Relationship Between Zinc Status and DNA Oxidative Damage in Patients with Type 2 Diabetes Mellitus

Phytochemical Profile and Antidiabetic, Antioxidant, and Anti-Inflammatory Activities of Gypsophila paniculata Ethanol Extract in Rat Streptozotocin-Induced Diabetes Mellitus

The present study aimed to investigate the effects of the Gypsophila paniculata ethanol extract (GPEE) on oxidative stress, inflammation, and metabolic markers in a rat model of streptozotocin-induced diabetes mellitus (DM). Phytochemical analysis using high-performance liquid chromatography coupled with mass spectrometry was performed to measure the total phenolic and flavonoid contents. In vitro antioxidant activity was evaluated through DPPH, FRAP, H2O2, and NO scavenging tests, and the in vivo effects of the GPEE were assessed in streptozotocin-induced DM rats. Treatments with the GPEE, metformin, and Trolox were administrated by gavage for 10 days. On day 11, blood was collected, and serum oxidative stress (total oxidative status, oxidative stress index, malondialdehyde, advanced oxidation protein products, 8-hydroxydeoxyguanosine, nitric oxide, 3-nitrotyrosine, advanced glycation end-products, total antioxidant reactivity, total thiols), inflammatory (IL-1β, NF-κB, IL-18, and gasdermin D), metabolic (fasting glucose, total cholesterol, triglycerides, and triglyceride-glucose index), and liver injury (AST, ALT, and AST:ALT ratio) markers were measured. The GPEE was found to have a significant polyphenols content and a moderate in vitro antioxidant effect. In vivo, the GPEE lowered oxidants and increased antioxidants, decreased inflammatory markers and blood glucose, and improved lipid profiles and transaminases in a dose-dependent manner, with higher doses having a better effect, being comparable to those of metformin and Trolox.

Oxidative DNA Damage and Zinc Status in Patients With Rheumatoid Arthritis in Duhok, Iraq

Background In patients with rheumatoid arthritis, oxidative DNA damage is increased by deficient zinc levels as well as increasing disease activity. However, the relationship between zinc levels, disease activity, and oxidative DNA damage remains unclear. In this study, we investigated serum zinc levels and disease activity and their association with 8-hydroxy-2-deoxyguanosine (8-OHdG). Methodology This case-control study was conducted among rheumatoid arthritis patients (n = 264) and healthy individuals (n = 192). Oxidative DNA damage was assessed by measuring serum 8-OHdG using enzyme-linked immunosorbent assay. Colorimetry was used to measure serum zinc levels. Disease activity was assessed using the Disease Activity Score-28 (DAS-28) score. Results Significantly higher 8-OHdG levels (p < 0.00) were found in the test group compared to the control group. Moreover, significantly lower serum zinc levels (p < 0.001) were noted in patients with rheumatoid arthritis compared to the control group. In addition, higher 8-OHdG levels were found in patients with low serum zinc levels compared to those with normal mean serum zinc levels. Lower levels of DNA oxidative damage were found in patients with moderate and low disease activity compared to those with high disease activity. A significant negative correlation was noted between serum zinc levels and DAS-28 scores and oxidative DNA damage marker (r = - 0.30, p = 0.038 and r = - 0.26, p = 0.043, respectively), while a significant positive correlation was observed between body mass index and 8-OHdG (r = 0.22, p = 0.02) in healthy individuals. Conclusions High serum 8-OHdG levels and high disease activity with low mean serum zinc levels may indicate a high degree of oxidative DNA damage in patients with rheumatoid arthritis.

Association of Serum Zinc Level with severity of chronic kidney disease in diabetic patients: a cross-sectional study

BACKGROUND

In recent years, it has been reported that diabetic patients tend to have a lower zinc intake due to unbalanced diet accompanying changes in lifestyle habits. We investigated serum zinc concentration in diabetic patients according to the stage of nephropathy.

METHODS

We enrolled 227 diabetic patients (119 men, 108 women, average age 65.7 ± 14.7 [mean ± standard deviation]) who were hospitalized for diabetes treatment due to poor blood glucose control. We investigated the relationship between fasting serum zinc concentration and estimated glomerular filtration rate (eGFR) and albuminuria (urinary albumin-to-creatinine ratio, UACR), as well as serum zinc concentration by stage of diabetic kidney disease and chronic kidney disease.

RESULTS

The mean HbA1c value was 10.5 ± 2.1%. Serum zinc concentration was 75.5 ± 16.0 μg/dL in males and 75.7 ± 12.2 μg/dL in females, showing no gender difference and no significant relationship with diabetes type. The serum zinc concentration was negatively correlated with age (r = - 0.309, P < 0.001) and positively correlated with eGFR (r = 0.144, P = 0.030). A tendency was observed of serum zinc concentration to decrease after overt nephropathy, with values of 76.4 ± 14.1 μg/dL in pre-nephropathy (stage 1, n = 131), 78.5 ± 13.2 μg/dL in incipient nephropathy (stage 2, n = 65), 66.4 ± 14.3 μg/dL in overt nephropathy (stage 3, n = 25), and 65.7 ± 11.9 μg/dL in kidney failure (stage 4, n = 6). Serum zinc showed a negative trend with estimated GFR (P = 0.004) and significant reduction in albuminuria, with stage A3 (n = 29, 65.7 ± 13.9 μg/dL) having lower levels than A1 (n = 131, 76.4 ± 14.1 μg/dL, P = 0.001) and A2 (n = 67, 78.4 ± 13.1 μg/dL, P < 0.001).

CONCLUSIONS

In diabetic patients, serum zinc concentration tended to decrease as age increased and also as renal function deteriorated. This study suggests that consideration of zinc deficiency is necessary in patients with overt albuminuria.

