Associations between metabolic syndrome and syndrome components and retinal microvascular signs in a rural Chinese population: the Handan Eye Study

Association of Metabolic Syndrome with Macular Thickness and Volume in Older Adults: A Population-Based Optical Coherence Tomography Study

Background: To explore the associations of the metabolic syndrome (MetS) and individual components with macular thickness and volume among rural-dwelling Chinese older adults. Methods: This population-based cross-sectional study included 705 participants (age ≥60 years) derived from the MIND-China study. In 2018-2019, we collected data through face-to-face interview, clinical examination, optical coherence tomography (OCT) examination, and blood test. We measured macular thickness and volume using spectral-domain OCT. MetS was defined following the International Diabetes Federation (IDF) criteria, the IDF/American Heart Association (AHA) criteria, the National Cholesterol Education Program-Adult Treatment Panel III criteria, and the Chinese Diabetes Society (CDS) criteria. Data were analyzed with multivariable general linear models. Results: MetS was significantly associated with thinner macula in central (multivariable-adjusted β = -5.29; 95% confidence interval: -9.31 to -1.26), parafoveal (-2.85; -5.73 to 0.04) and perifoveal regions (-4.37; -6.79 to -1.95) when using the IDF criteria, in the perifoveal regions (-3.82; -6.18 to -1.47) when using the IDF/AHA criteria, and in the central region (-5.63; -10.25 to -1.02) when using the CDS criteria, and with reduced macular volume when using the IDF (-0.16; -0.26 to -0.07) and IDF/AHA (-0.13; -0.22 to -0.04) criteria. In the parafoveal region, the IDF-defined MetS was significantly associated with thinner retina in men (β = -6.25; -10.94 to -1.56) but not in women. Abdominal obesity (-2.83; -5.41 to -0.25) and elevated fasting blood glucose (-2.65; -5.08 to -0.21) were associated with thinner macular thickness in the perifoveal region. Conclusion: MetS is associated with macular thinning and reduced macular volume among rural-dwelling older adults, and the associations vary by the defining criteria of MetS.

Association Between the Metabolic Syndrome and Retinal Microvascular Diameters Among Police Officers

OBJECTIVES

We examined the associations of the metabolic syndrome severity score (MSSS) and the metabolic syndrome (MetSyn) components with central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE).

METHODS

Participants in this cross-sectional study were 253 officers from the Buffalo Cardio-Metabolic Occupational Police Stress study (2011-2014). The MSSS is a z -score that represents the severity of MetSyn and was estimated using a sex/race-specific equation and the five MetSyn components. Associations of MSSS and the MetSyn with CRAE/CRVE were obtained using linear regression models or analysis of covariance.

RESULTS

For every 1-standard deviation of MSSS, CRAE decreased by 2.3 μm (SE = 1.2, P = 0.0262) and CRVE increased by 3.4 μm (SE = 1.6, P = 0.0308) after adjusting for confounders.

CONCLUSIONS

Officers with higher MSSS had narrower (ie, worse) arteriolar diameters and wider (ie, worse) venular diameters.

Higher prevalence of diabetic retinopathy among female Chinese diabetic patients with metabolic syndrome

PURPOSE

To investigate the association between metabolic syndrome (MetS) and diabetic retinopathy (DR), as well as the association between MetS and retinal vessel caliber, among Chinese patients with type 2 diabetes mellitus in north-eastern China.

STUDY DESIGN

Cross-sectional study.

PATIENTS AND METHODS

The patients were recruited from a community-based study, the Fushun Diabetic Retinopathy Cohort Study (FS-DIRECT). The presence of DR was determined using a modified version of the Early Treatment Diabetic Retinopathy Study (ETDRS) scale. The central retinal arteriolar equivalent (CRAE) and the central retinal venular equivalent (CRVE) were identified by use of Integrative Vessel Analysis software. The presence of MetS was defined according to the Joint Interim Statement proposed in 2009.

RESULTS

The prevalence of DR was significantly higher among female patients with MetS than among those without it (47.2% vs 30.9%, P = 0.002), and it increased as the number of MetS components increased (P = 0.003). Furthermore, the presence of MetS (odds ratio 2.43, 95% CI 1.39-4.26) as well as higher numbers of MetS components were significantly associated with DR in female patients, after adjustment for potential risk factors. Patients with MetS (multivariate β coefficient, 95% CI - 6.9, - 10.0, to - 3.8) or a higher number of Mets components tended to have significantly smaller CRAE.

