Alpha-Lipoic Acid and Glucose Metabolism: A Comprehensive Update on Biochemical and Therapeutic Features

Alpha-lipoic acid (ALA) is a natural compound with antioxidant and pro-oxidant properties which has effects on the regulation of insulin sensitivity and insulin secretion. ALA is widely prescribed in patients with diabetic polyneuropathy due to its positive effects on nerve conduction and alleviation of symptoms. It is, moreover, also prescribed in other insulin resistance conditions such as metabolic syndrome (SM), polycystic ovary syndrome (PCOS) and obesity. However, several cases of Insulin Autoimmune Syndrome (IAS) have been reported in subjects taking ALA. The aim of the present review is to describe the main chemical and biological functions of ALA in glucose metabolism, focusing on its antioxidant activity, its role in modulating insulin sensitivity and secretion and in symptomatic peripheral diabetic polyneuropathy. We also provide a potential explanation for increased risk for the development of IAS.

Pancreaticoduodenectomy model demonstrates a fundamental role of dysfunctional β cells in predicting diabetes

BACKGROUNDThe appearance of hyperglycemia is due to insulin resistance, functional deficits in the secretion of insulin, and a reduction of β cell mass. There is a long-standing debate as to the relative contribution of these factors to clinically manifesting β cell dysfunction. The aim of this study was to verify the acute effect of one of these factors, the reduction of β cell mass, on the subsequent development of hyperglycemia.METHODSTo pursue this aim, nondiabetic patients, scheduled for identical pancreaticoduodenectomy surgery, underwent oral glucose tolerance tests (OGTT) and hyperglycemic clamp (HC) procedures, followed by arginine stimulation before and after surgery. Based on postsurgery OGTT, subjects were divided into 3 groups depending on glucose tolerance: normal glucose tolerance (post-NGT), impaired glucose tolerance (post-IGT), or having diabetes mellitus (post-DM).RESULTSAt baseline, the 3 groups showed similar fasting glucose and insulin levels; however, examining the various parameters, we found that reduced first-phase insulin secretion, reduced glucose sensitivity, and rate sensitivity were predictors of eventual postsurgery development of IGT and diabetes.CONCLUSIONDespite comparable functional mass and fasting glucose and insulin levels at baseline and the very same 50% mass reduction, only reduced first-phase insulin secretion and glucose sensitivity predicted the appearance of hyperglycemia. These functional alterations could be pivotal to the pathogenesis of type 2 diabetes (T2DM).TRIAL REGISTRATIONClinicalTrials.gov NCT02175459.FUNDINGUniversità Cattolica del Sacro Cuore; Italian Ministry of Education, University and Research; European Foundation for the Study of Diabetes.

First-phase insulin secretion: can its evaluation direct therapeutic approaches?

Our work is aimed at unraveling the role of the first-phase insulin secretion in the natural history of type 2 diabetes mellitus (T2DM) and its interrelationship with insulin resistance and with β cell function and mass. Starting from pathophysiology, we investigate the impact of impaired secretion on glucose homeostasis and explore postmeal hyperglycemia as the main clinical feature, underlining its relevance in the management of the disease. We also review dietary and pharmacological approaches aimed at improving early secretory defects and restoring residual β cell function. Furthermore, we discuss possible approaches to detect early secretory defects in clinical practice. By providing a journey through human and animal data, we attempt a unification of the recent evidence in an effort to offer a new outlook on β cell secretion.

Blood pressure response to stress tests does not reflect blood pressure variability and degree of cardiovascular involvement in young hypertensives

