Search Results (15)

It is well established that vascular dysfunction is common in people with diabetes mellitus and is associated with increased risk of heart attack, ischaemic stroke and peripheral vascular disease. Although our understanding of the molecular mechanisms responsible is incomplete, persistent hyperglycaemia observed in poorly controlled diabetes has long been thought to be a critical factor. Multiple studies have, therefore, investigated the effects of poor glycaemic control on vascular function in multiple experimental settings, from in vitro and ex vivo models of primary human cells and tissues through to pre-clinical models. This review consolidates our current understanding of how metabolic and cell signalling pathways triggered by poor glycaemic control, impact vascular function in diabetes. We also evaluate how these pathways could be exploited to develop targeted therapeutic approaches to improve cardiovascular outcomes specifically in people with diabetes. Full article

Objectives: Cancer is a multifactorial disease determined by several factors. Metabolic disorders such as obesity and diabetes significantly contribute to cancer risk by promoting chronic inflammation, insulin resistance, and hormonal dysregulation. Obesity and hyperglycaemia elevate insulin-like growth factor-1 (IGF-1) levels, driving oncogenic pathways such as PI3K/Akt/mTOR, which promote tumour proliferation and survival. Furthermore, cancer cells undergo metabolic reprogramming, characterised by increased reliance on glycolysis (Warburg effect), facilitating tumour growth and therapy resistance. Hence, body weight reduction and glycaemic control may represent potential strategies for cancer prevention and treatment. Irisin, a myokine secreted by skeletal muscle, plays a critical role in cellular metabolism and energy homeostasis. Emerging evidence suggests that irisin may exert tumour-suppressive effects by modulating key metabolic and oncogenic pathways. Methods: A systematic literature search identified studies investigating irisin’s effects in various cancer models. Results: In vitro, irisin exerts dose- and time-dependent anti-proliferative effects in a variety of cancer cell lines, primarily via PI3K/Akt/mTOR inhibition and AMPK activation, leading to cell cycle arrest and apoptosis. Additionally, irisin inhibits epithelial–mesenchymal transition, which suppresses cancer cell migration and invasion. However, conflicting findings, particularly in hepatocellular carcinoma, suggest tissue-specific responses. Similarly, clinical data regarding systemic and tumoural irisin levels remain inconsistent and appear to vary based on cancer type and stage. Conclusions: Irisin represents a promising therapeutic target due to its ability to modulate metabolic and oncogenic pathways. However, further research is needed to elucidate its clinical relevance and optimise its application as an adjunct to existing cancer therapies. Full article

Background: The New Zealand pine bark has been demonstrated in vitro to inhibit digestive enzymes involved in carbohydrate digestion (alpha-amylase, alpha-glucosidase, and dipeptidyl-peptidase 4 (DPP-4)). Objective: This study aims to investigate the inhibitory effects of the New Zealand pine bark on sucrose uptake and glycaemic responses in humans. Methods: A single-blind, randomised, placebo-controlled, crossover trial was carried out involving healthy adults (n = 40 (M: 12, F: 28), 30.1 ± 1.3 years, BMI 23.4 ± 0.5 kg/m², HbA1c 32.5 ± 0.6 mmol/mol, FBG 4.7 ± 0.1 mmol/L). A control (75 g of sucrose powder only), and two doses of the pine bark extract (50 and 400 mg) were provided on separate occasions, with 75 g of sucrose mixed in 250 mL of water. Blood samples were collected at −10, 0, 15, 30, 45, 60, 90, and 120 min via a finger prick test. A linear mixed model for repeated measures (SPSS v30, IBM) was applied, and data presented as model-adjusted mean ± SEM. Results: Compared to control (247.5 ± 14.0 mmol/L⋅min), the iAUCglucose was significantly reduced with the 400 mg dose (211.8 ± 13.9 mmol/L⋅min, 14.4% reduction, and p = 0.037), but not with 50 mg dose (220.8 ± 14.2 mmol/L⋅min, 10.8% reduction, and p = 0.184). Compared to control (9.1 ± 0.2 mmol/L), glucose peak value was significantly reduced with the 50 mg dose (8.6 ± 0.2 mmol/L, 5.5% reduction, and p = 0.016) but not with the 400 mg dose (8.7 ± 0.2 mmol/L, 4.4% reduction, and p = 0.093). There were no statistically significant changes in postprandial insulin levels with the pine bark extract compared to control. Conclusions: The New Zealand pine bark extract attenuated sucrose uptake with improved glycaemic responses, and may therefore be useful as a hypoglycaemic adjunct to the diet. Full article

