Serum Lycopene Levels in Patients with Diabetic Retinopathy

Lycopene: A Potent Antioxidant with Multiple Health Benefits

Lycopene is a naturally occurring carotenoid predominantly found in tomatoes and tomato-based products. Like other phytochemicals, it exhibits health beneficial biological activities that can be exploited when it is used as a dietary supplement. In vitro and in vivo, lycopene has been demonstrated to mitigate oxidative stress-induced metabolic dysfunctions and diseases including inflammation, obesity, and diabetes mellitus. Lycopene has been shown to alleviate metabolic diseases that affect the bone, eye, kidney, liver, lungs, heart, and nervous system. This review presents the state of the art regarding lycopene's health benefits and its potential applications in health system delivery. Furthermore, lycopene's protective effects against toxins, safety in its use, and possible toxicity are explored.

Lycopene: A Potent Antioxidant for the Amelioration of Type II Diabetes Mellitus

Nutrition is of utmost importance in chronic disease management and has often been described as the cornerstone of a variety of non-communicable diseases. In particular, type II diabetes mellitus (T2DM) represents a prevalent and global public health crisis. Lycopene, a bright red carotenoid hydrocarbon found in tomatoes and other red fruits and vegetables, has been extensively studied for its biological activities and treatment efficiency in diabetes care. Epidemiological investigations indicate that lycopene has potential antioxidant properties, is capable of scavenging reactive species, and alleviates oxidative stress in T2DM patients. This review aims to summarize the characteristics and mechanisms of action of lycopene as a potent antioxidant for T2DM. In addition, the evidence demonstrating the effects of lycopene on glycemic control and oxidative stress biomarkers in T2DM are also highlighted using animal and human studies as literature approach.

Carotenoid status in type 2 diabetes patients with and without retinopathy

Diabetic retinopathy (DR) is one of the leading causes of blindness. Carotenoids are plant-derived pigments required for general health and particularly for vision. In this study, we evaluated the dietary intake and blood carotenoid levels of type 2 diabetes (T2D) patients with and without DR. A cross-sectional case-control study was conducted among 151 age-matched controls and 344 T2D patients, of which 194 had DR and 150 had no DR (NDR). After a complete ophthalmic examination, the demographic, anthropometric and clinical profiles were obtained. Carotenoids in the plasma were measured by HPLC and dietary intakes were obtained using a food frequency questionnaire. The mean plasma levels of carotenoids (except γ-carotene) were significantly lower in the DR group compared to the Control and NDR groups. The dietary intakes of zeaxanthin, lycopene, α-carotene and β-carotene were significantly lower in the NDR group compared to the Control group, and were further lower in the DR group compared to the NDR group. Plasma carotenoid levels were significantly inversely associated with the duration of diabetes, RBS and HbA1c but positively associated with HDL. This study demonstrated decreased plasma levels and lower dietary intakes of carotenoids in DR subjects.

The potential health benefits of dietary natural plant products in age related eye diseases

In the past decade, there has been a tremendous increase in the number of cases of age-related eye diseases such as age-related macular degeneration (AMD), cataract, diabetic retinopathy and glaucoma. These diseases are the leading causes of visual impairment and blindness all over the world and are associated with many pathological risk factors such as aging, pollution, high levels of glucose (hyperglycaemia), high metabolic rates, and light exposure. These risk factors lead to the generation of uncontrollable reactive oxygen species (ROS), which causes oxidative stress. Oxidative stress plays a crucial role in the pathogenesis of age-related eye diseases through the activation of nuclear factor kappa B (NF-κB), vascular endothelial growth factor (VEGF), and lipid peroxidation, which leads to the production of inflammatory cytokines, angiogenesis, protein and DNA damages, apoptosis that causes macular degeneration (AMD), cataract, diabetic retinopathy and glaucoma. This review provides updated information on the beneficial effects of dietary natural plant products (DPNPs) against age-related eye diseases. In this review, supplementation of DPNPs demonstrated preventive and therapeutic effects on people at risk of or with age-related eye diseases due to their capacity to scavenge free radicals, ameliorate inflammatory molecules, neutralize the oxidation reaction that occurs in photoreceptor cells, decrease vascular endothelial growth factor and the blood-retinal barrier and increase the antioxidant defence system. However, further experiments and clinical trials are required to establish the daily doses of DPNPs that will safely and effectively prevent age-related eye diseases.

