulcers (AUC=0.863). Alprostadil decreased copeptin concentration from 4.96 [4.02-6.01] to 3.86 pmol/L [3.17-4.63] (p<0.01) after 4-6 cycles of administration.

Conclusion

Our findings suggest that copeptin may be a promising biomarker of microcirculation alterations in systemic sclerosis.

The role of neurohumoral factors in the persistence of aseptic bone inflammation in patients with diabetic neuroosteoarthropathy

BACKGROUND: Diabetic neuroosteoarthropathy (DNOAP, Charcot foot) is a relatively rare complication of diabetes mellitus (DM), which can lead not only to impaired support function of the lower limb in such patients, but also to high amputation. DNOAP is characterized by persistent aseptic inflammation of the bone structures of the foot, which creates significant ­difficulties in planning therapeutic measures. In the medical literature, there are data demonstrating the role of individual ­cytokines and neurohumoral factors in the prolongation of the inflammatory process in diabetes, however, there are currently very few studies that determine reliable markers of aseptic inflammation in DNOAP.

AIM: To study the effect of neurohumoral factors and advanced glycation end products on the activity of aseptic inflammation in the bone structures of the foot in patients with type 2 diabetes mellitus (DM2) and diabetic neuroosteoarthropathy.

MATERIALS AND METHODS. The study included 88 patients with type 2 diabetes (45 men, 43 women). Group 1 consisted of patients with DM2 and inactive DNOAP (n= 43), group 2 (n= 45) consisted of patients with DM2 and distal diabetic neuropathy without osteoarticular pathology. The diagnosis of diabetic neuropathy was based on the analysis of the clinical picture and indicators of peripheral sensitivity. Diagnosis of DNOAP and determination of its stage was based on clinical data, the results of infrared thermometry and radiology tests of the foot bones. General clinical assessment was used, radiology tests (X-ray, MRI), evaluation of CRP, calprotectin, copeptin, glutathione peroxidase 1 (GP1).

RESULTS. According to the results of examination and palpation of the feet, as well as the analysis of the temperature gradient of the skin of the affected and contralateral limb (infrared thermometry), DNOAP was detected and the stage of this complication was determined. The diagnosis of the chronic stage of DNOAP was confirmed by the results of MRI and the clinical picture (no difference in skin temperature on the symmetrical areas of the feet). According to the results of laboratory analysis, a statistically significant difference in copeptin values was revealed — in group 1 — 0.232 µg/ml [0.147; 0.342], in group 2 — 0.115 µg/ml [0.065; 0.203] (p>0.05) and CRP — in group 1 — 7.113 mg/l [2.453; 16.505], in group 2 — 2.187 mg/l [1.131; 5.567] (p>0.05), leukocyte levels in the groups did not differ significantly: group 1 — 7.86 [6.40; 9.00]*10^9, group 2 — 7.00 [6.00; 8.15] (p>0.05). There was a trend towards an increase in the level of calprotectin and glutathione peroxidase-1 in the DNOAP group, however, the differences were not significant. calprotectin — in group 1 — 1.948 [1.229; 2.969], in group 2 — 1.692 [1.16; 2.514] μg/ml and glutathione peroxidase-1 in group 1 — 24.72 [20.1; 31.82], in group 2 — 22.98 [18.94; 31.2] ng/ml.

CONCLUSION. In the study, statistically significant differences were obtained in the levels of copeptin and C-reactive protein: in patients with DNOAP, their values were significantly higher, which indicates the persistence of the aseptic inflammatory process in the bone tissue of patients even in the chronic stage of DNOAP. These data may help in deciding whether to use one or another method of unloading the affected joints, which will affect the clinical prognosis. The study of neurohumoral markers of arthropathy in the blood serum of patients with DM2 is carried out for the first time, and therefore it is difficult to compare with the results of other authors. It can be assumed that copeptin and CRP are significant markers of persistent inflammation of the osteoarticular structures of the foot in DNOAP.