CONCLUSION

In this study cohort, female patients with MetS had a higher prevalence of DR. Patients tended to have thinner central retinal arterioles as the number of MetS components increased.

Ocular findings in metabolic syndrome: a review

Metabolic syndrome (MetS) has emerged as a worldwide health hazard of the modern lifestyle, representing a cluster of metabolic abnormalities and a risk factor for cardiovascular disease. Eye diseases, such as diabetic retinopathy, central retinal artery occlusion, cataract, age-related macular degeneration, glaucoma, and dry eye syndrome have been linked with many of MetS components. Their relationship with MetS itself is, however, a recent topic of investigation. This review aims to gather published evidence supporting associations between ocular findings and MetS and to explore the related physiopathological processes that congregate in this syndrome and lead to these diseases. Despite compiling interesting and compelling evidence, it raises awareness to the need of further studies in this field to keep solidifying these associations and unveiling the pathological processes that support them. It ultimately targets MetS patients as a population of individuals who are at increased risk of developing age-related eye diseases and vision loss.

Relationship of ideal cardiovascular health metrics with retinal vessel calibers and retinal nerve fiber layer thickness: a cross-sectional study

BACKGROUND

Ideal cardiovascular health (CVH) metrics have been found to be associated with subclinical vascular abnormalities. However, the relationship between ideal CVH metrics and retinal vessel calibers and retinal nerve fiber layer (RNFL) thickness in a Chinese population is unknown.

METHODS

We collected information on the seven ideal CVH metrics among 3376 participants aged 40 years or older from the Asymptomatic Polyvascular Abnormalities Community Study in 2012. Retinal vessel calibers and RNFL thickness were assessed by retinal photography and spectral-domain optical coherence tomography. Multivariable linear models were used to analyze the relationship between ideal CVH metrics and retinal parameters.

RESULTS

With the decreased number of ideal CVH metrics, central retinal arteriolar equivalents (CRAE) was significantly narrowed and arterio- venous ratio (AVR) significantly decreased (p < 0.0001). While the RNFL thickness and central retinal venous equivalents (CRVE) showed no significant changes with the decreased ideal CVH metrics. Linear regression showed that both CRAE and AVR was positively related with the number of ideal CVH metrics (regression coefficient beta: 0.806, 95% confidence interval (CI): 0.266-1.346 for CRAE (micron); and regression coefficient beta: 0.005, 95% CI: 0.002-0.009 for AVR) after adjusting for age (year), sex = male (n), education (n), average monthly income (¥) and other related risk factors.

CONCLUSIONS

These findings suggested a clear positive relationship between the number of ideal CVH metrics and CRAE and AVR in Chinese population, supporting the importance of ideal health behaviors and factors in subclinical vascular abnormalities prevention.

Retinal nerve fibre layer thickness is reduced in metabolic syndrome

AIMS

To investigate retinal nerve fibre layer (RNFL) thickness in people with metabolic syndrome (MetS) and healthy controls.

METHODS

A cross-sectional study was performed from March 2014 to January 2016. All participants underwent anthropometric and serological biochemical measurements, ophthalmological examination, and spectral-domain optical coherence tomography (SD-OCT). Individuals with elevated intraocular pressure, glaucoma, diabetic retinopathy and other ocular disorders were excluded. T-test, Chi square and general linear models were used to analyse the data.

RESULTS

In total, 278 eyes from 139 participants were investigated [median (interquartile range) age: 37 (32-43) years]. RNFL thickness was lower in the nasal superior (107.8 ± 19.5μm) and temporal superior (135.7 ± 18.9μm) sectors in MetS group compared with the control group (114.6 ± 22.4 μm, P = 0.013 and 140.7 ± 18.2 μm, P = 0.027, respectively). After multiple adjustments for age, gender and the side of the examined [right (OD)/left (OS)] eye, MetS was independently associated with a lower RFNL thickness in the nasal superior (β = 0.20, P = 0.009) and temporal superior (β = 0.14, P = 0.048) sectors. RNFL thickness was significantly reduced in participants with higher numbers of metabolic abnormalities, independent of age, gender and the side of the examined eye (P = 0.043).

CONCLUSION

Our findings demonstrate that MetS is independently associated with reduced RNFL thickness, suggesting that neurodegeneration is implicated in pathogenesis of MetS.

