Genes and environment in type 2 diabetes and atherosclerosis in aboriginal Canadians

Food System Transformation and Gut Microbiota Transition: Evidence on Advancing Obesity, Cardiovascular Diseases, and Cancers-A Narrative Review

Food, a vital component of our daily life, is fundamental to our health and well-being, and the knowledge and practices relating to food have been passed down from countless generations of ancestors. Systems may be used to describe this extremely extensive and varied body of agricultural and gastronomic knowledge that has been gathered via evolutionary processes. The gut microbiota also underwent changes as the food system did, and these alterations had a variety of effects on human health. In recent decades, the gut microbiome has gained attention due to its health benefits as well as its pathological effects on human health. Many studies have shown that a person's gut microbiota partially determines the nutritional value of food and that diet, in turn, shapes both the microbiota and the microbiome. The current narrative review aims to explain how changes in the food system over time affect the makeup and evolution of the gut microbiota, advancing obesity, cardiovascular disease (CVD), and cancer. After a brief discussion of the food system's variety and the gut microbiota's functions, we concentrate on the relationship between the evolution of food system transformation and gut microbiota system transition linked to the increase of non-communicable diseases (NCDs). Finally, we also describe sustainable food system transformation strategies to ensure healthy microbiota composition recovery and maintain the host gut barrier and immune functions to reverse advancing NCDs.

A combination of (+)-catechin and (-)-epicatechin underlies the in vitro adipogenic action of Labrador tea (Rhododendron groenlandicum), an antidiabetic medicinal plant of the Eastern James Bay Cree pharmacopeia

ETHNOPHARMACOLOGICAL RELEVANCE

Rhododendron groenlandicum (Oeder) Kron & Judd (Labrador tea) was identified as an antidiabetic plant through an ethnobotanical study carried out with the close collaboration of Cree nations of northern Quebec in Canada.

OBJECTIVES

In a previous study the plant showed glitazone-like activity in a 3T3-L1 adipogenesis bioassay. The current study sought to identify the active compounds responsible for this potential antidiabetic activity using bioassay guided fractionation based upon an in vitro assay that measures the increase of triglycerides content in 3T3-L1 adipocyte.

MATERIALS AND METHODS

Isolation and identification of the crude extract's active constituents was carried out. The 80% ethanol extract was fractionated using silica gel column chromatography. Preparative HPLC was then used to isolate the constituents. The identity of the isolated compounds was confirmed by UV and mass spectrometry.

RESULTS

Nine chemically distinct fractions were obtained and the adipogenic activity was found in fraction 5 (RGE-5). Quercetins, (+)-catechin and (-)-epicatechin were detected and isolated from this fraction. While (+)-catechin and (-)-epicatechin stimulated adipogenesis (238±26% and 187±21% relative to vehicle control respectively) at concentrations equivalent to their concentrations in the active fraction RGE-5, none afforded biological activity similar to RGE-5 or the plant's crude extract when used alone. When cells were incubated with a mixture of the two compounds, the adipogenic activity was close to that of the crude extract (280.7±27.8 vs 311± 30%).

CONCLUSION

Results demonstrate that the mixture of (+)-catechin and (-)-epicatechin is responsible for the adipogenic activity of Labrador tea. This brings further evidence for the antidiabetic potential of R. groenlandicum and provides new opportunities to profile active principles in biological fluids or in traditional preparations.

Labrador tea (Rhododendron groenlandicum) attenuates insulin resistance in a diet-induced obesity mouse model

PURPOSE

Using a diet-induced obesity (DIO) mouse model, we investigated the antidiabetic effect of Labrador tea [Rhododendron groenlandicum (Oeder) Kron and Judd], a beverage and medicinal tea used by the Cree Nations of northern Quebec.

METHODS

C57BL6 mice were divided into five groups and given standard chow (~4 % of lipids) or high-fat diet (~35 % of lipids) for 8 weeks until they became obese and insulin resistant. Treatment began by adding the plant extract at three doses (125, 250 and 500 mg/kg) to the high-fat diet for another 8 weeks. At the end of the study, insulin-sensitive tissues (liver, skeletal muscle, adipose tissue) were collected to investigate the plant's molecular mechanisms.

