Managing dyslipidaemia in type 2 diabetes mellitus

A decreased level of high-density lipoprotein is a possible risk factor for type 2 diabetes mellitus: A review

Introduction

Type 2 diabetes mellitus (T2DM) is characterized primarily by dyslipidemia and hyperglycemia due to insulin resistance. High-density lipoprotein (HDL) play a significant role in preventing the incidence of dyslipidemia and its complications. HDL has different protective functions, such as reducing oxidation, vascular inflammation, and thrombosis; additionally, its anti-diabetic role is one of the most significant recent discoveries about HDL and some of its constituent lipoproteins.

Methods

This research reviews ongoing studies and preliminary investigations into the assessment of relation between decreased level of HDL and T2DM.

Results

The levels of HDL and its functions contribute to glucose hemostasis and the development of T2DM through four possible mechanisms, including insulin secretion by beta cells, peripheral insulin sensitivity, non-insulin-dependent glucose uptake, and adipose tissue metabolic activity. Additionally, the anti-oxidant properties of HDL protect beta cells from apoptosis caused by oxidative stress and inflammation induced by low-density lipoprotein, which facilitate insulin secretion.

Conclusion

Therefore, HDL and its compositions, especially Apo A-I, play an important role in regulating glucose metabolism, and decreased levels of HDL can be considered a risk factor for DM. Different factors, such as hypoalphalipoproteinemia that manifests as a consequence of genetic factors, such as Apo A-I deficiency, as well as secondary causes arising from lifestyle choices and underlying medical conditions that decrease the level of HDL, could be associated with DM. Moreover, intricate connections between HDL and diabetic complications extend beyond glucose metabolism to encompass complications like cardiovascular disease and kidney disease. Therefore, the exact interactions between HDL level and DM should be evaluated in future studies.

Konjac Glucomannan: An Emerging Specialty Medical Food to Aid in the Treatment of Type 2 Diabetes Mellitus

There are many factors causing T2DM; thus, it is difficult to prevent and cure it with conventional treatment. In order to realize the continuous intervention of T2DM, the treatment strategy of combining diet therapy and traditional medication came into being. As a natural product with the concept of being healthy, konjac flour and its derivatives are popular with the public. Its main component, Konjac glucomannan (KGM), can not only be applied as a food additive, which greatly improves the taste and flavor of food and extends the shelf life of food but also occupies an important role in T2DM. KGM can extend gastric emptying time, increase satiety, and promote liver glycogen synthesis, and also has the potential to improve intestinal flora and the metabolic system through a variety of molecular pathways in order to positively regulate oxidative stress and immune inflammation, and protect the liver and kidneys. In order to establish the theoretical justification for the adjunctive treatment of T2DM, we have outlined the physicochemical features of KGM in this article, emphasizing the advantages of KGM as a meal for special medical purposes of T2DM.

Dyslipidemia is not associated with the development of glucose intolerance or diabetes in cystic fibrosis

BACKGROUND

A high-fat, high-calorie diet is recommended in patients with cystic fibrosis (CF) as it improves nutritional status, respiratory health and longevity. In the general population, this diet is associated with the risk of diabetes. It is unknown whether dyslipidemic changes might contribute to the development of CF-related diabetes (CFRD).

OBJECTIVE

This study aimed to (i) characterize dyslipidemia and (ii) examine the association between dyslipidemia and development of glucose intolerance.

METHODS

Prospective observational study with serial assessments of pulmonary function, glucose tolerance, and lipid profile. Due to intrinsically low total, HDL and LDL cholesterol in patients with CF, subjects were characterized as having dyslipidemia if they had i) HDL in the lowest quartile and/or ii) hypertriglyceridemia (≥1.7 mmol/L).

RESULTS

A total of 256 patients with CF were included (age: 25.5 ± 7.7 years; BMI: 21.7 ± 3.0 kg/m2; FEV1%: 73.2 ± 22.1%; pancreatic insufficiency: 87%). Amongst these patients, 22.7% had low HDL, 9.0% had hypertriglyceridemia and 3.9% had mixed dyslipidemia. There were no differences in HbA1c (p = 0.583) or estimated insulin resistance [HOMA-IR (p = 0.206) or Stumvoll index (p = 0.397)]. Patients with hypertriglyceridemia had higher fat mass (p = 0.038) and fewer had pancreatic insufficiency. Lipid profiles were similar between subjects with CF and subjects with de novo CFRD. There was no effect of low HDL or hypertriglyceridemia on the development of CFRD over 10 years (p = 0.683).

