Dietary Calanus oil recovers metabolic flexibility and rescues postischemic cardiac function in obese female mice

Long-term effects of different hypoglycemic drugs on carotid intima-media thickness progression: a systematic review and network meta-analysis

Objective

The progression of carotid intima-media thickness (cIMT) can partially predict the occurrence of future cardiovascular events. This network meta-analysis compared the effects of 14 antidiabetic drugs (acarbose, alogliptin, exenatide, glibenclamide, glimepiride, ipragliflozin, metformin, nateglinide, pioglitazone, rosiglitazone, sitagliptin, tofoglifozin, troglitazone, voglibose) on the progression of cIMT.

Method

PubMed, EMBASE, Cochrane Library, and Web of Science were searched to screen all clinical trials of treatment of cIMT with hypoglycemic agents before March 1, 2024. The differences in the changes in cIMT between the treatment group and control group were evaluated.

Result

After screening 8395 citations, 25 studies (6675 patients) were included. The results indicated that exenatide had the best efficacy in slowing down cIMT progress, and exenatide [MD=-0.13,95%CI (-0.25, -0.01)], alogliptin [MD=-0.08,95%CI (-0.13, -0.02)] and metformin [MD=-0.05, 95%CI (-0.09, -0.02)] are more effective than placebo.

Conclusion

Long-term treatment of exenatide, alogliptin, and metformin may be more effective than other hypoglycemic drugs in slowing the progression of cIMT.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42024519474.

Calanus oil attenuates isoproterenol-induced cardiac hypertrophy by regulating myocardial remodeling and oxidative stress

Calanus oil, an oil extracted from the marine crustacean Calanus finmarchicus, is one of the richest sources of omega-3 and poly-unsaturated fatty acids. Although calanus oil has been shown to have a significant anti-hypertensive, anti-inflammatory, anti-fibrotic and anti-obesity effects in various cardiovascular diseases, but little is known about its effect on pathological cardiac hypertrophy. Thus, the present study was carried out to evaluate the therapeutic effect of calanus oil on cardiac hypertrophy. Cardiac hypertrophy was induced by subcutaneous injections with isoproterenol (5 mg/kg b.w) for 14 consecutive days. Calanus oil (400 mg/kg) was given orally for 4 weeks. Cardiac pathological remodeling was evaluated by echocardiography, after which morphometric, biochemical, histological and ultrastructural analyses were performed. Calanus oil treatment significantly ameliorated isoproterenol-induced structural and functional alterations in echocardiography. Calanus oil also reduced the relative heart weight, significantly decreased the elevated cardiac enzymes (LDH and CK-MB) and the lipid peroxidation marker (MDA), augmented the myocardial antioxidant status (TAC), and ameliorated the histopathological and ultrastructural changes in cardiac tissues and prevented interstitial collagen deposition. The present study, for the first time, provided morphometric, biochemical, histological and ultrastructural evidences supporting the promising anti-hypertrophic effect of calanus oil against ISO-induced cardiac hypertrophy. This anti-hypertrophic effect of calanus oil is via regulating myocardial remodeling and oxidative stress. Therefore, it could be used as potential pharmacological intervention in the management of cardiac hypertrophy.

Impact of GLP-1 receptor agonist versus omega-3 fatty acids supplement on obesity-induced alterations of mitochondrial respiration

OBJECTIVE

To compare administration of the glucagon-like peptide-1 (GLP-1) analogue, exenatide, versus dietary supplementation with the omega-3 fatty acid-rich Calanus oil on obesity-induced alterations in mitochondrial respiration.

METHODS

Six-week-old female C57BL/6JOlaHSD mice were given high fat diet (HFD, 45% energy from fat) for 12 weeks to induce obesity. Thereafter, they were divided in three groups where one received exenatide (10 μg/kg/day) via subcutaneously implanted mini-osmotic pumps, a second group received 2% Calanus oil as dietary supplement, while the third group received HFD without any treatment. Animals were sacrificed after 8 weeks of treatment and tissues (skeletal muscle, liver, and white adipose tissue) were collected for measurement of mitochondrial respiratory activity by high-resolution respirometry, using an Oroboros Oxygraph-2k (Oroboros instruments, Innsbruck, Austria).