The beneficial effects of an insect-based diet on human health and, in particular, the regulatory ability of digested insects’ proteins on the glycaemic response in humans are topics that need to be investigated deeper. In this work, we performed an in vitro study on the modulatory activity of gastrointestinal digested black soldier fly (BSF) prepupae on the enterohormone GLP-1 and its natural inhibitor, DPP-IV. We verified whether actions intended to valorise the starting insect biomass, i.e., insect-optimised growth substrates and prior fermentation, can positively impact human health. Our results highlight that the digested BSF proteins from all the prepupae samples had a high stimulatory and inhibitory ability on the GLP-1 secretion and the DPP-IV enzyme in the human GLUTag cell line. Gastrointestinal digestion significantly improved the DPP-IV inhibitory capacity of the whole insect protein. Moreover, it was seen that optimised diets or fermentation processes preceding the digestion, in any case, did not positively affect the efficacy of the answer. BSF was already considered one of the edible insects more suitable for human consumption for its optimal nutritional profile. The BSF bioactivity here shown, after simulated digestion, on glycaemic control systems makes this species even more promising. Full article

The present study investigates the individual and interactional effects of α-amylase (6 and 10 ppm), xylanase (70 and 120 ppm) and cellulase (35 and 60 ppm) on the physicochemical characteristics and nutritional quality of Chinese steamed bread (CSB) incorporated with 15% oat bran. As a result, the single enzyme can significantly improve the specific volume and texture of CSB. Compared to the single enzyme, the combined enzymes improved the specific volume of CSB up to the highest value (2.51 mL/g) and decreased the hardness to the minimum value (233.61 g) when the concentration was 6, 70 and 35 ppm. With respect to chemical and nutritional properties, the addition of single enzyme had no great changes, while the combined enzymes (6, 70 and 35 ppm) significantly (p < 0.05) decreased the total starch from 37.52 to 34.11% and hence increased the area under the reducing sugar release curve during 2 h in vitro digestion (AUC) from 344.61 to 371.26. Consequently, enzymes combination can significantly improve the quality of oat bran CSB whereas reduce the nutritional value of oat bran CSB. Full article

Auricularia cornea, or wood ear mushroom (WEM), is an edible macrofungus that is popular as a delicacy and for various biological activities. This study aims to determine the nutrient composition, in vitro antioxidant activities and the effect on postprandial blood glucose in human subjects after consuming instant noodles incorporated with 5% WEM powder. The proximate composition of WEM powder was 9.76% moisture, 2.40% ash, 7.52% protein, 0.15% fat, 37.96% crude fibre, 42.21% carbohydrate, and a total dietary fibre was 69.43%. Meanwhile, the proximate composition of 5% WEM noodles was 10.21% moisture, 2.87% ash, 11.37% protein, 0.16% fat, 5.68% crude fibre and 68.96% carbohydrates, while the total dietary fibre was 13.30%. The mineral content of WEM powder in decreasing order: potassium > calcium > magnesium > sodium > iron > zinc > manganese > copper > selenium > chromium. The incorporation of 5% WEM powder significantly (p < 0.05) reduced carbohydrates and increased the ash, crude fibre and total dietary fibre, antioxidant activities and total phenolic content of the instant noodles. Furthermore, the incorporation of 5% WEM significantly increased potassium, calcium, magnesium, iron, and zinc content. The addition of WEM powder reduced the postprandial glycaemic response and produced a moderate glycaemic index (GI). In conclusion, the incorporation with WEM powder could be an effective way of developing nutritious and low GI instant noodles, thus, improving nutrient intake and human health. Full article