Clinical significance of copeptin as an early predictor of renal graft dysfunction in renal transplant recipients

Background: Copeptin is the carboxyl-terminal part of the vasopressin precursor protein, and its concentration is an independent predictor of the onset of chronic kidney disease and a rapid decline in the glomerular filtration rate. The glomerular filtration rate is regarded as the best indicator of kidney transplant function and is a predictor of graft and patient survival. We investigated the clinical significance of copeptin as an early predictor of renal graft dysfunction in renal transplant recipients.Methods: We measured serum creatinine, cystatin C, and copeptin concentrations in renal transplant recipients on the day of their operation, as well as on postoperative days 3, 7, 30, and 365. Acute rejection was defined as a sudden decrease in renal function accompanied by histological changes.Results: Eight renal transplant recipients were enrolled in the study from July 2018 to December 2019. Four patients experienced histologically confirmed transplant rejection. All four cases involved acute T-cell rejection. No significant correlation was found between the copeptin level and the presence or absence of rejection at any time point. In subgroup analyses, changes in creatinine, the estimated glomerular filtration rate, cystatin, and copeptin did not show statistical significance.Conclusions: We anticipated that copeptin would be useful to identify individuals at high risk of transplant rejection; however, our study failed to show an association. Further research will be needed to overcome the limitations of this study.

Plasma Adrenomedullin, Allelic Variations in the ADM Gene, and Risk for Lower-Limb Amputation in People With Type 2 Diabetes

OBJECTIVE

Patients with diabetes have an increased risk for lower-limb amputation (LLA), but biomarkers to assess risk of LLA are lacking. Adrenomedullin (ADM) is a vasodilator peptide that also plays a role in fluid and electrolyte homeostasis in the kidney, increasing natriuresis and diuresis. ADM was shown to be associated with cardiovascular and renal events in diabetes, but it was not investigated in terms of LLA risk. We investigated the hypothesis that ADM is associated with LLA in people with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We studied 4,375 participants in the DIABHYCAR and SURDIAGENE cohorts (men, 68%; mean 66 years of age; mean duration of diabetes 12 years; and median follow-up 5.3 years). Plasma midregional proadrenomedullin (MR-proADM; a surrogate for ADM) was measured by immunofluorescence. Five single nucleotide polymorphisms (SNPs) in the ADM gene region were genotyped.

RESULTS

LLA requirement during follow-up by increasing tertiles of plasma MR-proADM distribution was 1.0% (tertile 1 [T1]), 2.3% (T2), and 4.4% (T3) (P < 0.0001). In Cox multivariate analysis, the adjusted hazard ratio (95% CI) for LLA was 4.40 (2.30-8.88) (P < 0.0001) for T3 versus T1. Moreover, MR-proADM significantly improved indices for risk stratification of LLA. Four SNPs were associated with plasma MR-proADM concentration at baseline and with LLA during follow-up. Alleles associated with higher MR-proADM were associated with increased LLA risk.

CONCLUSIONS

We observed associations of plasma MR-proADM with LLA and of ADM SNPs with plasma MR-proADM and with LLA in people with type 2 diabetes. This pattern of Mendelian randomization supports the causality of the association of ADM with LLA.

Copeptin in fluid disorders and stress

Copeptin, a glycosylated peptide of 39 amino acids, is the C-terminal segment of arginine vasopressin (AVP) precursor peptide, which is consisted of two other fragments, vasopressin and neurophysin Ⅱ. The main physiological functions of AVP are fluid and osmotic balance, cardiovascular homeostasis and regulation of the endocrine stress response. Numerous studies have demonstrated that the endogenous AVP in plasma is a meaningful biomarker to guide diagnosis and therapy of diseases associated with fluids disorders and stress. However, due to its instability, short half-time life in circulation and lack of readily available AVP assays, clinical measurement of AVP is restricted. In contrast to AVP, copeptin which is released in an equimolar mode with AVP from the pituitary, has emerged as a stable and simple-to-measure surrogate marker of AVP and displays excellent potential in diagnosis, differentiation and prognosis of various diseases. This review will discuss the studies on the clinical value of copeptin in different diseases, especially in AVP-dependent fluids disorders, as well as issues and prospects of the application of this potential biomarker.

Association Between the ACE Insertion/Deletion Polymorphism and Risk of Lower-Limb Amputation in Patients With Long-Standing Type 1 Diabetes

OBJECTIVE

The ACE insertion/deletion (I/D) polymorphism has been widely studied in people with diabetes, albeit not with regard to lower-limb amputation (LLA). We examined associations among this polymorphism, plasma ACE concentration, and LLA in people with type 1 diabetes.