The aim of the study was to assess the clinical value of blood pressure response to stress tests and to study its relationship with ambulatory blood pressure monitoring, daily blood pressure variability and hypertensive complications. Cold pressor test for 2 min, hand grip test at 25% of maximal voluntary contraction for 5 min and orthostatism were performed in 223 young men found hypertensive (BP systolic > 140 mmHg and/or diastolic > 90 mmHg) at the military service recruitment check-up. On the basis of ECG and fundoscopic examination, each patient was attributed a score of target organ damage. All patients underwent non-invasive 24-h blood pressure monitoring and 169 patients underwent echocardiographic examination. Hypertension was confirmed in 54.2% of the subjects at ambulatory monitoring. No correlation was found between blood pressure response to stress tests and ambulatory blood pressure, daily blood pressure variability, target organ damage and left ventricular mass. Night-time ambulatory blood pressure were correlated with posterior wall thickness/ventricular diastolic internal diameter ratio (r = 0.26, P < 0.001). A negative correlation was found between the office-daytime blood pressure difference and systolic and diastolic response to orthostatic test (r = -0.309, P < 0.0001 for systolic blood pressure and r = -0.433, P < 0.0001 for diastolic blood pressure) and between supine office blood pressure and blood pressure response to orthostatism (r = -0.186. P = 0.013 for systolic blood pressure and r = -0.442, P < 0.0001 for diastolic blood pressure).(ABSTRACT TRUNCATED AT 250 WORDS)

Circulating 1,5-Anhydroglucitol as a Biomarker of ß-cell Mass Independent of a Diabetes Phenotype in Human Subjects

CONTEXT

During an asymptomatic prediabetic state, the functional ß-cell mass decreases to a critical threshold, triggering diabetes and related symptoms. To date, there are no reliable readouts able to capture in vivo a potential drop of the ß-cell mass.

OBJECTIVE

Beside its use as a short-term marker of glycemic control, the deoxyhexose 1,5-anhydroglucitol was identified in rodents as a circulating biomarker of the functional ß-cell mass already in the asymptomatic prediabetic stage. The present study investigated the putative corresponding relevance of circulating 1,5-anhydroglucitol in different human cohorts.

METHODS

We analyzed clinical and blood parameters in patients with established type 2 diabetes and subjects considered at high risk of developing diabetes, as well as patients with no history of diabetes scheduled for pancreaticoduodenectomy.

RESULTS

Circulating 1,5-anhydroglucitol was reduced in type 2 diabetic patients, negatively correlating with fasting plasma glucose (P < 0.0001) and hemoglobin A1c (P < 0.0001). In healthy subjects, 1,5-AG levels positively correlated with body mass index (P = 0.004) and Homeostatic Model Assessment of Insulin Resistance %S (P < 0.03) and was particularly high in nondiabetic obese individuals, potentially accounting for compensatory ß-cell expansion. Patients with no history of diabetes undergoing pancreaticoduodenectomy exhibited a 50% reduction of circulating 1,5-anhydroglucitol levels following surgery leading to an acute loss of their ß-cell mass (P = 0.002), regardless their glucose tolerance status.

CONCLUSION

In summary, plasma concentration of 1,5-anhydroglucitol follows the ß-cell mass and its noninvasive monitoring may alert about the loss of ß cells in subjects at risk for diabetes, an event that cannot be captured by other clinical parameters of glycemic control.

Physical Activity and Type 2 Diabetes: In Search of a Personalized Approach to Improving β-Cell Function

Type 2 diabetes mellitus (T2DM) is one of the most widespread diseases worldwide. Lifestyle interventions, including diet and physical activity (PA), are fundamental non-pharmacological components of T2DM therapy. Exercise interventions are strongly recommended for people with or at risk of developing or already with overt diabetes, but adherence to PA guidelines in this population is still challenging. Furthermore, the heterogeneity of T2DM patients, driven by differing residual β-cell functionality, as well as the possibility of practicing different types and intensities of PA, has led to the need to develop tailored exercise and training plans. Investigations on blood glucose variation in response to exercise could help to clarify why individuals do not respond in the same way to PA, and to guide the prescription of personalized treatments. The aim of this review is to offer an updated overview of the current evidence on the effects of different regimens and modalities of PA regarding glucose sensing and β-cell secretory dynamics in individuals with prediabetes or T2DM, with a special focus on β-cell function.

