Insulin Resistance and Inflammation in the Early Phase of Type 2 Diabetes: Potential for Therapeutic Intervention

Risk factors for surgical site infection in patients undergoing obstetrics and gynecology surgeries: A meta-analysis of observational studies

OBJECTIVE

The aim of this study was to identify the risk factors for surgical site infection (SSI) in patients undergoing obstetrics and gynecology surgeries through meta-analysis.

METHODS

Relevant original studies published from January 1945 to May 2023 were searched the CBM, PubMed, Embase, WOS, CNKI, Wanfang, vip, and Cochrane Library databases. Studies eligible were evaluated by two investigators following Newcastle-Ottawa Scale(NOS) criteria. Review Manager 5.3 software was used to analyse the combined effect sizes and test for heterogeneity, and Stata 14.0 software's Begg's Test and Egger's Test were used to test for bias.

RESULTS

13 case-control articles, including 860 cases in the case group and 13574 cases in the control group, met the inclusion criteria. Eventually, Our meta-analysis showed that SSI in patients undergoing obstetrics and gynecology surgeries was correlated with body mass index (BMI)≥24 (OR = 2.66; P < 0.0001), malignant lesions (OR = 4.65; P < 0.0001), operating time≥60min (OR = 2.58; P < 0.0001), intraoperative bleeding≥300ml (OR = 2.54; P < 0.0001), retained urinary catheter (OR = 4.45; P < 0.0001), and vaginal digital examination≥3times (OR = 2.52; P < 0.0001).

CONCLUSION

In this study, BMI≥24, intraoperative bleeding≥300ml, malignant lesions, operating time≥60min, retained urinary catheter, and vaginal digital examination≥3times were considered as independent risk factors for SSI in obstetrics and gynecology surgery. It is recommended that scholars be rigorous in designing the experimental process when conducting case-control or experimental studies in order to improve the quality of the study. Controlling patients' weight before obstetrical and gynecological surgery, shortening the operation time intraoperatively, and strictly controlling the indications of vaginal digital examination and retained urinary catheter can effectively reduce the incidence of SSI.

Inverse association of plasma hydrogen sulfide levels with visceral fat area among Chinese young men: a cross-sectional study

Objective

To investigate the association between plasma Hydrogen Sulfide (H₂S) levels and visceral fat area (VFA) among Chinese young men.

Methods

This cross-sectional study involved 156 Chinese male subjects, aged 18-45 years, who visited the First Hospital of Qinhuangdao (Hebei, China) in 2014 for annual health check-up. Participants were categorized into: low (VFA < 75.57 cm²), medium (75.57 cm² ≤ VFA<100.37 cm²), and high (VFA ≥ 100.37 cm²) (n = 52/group). We estimated VFA and plasma H₂S levels by using bioelectrical impedance analysis and a fluorescence probe-based approach, respectively. The associations of H₂S with VFA and obesity anthropometric measures were assessed.

Results

In the high VFA group, the body mass index (BMI, 30.4 ± 2.45 kg/m²), total body fat (TBF, 27.9 ± 3.23 kg), plasma H₂S (3.5 µmol/L), free fatty acid (FFA, 0.6 ± 0.24 mmol/L), triglyceride (TG, 2.0 mmol/L), and total cholesterol (TC, 5.5 ± 1.02 mmol/L) levels were significantly higher than that of those of the low and medium VFA groups, respectively (P < 0.05). Plasma H₂S levels were found to be inversely correlated with VFA, TBF, waist circumference, BMI, FFA, LnFINS, LnHOMA-IR, LnTG, TC, and LDL-C (P < 0.05). Multiple backward stepwise regression analysis revealed an inverse correlation of plasma H₂S levels with FFA (β = -0.214, P = 0.005) and VFA (β = -0.429, P < 0.001), independent of adiposity measures and other confounding factors.

Conclusion

VFA was independently and inversely associated with plasma H₂S levels among Chinese young men. Therefore, determining plasma H₂S levels could aid in the assessment of abnormal VAT distribution.

Plasma and adipose tissue level of angiopoietin-like 7 (ANGPTL7) are increased in obesity and reduced after physical exercise

Objective

ANGPTL7 is a member of the Angiopoietin-like (ANGPTL) protein family that is composed of eight proteins (1–8). Increasing evidence is associating ANGPTL proteins to obesity and insulin resistance. The biological role of ANGPTL7 is yet to be understood except for a recently proposed role in the pathophysiology of glaucoma. This study was designed to shed light on the function of ANGPTL7 in obesity and its modulation by physical exercise as well as its potential association with lipid profile.