Lycopene Ameliorated Oxidative Stress and Inflammation in Type 2 Diabetic Rats

We aim to study the antioxidative and anti-inflammatory effects of lycopene on type 2 diabetes mellitus (T2DM) rats, anticipating a complementary strategy for the prevention of long-term complications of T2DM. In this study, rats with streptozotocin-induced diabetes were divided into four groups, receiving a 10-week lycopene intervention: DM, DM + low dose of lycopene (L), DM + medium dose of lycopene (M), and DM + high dose of lycopene (H) group with 0, 5, 10, and 15 mg/kg BW lycopene, respectively. At the end of intervention, fasted blood glucose (FBG) level, oxidative stress indicators, including glycosylated hemoglobin (GHb), glycosylated low-density lipoprotein, oxidized low-density lipoprotein (ox-LDL). and malondialdehyde (MDA), as well as antioxidants, that is, catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx), and inflammatory factors like tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP) were determined. The results indicated that oxidative stress and inflammatory factors were elevated in DM rats. Lycopene intervention decreased the FBG level in DM rats compared with the untreated ones. It revealed a dose-dependent effect on decreasing serum oxidative stress biomarkers, including GHb, ox-LDL, and MDA. Inflammatory factors (TNF-α and CRP) in DM rats were also decreased by lycopene intervention. Total antioxidative capacity as well as the activities of antioxidants in DM rats including CAT, SOD, and GPx were increased after lycopene intervention. We conclude that lycopene protects against diabetic progression and prevents further complications of diabetic rats through ameliorating oxidative stress and inflammation, as well as improving the systemic antioxidative capacity. PRACTICAL APPLICATION: According to our study, lycopene intakes at experimental dosages appear to have beneficial effects on ameliorating oxidative stress and inflammation in type 2 diabetes mellitus (T2DM) rats, suggesting that lycopene might help improving T2DM progression when its daily intake is up to about 0.79 mg/kg BW in humans, which approximately equals to 5 mg/kg BW in rats. However, more clinical trials are needed to provide a more reliable and convincing conclusion in humans.

Nutrition for diabetic retinopathy: plummeting the inevitable threat of diabetic vision loss

Diabetic retinopathy (DR) is among the leading causes of preventable blindness. Hyperglycemia, hypertension, hyperlipidemia and anemia majorly predispose its pathogenesis. The current treatment modalities of DR include laser photocoagulation therapy, intravitreal corticosteroids, intravitreal anti-vascular endothelial growth factor (VEGF) agents and vitreo-retinal surgery which are costly, highly invasive, unproven for prolonged use and opted in advanced stages of DR. By then retina already encounters a vast damage. Nutrients by their natural physiological, biochemical and molecular action can preserve retinal structure and functions by interfering with the various pathological steps prompting DR incidence, thereby altering the risk of developing this ocular morbidity. Nutrients can also play a central role in DR patients resistant towards the conventional medical treatments. However due to the byzantine interplay existing between nutrients and DR, the worth of nutrition in curbing this vision-threatening ocular morbidity remains silent. This review highlights how nutrients can halt DR development. A nutritional therapy, if adopted in the initial stages, can provide superior-efficacy over the current treatment modalities and can be a complementary, inexpensive, readily available, anodyne option to the clinically unmet requirement for preventing DR. Assessment of nutritional status is presently considered relevant in various clinical conditions except DR. Body Mass Index (BMI) conferred inconclusive results in DR subjects. Subjective Global Assessment (SGA) of nutritional status has recently furnished relevant association with DR status. By integrating nutritional strategies, the risk of developing DR can be reduced substantially. This review summarizes the subsisting knowledge on nutrition, potentially beneficial for preventing DR and sustaining good vision among diabetic subjects.

Furan toxicity on testes and protective role of lycopene in diabetic rats

OBJECTIVE

Furan (C₄H₄O) is a heat-induced food contaminant that is utilized as an industrial chemical agent. Lycopene is a natural substance that is produced by plants and tomatoes. We aimed to evaluate the toxicity of furan on testes and the protective effect of lycopene in diabetic rats.

MATERIAL AND METHODS

Male Wistar albino rats were divided into five groups: Group 1 (control group) received 1 mL/kg corn oil. Group 2 (diabetic control group) received 55 mg/kg STZ and 1 mL/kg corn oil. Group 3 (diabetic lycopene group) received 55 mg/kg STZ and 4 mg/kg lycopene. Group 4 (diabetic furan group) received 55 mg/kg STZ and 40 mg/kg furan. Group 5 (diabetic furan + lycopene group) received 55 mg/kg STZ, 40 mg/kg furan, and 4 mg/kg lycopene. After 28 days, the testes were extirpated in all groups. In the testicular tissue samples, the level of malondialdehyde (MDA) and the activities of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), and reducted glutathione (GST) were studied. Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone levels were measured. Histopathologic examination was performed by light microscope.

RESULTS

The MDA level and the activities of CAT, GPx, SOD, and GST were found to be higher in the furan group than in the control and diabetic control groups (p<0.05). The MDA level and the activities of CAT, GPx, SOD, and GST were significantly lower in the furan + lycopene group than in the furan group (p<0.05).

CONCLUSION

The low blood testosterone level in the rats who received furan suggested the presence of endocrinological defects and cellular degenerative changes. Lycopene may be effective to reverse furan toxicity in diabetic rat testes.