CONCLUSION

In adult patients with CF, dyslipidemia is not associated with the risk of developing hyperglycemia or CFRD.

High prevalence of hyperlipidaemia in patients with AV re-entry tachycardia and AV nodal re-entry tachycardia

Diet rich in lipids and hyperlipidaemia increases incidence of atrial premature beats and all supraventricular arrhythmias. The aim of the study was to investigate the prevalence of hyperlipidaemia in patients with AV re-entry tachycardia (AVRT) and AV nodal re-entry tachycardia (AVNRT). We conducted a retrospective, cross-sectional, case-control study that included all consecutive patients for whom AVRT or AVNRT was confirmed during electrophysiology study. Age and gender-matched patients admitted to hospital or outpatient clinic for various reasons were randomly included and served as a control group. Hyperlipidaemia was defined according to 2016 European Society of Cardiology guidelines. A total of 1448 subjects were included: 725 patients with AVRT/AVNRT and 723 controls. AVRT/AVNRT patients had high hyperlipidaemia prevalence, which was significantly higher when compared to the control group (50.1 vs. 35.8%, p < 0.001). AVRT patients, with median age of 37.5 years, had hyperlipidaemia prevalence of 45.7%. In a multivariate analysis, hyperlipidaemia was independently associated with AVRT/AVNRT (OR 2.128, p < 0.001), both with AVNRT (OR 1.878, p < 0.001) and AVRT (OR 2.786, p < 0.001). Hypercholesterolemia was significantly more prevalent in patients with AVNRT and AVRT, while this was not the case for hypertriglyceridemia. There were no differences between the AVRT and AVNRT patients regarding hyperlipidaemia prevalence (51.9 vs. 45.7%, p = 0.801), even though AVRT patients were significantly younger (37.5 vs. 48.5, p < 0.001). In conclusion, this is the first study that investigated hyperlipidaemia prevalence in patients with AVRT or AVNRT. AVRT/AVNRT patients had higher prevalence of hyperlipidaemia and higher total and LDL cholesterol levels.

Triglycerides: Emerging Targets in Diabetes Care? Review of Moderate Hypertriglyceridemia in Diabetes

PURPOSE OF REVIEW

Moderate hypertriglyceridemia is exceedingly common in diabetes, and there is growing evidence that it contributes to residual cardiovascular risk in statin-optimized patients. Major fibrate trials yielded inconclusive results regarding the cardiovascular benefit of lowering triglycerides, although there was a signal for improvement among patients with high triglycerides and low high-density lipoprotein (HDL)-the "diabetic dyslipidemia" phenotype. Until recently, no trials have examined a priori the impact of triglyceride lowering in patients with diabetic dyslipidemia, who are likely among the highest cardiovascular-risk patients.

RECENT FINDINGS

In the recent REDUCE IT trial, omega-3 fatty acid icosapent ethyl demonstrated efficacy in lowering cardiovascular events in patients with high triglycerides, low HDL, and statin-optimized low-density lipoprotein (LDL). The ongoing PROMINENT trial is examining the impact of pemafibrate in a similar patient population. Emerging evidence suggests that lowering triglycerides may reduce residual cardiovascular risk, especially in high-risk patients with diabetic dyslipidemia.

Actions of metformin and statins on lipid and glucose metabolism and possible benefit of combination therapy

Patients with diabetes type 2 have an increased risk for cardiovascular disease and commonly use combination therapy consisting of the anti-diabetic drug metformin and a cholesterol-lowering statin. However, both drugs act on glucose and lipid metabolism which could lead to adverse effects when used in combination as compared to monotherapy. In this review, the proposed molecular mechanisms of action of statin and metformin therapy in patients with diabetes and dyslipidemia are critically assessed, and a hypothesis for mechanisms underlying interactions between these drugs in combination therapy is developed.

Dyslipidaemia in type 2 diabetes mellitus: bad for the heart

PURPOSE OF REVIEW

Type 2 diabetes mellitus (T2DM) is associated with increased coronary heart disease (CHD) morbidity and mortality. These patients are also more prone to heart failure, arrhythmias and sudden cardiac death. Furthermore, coronary interventions performed in such high-risk patients have worse outcomes. In this narrative review, we discuss the role of diabetic dyslipidaemia on the risk of CHD in patients with T2DM. The effects of hypolipidaemic, antihypertensive and antidiabetic drugs on lipid and glucose metabolism in T2DM are also considered.