Methods

A total of 144 subjects were enrolled in this study and finished three months of physical exercise. The participants were classified based on their BMI, 82 subjects were non-obese and 62 obese. ANGPTL7 levels in plasma and adipose tissue were measured by ELISA, RT-PCR and immunohistochemistry.

Results

In this study, we showed that ANGPTL7 level was increased in the plasma of obese subjects (1249.05± 130.39 pg/mL) as compared to non-obese (930.34 ± 87.27 pg/mL) (p-Value = 0.032). ANGPTL7 Gene and protein expression levels in adipose tissue also showed over two fold increase. Physical exercise reduced circulating level of ANGPTL7 in the obese subjects to 740.98± 127.18 pg/mL, (p-Value = 0.007). ANGPTL7 expression in adipose tissue was also reduced after exercise. Finally, ANGPTL7 circulating level showed significant association with TG level in the obese subjects (R² = 0.183, p-Value = 0.03).

Conclusion

In conclusion, our data shows for the first time that obesity increases the level of ANGPTL7 in both plasma and adipose tissue. Increased expression of ANGPTL7 might play a minor role in the regulation of TG level in obese subjects either directly or through interaction with other ANGPTL protein members. Physical exercise reduced the level of ANGPTL7 highlighting the potential for targeting this protein as a therapeutic target for regulating dyslipidemia.

Circulating Nesfatin-1 Levels and Type 2 Diabetes: A Systematic Review and Meta-Analysis

The role of nesfatin-1 in glucose homeostasis has been investigated previously. However, although numerous studies have examined the relationships between circulating nesfatin-1 levels and type 2 diabetes, the conclusions are contradictory. We aimed to probe the relationship between circulating nesfatin-1 levels and type 2 diabetes by meta-analysis. Seven studies including 328 type 2 diabetes patients and 294 control subjects were included. Although there was no obvious difference in circulating nesfatin-1 levels between patients with type 2 diabetes and the control group (MD = -0.04; 95% CI = -0.32 to -0.23), subgroup analysis showed higher nesfatin-1 levels in newly diagnosed type 2 diabetes patients (MD = 0.59; 95% CI = 0.45 to 0.74) and significantly lower nesfatin-1 levels in type 2 diabetes patients receiving antidiabetic treatment (MD = -0.26; 95% CI = -0.33 to -0.20). In conclusion, the analysis supports a relationship between circulating nesfatin-1 levels and type 2 diabetes, where newly diagnosed type 2 diabetes was associated with an elevated Nesfatin-1 level, and type 2 diabetes patients receiving antidiabetic treatment showed lower circulating nesfatin-1 levels.

Glucose-lowering therapy in type 2 diabetes. New hope after the EMPA-REG outcome trial

Prevention of cardiovascular morbidity and mortality remains the key factor in the treatment of type 2 diabetes (T2DM). In the early phase of T2DM, multifactorial intervention is mandatory and glucose levels should be near normal, in particular in younger patients presenting with the highest cardiovascular risk. Anti-diabetic drugs without any risk for hypoglycaemia should be preferred in order to reduce clinical inertia and increase the long-term adherence to the treatment. In patients already presenting with cardiovascular disease, the best outcome may be expected with the triple oral therapy of metformin, pioglitazone, and empagliflozin, although a controlled prospective study versus insulin therapy is needed to confirm the expectation.

A protein profile of visceral adipose tissues linked to early pathogenesis of type 2 diabetes mellitus

