Weight-sparing effect of insulin detemir: a consequence of central nervous system-mediated reduced energy intake?

Real-world study of the concomitant use of biphasic insulin aspart 30/70 with GLP-1 receptor agonist versus first-generation basal insulin with GLP-1 receptor agonist in type 2 diabetes

AIMS

Combining insulin with a glucagon-like peptide-1 receptor agonist (GLP-1RA) to treat type 2 diabetes (T2D) is common. While many studies have investigated concomitant therapy with basal insulin+GLP-1RA, few have reported on premixed insulin+GLP-1RA. We aimed to address this gap using data from the Clinical Practice Research Datalink Aurum database in England.

METHODS

This retrospective cohort study with propensity score matching assessed glycaemic levels and other clinical outcomes in people with T2D, comparing biphasic insulin aspart 30/70 (BIAsp 30) + GLP-1RA with basal insulin (insulin detemir/glargine U100) + GLP-1RA (from 2006 to 2021).

RESULTS

In total, 4770 eligible people were identified; 1511 had a BIAsp 30 + GLP-1RA regimen and were propensity score-matched to an equal number receiving basal+GLP-1RA. There was no significant difference in glycated haemoglobin (HbA1c) reduction between cohorts at 6 months (p = 0.15), with a decrease of -1.07 (95% CI: -1.16; -0.98) %-points (-11.7 mmol/mol [95% CI: -12.7; -10.7]) in the BIAsp 30 + GLP-1RA cohort, versus -0.97 (95% CI: -1.07; -0.88) %-points (-10.6 mmol/mol [95% CI: -11.7; -9.6]) in the basal+GLP-1RA cohort. Body mass index (BMI) decreased by -0.35 kg/m2 (95% CI: -0.52;-0.18) at 6 months with BIAsp 30 + GLP-1RA, versus -0.72 kg/m2 (95% CI: -0.90;-0.54) with basal+GLP-1RA (p = 0.003). BMI was influenced by the initiation sequence of GLP-1RA in relation to insulin (p < 0.0001). Hypoglycaemia rates were low and not significantly different between cohorts.

CONCLUSIONS

Combining BIAsp 30 + GLP-1RA provides glycaemic control with no significant difference to that of propensity score-matched people receiving basal insulin+GLP-1RA, with no increase in hypoglycaemia risk or weight gain.

Novel Noninvasive Approaches to the Treatment of Obesity: From Pharmacotherapy to Gene Therapy

Recent insights into the pathophysiologic underlying mechanisms of obesity have led to the discovery of several promising drug targets and novel therapeutic strategies to address the global obesity epidemic and its comorbidities. Current pharmacologic options for obesity management are largely limited in number and of modest efficacy/safety profile. Therefore, the need for safe and more efficacious new agents is urgent. Drugs that are currently under investigation modulate targets across a broad range of systems and tissues, including the central nervous system, gastrointestinal hormones, adipose tissue, kidney, liver, and skeletal muscle. Beyond pharmacotherapeutics, other potential antiobesity strategies are being explored, including novel drug delivery systems, vaccines, modulation of the gut microbiome, and gene therapy. The present review summarizes the pathophysiology of energy homeostasis and highlights pathways being explored in the effort to develop novel antiobesity medications and interventions but does not cover devices and bariatric methods. Emerging pharmacologic agents and alternative approaches targeting these pathways and relevant research in both animals and humans are presented in detail. Special emphasis is given to treatment options at the end of the development pipeline and closer to the clinic (ie, compounds that have a higher chance to be added to our therapeutic armamentarium in the near future). Ultimately, advancements in our understanding of the pathophysiology and interindividual variation of obesity may lead to multimodal and personalized approaches to obesity treatment that will result in safe, effective, and sustainable weight loss until the root causes of the problem are identified and addressed.