RESULTS

Labrador tea significantly reduced blood glucose (13 %), the response to an oral glucose tolerance test (18.2 %) and plasma insulin (65 %) while preventing hepatic steatosis (42 % reduction in hepatic triglyceride levels) in DIO mice. It stimulated insulin-dependent Akt pathway (55 %) and increased the expression of GLUT4 (53 %) in skeletal muscle. In the liver, Labrador tea stimulated the insulin-dependent Akt and the insulin-independent AMP-activated protein kinase pathways. The improvement in hepatic steatosis observed in DIO-treated mice was associated with a reduction in inflammation (through the IKK α/β) and a decrease in the hepatic content of SREBP-1 (39 %).

CONCLUSIONS

Labrador tea exerts potential antidiabetic action by improving insulin sensitivity and mitigating high-fat diet-induced obesity and hyperglycemia. They validate the safety and efficacy of this plant, a promising candidate for culturally relevant complementary treatment in Cree diabetics.

A new susceptibility locus for myocardial infarction, hypertension, type 2 diabetes mellitus, and dyslipidemia on chromosome 12q24

We examined the role of hepatic nuclear factor-1 alpha (HNF1a) gene polymorphism on coronary artery disease (CAD) traits in 4631 Saudi angiographed individuals (2419 CAD versus 2212 controls) using TaqMan assay on ABI Prism 7900HT sequence detection system. Following adjustment for confounders, the rs2259820_CC (1.19 (1.01–1.42); P = 0.041), rs2464196_TT (1.19 (1.00–1.40); P = 0.045), and rs2259816_T (1.13 (1.01–1.26); P = 0.031) were associated with MI. The rs2259820_T (1.14 (1.03–1.26); P = 0.011) and rs2464196_C (1.12 (1.02–1.24); P = 0.024) were associated with type 2 diabetes mellitus (T2DM), while the rs2393791_T (1.14 (1.01–1.28); P = 0.032), rs7310409_G (1.16 (1.03–1.30); P = 0.013), and rs2464196_AG+GG (1.25 (1.05–1.49); P = 0.012) were implicated in hypertension. Hypertriglyceridemia was linked to the rs2393791_T (1.14 (1.02–1.27); P = 0.018), rs7310409_G (1.12 (1.01–1.25); P = 0.031), rs1169310_G (1.15 (1.04–1.28); P = 0.010), and rs1169313_CT+TT (1.24 (1.06–1.45); P = 0.008) and high low density lipoprotein-cholesterol levels were associated with rs2259820_T (1.23 (1.07–1.41); P = 0.004), rs2464196_T (1.22 (1.06–1.39); P = 0.004), and rs2259816_T (1.18 (1.02–1.36); P = 0.023). A 7-mer haplotype CATATAC (χ² = 7.50; P = 0.0062), constructed from the studied SNPs, was associated with MI, and CATATA implicated in T2DM (χ² = 3.94; P = 0.047). Hypertriglyceridemia was linked to TGCGGG (χ² = 4.26; P = 0.039), and obesity to ACGGGT (χ² = 5.04; P = 0.025). Our results suggest that the HNF1a is a common susceptibility gene for MI, T2DM, hypertension, and dyslipidemia.

Larix laricina, an Antidiabetic Alternative Treatment from the Cree of Northern Quebec Pharmacopoeia, Decreases Glycemia and Improves Insulin Sensitivity In Vivo

Larix laricina K. Koch is a medicinal plant belonging to traditional pharmacopoeia of the Cree of Eeyou Istchee (Eastern James Bay area of Canada). In vitro screening studies revealed that, like metformin and rosiglitazone, it increases glucose uptake and adipogenesis, activates AMPK, and uncouples mitochondrial function. The objective of this study was to evaluate the antidiabetic and antiobesity potential of L. laricina in diet-induced obese (DIO) C57BL/6 mice. Mice were subjected for eight or sixteen weeks to a high fat diet (HFD) or HFD to which L. laricina was incorporated at 125 and 250 mg/kg either at onset (prevention study) or in the last 8 of the 16 weeks of administration of the HFD (treatment study). L. laricina effectively decreased glycemia levels, improved insulin resistance, and slightly decreased abdominal fat pad and body weights. This occurred in conjunction with increased energy expenditure as demonstrated by elevated skin temperature in the prevention study and improved mitochondrial function and ATP synthesis in the treatment protocol. L. laricina is thus a promising alternative and complementary therapeutic approach for the treatment and care of obesity and diabetes among the Cree.