RESEARCH DESIGN AND METHODS

ACE I/D genotype and plasma ACE were assessed in three prospective cohorts of participants with type 1 diabetes. LLA was defined as minor (below-the-ankle amputation consisting of at least one ray metatarsal resection) or major (transtibial or transfemoral) amputation. Linear, logistic, and Cox regression models were computed to evaluate the likelihood of prevalent and incident LLA by ACE genotype (XD [ID or ID] vs. II) and plasma ACE, after adjusting for confounders.

RESULTS

Among 1,301 participants (male 54%, age 41 ± 13 years), 90 (6.9%) had a baseline history of LLA. Baseline LLA was more prevalent in XD (7.4%) than in II genotype (4.5%, odds ratio [OR] 2.17 [95 %CI 1.03-4.60]). Incident LLA occurred in 53 individuals during the 14-year follow-up and was higher in XD versus II carriers (hazard ratio 3.26 [95% CI 1.16-13.67]). This association was driven by excess risk of minor, but not major, LLA. The D allele was associated with increased prevalent LLA at the end of follow-up (OR 2.48 [1.33-4.65]). LLA was associated with higher mean (95% CI) ACE levels in II (449 [360, 539] vs. 354 [286, 423] ng/mL), but not XD (512 [454, 570] vs. 537 [488, 586]), carriers.

CONCLUSIONS

This report is the first of an independent association between ACE D allele and excess LLA risk, mainly minor amputations, in patients with type 1 diabetes.

High serum copeptin may be a marker of an increased carotid intima-media thickness in asymptomatic patients with type 1 diabetes

We aimed to study the association of copeptin with carotid intima-media thickness in 60 patients with type 1 diabetes (T1DM-patients). Our results suggest that copeptin might improve the stratification of cardiovascular risk in T1DM-patients. Further research is needed to determine the value in identifying carotid disease of this biochemical marker.

ACE I/D Polymorphism, Plasma ACE Levels, and Long-term Kidney Outcomes or All-Cause Death in Patients With Type 1 Diabetes

OBJECTIVE

The deletion (D) allele of the ACE insertion/deletion (I/D) polymorphism is a risk factor for diabetic kidney disease. We assessed its contribution to long-term kidney outcomes and all-cause death in patients with long-standing type 1 diabetes.

RESEARCH DESIGN AND METHODS

A total of 1,155 participants from three French and Belgian cohorts were monitored for a median duration of 14 (interquartile range 13) years. The primary outcome was the occurrence of end-stage kidney disease (ESKD) or a 40% drop in the estimated glomerular filtration rate (eGFR). Secondary outcomes were the individual components of the primary outcome, rapid decline in eGFR (steeper than -3 mL/min/1.73 m² per year), incident albuminuria, all-cause death, and a composite ESKD or all-cause death. Hazard ratios (HRs) for XD versus II genotype and for baseline plasma ACE levels were computed by Cox analysis. Genotype performance in stratifying the primary outcome was tested.

RESULTS

Genotype distribution was 954 XD and 201 II. The primary outcome occurred in 20% of XD and 13% of II carriers: adjusted HR 2.07 (95% CI 1.32-3.40; P = 0.001). Significant associations were also observed for rapid decline in eGFR, incident albuminuria, ESKD, all-cause death, and ESKD or all-cause death. Baseline plasma ACE levels were higher in XD carriers and significantly associated with an increased risk of the primary outcome. The ACE genotype enhanced net reclassification improvement (0.154, 95% CI 0.007-0.279; P = 0.04) and integrated discrimination improvement (0.012, 95%CI 0.001-0.021; P = 0.02) for primary outcome stratification.

CONCLUSIONS

The D-allele of the ACE I/D polymorphism was associated with an increased risk of major kidney events and all-cause death in patients with long-standing type 1 diabetes.