Not All Type-2-Diabetes Patients Increase Body Mass Index After Initiating Insulin: Results of Latent Class Analysis from the DPV Registry

Background: Is insulin initiation linked to increasing body mass index (BMI) in all patients with type-2-diabetes (T2D)? To determine distinct longitudinal patterns of BMI change over time. Materials and Methods: 5057 patients with T2D (55% males, median BMI [IQR]: 30.0 [26.9-33.3] kg/m²) aged ≥40 years at diabetes diagnosis and with ≥2 years of follow-up after insulin initiation irrespective of previous or concurrent use of metformin/dipeptidyl peptidase-4-inhibitor from the multicenter prospective diabetes registry DPV were studied. To identify subgroups following a similar pattern of BMI change after insulin initiation, longitudinal group-based trajectory modeling was applied. Multinomial logistic regression was then used to analyze covariates associated with group membership. Results: Three heterogeneous groups with either relevant BMI increase (delta-BMI: +4.0 kg/m² after 2 years; 12% of patients); slight BMI increase (+0.4 kg/m²; 80%); or BMI decrease (-3.2 kg/m²; 8%) were identified. Patients with older age [OR (95% CI): 1.37 (1.11-1.69)] and obesity [2.05 (1.65-2.55)] before insulin start were more often in the BMI decreasing group, and less often in the BMI increasing class [0.80 (0.67-0.95); 0.82 (0.69-0.98)]. A worse HbA1c both at insulin start and during follow-up [1.90 (1.60-2.26); 1.17 (1.07-1.27)], a higher insulin dose [1.67 (1.33-2.10)], and severe hypoglycemic events [2.38 (1.60-3.53)] after insulin initiation were all linked with higher odds of belonging to the BMI increasing trajectory. Conclusions: Patient heterogeneity with respect to weight gain after initiation of insulin therapy in adult T2D was detected by an objective computer algorithm. Older people with obesity should not defer from insulin use due to fear of weight gain.

Choice of basal insulin therapy is associated with weight and height development in type 1 diabetes: A multicenter analysis from the German/Austrian DPV registry in 10 338 children and adolescents

BACKGROUND

Available basal insulin regimes differ in pharmacokinetic profiles, which may be related to subsequent changes in anthropometry in patients with type 1 diabetes. This analysis elucidates the standardized height and body mass index development (height and BMI standard deviation score [height-SDS and BMI-SDS]) in pediatric type 1 diabetes patients depending on the choice of basal insulin.

METHODS

Longitudinal data of 10 338 German/Austrian patients from the Diabetes Prospective Follow-up (DPV, Diabetes Patienten Verlaufsdokumentation) database were analyzed. Patients aged 5.0 to 16.9 years were treated exclusively with neutral protamine Hagedorn (NPH), insulin detemir (IDet), insulin glargine (IGla), or continuous subcutaneous insulin infusion (CSII) for at least 3 years. Population-based German reference data were used to calculate height-SDS and BMI-SDS. Multiple linear regression was conducted.

RESULTS

BMI-SDS increased significantly in all regimes (NPH P = .0365; IDet P = .0003; IGla P < .0001; and CSII P < .0001). Direct comparison of the therapies revealed a favorable association only for NPH vs IGla. A rise in BMI-SDS was observed for all insulins in females, but only for IGla in males. BMI-SDS increment was not observed before 8 years of age. Initially and at the end of the observation period, mean height was above the 50th percentile of the reference population. Across the cohort, height-SDS declined during the observation period, except for CSII. Apart from the 5.0- to 7.9-year-old subgroup, long-acting insulin analogues were associated with a significant loss of height-SDS.

CONCLUSIONS

Choice of basal insulin regimen might influence height development. CSII appeared to have a favorable effect on growth trajectories. All therapies were associated with an increase of BMI-SDS, most evident in females.