Adipose tissue is increasingly recognized as an endocrine organ playing important pathophysiological roles in metabolic abnormalities, such as obesity, cardiovascular disease, and type 2 diabetes mellitus (T2DM). In particular, visceral adipose tissue (VAT), as opposed to subcutaneous adipose tissue, is closely linked to the pathogenesis of insulin resistance and T2DM. Despite the importance of VAT, its molecular signatures related to the pathogenesis of T2DM have not been systematically explored. Here, we present comprehensive proteomic analysis of VATs in drug-naïve early T2DM patients and subjects with normal glucose tolerance. A total of 4,707 proteins were identified in LC-MS/MS experiments. Among them, 444 increased in abundance in T2DM and 328 decreased. They are involved in T2DM-related processes including inflammatory responses, peroxisome proliferator-activated receptor signaling, oxidative phosphorylation, fatty acid oxidation, and glucose metabolism. Of these proteins, we selected 11 VAT proteins that can represent alteration in early T2DM patients. Among them, up-regulation of FABP4, C1QA, S100A8, and SORBS1 and down-regulation of ACADL and PLIN4 were confirmed in VAT samples of independent early T2DM patients using Western blot. In summary, our profiling provided a comprehensive basis for understanding the link of a protein profile of VAT to early pathogenesis of T2DM.

Cardiometabolic risk reduction through lifestyle intervention programs in the Brazilian public health system

Public health strategies to reduce cardiovascular morbidity and mortality should focus on global cardiometabolic risk reduction. The efficacy of lifestyle changes to prevent type 2 diabetes have been demonstrated, but low-cost interventions to reduce cardiometabolic risk in Latin-America have been rarely reported. Our group developed 2 programs to promote health of high-risk individuals attending a primary care center in Brazil. This study compared the effects of two 9-month lifestyle interventions, one based on medical consultations (traditional) and another with 13 multi-professional group sessions in addition to the medical consultations (intensive) on cardiometabolic parameters. Adults were eligible if they had pre-diabetes (according to the American Diabetes Association) and/or metabolic syndrome (International Diabetes Federation criteria for Latin-America). Data were expressed as means and standard deviations or percentages and compared between groups or testing visits. A p-value < 0.05 was considered significant.

RESULTS

180 individuals agreed to participate (35.0% men, mean age 54.7 ± 12.3 years, 86.1% overweight or obese). 83 were allocated to the traditional and 97 to the intensive program. Both interventions reduced body mass index, waist circumference and tumor necrosis factor-α. Only intensive program reduced 2-hour plasma glucose and blood pressure and increased adiponectin values, but HDL-cholesterol increased only in the traditional. Also, responses to programs were better in intensive compared to traditional program in terms of blood pressure and adiponectin improvements. No new case of diabetes in intensive but 3 cases and one myocardial infarction in traditional program were detected. Both programs induced metabolic improvement in the short-term, but if better results in the intensive are due to higher awareness about risk and self-motivation deserves further investigation. In conclusion, these low-cost interventions are able to minimize cardiometabolic risk factors involved in the progression to type 2 diabetes and/or cardiovascular disease.

Glycerolipid/free fatty acid cycle and islet β-cell function in health, obesity and diabetes

Pancreatic β-cells secrete insulin in response to fluctuations in blood fuel concentrations, in particular glucose and fatty acids. However, chronic fuel surfeit can overwhelm the metabolic, signaling and secretory capacity of the β-cell leading to its dysfunction and death - often referred to as glucolipotoxicity. In β-cells and many other cells, glucose and lipid metabolic pathways converge into a glycerolipid/free fatty acid (GL/FFA) cycle, which is driven by the substrates, glycerol-3-phosphate and fatty acyl-CoA, derived from glucose and fatty acids, respectively. Although the overall operation of GL/FFA cycle, consisting of lipolysis and lipogenesis, is "futile" in terms of energy expenditure, this metabolic cycle likely plays an indispensable role for various β-cell functions, in particular insulin secretion and excess fuel detoxification. In this review, we discuss the significance of GL/FFA cycle in the β-cell, its regulation and role in generating essential metabolic signals that participate in the lipid amplification arm of glucose stimulated insulin secretion and in β-cell growth. We propose the novel concept that the lipolytic segment of GL/FFA cycle is instrumental in producing signals for insulin secretion, whereas, the lipogenic segment generates signals relevant for β-cell survival/death and growth/proliferation.

Insulin therapy and type 2 diabetes: management of weight gain

The potential for insulin-related weight gain in patients with type 2 diabetes presents a therapeutic dilemma and frequently leads to delays in the initiation of insulin therapy. It also poses considerable challenges when treatment is intensified. Addressing insulin-related weight gain is highly relevant to the prevention of metabolic and cardiovascular consequences in this high-risk population with type 2 diabetes. In addition to lifestyle changes (eg, diet and exercise) and available medical interventions to minimize the risk of weight gain with insulin treatment, familiarity with the weight gain patterns of different insulins may help deal with this problem. The use of basal insulin analogs may offer advantages over conventional human insulin preparations in terms of more physiologic time-action profiles, reduced risk of hypoglycemia, and reduced weight gain.