RECENT FINDINGS

Among CHD risk factors, diabetic dyslipidaemia characterized by moderately elevated low-density lipoprotein (LDL) cholesterol, increased triglycerides and small, dense LDL particles as well as decreased high-density lipoprotein cholesterol levels may contribute to the increased CHD risk associated with T2DM. Hypolipidaemic, antihypertensive and antidiabetic drugs can affect lipid and glucose parameters thus potentially influencing CHD risk. Such drugs may improve not only the quantity, but also the quality of LDL as well as postprandial lipaemia.

SUMMARY

Current data highlight the importance of treating diabetic dyslipidaemia in order to minimize CHD risk. Both fasting and postprandial lipids are influenced by drugs in patients with T2DM; physicians should take this into consideration in clinical decision making.

Retrograde cholesterol transport in the human Caco-2/TC7 cell line: a model to study trans-intestinal cholesterol excretion in atherogenic and diabetic dyslipidemia

AIMS

The dyslipidemia associated with type 2 diabetes is a major risk factor for the development of atherosclerosis. Trans-intestinal cholesterol excretion (TICE) has recently been shown to contribute, together with the classical hepatobiliary route, to fecal cholesterol excretion and cholesterol homeostasis. The aim of this study was to develop an in vitro cell model to investigate enterocyte-related processes of TICE.

METHODS

Differentiated Caco-2/TC7 cells were grown on transwells and incubated basolaterally (blood side) with human plasma and apically (luminal side) with lipid micelles. Radioactive and fluorescent cholesterol tracers were used to investigate cholesterol uptake at the basolateral membrane, intracellular distribution and apical excretion.

RESULTS

Our results show that cholesterol is taken up at the basolateral membrane, accumulates intracellularly as lipid droplets and undergoes a cholesterol acceptor-facilitated and progressive excretion through the apical membrane of enterocytes. The overall process is abolished at 4 °C, suggesting a biologically active phenomenon. Moreover, this trans-enterocytic retrograde cholesterol transport displays some TICE features like modulation by PCSK9 and an ABCB1 inhibitor. Finally, we highlight the involvement of microtubules in the transport of plasma cholesterol from basolateral to apical pole of enterocytes.

CONCLUSIONS

The human Caco-2/TC7 cell line appears a good in vitro model to investigate the enterocytic molecular mechanisms of TICE, which may help to identify intestinal molecular targets to enhance reverse cholesterol transport and fight against dyslipidemia.

Treatment of Dyslipidemias to Prevent Cardiovascular Disease in Patients with Type 2 Diabetes

PURPOSE OF REVIEW

Current preventive and treatment guidelines for type 2 diabetes have failed to decrease the incidence of comorbidities, such as dyslipidemia and ultimately heart disease. The goal of this review is to describe the physiological and metabolic lipid alterations that develop in patients with type 2 diabetes mellitus. Questions addressed include the differences in lipid and lipoprotein metabolism that characterize the dyslipidemia of insulin resistance and type 2 diabetes mellitus. We also examine the relevance of the new AHA/ADA treatment guidelines to dyslipidemic individuals.

RECENT FINDINGS

In this review, we provide an update on the pathophysiology of diabetic dyslipidemia, including the role of several apolipoproteins such as apoC-III. We also point to new studies and new agents for the treatment of individuals with type 2 diabetes mellitus who need lipid therapies. Type 2 diabetes mellitus causes cardiovascular disease via several pathways, including dyslipidemia characterized by increased plasma levels of apoB-lipoproteins and triglycerides, and low plasma concentrations of HDL cholesterol. Treatments to normalize the dyslipidemia and reduce the risk for cardiovascular events include the following: lifestyle and medication, particularly statins, and if necessary, ezetimibe, to significantly lower LDL cholesterol. Other treatments, more focused on triglycerides and HDL cholesterol, are less well supported by randomized clinical trials and should be used on an individual basis. Newer agents, particularly the PCSK9 inhibitors, show a great promise for even greater lowering of LDL cholesterol, but we await the results of ongoing clinical trials.