100 Years of Insulin: Lifesaver, immune target, and potential remedy for prevention

In this review, we bring our personal experiences to showcase insulin from its breakthrough discovery as a life-saving drug 100 years ago to its uncovering as the autoantigen and potential cause of type 1 diabetes and eventually as an opportunity to prevent autoimmune diabetes. The work covers the birth of insulin to treat patients, which is now 100 years ago, the development of human insulin, insulin analogues, devices, and the way into automated insulin delivery, the realization that insulin is the primary autoimmune target of type 1 diabetes in children, novel approaches of immunotherapy using insulin for immune tolerance induction, the possible limitations of insulin immunotherapy, and an outlook how modern vaccines could remove the need for another 100 years of insulin therapy.

The evolution of insulin therapy

Evolution in medicine is generally driven by clinical need, hand in hand with opportunities generated by novel chemical and mechanical engineering technologies. Since 1921 that has been a continuing paradigm for insulin therapy, some advances being a continual process, and others arising from external scientific or engineering developments. Purification of insulin preparations was an early issue, resolved in the 1970s, then challenged by the switch to manufacture in microorganisms. The nature of insulin was established serially, in 1928 as a polypeptide, in 1955 by amino acid sequence, and later by 3-dimensional structure (1969), laying foundations for understandings on routes of administration, and later the engineering of novel insulins. Insulin was the first, and remains the predominant, pharmaceutical therapy to benefit from scientific advances underlying the genetic code, and thus recombinant DNA technology. Advances in mechanical and chemical engineering have contributed to important changes in insulin delivery devices. Biological science, including both cellular mechanisms and whole organism physiology, has led to considerable understandings of clinical defects in insulin action, but currently has been disappointing in its applicability to the insulins available for clinical practice, something perhaps now changing. The pathways of these changes are reviewed here.

Asperuloside Enhances Taste Perception and Prevents Weight Gain in High-Fat Fed Mice

Asperuloside is an iridoid glycoside found in many medicinal plants that has produced promising anti-obesity results in animal models. In previous studies, three months of asperuloside administration reduced food intake, body weight, and adipose masses in rats consuming a high fat diet (HFD). However, the mechanisms by which asperuloside exerts its anti-obesity properties were not clarified. Here, we investigated homeostatic and nutrient-sensing mechanisms regulating food intake in mice consuming HFD. We confirmed the anti-obesity properties of asperuloside and, importantly, we identified some mechanisms that could be responsible for its therapeutic effect. Asperuloside reduced body weight and food intake in mice consuming HFD by 10.5 and 12.8% respectively, with no effect on mice eating a standard chow diet. Fasting glucose and plasma insulin were also significantly reduced. Mechanistically, asperuloside significantly reduced hypothalamic mRNA ghrelin, leptin, and pro-opiomelanocortin in mice consuming HFD. The expression of fat lingual receptors (CD36, FFAR1-4), CB1R and sweet lingual receptors (TAS1R2-3) was increased almost 2-fold by the administration of asperuloside. Our findings suggest that asperuloside might exert its therapeutic effects by altering nutrient-sensing receptors in the oral cavity as well as hypothalamic receptors involved in food intake when mice are exposed to obesogenic diets. This signaling pathway is known to influence the subtle hypothalamic equilibrium between energy homeostasis and reward-induced overeating responses. The present pre-clinical study demonstrated that targeting the gustatory system through asperuloside administration could represent a promising and effective new anti-obesity strategy.

Comparison of Insulin Glargine and Detemir Effects on Hormones of Appetite and Metabolic Control in Patients with Type 1 Diabetes: A Randomized Clinical Trial

