The presence of diabetes mellitus further impairs structural and functional capillary density in patients with chronic kidney disease

Nailfold capillaroscopic changes in patients with glomerular diseases

INTRODUCTION AND OBJECTIVES

Glomerulonephritis is a heterogenous group of diseases which is diagnosed mainly by renal biopsy. This study aims to assess nailfold capillaroscopic changes in patients with glomerular diseases.

PATIENTS AND METHODS

This study was conducted on 50 patients with glomerular disease confirmed by renal biopsy and 50 age and sex matched healthy controls. Clinical, laboratory evaluation and nailfold capillaroscopic examination were done for all participants.

RESULTS

Lupus nephritis was the most common pathological type among glomerulonephritis group [17 (34%)], followed by focal segmental glomerulosclerosis [9 (18%)]. Tortuous capillaries were significantly higher in patients with primary glomerular diseases compared to healthy persons (92.9% vs 58%, P<0.001). The diameter was significantly lower in patients with primary glomerular diseases compared to healthy control group (15.6μm vs 18.9μm, P=0.001). Subpapillary venous plexus (28.6% vs 6%, P=0.02) and capillary microhemorrhage (32% vs 0%, P<0.001) were significantly more frequent in patients with primary glomerular diseases compared to the control group. Patients with lupus nephritis had higher capillary diameter (19.5 vs 15.6μm, P=0.02), width (55.6 vs 44μm, P=0.003) and microhemorrhage (64.7% vs 32%, P=0.03) compared to patients with primary glomerulonephritis. There was a statistically significant difference as regard diameter (P=0.005) and length (P=0.02) between different classes of lupus nephritis.

CONCLUSION

More tortious capillaries and lower capillary diameter were found in patients with primary glomerular disease compared to healthy persons. Lupus nephritis patients had more dilated capillaries and more capillary microhemorrhage compared to primary glomerulonephritis patients.

Peripheral nailfold capillary microscopic abnormalities in rheumatoid arthritis are associated with arterial stiffness: Results from a cross-sectional study

Vascular injury eventually resulting in the establishment of cardiovascular disease is a serious complication in rheumatoid arthritis (RA). Nailfold videocapillaroscopy (NVC) is a non-invasive imaging modality that enables the quantitative and qualitative assessment of the peripheral microvasculature. Nevertheless, capillaroscopic patterns remain inadequately defined in RA, especially regarding their clinical significance as potential markers of systemic vascular impairment. Consecutive RA patients underwent NVC using a standardized protocol, to assess the following parameters: capillary density, avascular areas, capillary dimensions, microhemorrhages, subpapillary venous plexus, and presence of ramified, bushy, crossed and tortuous capillaries. Carotid-femoral pulse wave velocity (PWV) and pulse pressure were measured as well-acknowledged markers of large artery stiffening. The vast majority of our cohort (n = 44) presented a combination of non-specific and abnormal capillaroscopic parameters. Capillary ramification was associated with both PWV and pulse pressure, even after adjustment for cardiovascular risk factors and systemic inflammation. Our study highlights the high prevalence of a wide range of capillaroscopic deviations from the normal patterns in RA. Furthermore, it provides for the first time evidence of an association between structural disorders of the microcirculation and markers of macrovascular dysfunction, suggesting that NVC might have a role as an index of generalised vascular impairment in RA.

The Relationship between TNF-a, IL-35, VEGF and Cutaneous Microvascular Dysfunction in Young Patients with Uncomplicated Type 1 Diabetes

The aim of this study was to analyze the relationship between immunological markers and the dysfunction of cutaneous microcirculation in young patients with type 1 diabetes. The study group consisted of 46 young patients with type 1 diabetes and no associated complications. Microvascular function was assessed with the use of nail fold capillaroscopy before and after implementing post-occlusive reactive hyperemia. This evaluation was then repeated after 12 months. Patients were divided into two subgroups according to their baseline median coverage (defined as the ratio of capillary surface area to surface area of the image area), which was established during the initial exam (coverageBASE). Additionally, the levels of several serum biomarkers, including VEGF, TNF-a and IL-35, were assessed at the time of the initial examination. HbA1c levels obtained at baseline and after a 12-month interval were also obtained. Mean HbA1c levels obtained during the first two years of the course of the disease were also analyzed. Patients with coverageBASE below 16.85% were found to have higher levels of VEGF and TNF-α, as well as higher levels of HbA1c during the first two years following diabetes diagnosis. Our results support the hypothesis that the development of diabetic complications is strongly influenced by metabolic memory and an imbalance of pro- and anti-inflammatory cytokines, regardless of achieving adequate glycemic control.

