Effects of alpha-cyclodextrin on cholesterol control and Compound K on glycaemic control in people with pre-diabetes: Protocol for a Phase III randomized controlled trial

Natural compounds proposed for the management of non-alcoholic fatty liver disease

Although non-alcoholic fatty liver disease (NAFLD) presents as an intricate condition characterized by a growing prevalence, the often-recommended lifestyle interventions mostly lack high-level evidence of efficacy and there are currently no effective drugs proposed for this indication. The present review delves into NAFLD pathology, its diverse underlying physiopathological mechanisms and the available in vitro, in vivo, and clinical evidence regarding the use of natural compounds for its management, through three pivotal targets (oxidative stress, cellular inflammation, and insulin resistance). The promising perspectives that natural compounds offer for NAFLD management underscore the need for additional clinical and lifestyle intervention trials. Encouraging further research will contribute to establishing more robust evidence and practical recommendations tailored to patients with varying NAFLD grades.

Cyclodextrins as therapeutic drugs for treating lipid metabolism disorders

OBJECTIVE

This study sought to systematically compare the efficacy and mechanism of cyclodextrins as drug interventions in lipid metabolism diseases, potentially providing ideas for subsequent research directions and clinical applications.

METHODS

We used the bibliometric method for feature mining, applied VOSviewer software for clustering analysis, and applied content analysis for objective descriptions and accurate analysis.

RESULTS

(1) We collected more than 50 studies, which is the basic database of this study. (2) The academic bubble map showed that this research area was popular in the United States. (3) Cluster analysis showed that the intensively studied diseases in this field were Niemann-Pick type C (NPC), atherosclerosis (AS), and obesity. The hot-spot cyclodextrin types were HP-β-CD. (4) Literature measurement revealed the involvement of 15 types of lipid metabolism diseases. Among them, NPC, diabetes, and obesity were studied in clinical trials. Dyslipidemia and AS have been reported relatively more frequently in animal experiments. The studies of cellular experiments provide insight into the molecular mechanisms that intervene in lipid metabolism diseases from multiple perspectives. The exploration of the molecular mechanisms by which cyclodextrins exert their pharmacological effects mainly revolves around lipid metabolism.

CONCLUSION

It is worthwhile to investigate the role and mechanism of cyclodextrins in other lipid metabolism diseases. The potential efficacy evaluation of cyclodextrins as pharmaceutical drugs for oral or injectable formulations is less studied and may become a new focus in the future.

Cost-effectiveness analysis of recruitment strategies in a large diabetes prevention trial conducted across two sites in Sydney, Australia

BACKGROUND

Diabetes prevention trials require large samples and community-based recruitment, which can be protracted and expensive. We analysed the cost-effectiveness of recruitment strategies used in a randomised placebo-controlled supplement trial in adults with prediabetes and overweight or obesity conducted in Sydney, Australia.

METHODS

Recruitment strategies included advertising through local radio stations and newspapers, television news coverage, online advertising and editorials, advertising in and referral from primary care settings, university- and hospital-based advertising, and attending or hosting local events. For each strategy, the number of expressions of interest, screenings booked, and randomised participants were collated. The percentage contribution from each strategy, overall cost, and cost per participant were calculated.

RESULTS

Of 4498 expressions of interest, 551 (12%) were eligible for onsite screening and 401 (9%) were randomised. Recruitment costs totalled AU$218,501, averaging AU$545 per participant. The recruitment strategy was recorded for 49% who expressed interest in the trial, and for 75% randomised into the trial. From these data, advertising on local radio stations was the most cost-effective strategy, contributing 46% of participants at AU$286 per participant, then advertising in and referral from primary care settings (57 participants [19%], AU$1438 per participant). The least cost-effective strategy was television news coverage, which was not targeted to the Sydney-based audience, contributing only six participants (AU$10,000 per participant).