Obesity and type 2 diabetes in Northern Canada's remote First Nations communities: the dietary dilemma

First Nations populations in Northwestern Ontario have undergone profound dietary and lifestyle transformations in less than 50 years, which have contributed to the alarming rise in obesity and obesity-related diseases, in particular type 2 diabetes mellitus. Even though the genetic background of First Nations peoples differs from that of the Caucasians, genetics alone cannot explain such a high prevalence in obesity and type 2 diabetes. Modifications in lifestyle and diet are major contributors for the high prevalence of chronic diseases. What remains constant in the literature is the persistent view that locally harvested and prepared foods are of tremendous value to First Nations peoples providing important health and cultural benefits that are increasingly being undermined by western-based food habits. However, the complexities of maintaining a traditional diet require a multifaceted approach, which acknowledges the relationship between benefits, risks and viability that cannot be achieved using purely conventional medical and biological approaches. This brief review explores the biological predispositions and potential environmental factors that contribute to the development of the high incidence of obesity and obesity-related diseases in First Nations communities in Northern Canada. It also highlights some of the complexities of establishing exact physiological causes and providing effective solutions.

Evaluation of the antidiabetic potential of selected medicinal plant extracts from the Canadian boreal forest used to treat symptoms of diabetes: part II

Among the Cree of northern Quebec, the disproportionately high rate of diabetic complications is largely due to the cultural inadequacy of modern therapies for type 2 diabetes. To establish culturally adapted antidiabetic treatments, our team identified several candidate plant species used by the Cree to treat symptoms of diabetes. An initial study focused on 8 species and revealed that most possess significant in vitro antidiabetic activity. The purpose of the present study was to assess a further 9 species identified through the ethnobotanical survey. Crude plant extracts were screened for (i) potentiation of basal and insulin-stimulated glucose uptake by skeletal muscle cells (C2C12) and adipocytes (3T3-L1); (ii) potentiation of glucose-stimulated insulin secretion by pancreatic β cells (βTC); (iii) potentiation of adipogenesis in 3T3-L1 cells; (iv) protection against glucose toxicity and glucose deprivation in PC12-AC neuronal precursor cells; and (v) diphenylpicrylhydrazyl (DPPH) oxygen free radical scavenging. Four species potentiated basal glucose uptake in muscle cells or adipocytes, one species being as potent as metformin. Adipogenesis was accelerated by 4 species with a potency roughly half that of rosiglitazone. Five species protected PC12-AC cells against glucose toxicity and 4 protected against glucose deprivation. Five species exhibited antioxidant activity comparable to ascorbic acid. However, no species increased insulin secretion. The present study revealed that Gaultheria hispidula , Rhododendron tomentosum , and Vaccinium vitis-idaea exhibit a promising profile of antidiabetic potential and are good candidates for more in-depth evaluation.

Selected plant species from the Cree pharmacopoeia of northern Quebec possess anti-diabetic potential

Type II diabetes is a major health problem worldwide. Some populations, such as aboriginal peoples, are particularly at risk for this disease. In the Cree Nation of Quebec, Canada, prevalence in adults is approaching 20%, and the consequences are compounded by low compliance with modern medicine. In 2003, we conducted an ethnobotanical study of Cree medicinal plants used for the treatment of symptoms of diabetes. This served as the basis for a project designed to identify efficacious complementary treatment options more readily accepted by this population. The present study assesses the in vitro anti-diabetic potential of extracts from the 8 most promising plants to emerge from the ethnobotanical study. Cell-based bioassays were employed to screen for (i) potentiation of glucose uptake by skeletal muscle cells (C2C12) and adipocytes (3T3-L1); (ii) potentiation of glucose-stimulated insulin secretion (GSIS) and insulin production by pancreatic beta cells (INS 832/13); (iii) potentiation of triglyceride accumulation in differentiating 3T3-L1 cells; (iv) protection against glucose toxicity and glucose deprivation in pre-sympathetic neurons (PC12-AC). Additionally, anti-oxidant activity was measured biochemically by the diphenylpicrylhydrazyl (DPPH) reduction assay. All plant extracts potentiated basal or insulin-stimulated glucose uptake to some degree in muscle cells or adipocytes. Adipocyte differentiation was accelerated by 4 extracts. Five extracts conferred protection in PC12 cells. Three extracts displayed free radical scavenging activity similar to known anti-oxidants. None of the plant extracts enhanced GSIS or insulin content in INS 832/13 beta cells. It is concluded that the Cree pharmacopoeia contains several plants with significant anti-diabetic potential.