Dapagliflozin-Induced Myocardial Flow Reserve Improvement is not Associated with HDL Ability to Stimulate Endothelial Nitric Oxide Production

BACKGROUND

Sodium-glucose cotransporter-2 (SGLT2) inhibitors have shown controversial results in modulating plasma lipids in clinical trials. Most studies found slight increases in high-density lipoprotein (HDL) cholesterol but few have provided evidence on HDL functionality with disappointing results. However, there is broad agreement that these drugs provide cardiovascular protection through several mechanisms. Our group demonstrated that dapagliflozin improves myocardial flow reserve (MFR) in patients with type 2 diabetes (T2D) with coronary artery disease (CAD). The underlying mechanisms are still unknown, although in vitro studies have suggested the involvement of nitric oxide (NO).

AIM

To investigate changes in HDL-mediated modulation of NO production with dapagliflozin and whether there is an association with MFR.

METHODS

Sixteen patients with CAD-T2D were enrolled and randomized 1:1 to dapagliflozin or placebo for 4 weeks. Blood samples were collected before and after treatment for each group. The ability of HDL to stimulate NO production in endothelial cells was tested in vitro by incubating human umbilical vein endothelial cells (HUVEC) with apoB-depleted (apoB-D) serum of these patients. The production of NO was assessed by fluorescent assay, and results were expressed as fold versus untreated cells.

RESULTS

Change in HDL-mediated NO production remained similar in dapagliflozin and placebo group, even after adjustment for confounders. There were no significant correlations between HDL-mediated NO production and MFR either at baseline or after treatment. No changes were found in HDL cholesterol in either group, while low-density lipoprotein cholesterol (LDL cholesterol) significantly decreased compared to baseline only in treatment group (p = 0.043).

CONCLUSIONS

In patients with T2D-CAD, beneficial effects of dapagliflozin on coronary microcirculation seem to be unrelated to HDL functions. However, HDL capacity to stimulate NO production is not impaired at baseline; thus, the effect of drug treatments would be negligible. To conclude, we can assume that HDL-independent molecular pathways are involved in the improvement of MFR in this population.

TRIAL REGISTRATION

EudraCT No. 2016-003614-27; ClinicalTrials.gov Identifier: NCT03313752.

Altered GIP/GLP-1 Secretion Ratio is Associated With Impaired β Cell Function in Humans

INTRODUCTION

The entero-insular axis, mediated by the incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), is fundamental to maintaining glucose homeostasis. Dysregulation of these hormones' biology contributes to the pathogenesis of type 2 diabetes (T2D), but the existence of a dysfunctional secretory pattern of incretins toward deterioration of glucose tolerance is still debated. In this study, we evaluate possible impairments in the overall incretin secretion from normal glucose tolerance to overt diabetes, as well as their association with impaired insulin secretion.

METHODS

Sixty subjects with an unknown history of T2D who were not on antidiabetic treatments were divided into 3 groups according to oral glucose tolerance test-derived glucose tolerance: normal glucose tolerance (NGT) (n = 23), impaired glucose tolerance (IGT) (n = 16), and diabetes mellitus (DM) (n = 21). All subjects underwent deep metabolic evaluation with a mixed meal test (MMT) and euglycemic hyperinsulinemic clamp. During the MMT, we calculated the GIP/GLP-1 secretion ratio (SR) and the GIP/GLP-1 SR areas under the curve. Parameters of β cell function were obtained by mathematical modeling.

RESULTS

Linear mixed model analysis revealed similar GIP and GLP-1 responses to MMT among the 3 groups, while GIP/GLP-1 SR was reduced in DM subjects compared to NGT and IGT. Further, multiple regression analysis showed a predictive role of GIP/GLP-1 SR on rate sensitivity and standardized insulin secretion at 5 mmol/L.

CONCLUSION

Our findings demonstrate that, despite similar GIP and GLP-1 secretion, the GIP/GLP-1 SR declines as glucose tolerance deteriorates, reflecting an imbalance in incretin dynamics rather than absolute hormone secretion. This imbalance may indicate early β cell dysfunction and chronic incretin resistance.