Glycerolipid metabolism and signaling in health and disease

Maintenance of body temperature is achieved partly by modulating lipolysis by a network of complex regulatory mechanisms. Lipolysis is an integral part of the glycerolipid/free fatty acid (GL/FFA) cycle, which is the focus of this review, and we discuss the significance of this pathway in the regulation of many physiological processes besides thermogenesis. GL/FFA cycle is referred to as a "futile" cycle because it involves continuous formation and hydrolysis of GL with the release of heat, at the expense of ATP. However, we present evidence underscoring the "vital" cellular signaling roles of the GL/FFA cycle for many biological processes. Probably because of its importance in many cellular functions, GL/FFA cycling is under stringent control and is organized as several composite short substrate/product cycles where forward and backward reactions are catalyzed by separate enzymes. We believe that the renaissance of the GL/FFA cycle is timely, considering the emerging view that many of the neutral lipids are in fact key signaling molecules whose production is closely linked to GL/FFA cycling processes. The evidence supporting the view that alterations in GL/FFA cycling are involved in the pathogenesis of "fatal" conditions such as obesity, type 2 diabetes, and cancer is discussed. We also review the different enzymatic and transport steps that encompass the GL/FFA cycle leading to the generation of several metabolic signals possibly implicated in the regulation of biological processes ranging from energy homeostasis, insulin secretion and appetite control to aging and longevity. Finally, we present a perspective of the possible therapeutic implications of targeting this cycling.

Apolipoprotein AII is a regulator of very low density lipoprotein metabolism and insulin resistance

Apolipoprotein AII (apoAII) transgenic (apoAIItg) mice exhibit several traits associated with the insulin resistance (IR) syndrome, including IR, obesity, and a marked hypertriglyceridemia. Because treatment of the apoAIItg mice with rosiglitazone ameliorated the IR and hypertriglyceridemia, we hypothesized that the hypertriglyceridemia was due largely to overproduction of very low density lipoprotein (VLDL) by the liver, a normal response to chronically elevated insulin and glucose. We now report in vivo and in vitro studies that indicate that hepatic fatty acid oxidation was reduced and lipogenesis increased, resulting in a 25% increase in triglyceride secretion in the apoAIItg mice. In addition, we observed that hydrolysis of triglycerides from both chylomicrons and VLDL was significantly reduced in the apoAIItg mice, further contributing to the hypertriglyceridemia. This is a direct, acute effect, because when mouse apoAII was injected into mice, plasma triglyceride concentrations were significantly increased within 4 h. VLDL from both control and apoAIItg mice contained significant amounts of apoAII, with approximately 4 times more apoAII on apoAIItg VLDL. ApoAII was shown to transfer spontaneously from high density lipoprotein (HDL) to VLDL in vitro, resulting in VLDL that was a poorer substrate for hydrolysis by lipoprotein lipase. These results indicate that one function of apoAII is to regulate the metabolism of triglyceride-rich lipoproteins, with HDL serving as a plasma reservoir of apoAII that is transferred to the triglyceride-rich lipoproteins in much the same way as VLDL and chylomicrons acquire most of their apoCs from HDL.

Control of fatty acid metabolism by leptin in L6 rat myoblasts is regulated by hyperinsulinemia

The development of hypothalamic leptin resistance plays a role in the development of obesity, yet whether peripheral leptin resistance occurs in obesity and diabetes is controversial. Here we investigate whether hyperinsulinemia, as observed during the development of Type 2 diabetes, modifies the effects of leptin on long chain fatty acid metabolism in skeletal muscle cells. We used boron dipyrromethene difluoride (BODIPY)-labeled palmitate to show that leptin (60 nM) caused a time-dependent (0-60 min) increase in fatty acid uptake in L6 myoblasts. Quantitative analysis using 3H-palmitate showed that pre-incubation with insulin (100 nM, 24 h) prevented stimulation of fatty acid uptake by leptin. Insulin pre-treatment also attenuated the ability of leptin to phosphorylate acetyl Co-A carboxylase and increase palmitate oxidation. Suppressor of cytokine-3 (SOCS-3) has been proposed as a possible mediator of insulin-induced leptin resistance. Here we show that treatment of L6 cells with insulin elicited a time-dependent increase in both SOCS-3 mRNA and protein content. In summary, hyperinsulinemia can induce leptin resistance in L6 myoblasts and this may be mediated via a SOCS-3-dependent mechanism.