RESULTS

It was found that high-fat feeding led to a marked reduction of mitochondrial respiration in adipose tissue during all three states investigated - LEAK, OXPHOS and ETS. This response was to some extent attenuated by exenatide treatment, but not with Calanus oil treatment. High-fat feeding had no major effect on hepatic mitochondrial respiration, but exenatide treatment resulted in a significant increase in the various respiratory states in liver. Mitochondrial respiration in skeletal muscle was not significantly influenced by high-fat diet or any of the treatments. The precise evaluation of mitochondrial respiration considering absolute oxygen flux and ratios to assess flux control efficiency avoided misinterpretation of the results.

CONCLUSIONS

Exenatide increased hepatic mitochondrial respiration in high-fat fed mice, but no clear beneficial effect was observed in skeletal muscle or fat tissue. Calanus oil did not negatively affect respiratory activity in these tissues, which maintains its potential as a dietary supplement, due to its previously reported benefits on cardiac function.

A simple method to isolate fatty acids and fatty alcohols from wax esters in a wax-ester rich marine oil

Calanus finmarchicus is one of the most important zooplankton species in the North Atlantic. The zooplankton is currently being harvested and industrially processed to a marine oil product for human consumption as a marine nutraceutical containing long-chain omega-3 polyunsaturated fatty acids. This oil is very rich in wax esters, a lipid class where fatty acids are esterified to long chain fatty alcohols. In this paper we describe a simple method to 1) isolate the wax esters from the other lipid classes present in the oil, 2) hydrolyze the wax esters, and 3) separate the fatty acids from the fatty alcohol, all by means of solid phase extraction. Starting with an average of 322 mg Calanus oil, we obtained 75 mg fatty alcohols and 63 mg fatty acids. Contrary to previously described techniques, our method neither oxidize the fatty alcohols to fatty acids, nor are the fatty acids methylated, allowing the native, unesterified fatty acids and fatty alcohols to be used for further studies, such as in cell culture experiments to study the metabolic effects of these specific lipid fractions rather than the intact oil or wax esters.

Increased efficacy of dietary supplement containing wax ester-rich marine oil and xanthophylls in a mouse model of dry macular degeneration

Age-related macular degeneration (AMD) is nowadays considered among the retinal diseases whose clinical management lacks established treatment approaches, mainly for its atrophic (dry) form. In this respect, the use of dietary patterns enriched in omega-3 and antioxidant xanthophylls has emerged as a promising approach to counteract dry AMD progression although the prophylactic potential of omega-3 of fish origin has been discussed. Whether enriched availability of omega-3 and xanthophylls may increase the effectiveness of diet supplementation in preventing dry AMD remains to be fully established. The present study aims at comparing the efficacy of an existing orally administered formulation based on lutein and fish oil, as a source of omega-3, with a novel formulation providing the combination of lutein and astaxanthin with Calanus oil (COil), which contains omega-3 together with their precursors policosanols. Using a mouse model of dry AMD based on subretinal injection of polyethylene glycol (PEG)-400, we assessed the comparative efficacy of both formulations on PEG-induced major hallmarks including oxidative stress, inflammation, glial reactivity and outer retinal thickness. Dietary supplementation with both mixtures has been found to exert a significant antioxidant and anti-inflammatory activity as reflected by the overall amelioration of the PEG-induced pathological hallmarks. Noteworthy, the formulation based on COil appeared to be more protective than the one based on fish oil, presumably because of the higher bioavailability of omega-3 in COil. These results support the use of dietary supplements combining omega-3 and xanthophylls in the prevention and treatment of AMD and suggest that the source of omega-3 might contribute to treatment efficacy.

No Effect of Calanus Oil on Maximal Oxygen Uptake in Healthy Participants: A Randomized Controlled Study

We aimed to investigate the long-term effect of daily Calanus oil supplementation on maximal oxygen uptake (VO2max) in healthy 30- to 50-year-old participants. The study was motivated by preclinical studies reporting increased VO2max and metabolic health with omega-3 rich Calanus oil. In a double-blinded study, 71 participants were randomized to receive 2 g/day of Calanus or placebo supplementation for a total of 6 months. The participants underwent exercise testing and clinical investigations at baseline, 3 months, and 6 months. Main study endpoint was change in VO2max from baseline to 6 months. Fifty-eight participants completed the 6-month test and were included in the final data analysis (age: Calanus, 39.7 [38.0, 41.4] and placebo, 38.8 [36.8, 40.9] years; body mass index: Calanus, 24.8 [24.0, 25.6] and placebo, 24.8 [23.7, 25.8] kg/m2; and VO2max: Calanus, 50.4 [47.1, 53.8] and placebo, 50.2 [47.2, 53.1] ml·kg-1·min-1). There were no between-group differences at baseline, nor were there any between-group differences in absolute (Calanus, 3.74 [3.44, 4.04] and placebo, 3.79 [3.44, 4.14] L/min) or relative VO2max (Calanus, 49.7 [46.2, 53.2] and placebo, 49.5 [46.0, 53.1] ml·kg-1·min-1) at 6 months (mean [95% confidence interval]). There were no between-groups change in clinical measures from baseline to 3 and 6 months. In conclusion, VO2max was unaffected by 6 months of daily Calanus oil supplementation in healthy, physically fit, normal to overweight men and women between 30 and 50 years old.