Dietary Intake of Lutein and Diabetic Retinopathy in the Atherosclerosis Risk in Communities Study (ARIC)

PURPOSE

We tested the hypothesis that dietary intake of lutein is inversely associated with prevalence of diabetic retinopathy (DR) due to its antioxidant and anti-inflammatory properties and location within the retina.

METHODS

We used logistic regression to examine the association between prevalent DR and energy-adjusted lutein intake by quartile (Q) using data collected from 1430 Atherosclerosis Risk in Communities Study (ARIC) participants with diabetes (n = 994 white, n = 508 black). DR was assessed from 45° non-mydriatic retinal photographs of one randomly chosen eye taken at visit 3 (1993-1995). Dietary lutein intake was estimated using a 66-item food frequency questionnaire at visit 1 (1987-1989).

RESULTS

Median estimated daily lutein intake was 1370 µg/1000 kcals and prevalence of DR was ~21%. We found a crude association between lutein and DR (odds ratio, OR, 2.11, 95% confidence interval, CI, 1.45-3.09 for Q4, high intake, vs. Q1, low intake; p for trend <0.0001), which was attenuated after adjustment for ethnicity, duration of diabetes, glycosylated hemoglobin levels, field center and energy intake (OR 1.41, 95% CI 0.87-2.28; p for trend = 0.01). In analyses limited to persons with short diabetes duration (<6 years), the association no longer persisted (OR 0.94, 95% CI 0.31-2.16; p for trend =0.72) compared to the association in those with longer diabetes duration (≥6 years; OR 1.58, 95% CI 0.91-2.75; p for trend = 0.01).

CONCLUSION

Contrary to our hypothesis, we found that the odds of higher lutein intake were greater among those with DR than those without DR. However, after adjusting for confounders, intake of lutein was not associated with DR.

Tomato and tomato byproducts. Human health benefits of lycopene and its application to meat products: a review

During recent decades, the food industry, consumers, and regulatory authorities have developed a significant interest in functional foods because of their potential benefits for human health over and above their basic nutritional value. Tomato is the second most important vegetable crop in the world. The amount of the related wastes is estimated at up to 50,000 tons per year, representing a serious disposal problem with a consequent negative impact on the environment. Tomato byproducts contain a great variety of biologically active substances, principally lycopene, which have been demonstrated by in vitro and in vivo studies to possess antioxidant, hypolipidemic, and anticarcinogenic activities. The aim of this review is to present an overview of the functional and physiological properties of the principal bioactive compound present in tomato and tomato byproducts, lycopene, its addition to meat, and meat products.

The electrophoretical determination of serum protein fractions in lycopene treated experimental diabetic rats

This study was planned to determine the effects of lycopene treatment on serum protein fractions in experimental diabetic rats. In order to induce diabetes in rats in the diabetes (D) and diabetes + lycopene (DL) groups, rats were given 45 mg/kg single-dose streptozotocin intraperitoneally. Lycopene (10 mg/kg/day dissolved in sunflower oil) was administered to the rats in the lycopene-only (L) and DL groups. Blood glucose levels and HbA1c% in DL group and diabetes group increased (p < 0.05) compared to control and L group. Total protein, albumin, α1, α2, and β globulin fractions of diabetic and DL groups were lower than control and L groups (p < 0.05). D group had lowest gamma (γ) globulin levels among other groups (p < 0.05). The γ globulin levels was slightly increased than diabetic groups (D and DL), but it was still lower than control and L groups (p < 0.05). The highest value of A/G ratio was observed in diabetic group. Similarly, the % level of A/G ratio of D group was higher than other groups. It was noted that the A/G ratio decreased and reached to control group levels after lycopene treatment.

The effect of lycopene treatment on ACE activity in rats with experimental diabetes

In this study, the anti-inflammatory and antioxidant known as lycopene was applied to rats with experimental diabetes with the aim of investigating the detection of diabetes-related complications, and to determine the possible role of lycopene in diabetes complications regarding the effects of ACE activity. In order to induce diabetes in rats in the diabetes (D) and diabetes+lycopene (DL) groups, rats were given 45 mg/kg single-dose streptozotocin (STZ) intraperitoneally (i.p.); lycopene (10 mg/kg/day dissolved in sunflower oil) was administered to the rats in the lycopene-only (L) and DL groups. Blood glucose levels and HbA1c% in diabetes+lycopene group and diabetes group increased (p <0.05) compared to control and only lycopene treated group. The highest level of ACE activity was observed in the (D) group ( p < 0.05). Activity in the (L) group was also significantly greater than in the control group ( p < 0.05). The (DL) group had lower ( p < 0.05). ACE activity than the (D) group. Lycopene implementation was found to be effective in the inhibition of ACE activity, an important indicator of diabetes-related complications.