In humans increase in intrapancreatic adipose tissue predicts beta-cell dedifferentiation score before diabetes onset: A pilot study

BACKGROUND

The role of intrapancreatic fat (WAT) in the development of T2D remains debated. In T2D, β-cell dedifferentiation is one of the mechanisms responsible for β-cell failure but its role in prediabetes is unknown. We aimed to investigate the relation between WAT and β-cell dedifferentiation prior to diabetes onset.

METHODS

We evaluated pancreatic samples from patients without history of diabetes, who had previously undergone an oral glucose tolerance test and hyperglycemic clamp. Subjects were divided into 3 glucose tolerance groups: normal (NGT), altered (IGT) or newly diagnosed diabetes (nDM). Dedifferentiation and WAT% were morphologically assessed.

RESULTS

WAT was higher in nDM patients compared to NGT and IGT (WAT nDM 43.79 ± 20.83 %, IGT 10.67 ± 8.5 %, NGT 4.43 ± 4.37 %). We observed a progressive increase in dedifferentiation score, in parallel with worsening glucose tolerance (from NGT to IGT to nDM; 4.8 ± 3.8; 32.37 ± 7.4; 40.38 ± 19 respectively). A strong linear regression established that WAT could statistically significantly predict dedifferentiated β-cells (R = 0.86, p = 0.005), and that the predicted increase in dedifferentiated β-cells was 1.25 points for every extra one-point change in WAT. Interestingly, the WAT and dedifferentiation score variable pair were significantly related to 1-hour post-load glycemia.

CONCLUSIONS

The accumulation of WAT might be responsible for dedifferentiation, making it a potential new target to curb diabetes onset.

Lynch Syndrome and Thyroid Nodules: A Single Center Experience

BACKGROUND

Lynch syndrome (LS) is a genetic disease with increased risk of colorectal cancer and other malignancies. There are few reported cases of thyroid cancer in LS patients. The aim of this study is to investigate the presence of thyroid nodules in LS patients and to explore their association with the genetic features of the disease.

METHODS

A retrospective and descriptive analysis was conducted to include all LS patients followed at the CEMAD (Centro Malattie Apparato Digerente) of Fondazione Policlinico Universitario A. Gemelli IRCCS. The characteristics of LS disease, gene mutations, and previous history of thyroid disease were evaluated. Majority of patients underwent thyroid ultrasound (US), and nodule cytology was performed when needed.

RESULTS

Of a total of 139 patients with LS, 110 patients were included in the study. A total of 103 patients (74%) underwent thyroid ultrasound examinations, and 7 patients (5%) had a previous history of thyroid disease (cancer or multinodular goiter). The mean age was 51.9 years. Thyroid nodules were found in 62 patients (60%) who underwent US, and 9 of them (14%) had suspicious features of malignancy, inducing a fine-needle aspiration biopsy. A cytologic analysis classified 7 of 9 cases (78%) as TIR2 and 2 (22%) as TIR3a. Between patients with nodular thyroid disease (single nodule, multinodular goiter, and cancer), most of them (25 patients, 36% of total) were carriers of the MSH6 mutation, while 22 (32%), 17 (24%), and 5 (7%) had MSH2, MLH1, and PMS2 mutations, respectively.

CONCLUSIONS

A high prevalence of thyroid nodules was found in patients with LS, especially in MSH6-carrying patients. Performing at least one thyroid ultrasound examination is suggested for the detection of nodular thyroid disease in LS patients. Systematic investigations are needed to estimate their prevalence, features, and risk of malignant transformation.