Triangulating evidence for the causal impact of single-intervention zinc supplement on glycaemic control for type 2 diabetes: systematic review and meta-analysis of randomised controlled trial and two-sample Mendelian randomisation

Although previous studies suggested the protective effect of Zn for type 2 diabetes (T2D), the unitary causal effect remains inconclusive. We investigated the causal effect of Zn as a single intervention on glycaemic control for T2D, using a systematic review of randomised controlled trials and two-sample Mendelian randomisation (MR). Four primary outcomes were identified: fasting blood glucose/fasting glucose, HbA1c, homeostatic model assessment for insulin resistance (HOMA-IR) and serum insulin/fasting insulin level. In the systematic review, four databases were searched until June 2021. Studies, in which participants had T2D and intervention did not comprise another co-supplement, were included. Results were synthesised through the random-effects meta-analysis. In the two-sample MR, we used single-nucleotide polymorphisms (SNP) from MR-base, strongly related to Zn supplements, to infer the relationship causally, but not specified T2D. In the systematic review and meta-analysis, fourteen trials were included with overall 897 participants initially. The Zn supplement led to a significant reduction in the post-trial mean of fasting blood glucose (mean difference (MD): −26·52 mg/dl, 95 % CI (−35·13, −17·91)), HbA1c (MD: −0·52 %, 95 % CI: (−0·90, −0·13)) and HOMA-IR (MD: −1·65, 95 % CI (−2·62, −0·68)), compared to the control group. In the two-sample MR, Zn supplement with two SNP reduced the fasting glucose (inverse-variance weighted coefficient: −2·04 mmol/l, 95 % CI (−3·26, −0·83)). From the two methods, Zn supplementation alone may causally improve glycaemic control among T2D patients. The findings are limited by power from the small number of studies and SNP included in the systematic review and two-sample MR analysis, respectively.

Serum Copper and Zinc Concentrations and Cognitive Impairment in Older Adults Aged 60 Years and Older

Epidemiological evidence on serum zinc and copper and cognitive impairment in older adults are not consistent. Results on serum zinc and copper and cognitive impairment in older adults from the National Health and Nutrition Examination Survey (NHANES) have not been reported. Data on serum zinc and copper and cognitive impairment from individuals ≥ 60 years of age were obtained from the 2011-2014 NHANES. Serum zinc and copper concentrations were determined with inductively coupled plasma dynamic reaction cell mass spectrometry. Cognitive impairment was assessed with four cognitive tests: the Digit Symbol Substitution Test (DSST), the Animal Fluency (AF), the Consortium to Establish a Registry for Alzheimer's Disease Delayed Recall (CERAD-DR), and the Word Learning (CERAD-WL) tests. Compared with the lowest tertile of serum copper, the multivariate-adjusted odds ratios of scoring low on the AF were 0.86 (0.44-1.68) in tertile 2 and 0.46 (0.25-0.82) in tertile 3, and the inverse association was also found in women. No association was found between serum copper and the DSST, CERAD-DR, and CRAD-WL, respectively. Compared with the lowest tertile of serum zinc, the multivariate-adjusted odds ratios of scoring low on the DSST were 0.83 (0.37-1.90) in tertile 2 and 0.42 (0.22-0.80) in tertile 3, and the inverse association was also found in men. No association was found between serum zinc and the AF, CERAD-DR, and CRAD-WL, respectively. In conclusion, serum copper and zinc were associated with certain cognitive performance tests among older adults, and the causality deserves to be confirmed further.

Mechanisms underlying the pathophysiology of type 2 diabetes: From risk factors to oxidative stress, metabolic dysfunction, and hyperglycemia

Type 2 diabetes (T2D) is a complex multifactorial disease that emerges from the combination of genetic and environmental factors, and obesity, lifestyle, and aging are the most relevant risk factors. Hyperglycemia is the main metabolic feature of T2D as a consequence of insulin resistance and β-cell dysfunction. Among the cellular alterations induced by hyperglycemia, the overproduction of reactive oxygen species (ROS) and consequently oxidative stress, accompanied by a reduced antioxidant response and impaired DNA repair pathways, represent essential mechanisms underlying the pathophysiology of T2D and the development of late complications. Mitochondrial dysfunction, endoplasmic reticulum (ER) stress, and inflammation are also closely correlated with insulin resistance and β-cell dysfunction. This review focus on the mechanisms by which oxidative stress, mitochondrial dysfunction, ER stress, and inflammation are involved in the pathophysiology of T2D, highlighting the importance of the antioxidant response and DNA repair mechanisms counteracting the development of the disease. Moreover, we indicate evidence on how nutritional interventions effectively improve diabetes care. Additionally, we address key molecular characteristics and signaling pathways shared between T2D and Alzheimer's disease (AD), which might probably be implicated in the risk of T2D patients to develop AD.

Environmental pollution and diabetes mellitus

Diabetes mellitus (DM) is a chromic metabolic disease that affects a large segment of the population worldwide. Physical inactivity, poor nutrition, and genetic predisposition are main risk factors for disease development. In the last decade, it was clear to the scientific community that DM development is linked to a novel disease inducer that was later defined as diabetogenic factors of pollution and endocrine disrupting agents. Environmental pollution is exponentially increasing in uncontrolled manner in several countries. Environmental pollutants are of diverse nature and toxicities, including polyaromatic hydrocarbons (PAHs), pesticides, and heavy metals. In the current review, we shed light on the impact of each class of these pollutants and the underlined molecular mechanism of diabetes induction and biological toxicities. Finally, a brief overview about the connection between coronavirus disease 2019 and diabetes pandemics is presented.