Altered post-capillary and collecting venular reactivity in skeletal muscle with metabolic syndrome

KEY POINTS

With the development of the metabolic syndrome, both post-capillary and collecting venular dilator reactivity within the skeletal muscle of obese Zucker rats (OZR) is impaired. The impaired dilator reactivity in OZR reflects a loss in venular nitric oxide and PGI₂ bioavailability, associated with the chronic elevation in oxidant stress. Additionally, with the impaired dilator responses, a modest increase in adrenergic constriction combined with an elevated thromboxane A₂ production may contribute to impaired functional dilator and hyperaemic responses at the venular level. For the shift in skeletal muscle venular function with development of the metabolic syndrome, issues such as aggregate microvascular perfusion resistance, mass transport and exchange within with capillary networks, and fluid handling across the microcirculation are compelling avenues for future investigation.

ABSTRACT

While research into vascular outcomes of the metabolic syndrome has focused on arterial/arteriolar and capillary levels, investigation into venular function and how this impacts responses has received little attention. Using the in situ cremaster muscle of obese Zucker rats (OZR; with lean Zucker rats (LZR) as controls), we determined indices of venular function. At ∼17 weeks of age, skeletal muscle post-capillary venular density was reduced by ∼20% in LZR vs. OZR, although there was no evidence of remodelling of the venular wall. Venular tone at ∼25 μm (post-capillary) and ∼75 μm (collecting) diameter was elevated in OZR vs. LZR. Venular dilatation to acetylcholine was blunted in OZR vs. LZR due to increased oxidant stress-based loss of nitric oxide bioavailability (post-capillary) and increased α₁ - (and α₂ -) mediated constrictor tone (collecting). Venular constrictor responses in OZR were comparable to LZR for most stimuli, although constriction to α₁ -adrenoreceptor stimulation was elevated. In response to field stimulation of the cremaster muscle (0.5, 1, 3 Hz), venular dilator and hyperaemic responses to lower frequencies were blunted in OZR, but responses at 3 Hz were similar between strains. Venous production of TxA₂ was higher in OZR than LZR and significantly higher than PGI₂ production in either following arachidonic acid challenge. These results suggest that multi-faceted alterations to skeletal muscle venular function in OZR may contribute to alterations in upstream capillary pressure profiles and the transcapillary exchange of solutes and water under conditions of metabolic syndrome.

Pyrethroid insecticide lambda-cyhalothrin and its metabolites induce liver injury through the activation of oxidative stress and proinflammatory gene expression in rats following acute and subchronic exposure

Lambda-cyhalothrin (LTC) [α-cyano-3-phenoxybenzyl-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclo-propanecarboxylate] is a synthetic type II pyrethroid insecticide commonly used in residential and agricultural areas. The potential hepatotoxicity of pyrethroids remains unclear and could easily be assessed by measuring common clinical indicators of liver disease. To understand more about the potential risks for humans associated with LTC exposure, male adult rats were orally exposed to 6.2 and 31.1 mg/kg bw of LTC for 7, 30, 45, and 60 days. Histopathological changes and alterations of main parameters related to oxidative stress and inflammatory responses in the liver were evaluated. Further, lambda-cyhalothrin metabolites [3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2-dimethyl-cyclopropane carboxylic acid (CFMP), 4-hydroxyphenoxybenzoic acid (4-OH-3-PBA), and 3-phenoxybenzoic acid (3-PBA)] in the liver tissues were identified and quantified by ultra-high-performance liquid chromatography coupled to quadripole time-of-flight mass spectrometry (UHPLC-MS-Q-ToF). Results revealed that LTC exposure significantly increased markers of hepatic oxidative stress in a time-dependent and dose-dependent manner, and this was associated with an accumulation of CFMP and 3-PBA in the liver tissues. In addition, the levels of tumor necrosis factor-α (TNF-α) and interleukin (IL-6 and IL-1β) gene expressions were significantly increased in the liver of exposed rats compared to controls. Correlation analyses revealed that CFMP and 3-PBA metabolite levels in the liver tissues were significantly correlated with the indexes of oxidative stress, redox status, and inflammatory markers in rats exposed to lambda-cyhalothin. Overall, this study provided novel evidence that hepatic damage is likely due to increased oxidative stress and inflammation under the condition of acute and subchronic exposure to lambda-cyhalothrin and that LTC metabolites (CFMP and 3-PBA) could be used as potential biomarker in human biomonitoring studies.

Relationship between Metabolic Syndrome and Ocular Microcirculation Shown by Laser Speckle Flowgraphy in a Hospital Setting Devoted to Sleep Apnea Syndrome Diagnostics

PURPOSE

To clarify whether the incidence of metabolic syndrome (MetS) and the overlap of MetS components are affecting the ocular circulation shown by laser speckle flowgraphy (LSFG).