Curcumin has been suggested as a promising treatment for metabolic diseases, but the high doses required limit its therapeutic use. In this study, a new curcuminoid is synthesised to increase curcumin anti-inflammatory and antioxidant potential and to achieve hypoglycaemic and protective vascular effects in type 2 diabetic rats in a lower dose. In vitro, the anti-inflammatory effect was determined through the Griess reaction, and the antioxidant activity through ABTS and TBARS assays. In vivo, Goto-Kakizaki rats were treated for 2 weeks with the equimolar dose of curcumin (40 mg/kg/day) or curcuminoid (52.4 mg/kg/day). Fasting glycaemia, insulin tolerance, plasma insulin, insulin signalling, serum FFA, endothelial function and several markers of oxidative stress were evaluated. Both compounds presented a significant anti-inflammatory effect. Moreover, the curcuminoid had a marked hypoglycaemic effect, accompanied by higher GLUT4 levels in adipose tissue. Both compounds increased NO-dependent vasorelaxation, but only the curcuminoid exacerbated the response to ascorbic acid, consistent with a higher decrease in vascular oxidative and nitrosative stress. SOD1 and GLO1 levels were increased in EAT and heart, respectively. Altogether, these data suggest that the curcuminoid developed here has more pronounced effects than curcumin in low doses, improving the oxidative stress, endothelial function and glycaemic profile in type 2 diabetes. Full article

Wheat bread supplemented with mushroom powder from three different species of mushrooms was investigated in terms of starch characteristics (content, gelatinisation, and digestibility) and antioxidant capacities. The decrease in total starch contents, and increase in phenolic contents of the breads, were associated with increased mushroom powder contents. Mushroom inclusion reduced the rate of reducing sugar released over 120 min in an in vitro digestion compared to the control sample, implying a lower area under the curve (AUC) value with the inclusion of mushroom powder and a potentially lower predicted glycaemic response of the bread. Mushroom powder incorporation also enhanced the DPPH radical scavenging assay and oxygen radical absorbance capacity (ORAC) compared to control bread. The action of the addition of different mushroom powders on the bread crust and crumb microstructure properties was also studied. Mushroom powder altered the internal microstructure of the bread crust and crumb by affecting the interactions between starch and the other components of the bread. Overall, this shows that mushroom powder could be added to bread to deliver health benefits to consumers. Full article

Resistant starch (RS) in foods has positive benefits for potentially alleviating lifestyle diseases. RS is correlated positively with starch amylose content. This study aimed to see what level of amylose in durum wheat is needed to lower pasta GI. The silencing of starch synthases IIa (SSIIa) and starch branching enzymes IIa (SBEIIa), key genes involved in starch biosynthesis, in durum wheat cultivar Svevo was performed and spaghetti was prepared and evaluated. The SSIIa and SBEIIa mutants have a 28% and 74% increase in amylose and a 2.8- and 35-fold increase in RS, respectively. Cooked pasta was softer, with higher cooking loss but lower stickiness compared to Svevo spaghetti, and with acceptable appearance and colour. In vitro starch digestion extent (area under the digestion curve) was decreased in both mutants, but much more in SBEIIa, while in vivo GI was only significantly reduced from 50 to 38 in SBEIIa. This is the first study of the glycaemic response of spaghetti prepared from SBEIIa and SSIIa durum wheat mutants. Overall pasta quality was acceptable in both mutants but the SBEIIa mutation provides a clear glycaemic benefit and would be much more appealing than wholemeal spaghetti. We suggest a minimum RS content in spaghetti of ~7% is needed to lower GI which corresponded to an amylose content of ~58%. Full article