The aim of this study was to compare the insulin glargine and detemir effects on hormons affecting appetite and metabolic control of patients with type 1 diabetes. This single-blind randomized clinical trial was conducted on patients aged 2 to 18 years with type 1 diabetes who were referred to the endocrinology department of Ali-Asghar Children Hospital in Tehran, from April to September 2019. Patients were randomly allocated to receive insulin Glargine or insulin Detemir. Before starting treatment, blood samples were obtained for routine biochemical tests and factors affecting appetite, including Leptin, Ghrelin, Aguti-Related Peptide (AGRP), and Peptide-YY3-36 (PYY 3-36). Patients were evaluated monthly and insulin dose was adjusted based on target glucose and carbohydrate counting. At the end of three months, the anthropometric values , HbA1C and factors that influence appetite were measured again in both groups, and the results were compared. A total of 40 children with a new onset of type 1 diabetes under 18 years who were hospitalized in Ali Asghar Children Hospital were randomly assigned into two groups as Glargine (n = 20) and Detemir (n = 20). The mean age of patients in the Glargine group was 11.07 ±4.18 years and in the Detemir group was 8.06 ± 3.56. In Glargine group HbA1C, Cholesterol, LDL, AGRP significantly decreased and leptin increased after treatment., while the change of BMI Z-score was not significant. There was a significant decrease of HbA1C in the Detemir group after treatment but there was no significant change of other variables. There was no significant difference for all the variables between two groups after treatment. There was no significant difference for BMI, metabolic control and appetite hormones between Glargine and Detemir groups. BMI-z score did not change in Glargine group while leptin increased and AGRP decreased after treatment. HbA1C decreased significantly after treatment in both groups.

Design of novel Xenopus GLP-1-based dual glucagon-like peptide 1 (GLP-1)/glucagon receptor agonists

Dual activation of the glucagon receptor (GCGR) and glucagon-like peptide 1 receptor (GLP-1R) has the potential to lead to an effective therapy for the treatment of diabetes and obesity. Here, we report the discovery of a series of peptides with dual activity on GLP-1R and GCGR that were discovered by rational design. Structural elements of oxyntomodulin (OXM), glucagon or exendin-4 were engineered into the selective GLP-1R agonist Xenopus GLP-1 (xGLP-1) on the basis of sequence analysis, resulting in hybrid peptides with potent dual activity at GLP-1R and GCGR. Further modifications with fatty acid resulted in a novel metabolically stable peptide (xGLP/GCG-15) with enhanced and balanced GLP-1R and GCGR activations. This lead peptide was further explored pharmacologically in both db/db and diet-induced obesity (DIO) rodent models. Chronic administration of xGLP/GCG-15 significantly induced hypoglycemic effects and body weight loss, improved glucose tolerance, and normalized lipid metabolism, adiposity, and liver steatosis in relevant rodent models. These preclinical studies suggest that xGLP/GCG-15 has potential for development as a novel anti-obesity and/or anti-diabetic candidate. Considering the equal effects of xGLP/GCG-15 and the clinical candidate MEDI0382 on reverse hepatic steatosis, it may also be explored as a new therapy for nonalcoholic steatohepatitis (NASH) in the future.

An effect of dietary phloretin supplementation on feed intake in mice

Dietary phloretin supplementation promotes feed intake in mice.

Lessons for modern insulin development

There have been many advances in insulin with a realistic possibility of mimicking nature to improve insulin replacement, with a view to achieving improved metabolic control. Lessons can be learnt from the evolution of insulin, insulin development, and new advances in technology. This may lead to fewer side effects of therapy resulting in a lower risk of hypoglycaemia and less weight gain, which could in turn could reduce long-term complications for people with diabetes.

The influence of dopamine-beta-hydroxylase and catechol O-methyltransferase gene polymorphism on the efficacy of insulin detemir therapy in patients with type 2 diabetes mellitus

BACKGROUND

Type II diabetes is an important health problem with a complex connection to obesity, leading to a broad range of cardiovascular complications. Insulin therapy often results in weight gain and does not always ensure adequate glycemic control. However, previous studies reported that insulin detemir is an efficient long-acting insulin with a weight sparing effect. The aim of this study was to determine the association of catechol O-methyltransferase (COMT) Val108/158Met and dopamine-beta-hydroxylase (DBH) 1021C/T polymorphisms with the effectiveness of insulin detemir in achieving glucose control and body weight control. Participants and methods: This 52-week observational study included 185 patients with inadequate glycemic control treated with premix insulin analogues, which were replaced with insulin aspart and insulin detemir, and 156 healthy controls. After DNA isolation from blood samples, genotyping of DBH-1021C/T polymorphism (rs1611115) and COMT Val108/158Met polymorphism (rs4680) was performed.