Lysophosphatidylinositols Are Upregulated After Human β-Cell Loss and Potentiate Insulin Release

In this study, we identified new lipid species associated with the loss of pancreatic β-cells triggering diabetes. We performed lipidomics measurements on serum from prediabetic mice lacking β-cell prohibitin-2 (a model of monogenic diabetes) patients without previous history of diabetes but scheduled for pancreaticoduodenectomy resulting in the acute reduction of their β-cell mass (∼50%), and patients with type 2 diabetes (T2D). We found lysophosphatidylinositols (lysoPIs) were the main circulating lipid species altered in prediabetic mice. The changes were confirmed in the patients with acute reduction of their β-cell mass and in those with T2D. Increased lysoPIs significantly correlated with HbA1c (reflecting glycemic control), fasting glycemia, and disposition index, and did not correlate with insulin resistance or obesity in human patients with T2D. INS-1E β-cells as well as pancreatic islets isolated from nondiabetic mice and human donors exposed to exogenous lysoPIs showed potentiated glucose-stimulated and basal insulin secretion. Finally, addition of exogenous lysoPIs partially rescued impaired glucose-stimulated insulin secretion in islets from mice and humans in the diabetic state. Overall, lysoPIs appear to be lipid species upregulated in the prediabetic stage associated with the loss of β-cells and that support the secretory function of the remaining β-cells.

ARTICLE HIGHLIGHTS

Circulating lysophosphatidylinositols (lysoPIs) are increased in situations associated with β-cell loss in mice and humans such as (pre-)diabetes, and hemipancreatectomy. Pancreatic islets isolated from nondiabetic mice and human donors, as well as INS-1E β-cells, exposed to exogenous lysoPIs exhibited potentiated glucose-stimulated and basal insulin secretion. Addition of exogenous lysoPIs partially rescued impaired glucose-stimulated insulin secretion in islets from mice and humans in the diabetic state. LysoPIs appear as lipid species being upregulated already in the prediabetic stage associated with the loss of β-cells and supporting the function of the remaining β-cells.

Exploring nutraceutical approaches linking metabolic syndrome and cognitive impairment

Metabolic syndrome (MetS) and mild cognitive impairment (MCI) are interconnected conditions sharing common pathological pathways, such as inflammation and oxidative stress, leading to the concept of "metabolic-cognitive syndrome." This highlights their mutual influence and potential overlapping therapeutic strategies. Although lifestyle modifications remain essential, nutraceutical supplementation has emerged as a promising adjunct for the prevention and management of these preclinical conditions. This review examines clinical and translational evidence on commonly used nutraceuticals targeting shared pathophysiological mechanisms of MetS and MCI. By addressing inflammation, oxidative stress, and metabolic dysfunction, these supplements may offer a valuable approach to mitigating the progression and consequences of both conditions. Understanding their efficacy could provide practical tools to complement lifestyle changes, offering a more comprehensive strategy for managing metabolic-cognitive syndrome.

The interplay of extracellular vesicles in the pathogenesis of metabolic impairment and type 2 diabetes

The pathogenesis of type 2 diabetes (T2D) involves dysfunction in multiple organs, including the liver, muscle, adipose tissue, and pancreas, leading to insulin resistance and β cell failure. Recent studies highlight the significant role of extracellular vesicles (EVs) in mediating inter-organ communication in T2D. This review investigates the role of EVs, focusing on their presence and biological significance in human plasma and tissues affected by T2D. We explore specific EV cargo, such as miRNAs and proteins, which affect insulin signaling and glucose metabolism, emphasizing their potential as biomarkers. By highlighting the diagnostic and therapeutic potential of EVs, we aim to provide new insights into their role in early detection, disease monitoring, and innovative treatment strategies for T2D.

Erythrocyte Membrane Fluidity and Omega-3 Fatty Acid Intake: Current Outlook and Perspectives for a Novel, Nutritionally Modifiable Cardiovascular Risk Factor

Omega-3 fatty acids reduce triglycerides and have several positive effects on different organs and systems. They are also found in the plasma membrane in variable amounts in relation to genetics and diet. However, it is still unclear whether omega-3 supplementation can reduce the occurrence of major cardiovascular events (MACEs). Two trials, REDUCE-IT (Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial), with highly purified EPA, and STRENGTH (Effect of High-Dose Omega-3 Fatty Acids vs. Corn Oil on Major Adverse Cardiovascular Events in Patients at High Cardiovascular Risk), with a combination of EPA and DHA, have produced different outcomes, triggering a scientific debate on possible explanations for the discrepancies. Furthermore, doubts have arisen as to the anti-inflammatory and anti-aggregating activity of these compounds. Recent studies have, however, highlighted interesting effects of EPA and DHA on erythrocyte membrane fluidity (EMF). EMF is governed by a complex and dynamic biochemical framework, with fatty acids playing a central role. Furthermore, it can be easily measured in erythrocytes from a blood sample using fluorescent probes. Recent research has also shown that EMF could act as a possible cardiovascular risk factor biomarker. This review aims to synthetize the latest evidence on erythrocyte membrane fluidity, exploring its potential role as a biomarker of residual cardiovascular risk and discussing its clinical relevance. Further, we aim to dissect the possible biological mechanisms that link omega-3 modifiable membrane fluidity to cardiovascular health.