Guidelines on Models of Diabetic Heart Disease

Diabetes is a major risk factor for cardiovascular diseases, including diabetic cardiomyopathy, atherosclerosis, myocardial infarction, and heart failure. As cardiovascular disease represents the number one cause of death in people with diabetes, there has been a major emphasis on understanding the mechanisms by which diabetes promotes cardiovascular disease, and how antidiabetic therapies impact diabetic heart disease. With a wide array of models to study diabetes (both type 1 and type 2), the field has made major progress in answering these questions. However, each model has its own inherent limitations. Therefore, the purpose of this guidelines document is to provide the field with information on which aspects of cardiovascular disease in the human diabetic population are most accurately reproduced by the available models. This review aims to emphasize the advantages and disadvantages of each model, and to highlight the practical challenges and technical considerations involved. We will review the preclinical animal models of diabetes (based on their method of induction), appraise models of diabetes-related atherosclerosis and heart failure, and discuss in vitro models of diabetic heart disease. These guidelines will allow researchers to select the appropriate model of diabetic heart disease, depending on the specific research question being addressed.

Exercise Training Combined with Calanus Oil Supplementation Improves the Central Cardiodynamic Function in Older Women

The aim of this study was to investigate the possible beneficial effects of exercise training (ET) with omega-3/Calanus oil supplementation on cardiorespiratory and adiposity parameters in elderly women. Fifty-five women (BMI: 19–37 kg/m², 62–80 years old) were recruited and randomly assigned to the 4 month intervention with ET and omega-3 supplementation (Calanus oil, ET-Calanus) or ET and the placebo (sunflower oil; ET-Placebo). The body composition was determined by dual-energy X-ray absorptiometry (DXA), and cardiorespiratory parameters were measured using spiroergometry and PhysioFlow hemodynamic testing. Both interventions resulted in an increased lean mass whereas the fat mass was reduced in the leg and trunk as well as the android and gynoid regions. The content of trunk fat (in percent of the total fat) was lower and the content of the leg fat was higher in the ET-Calanus group compared with the ET-Placebo. Although both interventions resulted in similar improvements in cardiorespiratory fitness (VO_2max), it was explained by an increased peripheral oxygen extraction (a-vO₂diff) alone in the ET-Placebo group whereas increased values of both a-vO₂diff and maximal cardiac output (CO_max) were observed in the ET-Calanus group. Changes in CO_max were associated with changes in systemic vascular resistance, circulating free fatty acids, and the omega-3 index. In conclusion, Calanus oil supplementation during a 4 month ET intervention in elderly women improved the cardiorespiratory function, which was due to combined central and peripheral cardiodynamic mechanisms.

Impact of Obesity-Related Inflammation on Cardiac Metabolism and Function

This review focuses on the role of adipose tissue in obese individuals in the development of metabolic diseases, and their consequences for metabolic and functional derangements in the heart. The general idea is that the expansion of adipocytes during the development of obesity gives rise to unhealthy adipose tissue, characterized by low-grade inflammation and the release of proinflammatory adipokines and fatty acids (FAs). This condition, in turn, causes systemic inflammation and elevated FA concentrations in the circulation, which links obesity to several pathologies, including impaired insulin signaling in cardiac muscle and a subsequent shift in myocardial substrate oxidation in favor of FAs and reduced cardiac efficiency. This review also argues that efforts to prevent obesity-related cardiometabolic disease should focus on anti-obesogenic strategies to restore normal adipose tissue metabolism.