CONCLUSION

Radio advertising and recruitment through healthcare were the most effective recruitment strategies in this trial. Recruitment strategies should be location-specific and appropriate for the target population, prioritising low-effort high-yield strategies. Trial investigators should seek opportunities for free advertising.

Protective Effect of Monoterpene Isoespintanol in a Rat Model of Prediabetes Induced by Fructose

A high-fructose diet (HFD) induces murine alterations like those recorded in human prediabetes. Protective effects of isoespintanol (monoterpene isolated from Oxandra cf. xylopioides) on changes induced by HFD were evaluated. Animals were maintained for 21 days with a standard diet (C), 10% fructose (F), and F plus isoespintanol (FI, 10 mg/kg, i.p.). Glycemia, triglyceridemia, total and HDL-cholesterol, and insulin resistance index (IRX) were determined. Intraperitoneal glucose tolerance test (IGTT) was performed. In the liver, we measured glycogen, lipogenic gene expression (SREBP-1c, GPAT, FAS, and CPT1), oxidative stress (GSH and 3'-nitrotyrosine content), inflammation markers (iNOS, TNF-α, and PAI-1 gene expression; iNOS and COX-2 protein levels), p-eNOS, p-Akt, and p-GSK3β protein levels. Isoespintanol corrected enhanced triglycerides, lipogenic genes, and IRX, and reduced HDL-cholesterol induced by HFD. Increased liver glycogen and inflammatory markers and decreased GSH, p-Akt, and p-GSK3β measured in F rats were reversed by isoespintanol, and p-eNOS/e-NOS and iNOS/GADPH ratios were normalized. Isoespintanol restored glucose tolerance (IGTT) compared to F rats. These results demonstrate for the first time that isoespintanol prevents endocrine-metabolic alterations induced by HFD in prediabetic rats. These effects could be mediated by Akt/eNOS and Akt/GSK3β pathways, suggesting its possible use as a therapeutic tool for the prevention of diabetes at early stages of its development (prediabetes).

Changes in Prediabetes Status Among Adults During a 6-Month Randomized Placebo-controlled Supplement Trial With Nutrition and Lifestyle Counselling and 6-Month Follow-up

OBJECTIVES

In this work, we present an exploratory within-trial analysis of the changing prevalence of prediabetes in response to nutrition and lifestyle counselling provided as part of a randomized placebo-controlled supplement trial with follow-up. We aimed to identify factors associated with changing glycemia status.

METHODS

Participants (n=401) in this clinical trial were adults with a body mass index (BMI) of ≥25 kg/m2 and prediabetes (defined by the American Diabetes Association as a fasting plasma glucose [FPG] of 5.6 to 6.9 mmol/L or a glycated hemoglobin [A1C] of 5.7% to 6.4%) within 6 months before trial entry. The trial consisted of a 6-month randomized intervention with 2 dietary supplements and/or placebo. At the same time, all participants received nutrition and lifestyle counselling. This was followed by a 6-month follow-up. Glycemia status was assessed at baseline and at 6 and 12 months.

RESULTS

At baseline, 226 participants (56%) met a threshold for prediabetes, including 167 (42%) with elevated FPG and 155 (39%) with elevated A1C. After the 6-month intervention, the prevalence of prediabetes decreased to 46%, driven by a reduction in prevalence of elevated FPG to 29%. The prevalence of prediabetes then increased to 51% after follow-up. Risk of prediabetes was associated with older age (odds ratio [OR], 1.05; p<0.01), BMI (OR, 1.06; p<0.05), and male sex (OR, 1.81; p=0.01). Participants who reverted to normoglycemia had greater weight loss and lower baseline glycemia.

CONCLUSIONS

Glycemia status can fluctuate over time and improvements can be gained from lifestyle interventions, with certain factors associated with a higher likelihood of reverting to normoglycemia.