Free fatty acids and insulin resistance

PURPOSE OF REVIEW

Dysregulation of free fatty acid metabolism is a key event responsible for insulin resistance and type 2 diabetes. According to the glucose-fatty acid cycle of Randle, preferential oxidation of free fatty acids over glucose plays a major role in insulin sensitivity and the metabolic disturbances of diabetes mellitus. However, other mechanisms are now described to explain the molecular basis of insulin resistance.

RECENT FINDINGS

Recent studies have suggested that local accumulation of fat metabolites such as ceramides, diacylglycerol or acyl-CoA, inside skeletal muscle and liver, may activate a serine kinase cascade leading to defects in insulin signalling and glucose transport. Inflammation and oxidative stress are also potent mechanisms which could lead to a state of insulin resistance. Finally, modulation of transcription by free fatty acids through their binding to peroxisome proliferator-activated receptors could also contribute to impaired glucose metabolism.

SUMMARY

The increase in free fatty acid flux resulting from increased lipolysis secondary to adipose-tissue insulin resistance induces or aggravates insulin resistance in liver and muscle through direct or indirect (from triglyceride deposits) generation of metabolites, altering the insulin signalling pathway. Alleviating the excess of free fatty acids is a target for the treatment of insulin resistance.

The metabolic syndrome

The metabolic syndrome (MS) is a cluster of metabolic abnormalities leading to increased risk for cardiovascular diseases and diabetes type 2. Its prevalence is increasing with aging. There exists actually an epidemic of MS. Visceral obesity and the resulting insulin resistance (IR) are the major determinant in the development of the MS. Abdominal obesity results in a low grade inflammation via the adipose tissue and macrophages secreted adipokines. This inflammation, via the generated pro-inflammatory molecules, interferes with the normal insulin signalling and thus contributes to the etiopathogenesis of the MS. Large clinical studies showed that CRP is increased in obese subjects and concomitantly to the number of existing component of the MS. Treatment of the MS is aimed to improve the IR by lifestyle changes including exercise and diet alone or in combination with medication targeting the individual components but having also anti-inflammatory actions. More research is needed to bring new therapies to be able to decrease the incidence and prevalence of the MS among the population and thus increasing their quality of life.

Increased visfatin concentrations in women with gestational diabetes mellitus

The recently discovered adipocytokine visfatin has insulin-like properties. It lowers blood glucose and improves insulin sensitivity; however, clinical data on visfatin are limited. To evaluate the role of visfatin in GDM (gestational diabetes mellitus), we determined visfatin levels in women with GDM and in healthy pregnant controls. Furthermore, visfatin concentrations were investigated longitudinally during pregnancy and after delivery in a subgroup of women with GDM. Blood for measurement of visfatin and metabolic parameters was obtained from 64 women with GDM [median week of gestation, 34 (interquartile range, 27-36) weeks] and 30 healthy pregnant controls [median week of gestation, 34 (interquartile range, 28-36) weeks]. In a subgroup of 24 women with GDM, visfatin, leptin and metabolic parameters were investigated twice during pregnancy (28-30 and 38-40 weeks of gestation) and 2 weeks after delivery. In the cross-sectional analysis, median visfatin levels were significantly elevated in women with GDM [64.0 (interquartile range, 50.9-74.8) ng/ml] compared with controls [46.0 (interquartile range, 36.9-54.6) ng/ml; P<0.0001]. In women with GDM, visfatin correlated with week of gestation at the time of blood draw (R=0.35, P=0.005). No association with fasting glucose, insulin, homoeostasis model assessment-insulin resistance or body mass index was observed. According to the longitudinal analysis, visfatin increased during pregnancy (P=0.002) and rose further after delivery (P=0.014), whereas leptin and insulin levels decreased after parturition (both P<0.001). In conclusion, visfatin is elevated in women with GDM and increases during the course of pregnancy as well as after delivery. Furthermore, visfatin shows no association with insulin and leptin in women with GDM.