Indigenous health: update on the impact of diabetes and chronic kidney disease

PURPOSE OF REVIEW

With respect to chronic diseases such as diabetes and its complications, indigenous populations are known to suffer from poor health outcomes in comparison with whites. The purpose of this review is to highlight recent epidemiologic and intervention studies that have occurred in the areas of diabetes and renal disease among indigenous populations.

RECENT FINDINGS

The burden of diabetes is increasing among younger indigenous groups with epidemic levels of end-stage kidney disease. As dialysis therapy has contributed to prolong life among indigenous patients, cardiovascular disease has now become the leading cause of mortality in these populations. Clear preventive intervention strategies to improve rates of progression to end-stage kidney disease are not prevalent nor are they emerging over time. Access to kidney transplantation is also reduced among indigenous populations in Australia, New Zealand, the USA and Canada. Reasons for this disparity are unclear but likely multifactorial.

SUMMARY

Diabetes and its complications have produced a health crisis among indigenous populations. The impact on healthcare systems in countries where these indigenous populations reside will be substantial unless significant efforts are made to improve diabetic renal disease outcomes in the near future.

Plants used by the Cree Nation of Eeyou Istchee (Quebec, Canada) for the treatment of diabetes: A novel approach in quantitative ethnobotany

In the last decade, the Cree Nation of Eeyou Istchee has witnessed a 150% increase in the prevalence of Type II Diabetes (T2D) for people aged over 20 years. Clinical intervention using conventional therapeutic methods has yielded only a limited success within this population. An ethnobotanical survey was carried out to identify potentially antidiabetic plant species used within the traditional pharmacopoeia of the Cree. Interviews were held with 34 Cree Elders using a list of 15 symptoms ranked according to their association to T2D. A total of 18 species were cited during the survey, spanning 9 plant families. Species were prioritized for pharmacological analysis according to a Syndromic Importance Value, based on their frequency of citation by informants and the number and specificity of symptoms for which they were used. Correspondence and clustering analyses were also performed to determine the specificity of association between species and symptoms and the symptom-based correlation between species. A data matrix and species ranking order generated from Cree-specific literature demonstrates significant similarity and correlation to our original matrix and ranking, respectively. This article demonstrates the applicability of various underutilized quantitative tools in ethnobotany, while taking a convincing preliminary step towards a therapy more in harmony with Cree culture and lifestyle.

Genetic determinants of type 2 diabetes mellitus

Type 2 diabetes refers to a group of disparate metabolic diseases, which are typically characterized by insulin resistance in peripheral tissues, together with impaired insulin secretion from pancreatic beta-cells. The complexity of type 2 diabetes is related to factors such as genetic heterogeneity, interactions between genes, and the modulating role played by the environment. Recent progress has included defining the molecular basis of monogenic forms of type 2 diabetes, such as familial partial lipodystrophy and the subtypes of maturity-onset diabetes of the young (MODY), and also the identification of chromosomal regions that may harbor type 2 diabetes susceptibility genes. Many common variants in functional and positional candidate genes, including ADRB3, PPARG, ENPP1, and CAPN10, have also been studied for their possible role as determinants of type 2 diabetes, with varying levels of agreement between studies. The availability of a relatively complete sequence of the human genome will increase the amount of genetic information that can be used to evaluate hypotheses for the genetic basis of type 2 diabetes. To make sense of human type 2 diabetes in the post-genomic era, it is essential to have well-defined phenotypes in addition to sufficient numbers of individuals with the appropriate pedigree structure from families and/or communities.