Terpenes: Modulating anti-inflammatory signaling in inflammatory bowel disease

Inflammatory Bowel Disease (IBD) are autoimmune diseases characterized by chronic intestinal inflammation. Considered a western disease, IBD incidence in newly developed countries is skyrocketing. Accordingly, global prevalence is steadily increasing. There are two major IBD phenotypes, ulcerative colitis (UC) and Crohn's disease (CD). UC manifests as uninterrupted inflammation localized in the colon and rectum. Meanwhile, CD presents as interrupted inflammation that can occur throughout the digestive tract. As a result, therapeutics have focused on anti-inflammatory approaches for its treatment. Unfortunately, only 50% of patients benefit from current Food and Drug Administration approved treatments, and all are associated with serious adverse effects. Thus, there is a need for safer and novel therapeutics to increase the efficacy in this population. One aspect that is critical in understanding IBD is how food and phytochemicals therein may be associated with modifying the pathogenesis of IBD. A variety of retrospective and prospective studies, and clinical trials have shown benefits of plant-rich diets on the prevention and symptomatic improvement of IBD. The Mediterranean diet is rich in vegetables, fruits, legumes, and herbs; and characterized by the abundance of anti-inflammatory phytochemicals. An understudied phytochemical class enriched in this diet is terpenes; isoprene-based molecules are widely available in Mediterranean herbs and citrus fruits. Various terpenes have been evaluated in different IBD models. However, some present contradictory or inconclusive results. Therefore, in this review we evaluated preclinical studies of terpenes modulating basic inflammatory signaling related to IBD.

The Effect of Alpha-Cyclodextrin on Postprandial Glucose Excursions: a Systematic Meta-Analysis

Alpha-cyclodextrin (αCD) is a bacterial product that is widely used as a food ingredient. In the European Union (EU), αCD is regulated as a dietary fiber with an authorized health claim “for contributing to the reduction of postprandial glycemic responses.” In the US, αCD is generally recognized as save (GRAS), but on April 25, 2022, the U.S. Food and Drug Administration (FDA) rejected the inclusion of αCD in the list of dietary fibers because “the strength of the scientific evidence does not support a finding of a beneficial effect of αCD on postprandial blood glucose …” To evaluate the strength of this scientific evidence, this meta-analysis reviews clinical trials conducted to test the effect of αCD on the rise of blood glucose and insulin levels during three hours after consumption of a meal comprising carbohydrates, fats, and proteins.

Several issues related to the standardization of the outcomes, the choice of the statistical methods in the cross-over studies conducted, and the choice of methods for the aggregation of P-values are discussed. It is concluded that the administration of αCD not only reduces the postprandial glycemic responses, but the absence of an increase in insulin levels suggests that αCD acts independently of increasing insulin production and, thus, the beneficial effect of αCD is not affected by insulin resistance.

Single-gene long-read sequencing illuminates Escherichia coli strain dynamics in the human intestinal microbiome

Gut microbiome is of major interest due to its close relationship to health and disease. Bacteria usually vary in gene content, leading to functional variations within species, so resolution higher than species-level methods is needed for ecological and clinical relevance. We design a protocol to identify strains in selected species with high discrimination and in high numbers by amplicon sequencing of the flagellin gene. We apply the protocol to fecal samples from a human diet trial, targeting Escherichia coli. Across the 119 samples from 16 individuals, there are 1,532 amplicon sequence variants (ASVs), but only 32 ASVs are dominant in one or more fecal samples, despite frequent dominant strain turnover. Major strains in an intestine are found to be commonly accompanied by a large number of satellite cells, and many are identified as potential extraintestinal pathogens. The protocol could be used to track epidemics or investigate the intra- or inter-host diversity of pathogens.

A comprehensive review on the phytochemistry, pharmacokinetics, and antidiabetic effect of Ginseng

BACKGROUND

Radix Ginseng, one of the well-known medicinal herbs, has been used in the management of diabetes and its complications for more than 1000 years.

PURPOSE

The aim of this review is devoted to summarize the phytochemistry and pharmacokinetics of Ginseng, and provide evidence for the antidiabetic effects of Ginseng and its ingredients as well as the underlying mechanisms involved.