RESULTS

Our results confirmed that insulin detemir did not lead to weight gain. The most significant finding was that A carriers (the combined AG and AA genotype) of the COMT Val108/158Met achieved significantly better hemoglobin A1c (HbA1c) values compared to patients carrying GG genotype. No association between DBH-1021C/T genotypes and weight and/or glucose control was detected in diabetes patients or in healthy control subjects.

CONCLUSIONS

This study showed that the presence of one or two A allele of the COMT Val108/158Met was associated with improved glycemic response, and with a better response to insulin detemir therapy in patients with type II diabetes, separating them as best candidates for detemir therapy.

Insulin-associated weight gain in obese type 2 diabetes mellitus patients: What can be done?

Insulin therapy (IT) is initiated for patients with type 2 diabetes mellitus when glycaemic targets are not met with diet and other hypoglycaemic agents. The initiation of IT improves glycaemic control and reduces the risk of microvascular complications. There is, however, an associated weight gain following IT, which may adversely affect diabetic and cardiovascular morbidity and mortality. A 3 to 9 kg insulin-associated weight gain (IAWG) is reported to occur in the first year of initiating IT, predominantly caused by adipose tissue. The potential causes for this weight gain include an increase in energy intake linked to a fear of hypoglycaemia, a reduction in glycosuria, catch-up weight, and central effects on weight and appetite regulation. Patients with type 2 diabetes who are receiving IT often have multiple co-morbidities, including obesity, that are exacerbated by weight gain, making the management of their diabetes and obesity challenging. There are several treatment strategies for patients with type 2 diabetes, who require IT, that attenuate weight gain, help improve glycaemic control, and help promote body weight homeostasis. This review addresses the effects of insulin initiation and intensification on IAWG, and explores its potential underlying mechanisms, the predictors for this weight gain, and the available treatment options for managing and limiting weight gain.

Weight effects of antidiabetic agents

Obesity and diabetes are on the rise, which remains a continuous health concern worldwide. It is important to consider weight effects of antidiabetic agents prior to initiation as different antidiabetic agents impact weight differently. Areas covered: New agents to treat diabetes, glucagon-like peptide-1 receptor agonists and sodium glucose cotransporter 2 inhibitors, have emerged over recent years that have been shown to result in weight reduction. Unfortunately, other antidiabetic medications used can cause weight gain such as with insulin, sulfonylureas, and thiazolidediones while some remain weight neutral (metformin and dipeptidyl peptidase-4 inhibitors). The weight effects of these antidiabetic medications described are from select relevant guidelines, clinical trials, reviews, and meta-analysis found through PubMed and Ovid databases up to July 2017. Expert commentary: This article summarizes the current evidence available on the weight effects of these agents in patients with diabetes. Evaluating potential risks, such as weight gain, with potential benefits, such as improvement in glycemic control, will help with designing optimal therapeutic diabetes regimens.

Observational Registry of Basal Insulin Treatment in Patients with Type 2 Diabetes in China: Safety and Hypoglycemia Predictors

BACKGROUND

The Observational Registry of Basal Insulin Treatment (ORBIT) study evaluated the safety of basal insulin (BI) in real-world settings in China.

METHODS

We analyzed 9002 patients with type 2 diabetes (T2D) inadequately controlled with oral hypoglycemic agents from 8 geographic regions and 2 hospital tiers in China who initiated and maintained BI treatment. Body weight and hypoglycemic episodes were recorded at baseline and 3 and 6 months. Serious adverse events (SAEs) were recorded at 3 and 6 months.