SGLT2 inhibitors and lower limb complications: the diuretic-induced hypovolemia hypothesis

In a recent meta-analysis of randomized controlled trials of sodium glucose co-transporter 2 inhibitors (SGLT2i) in patients with diabetes, Lin and colleagues showed a positive association between SGLT2i-induced blood pressure and weight reduction and the risk of lower limb events. These results support the potential mechanism of a volume depletion effect of SGLT2i to explain the increase risk of amputation observed with this pharmacological class. Since the first result of the CANVAS trial raised a concern regarding the risk of amputation with SGLT2i, this hypothesis emerged from studies showing a higher incidence of amputations in patients with diabetes using diuretics. Furthermore, recent data found that copeptin, a surrogate marker of hydration status was also associated with lower limb outcomes. In conclusion, this assumption of diuretic-induced hypovolemia explanation highlights the fact that medications that induce a contraction of plasma volume, both traditional and novel agents with a diuretic mode of action should be introduced cautiously in patients with diabetes at high risk of diabetic foot events.

Serum copeptin and NT-proBNP is associated with central aortic stiffness and flow hemodynamics in adolescents with type 1 diabetes: A pilot study

AIMS

Cardiovascular disease (CVD) is the major cause of mortality in type 1 diabetes (T1D). Biomarkers, N-terminal pro-brain natriuretic peptide (NT-proBNP) and copeptin have been linked with measures of CVD, but their relationship in adolescents with T1D remains incompletely understood. Accordingly, we examined the associations between NT-proBNP and copeptin and hemodynamic markers of central aortic stiffness in adolescents with T1D.

METHODS

In this pilot study, forty-nine pubertal adolescents with T1D (mean age 17 ± 2 years, median [Q1-Q3] Tanner Stage 5 [5, 5] and HbA1c 8.5 ± 1.5%), from the EMERALD study, were assessed for copeptin and NT-proBNP, and indices of central aortic stiffness non-invasively assessed by MRI. Pearson correlations and generalized linear regression models, adjusting for confounders, were applied to examine the relationships between biomarkers and vascular measures.

RESULTS

Copeptin correlated independently with both ascending aortic (AA) (β ± SE: -4.28 ± 1.87, p = 0.03) and descending aortic (DA) relative area change (RAC) (-3.41 ± 1.55, p = 0.04). NT-proBNP was independently associated with DA time-averaged wall shear stress (WSSTA) (0.87 ± 0.25, p = 0.001) and DA maximum wall shear stress (WSSmax) (2.45 ± 1.00, p = 0.02).

CONCLUSIONS

Serum copeptin and NT-proBNP may be associated with central aortic stiffness and elevated WSS in youth with T1D, potentially offering a non-invasive way to identify and monitor the development of early CVD in an at-risk population.

Vasopressin associated with renal vascular resistance in adults with longstanding type 1 diabetes with and without diabetic kidney disease

OBJECTIVE

Arginine vasopressin (AVP) and its surrogate, copeptin, have been implicated in diabetic kidney disease (DKD) pathogenesis, which develops in a subset of people with longstanding type 1 diabetes, but not in others (DKD Resistors). We hypothesized that patients with DKD would exhibit higher copeptin concentrations vs. DKD Resistors.

METHODS

Participants with type 1 diabetes (n = 62, duration ≥50 years) were stratified into 42 DKD Resistors and 20 with DKD (eGFR ≤60 mL/min/1.73m² or ≥30 mg/day urine albumin), and age/sex-matched controls (HC, n = 74) were included. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were calculated by inulin and p-aminohippurate clearance before and after angiotensin II (ang II) infusion. Renal vascular resistance (RVR) was calculated as mean arterial pressure/renal blood flow. Plasma copeptin, renin, aldosterone, neutrophil gelatinase-associated lipocalin (NGAL), and urea concentrations were measured, along with 24-h urine volume.

RESULTS

DKD resistors had lower copeptin (95% CI: 4.0 [3.4-4.8] pmol/l) compared to DKD (5.8 [4.5-7.6] pmol/l, p = 0.02) and HC (4.8 [4.1-5.5] pmol/l, p = 0.01) adjusting for age, sex and HbA1c. In type 1 diabetes, higher copeptin correlated with lower GFR (r: -0.32, p = 0.01) and higher renin concentration (r: 0.40, p = 0.002) after multivariable adjustments. These relationships were not evident in HC. Copeptin inversely associated with RVR change following exogenous ang II only in participants with type 1 diabetes (β ± SE: -6.9 ± 3.4, p = 0.04).