METHODS

For the purpose of this review, the following databases were consulted: the PubMed Database (https://pubmed.ncbi.nlm.nih.gov), Chinese National Knowledge Infrastructure (http://www.cnki.net), National Science and Technology Library (http://www.nstl.gov.cn/), Wanfang Data (http://www.wanfangdata.com.cn/) and the Web of Science Database (http://apps.webofknowledge.com/).

RESULTS

Ginseng exhibits glucose-lowering effects in different diabetic animal models. In addition, Ginseng may prevent the development of diabetic complications, including liver, pancreas, adipose tissue, skeletal muscle, nephropathy, cardiomyopathy, retinopathy, atherosclerosis and others. The main ingredients of Ginseng include ginsenosides and polysaccharides. The underlying mechanisms whereby this herb exerts antidiabetic activities may be attributed to the regulation of multiple signaling pathways, including IRS1/PI3K/AKT, LKB1/AMPK/FoxO1, AGEs/RAGE, MAPK/ERK, NF-κB, PPARδ/STAT3, cAMP/PKA/CERB and HIF-1α/VEGF, etc. The pharmacokinetic profiles of ginsenosides provide valuable information on therapeutic efficacy of Ginseng in diabetes. Although Ginseng is well-tolerated, dietary consumption of this herb should follow the doctors' advice.

CONCLUSION

Ginseng may offer an alternative strategy in protection against diabetes and its complications through the regulations of the multi-targets via various signaling pathways. Efforts to understand the underlying mechanisms with strictly-controlled animal models, combined with well-designed clinical trials and pharmacokinetic evaluation, will be important subjects of the further investigations and weigh in translational value of this herb in diabetes management.

Spatiotemporal Developmental Upregulation of Prestin Correlates With the Severity and Location of Cyclodextrin-Induced Outer Hair Cell Loss and Hearing Loss

2-Hyroxypropyl-beta-cyclodextrin (HPβCD) is being used to treat Niemann-Pick C1, a fatal neurodegenerative disease caused by abnormal cholesterol metabolism. HPβCD slows disease progression, but unfortunately causes severe, rapid onset hearing loss by destroying the outer hair cells (OHC). HPβCD-induced damage is believed to be related to the expression of prestin in OHCs. Because prestin is postnatally upregulated from the cochlear base toward the apex, we hypothesized that HPβCD ototoxicity would spread from the high-frequency base toward the low-frequency apex of the cochlea. Consistent with this hypothesis, cochlear hearing impairments and OHC loss rapidly spread from the high-frequency base toward the low-frequency apex of the cochlea when HPβCD administration shifted from postnatal day 3 (P3) to P28. HPβCD-induced histopathologies were initially confined to the OHCs, but between 4- and 6-weeks post-treatment, there was an unexpected, rapid and massive expansion of the lesion to include most inner hair cells (IHC), pillar cells (PC), peripheral auditory nerve fibers, and spiral ganglion neurons at location where OHCs were missing. The magnitude and spatial extent of HPβCD-induced OHC death was tightly correlated with the postnatal day when HPβCD was administered which coincided with the spatiotemporal upregulation of prestin in OHCs. A second, massive wave of degeneration involving IHCs, PC, auditory nerve fibers and spiral ganglion neurons abruptly emerged 4–6 weeks post-HPβCD treatment. This secondary wave of degeneration combined with the initial OHC loss results in a profound, irreversible hearing loss.

Cyclodextrin Monomers and Polymers for Drug Activity Enhancement

Cyclodextrins (CDs) and cyclodextrin (CD)-based polymers are well-known complexing agents. One of their distinctive features is to increase the quantity of a drug in a solution or improve its delivery. However, in certain instances, the activity of the solutions is increased not only due to the increase of the drug dose but also due to the drug complexation. Based on numerous studies reviewed, the drug appeared more active in a complex form. This review aims to summarize the performance of CDs and CD-based polymers as activity enhancers. Accordingly, the review is divided into two parts, i.e., the effect of CDs as active drugs and as enhancers in antimicrobials, antivirals, cardiovascular diseases, cancer, neuroprotective agents, and antioxidants.