SGLT2 inhibition and adipose tissue metabolism: current outlook and perspectives

Sodium-glucose co-transporter 2 inhibitors (SGLT2i) have emerged as important agents for the treatment of type 2 diabetes mellitus (T2DM). SGLT2 inhibitors have been associated with improved cardiovascular outcomes, not only through their immediate hemodynamic effects-such as glycosuria and (at least temporary) increased natriuresis-but also due to their multifaceted impact on metabolism. Recently, studies have also focused on the effects of SGLT2 inhibitors on adipose tissue. Aside from the well-documented effects on human adiposity, SGLT2i have shown, both in vitro and in murine models, the ability to reduce fat mass, upregulate genes related to browning of white adipose tissue, influence adipocyte size and fatty acid oxidation, and improve oxidative stress and overall metabolic health. In humans, even though data are still limited, recent evidence seems to confirm that the SGLT2i effects observed in cardiovascular outcome trials could be partially explained by their impact on adipose tissue. This review aims to clarify the impact of SGLT2i on adipose tissue, highlighting their role in metabolic health and their potential to transform treatment strategies for T2DM beyond glucose metabolism.

An update on pancreatic regeneration mechanisms: searching for paths to a cure for type 2 diabetes

Over the last decades, various approaches have been explored to restore sufficient β-cell mass in diabetic patients. Stem cells are certainly an attractive source of new β-cells, but an alternative option is to induce the endogenous regeneration of these cells. Since the exocrine and endocrine pancreatic glands have a common origin and a continuous crosstalk unites the two, we believe that analyzing the mechanisms that induce pancreatic regeneration in different conditions could further advance our knowledge in the field. In this review, we summarize the latest evidence on physiological and pathological conditions associated with the regulation of pancreas regeneration and proliferation, as well as the complex and coordinated signaling cascade mediating cell growth. Unraveling the mechanisms involved in intracellular signaling and regulation of pancreatic cell proliferation and regeneration may inspire future investigations to discover potential strategies to cure diabetes.

A single bout of physical exercise improves 1-hour post-load plasma glucose in healthy young adults

PURPOSE

Physical exercise is a key component in the treatment of type 2 diabetes and plays an important role in maintaining a healthy glucose metabolism even in healthy subjects. To date, no studies have investigated the effect of a single bout of aerobic physical exercise on glucose metabolism in young, moderately active, healthy adults.

METHODS

We performed an OGTT 7 days before and 24 h after a single bout of physical exercise, to evaluate 1-hour post-load plasma glucose and surrogate indexes of insulin sensitivity and insulin secretion.

RESULTS

Glucose levels were significantly reduced after exercise at baseline and one hour after glucose load; similarly, insulin was significantly lower 1 h after glucose load. We found a significant increase in the Matsuda index, confirmed by OGIS index, QUICKI index, and by significant reduction in HOMA-IR. Conversely, we observed a trend to increase in HOMA-B.

CONCLUSION

This is the first study to evaluate the effect of a single bout of exercise on 1-hour glucose levels following OGTT. We found a significant reduction in 1-hour glucose levels following OGTT together with an increased insulin sensitivity. A single 30-minute bout of aerobic exercise also seemed to improve the insulin secretion pattern. Modifications in beta cell secretory capacity during exercise are likely secondary to an improvement in insulin action in insulin dependent tissues.