Diet-induced obese mouse hearts tolerate an acute high-fatty acid exposure that also increases ischemic tolerance

An ischemic insult is accompanied by an acute increase in circulating fatty acid (FA) levels, which can induce adverse changes related to cardiac metabolism/energetics. Although chronic hyperlipidemia contributes to the pathogenesis of obesity-/diabetes-related cardiomyopathy, it is unclear how these hearts are affected by an acute high FA-load. We hypothesize that adaptation to chronic FA exposure enhances the obese hearts' ability to handle an acute high FA-load. Diet-induced obese (DIO) and age-matched control (CON) mouse hearts were perfused in the presence of low- or high FA-load (0.4 and 1.8 mM, respectively). Left ventricular (LV) function, FA oxidation rate, myocardial oxygen consumption, and mechanical efficiency were assessed, followed by analysis of myocardial oxidative stress, mitochondrial respiration, protein acetylation, and gene expression. Finally, ischemic tolerance was determined by examining LV functional recovery and infarct size. Under low-FA conditions, DIO hearts showed mild LV dysfunction, oxygen wasting, mechanical inefficiency, and reduced mitochondrial OxPhos. High FA-load increased FA oxidation rates in both groups, but this did not alter any of the above parameters in DIO hearts. In contrast, CON hearts showed FA-induced mechanical inefficiency, oxidative stress, and reduced OxPhos, as well as enhanced acetylation and activation of PPARα-dependent gene expression. While high FA-load did not alter functional recovery and infarct size in CON hearts, it increased ischemic tolerance in DIO hearts. Thus, this study demonstrates that acute FA-load affects normal and obese hearts differently and that chronically elevated circulating FA levels render the DIO heart less vulnerable to the disadvantageous effects of an acute FA-load.NEW & NOTEWORTHY An acute myocardial fat-load leads to oxidative stress, oxygen wasting, mechanical inefficiency, hyperacetylation, and impaired mitochondrial function, which can contribute to reduced ischemic tolerance. Following obesity/insulin resistance, hearts were less affected by a high fat-load, which subsequently also improved ischemic tolerance. This study highlights that an acute fat-load affects normal and obese hearts differently and that obesity renders hearts less vulnerable to the disadvantageous effects of an acute fat-load.

Possible Health Effects of a Wax Ester Rich Marine Oil

The consumption of seafood and the use of fish oil for the production of nutraceuticals and fish feed have increased over the past decades due the high content of long-chain polyunsaturated omega-3 fatty acids. This increase has put pressure on the sustainability of fisheries. One way to overcome the limited supply of fish oil is to harvest lower in the marine food web. Calanus finmarchicus, feeding on phytoplankton, is a small copepod constituting a considerable biomass in the North Atlantic and is a novel source of omega-3 fatty acids. The oil is, however, different from other commercial marine oils in terms of chemistry and, possibly, bioactivity since it contains wax esters. Wax esters are fatty acids that are esterified with alcohols. In addition to the long-chain polyunsaturated omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the oil is also rich in stearidonic acid (SDA), long-chain monounsaturated fatty acids, and the long-chain fatty alcohols eicosenol and docosenol. Recent animal studies have indicated anti-inflammatory and anti-obesogenic actions of this copepod oil beyond that provided by EPA and DHA. This review will discuss potential mechanisms behind these beneficial effects of the oil, focusing on the impact of the various components of the oil. The health effects of EPA and DHA are well recognized, whereas long-chain monounsaturated fatty acids and long-chain fatty alcohols have to a large degree been overlooked in relation to human health. Recently, however the fatty alcohols have received interest as potential targets for improved health via conversion to their corresponding fatty acids. Together, the different lipid components of the oil from C. finmarchicus may have potential as nutraceuticals for reducing obesity and obesity-related metabolic disorders.

Calanus oil in the treatment of obesity-related low-grade inflammation, insulin resistance, and atherosclerosis

Calanus oil (COil) is a natural product extracted from marine zooplankton Calanus finmarchicus found in the North Atlantic Ocean. This oil is rich in wax esters of polyunsaturated fatty acids (PUFAs) and has been projected as the best alternative to fish oil because its production cannot keep pace with the demands from the growing markets. The COil is the only commercially available marine source of wax esters, whereas classic ω-3 PUFAs comes from triglycerides, ethyl esters, and phospholipids. It has, in recent decades, been seen that there is an unprecedented rise in the use of PUFA-rich oil in the aquaculture industry. A simultaneous rise in the demand of PUFAs is also observed in the health care industry, where PUFAs are suggested preventing various disorders related to lifestyles such as obesity, diabetes mellitus, chronic low-grade inflammation, atherosclerosis, and brain and cardiovascular disorders (CVDs). In this review, we will explore the metabolic aspects related to the use of COil as an antioxidant, anticholesterinemic, and anti-inflammatory dietary source and its impact on the prevention and therapy of obesity-related metabolic disorders.