Nano- and Micro-Technologies Applied to Food Nutritional Ingredients

New technologies are currently investigated to improve the quality of foods by enhancing their nutritional value, freshness, safety, and shelf-life, as well as by improving their tastes, flavors and textures. Moreover, new technological approaches are being explored, in this field, to address nutritional and metabolism-related diseases (i.e., obesity, diabetes, cardiovascular diseases), to improve targeted nutrition, in particular for specific lifestyles and elderly population, and to maintain the sustainability of food production. A number of new processes and materials, derived from micro- and nano-technology, have been used to provide answers to many of these needs and offer the possibility to control and manipulate properties of foods and their ingredients at the molecular level. The present review focuses on the importance of micro- and nano-technology in the food and nutritional sector and, in particular, provides an overview of the micro- and nano-materials used for the administration of nutritional constituents essential to maintain and improve health, as well as to prevent the development and complications of diseases.

Effects of α-Cyclodextrin on Cholesterol Control and Hydrolyzed Ginseng Extract on Glycemic Control in People With Prediabetes: A Randomized Clinical Trial

IMPORTANCE

Effective strategies for preventing type 2 diabetes are needed. Many people turn to complementary medicines, but there is little well-conducted scientific evidence to support their use.

OBJECTIVE

To assess the efficacy of α-cyclodextrin for cholesterol control and that of hydrolyzed ginseng for glycemic control in people with prediabetes and overweight or obesity.

DESIGN, SETTING, AND PARTICIPANTS

This 6-month double-blind, placebo-controlled, randomized clinical trial, with a 2 × 2 factorial design, was conducted between July 2015 and October 2018 at 2 locations in Sydney, Australia. Eligible participants were aged 18 years or older, had a body mass index (weight in kilograms divided by height in meters squared) of 25 or higher, and had prediabetes within 6 months of study entry according to the American Diabetes Association guidelines. Data analysis was performed from May to August 2019.

INTERVENTIONS

Participants were randomized to 1 of 4 groups to take active or placebo versions of each supplement (α-cyclodextrin plus hydrolyzed ginseng, α-cyclodextrin plus placebo, placebo plus hydrolyzed ginseng, or placebo plus placebo) for 6 months. All participants received dietetic advice for weight loss.

MAIN OUTCOMES AND MEASURES

The primary outcomes were the differences in total cholesterol and fasting plasma glucose between groups after 6 months. The primary analysis used the intention-to-treat principle. Multiple predetermined subsample analyses were conducted.

RESULTS

A total of 401 participants were eligible for the study (248 women [62%]; mean [SD] age, 53.5 [10.2] years; mean [SD] body mass index, 34.6 [6.2]). One hundred one patients were randomized to receive α-cyclodextrin plus hydrolyzed ginseng, 99 were randomized to receive α-cyclodextrin plus placebo, 101 were randomized to receive placebo plus hydrolyzed ginseng, and 100 were randomized to receive placebo plus placebo. For 200 participants taking α-cyclodextrin compared with 201 participants taking placebo, there was no difference in total cholesterol after 6 months (-1.5 mg/dL; 95% CI, -6.6 to 3.5 mg/dL; P = .51). For 202 participants taking hydrolyzed ginseng compared with 199 participants taking placebo, there was no difference in fasting plasma glucose after 6 months (0.0 mg/dL; 95% CI, -1.6 to 1.8 mg/dL; P = .95). Use of α-cyclodextrin was associated with constipation (16 participants vs 4 participants; P = .006) and cough (8 participants vs 1 participant; P = .02). Use of hydrolyzed ginseng was associated with rash and pruritus (13 participants vs 2 participants; P = .006). Only 37 of 401 participants (9.2%) experienced these adverse events.