Human subjects with impaired beta-cell function and glucose tolerance have higher levels of intra-islet intact GLP-1

AIMS

A number of studies have suggested that pancreatic α cells produce intact GLP-1, thereby constituting a gut-independent paracrine incretin system. However, the debate on whether human α cells contain intact GLP-1 and whether this relates to the presence of diabetes is still ongoing. This study aimed to determine the presence of proglucagon-derived peptides, including GLP-1 isoforms, in pancreas biopsies obtained during partial pancreatectomy from metabolically profiled human donors, stratified according to pre-surgery glucose tolerance.

METHODS

We enrolled 61 individuals with no known history of type 2 diabetes (31F/30M, age 64.6 ± 10.6 yrs., BMI 24.2 ± 3.68 kg/m2) scheduled for partial pancreatectomy for periampullary neoplasm. Differences in glucose tolerance and insulin secretion/sensitivity were assessed using preoperative 2 h OGTT, 4 h-Mixed Meal Test and Hyperinsulinemic Euglycemic Clamp. Subjects were subsequently classified as normal glucose tolerant (NGT, n = 19), impaired glucose tolerant (IGT, n = 20) or newly diagnosed diabetes (DM) (n = 22). We measured total GLP-1, intact GLP-1, glucagon, insulin, and C-peptide in pancreas biopsies and plasma from these subjects and correlated the results with their secretory and metabolic parameters.

RESULTS

Extractable levels of total GLP-1 were 23.9 ± 2.66 pmol/g, while intact GLP-1 levels were 1.15 ± 0.18 pmol/g. When we examined proglucagon derived peptides (adjusted for glucagon levels), in subjects classified according to glucose tolerance, we observed similar levels of total GLP-1, however, intact GLP-1 was significantly increased in IGT and DM groups and inversely associated with beta cell glucose sensitivity and insulin secretion in vivo.

CONCLUSIONS

Our data show that development of glucose intolerance and beta cell dysfunction are significantly associated with increased levels of intra-islet intact GLP-1, a potentially beneficial adaptation of the paracrine regulation of insulin secretion in type 2 diabetes.

The influence of insulin and incretin-based therapies on renal tubular transport

The tubular function of the kidney is very complex and is finely regulated by many factors. These include a variety of hormonal signaling pathways which are involved in the expression, activation and regulation of renal transporters responsible for the handling of electrolytes. Glucose-lowering drugs such as insulin and incretin-based therapies, exert a well-known renal protective role in diabetic kidney disease, mainly acting at the glomerular level. In the literature, several studies have described the effect of insulin and the incretin hormones on tubular transport. Most of these studies focused on the variations in excretion and clearance of sodium but did not extensively and systematically investigate the possible variations that these hormones may induce in the tubular regulation of all the other electrolytes, urea metabolism, acid-base balance and urinary pH. While insulin action on the kidney is very well-described, the renal tubular impact of incretin-based therapies is less consistent and the results available are scarce. To our knowledge, this is the first review summarizing the effects induced on renal tubules by insulin, glucagon-like peptide-1 (GLP-1) receptor agonists and serine protease dipeptidyl peptidase-4 (DPP4) inhibitors in both healthy and diabetic human subjects. This is significant because it highlights the existence of a renal-gut and pancreas axis which also has a direct tubular effect and enables a deeper understanding of renal physiology.

The multifaceted role of agents counteracting metabolic syndrome: A new hope for gastrointestinal cancer therapy

Metabolic syndrome (MetS) is defined by the presence of at least three of five clinical parameters including abdominal obesity, insulin resistance, elevated triglycerides, reduced high-density lipoprotein (HDL) and hypertension. Major features describing MetS have been recognized risk factors for cancer onset, with an alarming impact on gastrointestinal (GI) tumors. Intriguingly, therapeutic administration of drugs to improve glycemic control and dyslipidemia (including metformin, statins) has been shown to have a preventive role in the development and in prognosis improvement of several cancer types. Overall, these observations highlight the key role of altered metabolism prevalently in cancer risk development and unveil anti-MetS agent repurposing potential beyond their conventional pharmacological action. The objective of this review is to summarize the current knowledge about the antitumor activity of anti-diabetic and anti-lipemic agents in GI cancer onset and progression. Here, pre-clinical evidence of their therapeutic potential and of their integration in novel compelling therapeutic strategies will be discussed. Possible clinical outcomes of these novel therapeutic combined protocols specifically dedicated to GI cancer patients will be put under the spotlight. In the future, these novel therapeutic options should be considered to improve conventional chemotherapy response and prognosis of this group of patients.