MATERIALS AND METHODS

We studied 76 consistent patients. Blowout score (BOS) and blowout time (BOT), which are the pulse waveform analysis parameters, and mean blur rate (MBR) using LSFG in the optic nerve head (ONH) and choroid were evaluated. Throughout, the ONH was separated out from the vessels and tissue for analysis and MBRs in the ONH were divided into four sections (superior, temporal, inferior, and nasal).

RESULTS

Thirty-two patients were diagnosed having Mets. MBR-Tissue (P = 0.003), MBR-All (P = 0.01), MBR-Choroid (P = 0.04), and BOS-Choroid (P = 0.03) were significantly lower in patients with MetS than in the patients without MetS. Multiple-regression analysis revealed the temporal side of MBR-Tissue and BOS-Choroid which were identified as factors contributing independently to the overlap of the MetS components. Multiple-regression analysis also revealed that the MetS components were identified to be factors independently contributing to the BOS-Choroid and temporal side of MBR-Tissue.

CONCLUSION

Our study clarified that the incidence of MetS and the overlap of the MetS components are significantly affecting the ONH and choroidal microcirculation.

Serum high-sensitivity C-reactive protein as a biomarker in patients with metabolic syndrome: evidence-based study with 7284 subjects

BACKGROUND/OBJECTIVES

Metabolic syndrome (MetS) is characterized by abdominal obesity, dyslipidemia, hypertension and glucose intolerance, and is associated with an increased risk of developing cardiovascular disease (CVD), diabetes mellitus and related diseases. Circulating levels of inflammatory markers such as C-reactive-protein (CRP) have reported to be associated with CVD. Against this background, the prevalence of MetS is increasing globally, and thus predictive biomarkers are required for identification of MetS patients at an increased risk. Here we explored the value of CRP as a biomarker in 7284 subjects and also investigated which features of MetS have the greatest association with the hs-CRP level.

SUBJECTS/METHODS

The subjects were recruited from the Mashhad stroke and heart atherosclerotic disorder study. Anthropometric factors and biochemical parameters (for example, high-sensitivity CRP (hs-CRP), high-density lipoprotein/low-density lipoprotein, triglycerides (TGs) and fasting blood glucose (FBG)) were determined. Univariate and multivariate analyses were conducted to evaluate the association of hs-CRP and MetS.

RESULTS

Our results illustrated that the concentration of serum hs-CRP increased progressively with the number of MetS components, and subjects who fulfilled the criteria of MetS for waist circumference, TGs, blood pressure and FBG were found to have hs-CRP of 0.53, 0.38, 0.34 and 0.71 mg/l, respectively, higher than matched-subjects. Importantly, FBG had the greatest association with hs-CRP concentration.

CONCLUSIONS

Our data demonstrate the significant association between MetS components with hs-CRP, indicating that this association was cumulative by increasing the number of the defining features of MetS, supporting further studies to explore the value of emerging marker as a novel method for detecting individuals at high risk of developing MetS.

Metabolic syndrome and eye diseases

Metabolic syndrome is becoming a worldwide medical and public health challenge as it has been seen increasing in prevalence over the years. Age-related eye diseases, the leading cause of blindness globally and visual impairment in developed countries, are also on the rise due to aging of the population. Many of the individual components of the metabolic syndrome have been shown to be associated with these eye diseases. However, the association of metabolic syndrome with eye diseases is not clear. In this review, we reviewed the evidence for associations between metabolic syndrome and certain ocular diseases in populations. We also reviewed the association of individual metabolic syndrome components with ocular diseases due to a paucity of research in this area. Besides, we also summarised the current understanding of etiological mechanisms of how metabolic syndrome or the individual components lead to these ocular diseases. With increasing evidence of such associations, it may be important to identify patients who are at risk of developing metabolic syndrome as prompt treatment and intervention may potentially decrease the risk of developing certain ocular diseases.

Retinal Vessel Diameter and Chronic Kidney Disease in Rural China: A Cross-Sectional Study