RESULTS

Age, gender, inpatient/outpatient status, body mass index, glycated hemoglobin (HbA1c) at baseline and at the end of study, T2D duration, microvascular complications, BI type, combination with insulin secretagogues, self-monitoring of blood glucose frequency, and insulin dosage, all predicted hypoglycemia. BI use generally did not induce significant weight gain (0.02 kg); weight gain with insulin detemir (-0.30 kg) was less than that with neutral protamine Hagedorn (NPH) insulin (0.20 kg) or insulin glargine (0.05 kg). Overall, general hypoglycemia incidence (5.6% vs. 7.7%) and annual event rate (1.6 vs. 1.8) were similar before and after BI initiation, whereas a slight decrease was noted in severe hypoglycemia incidence (0.6%-0.3%) and frequency (0.05-0.03 events/patient-year). The general hypoglycemia rate was lowest with insulin glargine, whereas there was no significant difference in severe hypoglycemia among the three BI groups. Overall, 3.5% of patients had at least one SAE during the study. Most SAEs were found to be unrelated to BI treatment.

CONCLUSIONS

Real-world BI use, particularly insulin detemir and glargine, was associated with only slight weight gain and low hypoglycemia risk in patients with T2D in China.

Central effects of insulin detemir on feeding, body weight, and metabolism in rats

Insulin detemir (DET) is a basal insulin analog that, in contrast to other long-acting forms of insulin, has significant weight-gain-sparing effects in diabetic patients. We hypothesized that this effect of DET may be due to its enhanced catabolic action in the central nervous system. We investigated the long-term effects of single third ventricular (3V) microinjections of equimolar doses of DET and regular insulin in normal male rats on feeding, body weight, energy expenditure (EE), and respiratory quotient (RQ). Also, in acute testing, we assessed the ability of lower doses of DET to alter feeding, EE, and RQ when microinjected directly into the paraventricular nucleus (PVN). The anabolic peptide ghrelin served as a positive control in acute testing. 3V administration of both DET (0.5-2.0 mU) and regular insulin (2.0-8.0 mU) significantly reduced feeding and body weight over 48 and 120 h, respectively, with DET yielding greater inhibitory effects. DET also stimulated greater elevations of EE and reductions of RQ over 72 and 48 h postinjection, respectively. In acute (4 h) testing, microinjections of DET (0.5 mU) into the PVN reduced feeding, increased EE, and reduced RQ, while ghrelin (100 pmol) had the opposite effects. When administered sequentially into the PVN, DET (0.25 and 0.5 mU) reversed ghrelin-induced feeding, EE, and RQ effects. These data support the notion that the weight-sparing effect of DET is at least in part based on its central catabolic action and that enhanced EE and reduced RQ may participate in this effect.

Using the cerebrospinal fluid to understand ingestive behavior

The cerebrospinal fluid (CSF) offers a window into the workings of the brain and blood-brain barrier (BBB). Molecules that enter into the central nervous system (CNS) by passive diffusion or receptor-mediated transport through the choroid plexus often appear in the CSF prior to acting within the brain. Other molecules enter the CNS by passing through the BBB into the brain's interstitial fluid prior to appearing in the CSF. This pattern is also often observed for molecules synthesized by neurons or glia within the CNS. The CSF is therefore an important conduit for the entry and clearance of molecules into/from the CNS and thereby constitutes an important window onto brain activity and barrier function. Assessing the CSF basally, under experimental conditions, or in the context of challenges or metabolic diseases can provide powerful insights about brain function. Here, we review important findings made by our labs, as influenced by the late Randall Sakai, by interrogating the CSF.

Exploring the characteristics of suboptimally controlled patients after 24weeks of basal insulin treatment: An individualized approach to intensification

AIM

To identify characteristics of suboptimally controlled patients with type 2 diabetes (T2DM) on basal insulin treatment who may benefit from intensive titration or further intensification of treatment.