The development of rice that can produce slow and steady postprandial glucose in the bloodstream is a response to alarmingly high global rates of obesity and related chronic diseases. However, rice grain quality programs from all over the world currently do not have access to a high-throughput method to distinguish rice breeding materials that are digested slowly. The objective of this study was to develop a high-throughput in vitro assay to screen the digestibility of cooked white rice grains and to investigate its ability to differentiate rice genotypes with a low starch digestibility rate. The digestibility rate and extent of three commercial rice genotypes with diverse GI values (Doongara, Reiziq and Waxy) were successfully differentiated using the protocol. Further investigations with eight rice genotypes indicated the percentage of starch hydrolysed at a single time point of the assay (SH-60) successfully differentiated genotypes with a low digestibility rate (the SH-60 of Doongara and YRL127 was 50% and 59%, respectively) from genotypes with an intermediate or high digestibility rate (SH-60 values were between 64% and 93%). Application of this methodology in rice breeding programs may assist in the screening and development of new varieties with a desirable postprandial glycaemic response. Full article

Consumption of dietary bioactives is an avenue to enhancing the effective healthiness of diets by attenuating the glycaemic response. The intestinal brush border enzyme sucrase-isomaltase (SI) is the sole enzyme hydrolysing consumed sucrose, and we previously showed the acute effects of olive leaf extract (OLE) on sucrase activity when given together with sugars both in vitro and in vivo. Here we tested whether OLE could affect sucrase expression when pre-incubated chronically, a “priming” effect not dependent on competitive interaction with SI, in both a cell model and a human intervention. Using differentiated Caco-2/TC7 cells, long-term pre-treatment with oleuropein-rich olive leaf extract (OLE) lowered SI mRNA, surface protein and activity, and attenuated subsequent sucrose hydrolysis. Based on these results, a randomised, double-blinded, placebo-controlled, crossover pilot study was conducted. OLE (50 mg oleuropein) was consumed in capsule form 3 times a day for 1 week by 11 healthy young women followed by an oral sucrose tolerance test in the absence of OLE. However this treatment, compared to placebo, did not induce a change in post-prandial blood glucose maximum concentration (Glc_max), time to reach Glc_max and incremental area under the curve. These results indicate that changes in SI mRNA, protein and activity in an intestinal cell model by OLE are not sufficient under these conditions to induce a functional effect in vivo in healthy volunteers. Full article

Background: Kiwifruit are nutrient-rich and have properties which indicate a low glycaemic impact compared with many cooked cereal foods, suggesting that they may be used for dietary enrichment of vitamin C without glycaemic cost. Aim: To develop tables for equi-carbohydrate and equi-glycaemic partial exchange of kiwifruit for glycaemic carbohydrate foods. Method: The available carbohydrate content of Zespri^® Green and Zespri^® SunGold kiwifruit was determined as sugars released during in vitro digestive analysis. Glycaemic potency was determined as grams of glucose equivalents (GGEs) in a clinical trial using 200 g (a two-kiwifruit edible portion) of each cultivar, non-diabetic subjects (n = 20), and a glucose reference. GGE values were also estimated for a range of carbohydrate foods in the New Zealand Food Composition Database for which available carbohydrate and glycaemic index values were available. The values allowed exchange tables to be constructed for either equi-carbohydrate or equi-glycaemic partial exchange of kiwifruit for the foods. Results: GGE values of both kiwifruit cultivars were low (“Hayward”, 6.6 glucose equivalents/100 g; “Zesy002”, 6.7 glucose equivalents/100 g). Partial equi-carbohydrate substitution of foods in most carbohydrate food categories substantially increased vitamin C with little change in glycaemic impact, while equi-glycaemic partial substitution by kiwifruit could be achieved with little change in carbohydrate intake. Conclusion: Equi-carbohydrate partial exchange of kiwifruit for starchy staple foods is a means of greatly increasing nutrient richness in a diet without the physiological costs of increased glycaemia and insulin responses or carbohydrate intake. Full article