Few studies have examined the relationship between retinal microvascular abnormalities and chronic kidney disease (CKD). This study aims to examine the association between retinal vessel diameters and CKD in the rural China in order to provide the scientific basis for the early detection and diagnosis for CKD.Participants and data were extracted from the Handan Eye Study, a population-based cross-sectional study performed from 2006 to 2007. The central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were summarized by the average arteriolar and venular caliber of each eye. The estimated glomerular filtration rate (eGFR) and a urinary albumin to creatinine ratio (ACR) were recorded. Multivariate logistic regression models were used to determine any associations between CRAE, CRVE, arteriole-to-venule ratio (AVR), retinopathy, and CKD in the recruited participants.CKD was found in was 17.3% (892/5158) of this population with a 0.9% (48/5545) rate of reduced renal function and 16.7% (922/5538) rate of albuminuria. Retinopathy was present in 9.6% (571/5925) of participants. Compared to the 4th quartile of AVR, the first group was found to have a higher risk of albuminuria (odds ratio [OR] = 1.261, 95% confidence interval [95%CI]: 1.015-1.567, P = 0.037) and CKD (OR = 1.240, 95%CI: 1.000-1.537, P = 0.049) after adjustment for potential confounding variables. Retinopathy was associated with the occurrence of albuminuria (OR = 1.340, 95%CI: 1.067-1.685, P = 0.012) and CKD (OR = 1.341, 95%CI: 1.071-1.681, P = 0.010). In participants with diabetes, the ORs for the 1st and 4th quartiles of CRAE and CRVE were 2.292 (95%CI: 1.076-4.881, P = 0.032) and 2.113 (95%CI: 1.006-4.438, P = 0.048), respectively. Among the participants with hypertension, retinopathy was also observed to be associated with CKD (OR = 1.306, 95%CI: 1.003-1.699, P = 0.047).The parameters of retinal vessel diameter may be a useful index evaluating the occurrence and development of CKD.

Association between retinal artery lesions and nonalcoholic fatty liver disease

Objective

Retinal artery lesions have been reported to be a risk marker of morbidity and mortality for cardiovascular and cerebrovascular diseases in various study populations. Nonalcoholic fatty liver disease (NAFLD) is also a risk factor for cardiovascular disease. However, the relationship between retinal artery lesions and NAFLD is less certain.

Methods

Data were obtained from 2,454 patients who attended their annual health examination (2,143 males and 311 females, aged 62.34 ± 10.03 years). NAFLD was diagnosed by hepatic ultrasonography. Retinal artery lesions were diagnosed according to the criteria. Total plasma cholesterol, plasma triglyceride and fasting glucose levels were determined by using a multichannel analyzer; the body mass index, systolic blood pressure, diastolic blood pressure, incidence of hypertension and coronary artery disease were measured or analyzed by statistical analysis.

Results

Patients with NAFLD had older age and higher values of BMI, systolic blood pressure, diastolic blood pressure, fasting glucose, total cholesterol and triglycerides and had a higher incidence of hypertension, coronary artery disease and retinal artery lesions (p < 0.01). Retinal artery lesions were taken as a dependent variable, and age, gender, BMI, systolic blood pressure, diastolic blood pressure, fasting glucose, total cholesterol and triglyceride levels, and NAFLD were taken as covariates. We found that age ≥65 years (p < 0.01, OR 1.968), being male (p < 0.01, OR 1.668), BMI ≥ 25 (p < 0.01, OR 0.743), SBP ≥ 140 mmHg (p < 0.01, OR 1.368) and NAFLD (p < 0.01, OR 2.378) were significantly associated with a risk of retinal artery lesions by binary logistic regression analysis.

Conclusions

Patients with NAFLD were older and had higher values for BMI, systolic blood pressure, diastolic blood pressure, fasting glucose, total cholesterol and triglycerides, and higher incidence of hypertension, coronary artery disease and retinal artery lesions. NAFLD is a risk factor for retinal artery lesions.

Oxidative stress: implications for the development of diabetic retinopathy and antioxidant therapeutic perspectives

In recent decades, localized tissue oxidative stress has been implicated as a key component in the development of diabetic retinopathy (DR). Increasing evidence shows that oxidative stress caused by diabetes-induced metabolic abnormalities is the most common mechanism associated with the pathogenesis of DR for both type 1 and type 2 diabetes. Increase in intracellular reactive oxygen species (ROS) concentrations results in the activation of several mechanisms involved in the pathogenesis of DR. In particular, damage or dysfunction caused by oxidative stress still persists even after glycemia has been normalized. Despite considerable evidence showing the beneficial effects of antioxidants in preventing the development of retinopathy, results from large-scale clinical trials on classic antioxidants are somewhat ambiguous. Scavenging reactive radicals may not be the most ideal antioxidant strategy in DR. Advances in understanding the function of ROS in the development of DR can lead to the development of new therapeutic strategies based on the mechanisms of ROS generation and scavenging. Increasing amounts of data have demonstrated the promising prospect of antioxidant therapy and its beneficial effects in vision protection. Therefore, new strategies that utilize antioxidants as additive therapy should be implemented in the treatment of DR.