CONCLUSIONS

In longstanding type 1 diabetes, copeptin was associated with intrarenal renin-angiotensin-aldosterone system (RAAS) activation and renal hemodynamic function, suggesting interplay between AVP and RAAS in DKD pathogenesis.

Serum IRAP, a Novel Direct Biomarker of Prediabetes and Type 2 Diabetes?

Insulin resistance (IR), currently called prediabetes (PD), affects more than half of the adult population worldwide. Type 2 diabetes (T2D), which often follows in the absence of treatment, affects more than 475 million people and represents 10–20% of the health budget in industrialized countries. A preventive public health policy is urgently needed in order to stop this constantly progressing epidemic. Indeed, early management of prediabetes does not only strongly reduce its evolution toward T2D but also strongly reduces the appearance of cardiovascular comorbidity as well as that of associated cancers. There is however currently no simple and reliable test available for the diagnosis or screening of prediabetes and it is generally estimated that 20–60% of diabetics are not diagnosed. We therefore developed an ELISA for the quantitative determination of serum Insulin-Regulated AminoPeptidase (IRAP). IRAP is associated with and translocated in a stoechiometric fashion to the plasma membrane together with GLUT4 in response to insulin in skeletal muscle and adipose tissue which are the two major glucose storage sites. Its extracellular domain (IRAPs) is subsequently cleaved and secreted in the blood stream. In T2D, IRAP translocation in response to insulin is strongly decreased. Our patented sandwich ELISA is highly sensitive (≥10.000-fold “normal” fasting concentrations) and specific, robust and very cost-effective. Dispersion of fasting plasma concentration values in a healthy population is very low (101.4 ± 15.9 μg/ml) as compared to those of insulin (21–181 pmol/l) and C-peptide (0.4–1.7 nmol/l). Results of pilot studies indicate a clear correlation between IRAPs levels and insulin sensitivity. We therefore think that plasma IRAPs may be a direct marker of insulin sensitivity and that the quantitative determination of its plasma levels should allow large-scale screening of populations at risk for PD and T2D, thereby allow the enforcement of a preventive health policy aiming at efficiently reducing this epidemic.

Fasting serum copeptin and asymptomatic peripheral artery disease: No association in patients with type 1 diabetes mellitus

OBJECTIVE

As copeptin is associated with lower-extremity amputation in patients with type 1 diabetes mellitus (T1DM), our study aimed to address the putative association between copeptin and asymptomatic peripheral artery disease (aPAD) in those patients.

DESIGN AND METHODS

This observational cross-sectional study included 112 patients with T1DM from a larger cohort (ClinicalTrials.gov: NCT02910271), selected (1:2) as per the presence of aPAD (n = 37) or not (n = 75). aPAD was evaluated by ankle-brachial index (ABI), toe-brachial index (TBI), and peripheral Doppler ultrasound. The two groups of patients were matched by age, gender distribution and duration of T1DM. Fasting serum copeptin was measured by high-sensitivity ELISA, and its relationships with clinical and biochemical variables as well as aPAD were evaluated too.

RESULTS

The study population was aged 42 ± 8 years, duration of T1DM was 27 ± 7 years, and mean HbA_1c was 7.7 ± 1.1%. No significant differences in copeptin concentrations were found between patients with or without aPAD (16.9 ± 10.8 vs 17.3 ± 14.7 pmol/L, respectively; P = 0.462). Considering all patients as a whole, copeptin correlated with systolic blood pressure (SBP; ρ = -0.209, P = 0.027), eGFR ρ = -0.271, P = 0.004), and serum sodium (ρ = -0.208, P = 0.027), but not with ABI (ρ = -0.068, P = 0.476). Stepwise multiple linear regression analysis (R²: 0.059; P = 0.035) retained SBP (β: -0.219, 95% CI: -1.391; -0.089) as the only significant predictor of copeptin concentration.

CONCLUSION

As serum copeptin does not appear to be associated with aPAD in patients with T1DM, further studies are now needed to elucidate whether it has any other potential role to play in the subclinical vascular disease of this patient population.