Pancreatic islet transplantation is a promising treatment for type 1 diabetes mellitus offering improved glycaemic control by restoring insulin production. Improved human pancreatic islet isolation has led to higher islet transplantation success. However, as many as 50% of islets are lost after transplantation due to immune responses and cellular injury, gene therapy presents a novel strategy to protect pancreatic islets for improved survival post-transplantation. To date, most of the vectors used in clinical trials and gene therapy studies have been derived from mammalian viruses such as adeno-associated or retrovirus. However, baculovirus BacMam vectors provide an attractive and safe alternative. Here, a novel BacMam was constructed containing a frameshift mutation within fp25, which results in virus stocks with higher infectious titres. This improved in vitro transduction when compared to control BacMams. Additionally, incorporating a truncated vesicular stomatitis virus G protein increased transduction efficacy and production of EGFP and BCL2 in human kidney (HK-2) and pancreatic islet β cells (EndoC βH3). Lastly, we have shown that our optimized BacMam vector can deliver and express egfp in intact pancreatic islet cells from human cadaveric donors. These results confirm that BacMam vectors are a viable choice for providing delivery of transgenes to pancreatic islet cells. Full article

Functional foods containing peptides offer the possibility to modulate the absorption of sugars and insulin levels to prevent diabetes. This study investigates the potential of germinated soybean peptides to modulate postprandial glycaemic response through inhibition of dipeptidyl peptidase IV (DPP-IV), salivary α-amylase, and intestinal α-glucosidases. A protein isolate from soybean sprouts was digested by pepsin and pancreatin. Protein digest and peptide fractions obtained by ultrafiltration (<5, 5–10 and >10 kDa) and subsequent semipreparative reverse phase liquid chromatography (F1, F2, F3, and F4) were screened for in vitro inhibition of DPP-IV, α-amylase, maltase, and sucrase activities. Protein digest inhibited DPP-IV (IC₅₀ = 1.49 mg/mL), α-amylase (IC₅₀ = 1.70 mg/mL), maltase, and sucrase activities of α-glucosidases (IC₅₀ = 3.73 and 2.90 mg/mL, respectively). Peptides of 5–10 and >10 kDa were more effective at inhibiting DPP-IV (IC₅₀ = 0.91 and 1.18 mg/mL, respectively), while peptides of 5–10 and <5 kDa showed a higher potency to inhibit α-amylase and α-glucosidases. Peptides in F1, F2, and F3 were mainly fragments from β-conglycinin, glycinin, and P34 thiol protease. The analysis of structural features of peptides in F1–F3 allowed the tentative identification of potential antidiabetic peptides. Germinated soybean protein showed a promising potential to be used as a nutraceutical or functional ingredient for diabetes prevention. Full article

Marine-based food supplements can improve human nutrition. In an effort to modulate glycaemic response and enhance nutritional aspects, marine-derived algal food rich in astaxanthin was used in the formulation of a model food (wholemeal cookie). Astaxanthin substitution of cookies made from three flours (wheat, barley and oat) demonstrated a significant reduction in the rate of glucose released during in vitro digestion together with an increase in the total phenolic content (TPC) and antioxidant capacity of the food. The significantly (p < 0.005) lower free glucose release was observed from cookies with 15% astaxanthin, followed by 10% and then 5% astaxanthin in comparison with control cookies of each flour. Total phenolic content, DPPH radical scavenging and Oxygen Radical Absorbance Capacity (ORAC) value also notably increased with increase in astaxanthin content. The results evidence the potential use of microalgae to enhance the bioactive compounds and lower the glycaemic response of wholemeal flour cookie. Full article