METHODS

A post hoc analysis of SOLVE: a 24-week, international, observational study conducted in 17,374 patients with T2DM inadequately controlled on oral antidiabetic drugs (OADs) started on once-daily insulin detemir. Patients were divided into two groups based on whether they achieved HbA1c<7.0% (<53.0mmol/mol) or not at final visit.

RESULTS

Suboptimal glycemic control (HbA1c⩾7.0 [⩾53.0mmol/mol]) was independently associated with several baseline characteristics including higher baseline HbA_1c (odds ratio [95% confidence interval]: 1.56 [1.50;1.62]; p<0.0001) and body mass index (BMI) (1.03 [1.02;1.04]; p<0.0001), longer duration of diabetes (5-10years: 1.44 [1.25;1.66]; >10years: 1.44 [1.17;1.77]; p<0.0001), and greater number of OADs (two OADs: 1.27 [1.12;1.44]; >2 OADs: 1.38 [1.14;1.66]; p=0.0003). Overall reporting of hypoglycemia was low; fewer patients with HbA1c⩾7.0% (⩾53.0mmol/mol) reported hypoglycemic events compared with patients with HbA1c<7.0% (9.8% vs. 12.5%, respectively; p<0.001).

CONCLUSIONS

Baseline characteristics related to severity of disease were strongly associated with suboptimal glycemic control in patients with T2DM receiving basal insulin. These factors may help clinicians in identifying patients who may require an individualized approach to titration or intensification of treatment.

TRIAL REGISTRATION

NCT00740519.

Brain Insulin Resistance at the Crossroads of Metabolic and Cognitive Disorders in Humans

Ever since the brain was identified as an insulin-sensitive organ, evidence has rapidly accumulated that insulin action in the brain produces multiple behavioral and metabolic effects, influencing eating behavior, peripheral metabolism, and cognition. Disturbances in brain insulin action can be observed in obesity and type 2 diabetes (T2D), as well as in aging and dementia. Decreases in insulin sensitivity of central nervous pathways, i.e., brain insulin resistance, may therefore constitute a joint pathological feature of metabolic and cognitive dysfunctions. Modern neuroimaging methods have provided new means of probing brain insulin action, revealing the influence of insulin on both global and regional brain function. In this review, we highlight recent findings on brain insulin action in humans and its impact on metabolism and cognition. Furthermore, we elaborate on the most prominent factors associated with brain insulin resistance, i.e., obesity, T2D, genes, maternal metabolism, normal aging, inflammation, and dementia, and on their roles regarding causes and consequences of brain insulin resistance. We also describe the beneficial effects of enhanced brain insulin signaling on human eating behavior and cognition and discuss potential applications in the treatment of metabolic and cognitive disorders.

What's in a Name? Classification of Diabetes Mellitus in Veterinary Medicine and Why It Matters

Diabetes Mellitus (DM) is a syndrome caused by various etiologies. The clinical manifestations of DM are not indicative of the cause of the disease, but might be indicative of the stage and severity of the disease process. Accurately diagnosing and classifying diabetic dogs and cats by the underlying disease process is essential for current and future studies on early detection, prevention, and treatment of underlying disease. Here, we review the current etiology-based classification of DM and definitions of DM types in human medicine and discuss key points on the pathogenesis of each DM type and prediabetes. We then review current evidence for application of this etiology-based classification scheme in dogs and cats. In dogs, we emphasize the lack of consistent evidence for autoimmune DM (Type 1) and the possible importance of other DM types such as DM associated with exocrine pancreatic disease. While most dogs are first examined because of DM in an insulin-dependent state, early and accurate diagnosis of the underlying disease process could change the long-term outcome and allow some degree of insulin independence. In cats, we review the appropriateness of using the umbrella term of Type 2 DM and differentiating it from DM secondary to other endocrine disease like hypersomatotropism. This differentiation could have crucial implications on treatment and prognosis. We also discuss the challenges in defining and diagnosing prediabetes in cats.