Hyperketonemia (ketosis), oxidative stress and type 1 diabetes

The long-term complications of diabetes are the leading causes of morbidity and mortality in the type 1 diabetic population and remain a major public health issue. Hyperglycemia is one of the major risk factors in the development of vascular complications. A growing body of evidence indicates that hyperglycemia leads to increased oxidative stress and monocyte and endothelial cell dysfunction. In addition to hyperglycemia, type 1 diabetic patients frequently experience ketosis (hyperketonemia). The blood concentration of ketone bodies reaches higher than 25mM in diabetics with severe ketosis. Traditionally, clinical practice has considered hypertketonemia to be present only in type 1 diabetic patients. Newer data indicate that diabetic ketoaciosis or hyperketonemia co-exists with hyperglycemia among older type 2 diabetic patients and in African Americans and other minority groups with type 2 diabetes. This review will focus on the role of hyperketonemia in the etiology of oxidative stress in diabetic patients. The data presented here illustrate that the ketone body acetoacetate (AA) can generate superoxide radicals and cause increases in oxidative stress and cellular dysfunction. The data included in this review demonstrate that blood levels of markers of oxidative stress are elevated in hyperketonemic patients compared with those of normoketonemic diabetic patients. Thus, both in vitro and in vivo research indicate that ketosis can generate oxygen radicals and result in excess cellular oxidative stress in type 1 diabetic patients. Elevated oxidative stress levels in ketotic patients can play a significant role in the development of vascular inflammation and contribute to the increased incidence of vascular disease and complications associated with type 1 diabetes.

Lipid-lowering drugs

Although a change in life-style is often the method of first choice for lipid lowering, lipid-lowering drugs, in general, help to control elevated levels of different forms of lipids in patients with hyperlipidemia. While one group of drugs, statins, lowers cholesterol, the other group, fibrates, is known to take care of fatty acids and triglycerides. In addition, other drugs, such as ezetimibe, colesevelam, torcetrapib, avasimibe, implitapide, and niacin are also being considered to manage hyperlipidemia. As lipids are very critical for cardiovascular diseases, these drugs reduce fatal and nonfatal cardiovascular abnormalities in the general population. However, a number of recent studies indicate that apart from their lipid-lowering activities, statins and fibrates exhibit multiple functions to modulate intracellular signaling pathways, inhibit inflammation, suppress the production of reactive oxygen species, and modulate T cell activity. Therefore, nowadays, these drugs are being considered as possible therapeutics for several forms of human disorders including cancer, autoimmunity, inflammation, and neurodegeneration. Here I discuss these applications in the light of newly discovered modes of action of these drugs.

Lipid and lipoprotein dysregulation in insulin resistant states

Insulin resistant states are commonly associated with an atherogenic dyslipidemia that contributes to significantly higher risk of atherosclerosis and cardiovascular disease. Indeed, disorders of carbohydrate and lipid metabolism co-exist in the majority of subjects with the "metabolic syndrome" and form the basis for the definition and diagnosis of this complex syndrome. The most fundamental defect in these patients is resistance to cellular actions of insulin, particularly resistance to insulin-stimulated glucose uptake. Insulin insensitivity appears to cause hyperinsulinemia, enhanced hepatic gluconeogenesis and glucose output, reduced suppression of lipolysis in adipose tissue leading to a high free fatty acid flux, and increased hepatic very low density lipoprotein (VLDL) secretion causing hypertriglyceridemia and reduced plasma levels of high density lipoprotein (HDL) cholesterol. Although the link between insulin resistance and dysregulation of lipoprotein metabolism is well established, a significant gap of knowledge exists regarding the underlying cellular and molecular mechanisms. Emerging evidence suggests that insulin resistance and its associated metabolic dyslipidemia result from perturbations in key molecules of the insulin signaling pathway, including overexpression of key phosphatases, downregulation and/or activation of key protein kinase cascades, leading to a state of mixed hepatic insulin resistance and sensitivity. These signaling changes in turn cause an increased expression of sterol regulatory element binding protein (SREBP) 1c, induction of de novo lipogensis and higher activity of microsomal triglyceride transfer protein (MTP), which together with high exogenous free fatty acid (FFA) flux collectively stimulate the hepatic production of apolipoprotein B (apoB)-containing VLDL particles. VLDL overproduction underlies the high triglyceride/low HDL-cholesterol lipid profile commonly observed in insulin resistant subjects.