Activation of aryl hydrocarbon receptor by azatyrosine-phenylbutyric hydroxamide inhibits progression of diabetic retinopathy mice

Diabetic retinopathy (DR) is a severe consequence of long-term diabetes mellitus and may lead to vision loss. Retinal pigment epithelial (RPE) cells are a diverse group of retinal cells with varied metabolic and functional roles. In hypoxic conditions, RPE cells have been shown to produce angiogenic factors, such as vascular endothelial growth factor (VEGF), which is regulated by hypoxia-inducible factor 1-alpha (HIF1A). VEGF plays a crucial role in angiogenesis in DR. In the present study, we investigated whether azatyrosine-phenylbutyric hydroxamide (AZP) has therapeutic effect on DR therapy. In this study, we treated high glucose-activated human retinal pigment epithelial cells (ARPE-19) with and without AZP. The effector proteins were evaluated using western blotting. In the in vivo study, AZP was administered to the db/db mice as a DR animal model. Moreover, invasive imaging techniques such as optical coherence tomography (OCT), fundus photography, and fundus fluorescein angiography (FFA) were performed on the mice to assess DR progression. We found that treatment of AZP for 12 weeks reversed increasing DR retinal alterations in db/db mice, decreasing vascular density, retinal blood perfusion, retinal thickness, decreasing DR lesion, lipofuscin accumulation, HIF1A, VEGF, and inflammation factor expression. In addition, AZP treatment could activate the aryl hydrocarbon receptor AHR and reverse the high-glucose-induced HIF1A and VEGF in ARPE-19 cells and db/db mice. In conclusion, AZP activated AHR while inhibiting HIF1A and VEGF. This study indicates that AZP may be a promising therapeutic agent for treating DR.

Correlation of ACR and TcPO2 in diabetic kidney disease patients: A pilot study

OBJECTIVE

Transcutaneous oxygen pressure (TcPO2) is used to assess microcirculation clinically; however, it is not widely available especially in rural hospital. The study was designed to explore potential alternatively biomarkers to assess microcirculation in diabetic kidney disease (DKD).

METHODS

A total of 404 patients from Xuzhou first hospital were recruited according to the case records system. Patients were grouped via the ratio of albuminuria and creatinine (ACR; <30 mg/g, 30-300 mg/g, >300 mg/g). Biomarkers in different ACR groups were compared by analysis of variance. Correlation analysis was determined by Pearson or Spearman analysis and binary logistic regression. The receiver operating characteristics (ROC) curve was performed to elucidate the prediction effect of ACR on TcPO2.

RESULTS

A total of 404 diabetic patients were recruited with 248 patients diagnosed as DKD and 156 non-DKDs. Age and cystatin C were significantly higher in the ACR3 group compared with those in the ACR1 group, whereas glomerular filtration rate, low-density lipoprotein cholesterol, and TcPO2 were markedly decreased in the ACR3 group (p < .05). Frequency of low TcPO2 (<40 mm Hg) was markedly increased as increment of ACR stages with 30.2% in the ACR3 group (p < .01). There was a negative correlation between TcPO2 and age, ACR, chronic kidney disease (CKD), fast blood glucose, diabetes mellitus (DM) duration, and diabetic neuropathy. Further, binary logistic regression showed ACR was an independent influence factor for low TcPO2. After adjusting for age, gender, hypertension, DM duration, body mass index, glycated hemoglobin, diabetic neuropathy, and CKD, ACR was still an independent influence factor for TcPO2 (odds ratio = 2.464, p < .01). The area under the ROC curve was 0.768 (95% confidence interval: 0.700-0.836, p < .001) for ACR. The analysis of ROC curves revealed a best cutoff for ACR was 75.25 mg/g and yielded a sensitivity of 71.7% and a specificity of 71.7%.

CONCLUSIONS

ACR could be used as an alternative biomarker for assessing microcirculation in DKD patients.

Classifying Kidney Disease in a Vervet Model Using Spatially Encoded Contrast-Enhanced Ultrasound Perfusion Parameters

Early stages of diabetic kidney disease (DKD) are difficult to diagnose in patients with type 2 diabetes. This work was aimed at identifying contrast-enhanced ultrasound (CEUS) perfusion parameters, a microcirculatory biomarker indicative of early DKD progression. CEUS kidney flash-replenishment data were acquired in control, insulin resistant and diabetic vervet monkeys (N = 16). By use of a mono-exponential model, time-intensity curve parameters related to blood volume (A), velocity (β) and flow rate (perfusion index [PI]) were extracted from 10 concentric kidney layers to study spatial perfusion patterns that could serve as strong indicators of disease. Mean squared error (MSE) was used to assess model performance. Features calculated from the perfusion parameters were inputs for the linear regression models to determine which features could distinguish between cohorts. The mono-exponential model performed well, with average MSEs (±standard deviation) of 0.0254 (±0.0210), 0.0321 (±0.0242) and 0.0287 (±0.0130) for the control, insulin resistant and diabetic cohorts, respectively. Perfusion index features, with blood pressure, were the best classifiers between cohorts (p < 0.05). CEUS has the potential to detect early microvascular changes, providing insight into disease-related structural changes in the kidney. The sensitivity of this technique should be explored further by assessing various stages of DKD.