CONCLUSIONS AND RELEVANCE

Although they are safe for use, there was no benefit found for either α-cyclodextrin for cholesterol control or hydrolyzed ginseng for glycemic control in people with prediabetes and overweight or obesity.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry Identifier: ACTRN12614001302640.

Cyclic Oligosaccharides as Active Drugs, an Updated Review

There have been many reviews of the cyclic oligosaccharide cyclodextrin (CD) and CD-based materials used for drug delivery, but the capacity of CDs to complex different agents and their own intrinsic properties suggest they might also be considered for use as active drugs, not only as carriers. The aim of this review is to summarize the direct use of CDs as drugs, without using its complexing potential with other substances. The direct application of another oligosaccharide called cyclic nigerosyl-1,6-nigerose (CNN) is also described. The review is divided into lipid-related diseases, aggregation diseases, antiviral and antiparasitic activities, anti-anesthetic agent, function in diet, removal of organic toxins, CDs and collagen, cell differentiation, and finally, their use in contact lenses in which no drug other than CDs are involved. In the case of CNN, its application as a dietary supplement and immunological modulator is explained. Finally, a critical structure-activity explanation is provided.

Ginsenoside Compound K: Insights into Recent Studies on Pharmacokinetics and Health-Promoting Activities

Ginseng (Panax ginseng) is an herb popular for its medicinal and health properties. Compound K (CK) is a secondary ginsenoside biotransformed from major ginsenosides. Compound K is more bioavailable and soluble than its parent ginsenosides and hence of immense importance. The review summarizes health-promoting in vitro and in vivo studies of CK between 2015 and 2020, including hepatoprotective, anti-inflammatory, anti-atherosclerosis, anti-diabetic, anti-cancer, neuroprotective, anti-aging/skin protective, and others. Clinical trial data are minimal and are primarily based on CK-rich fermented ginseng. Besides, numerous preclinical and clinical studies indicating the pharmacokinetic behavior of CK, its parent compound (Rb1), and processed ginseng extracts are also summarized. With the limited evidence available from animal and clinical studies, it can be stated that CK is safe and well-tolerated. However, lower water solubility, membrane permeability, and efflux significantly diminish the efficacy of CK and restrict its clinical application. We found that the use of nanocarriers and cyclodextrin for CK delivery could overcome these limitations as well as improve the health benefits associated with them. However, these derivatives have not been clinically evaluated, thus requiring a safety assessment for human therapy application. Future studies should be aimed at investigating clinical evidence of CK.

Cyclodextrins: Potential therapeutics against atherosclerosis

Atherosclerosis is an inflammatory disease resulting from subendothelial accumulation of lipoprotein-derived cholesterol in susceptible arterial segments, ultimately leading to the formation of clinically significant atherosclerotic plaques. Despite significant advances in the treatment of atherosclerosis, atherosclerotic cardiovascular diseases remain the leading cause of death and disabilities worldwide. Accordingly, there is an urgent need for novel therapies. Cyclodextrins are cyclic oligosaccharides produced from many sources of starch by enzymatic degradation. The frequently used cyclodextrins are α-, β-, and γ-cyclodextrins, which are composed of six, seven, and eight glucose moieties, respectively. Especially β-cyclodextrin can entrap hydrophobic compounds, such as cholesterol, into its hydrophobic cavity and form stable inclusion complexes with cholesterol. This inherent affinity of cyclodextrins has been exploited to extract excess cholesterol from cultured cells, as well as intra- and extracellular cholesterol stores present in atherosclerotic lesions of experimental animals. Accordingly, cyclodextrins could be considered as potentially effective therapeutic agents for the treatment of atherosclerosis. In this review, we address recent advances and the current status of the development of cyclodextrins and provide an update of the latest in vitro and in vivo experiments that pave the way to clinical studies. The emerging therapeutic opportunities by using cyclodextrins could aid us in our efforts to ultimately eradicate the residual risk after other cholesterol-lowering pharmacotherapies, and also reduce the associated burden of premature deaths due to atherosclerotic cardiovascular diseases.