Effects of PCSK9 inhibition on glucose metabolism and β-cell function in humans: a pilot study

Background

Anti-PCSK9 monoclonal antibodies are effective in reducing LDL-C and cardiovascular events by neutralizing circulating PCSK9. PCSK9, however, is also expressed in tissues, including the pancreas, and studies on PCSK9 KO mice have shown impaired insulin secretion. Statin treatment is already known to affect insulin secretion. Our aim was to conduct a pilot study to evaluate the effect of anti-PCSK9 mAb on glucose metabolism and β-cell function in humans.

Methods

Fifteen non-diabetic subjects, candidates for anti-PCSK9 mAb therapy, were enrolled. All underwent OGTT at baseline and after 6 months of therapy. During OGTT, insulin secretion parameters were derived from C-peptide by deconvolution (β cell glucose sensitivity). Surrogate insulin sensitivity indices were also obtained from OGTT (Matsuda).

Results

Glucose levels during OGTT were unchanged after 6 months of anti-PCSK9 mAb treatment, as well as insulin and C-peptide levels. The Matsuda index remained unchanged, while β-cell glucose sensitivity improved post-therapy (before: 85.3 ± 65.4; after: 118.6 ± 70.9 pmol min-1m-2mM-1; p<0.05). Using linear regression, we found a significant correlation between βCGS changes and BMI (p=0.004). Thus, we compared subjects with values above and below the median (27.6 kg/m2) and found that those with higher BMI had a greater increase in βCGS after therapy (before: 85.37 ± 24.73; after: 118.62 ± 26.83 pmol min-1m-2mM-1; p=0.007). There was also a significant correlation between βCGS change and Matsuda index through linear regression (p=0.04), so we analyzed subjects who had values above and below the median (3.8). This subgroup analysis showed a slight though not significant improvement in βCGS in more insulin resistant patients, (before: 131.4 ± 69.8; after: 170.8 ± 92.7 pmol min-1m-2mM-1; p=0.066).

Conclusions

Our pilot study demonstrates that six-month treatment with anti-PCSK9 mAb improves β-cell function, and does not alter glucose tolerance. This improvement is more evident in patients with greater insulin-resistance (low Matsuda) and higher BMI.

Advancing Diabetes Research: A Novel Islet Isolation Method from Living Donors

Pancreatic islet isolation is critical for type 2 diabetes research. Although -omics approaches have shed light on islet molecular profiles, inconsistencies persist; on the other hand, functional studies are essential, but they require reliable and standardized isolation methods. Here, we propose a simplified protocol applied to very small-sized samples collected from partially pancreatectomized living donors. Islet isolation was performed by digesting tissue specimens collected during surgery within a collagenase P solution, followed by a Lympholyte density gradient separation; finally, functional assays and staining with dithizone were carried out. Isolated pancreatic islets exhibited functional responses to glucose and arginine stimulation mirroring donors' metabolic profiles, with insulin secretion significantly decreasing in diabetic islets compared to non-diabetic islets; conversely, proinsulin secretion showed an increasing trend from non-diabetic to diabetic islets. This novel islet isolation method from living patients undergoing partial pancreatectomy offers a valuable opportunity for targeted study of islet physiology, with the primary advantage of being time-effective and successfully preserving islet viability and functionality. It enables the generation of islet preparations that closely reflect donors' clinical profiles, simplifying the isolation process and eliminating the need for a Ricordi chamber. Thus, this method holds promises for advancing our understanding of diabetes and for new personalized pharmacological approaches.