New Noninvasive Methods to Evaluate Microvascular Structure and Function

The structural and functional alterations of microvessels are detected because of physiological aging and in several cardiometabolic diseases, including hypertension, diabetes, and obesity. The small resistance arteries of these patients show an increase in the media or total wall thickness to internal lumen diameter ratio (MLR or WLR), often accompanied by endothelial dysfunction. For decades, micromyography has been considered as a gold standard method for evaluating microvascular structural alterations through the measurement of MLR or WLR of subcutaneous small vessels dissected from tissue biopsies. Micromyography is the most common and reliable method for assessing microcirculatory endothelial function ex vivo, while strain-gauge venous plethysmography is considered the reference technique for in vivo studies. Recently, several noninvasive methods have been proposed to extend the microvasculature evaluation to a broader range of patients and clinical settings. Scanning laser Doppler flowmetry and adaptive optics are increasingly used to estimate the WLR of retinal arterioles. Microvascular endothelial function may be evaluated in the retina by flicker light stimulus, in the finger by tonometric approaches, or in the cutaneous or sublingual tissues by laser Doppler flowmetry or intravital microscopy. The main limitation of these techniques is the lack of robust evidence on their prognostic value, which currently reduces their widespread use in daily clinical practice. Ongoing and future studies will overcome this issue, hopefully moving the noninvasive assessment of the microvascular function and structure from bench to bedside.

Nail Folds Capillaries Abnormalities Associated With Type 2 Diabetes Mellitus Progression and Correlation With Diabetic Retinopathy

Background:

Diabetic retinopathy (DR) is an important microvascular consequence of long-term type 2 diabetes mellitus (T2DM), and it can lead to blindness if not properly diagnosed and managed. Nailfold video capillaroscopy (NVC) is a non-invasive technique for observing capillary microvasculature.

Aim:

We aimed to evaluate the nail folds capillaroscopic alterations in patients with T2DM by NVC and correlated the results to DR, and their relation to disease duration and hemoglobin A1c (HbA1c).

Methods:

This cross-sectional study enrolled 62 cases with T2DM (as per the American Diabetes Association criteria). All patients were subjected to NVC and ophthalmological assessment.

Results:

NVC revealed that Patients with DR showed significantly higher frequencies of tortuous capillaries, branched capillaries and precapillary edema versus non-DR patients with P < .05. The DR patients with longer disease duration (15-20) years had significantly higher frequencies of branched capillaries, tortuous capillaries, microhemorrhages, and dilated apical capillaries. The frequency of tortuosity and precapillary edema were significantly higher in patients with poor glycemic control. The increased capillary width and branched capillaries were detected as predictors of DR in multivariate analysis.

Conclusion:

NVC is a cost-effective, quick, safe, simple, non-invasive, and newly emerging tool to assess the capillaroscopic alterations in diabetic patients as an indicator of severity of DR.

Nailfold capillaroscopy and microvascular involvement in Diabetes Mellitus

Objective: to study the relationship between microvascular lesions of Diabetes Mellitus and alterations in the nailfold capillaroscopy. Subjects and Methods: cross-sectional study including 140 individuals (70 with Diabetes Mellitus and 70 controls). Epidemiological and clinical variables were collected from patient’s charts. Fundus ophthalmoscopy, nailfold capillaroscopy, analysis of microalbuminuria and renal clearance as well as fasting glycaemia and HbA1c values were studied simultaneously.Results: capillary density was reduced, and vascular dilatation was increased in Diabetes Mellitus patients when compared to controls (both with p<0.0001). In diabetic individuals the number of dermal papillary capillaries/mm3 correlated negatively with microalbuminuria (p=0.02), patient’s age (p=0.03), values of HbA1c (p=0.03). Patients with diabetic retinopathy and using antiplatelet agents had lower capillary density (p<0.0001 and 0.04 respectively). Capillary dilatation was associated with disease duration (p=0.04).Conclusion: microvascular disease in Diabetes Mellitus is reflected in nailfold capillaroscopy. Decreased capillary density, increased number of ectasias and increased presence of avascular areas were observed in patients with diabetes when compared to controls. In the present study, capillary density correlated/ associate with age, retinopathy, use of antiplatelet medication, HbA1c, microalbuminuria and diabetes duration. Ectasias or dilatations were related to retinopathy, glomerular filtration rate and longer disease duration.

Peripheral microcirculatory abnormalities are associated with cardiovascular risk in systemic sclerosis: a nailfold video capillaroscopy study

INTRODUCTION

Microvascular dysfunction is the key element in the pathogenesis of systemic sclerosis (SSc), whereas the contribution of large and medium size vessel abnormalities is yet to be established. The aim of the present study is to assess the association between micro- and macrovascular function by utilizing a broad spectrum of assessments of vascular performance.

METHODS

We included consecutive, consenting SSc patients who underwent nailfold video capillaroscopy (NVC) for microcirculation evaluation. Peripheral and central systolic and diastolic blood pressure, carotid intima-media thickness (cIMT), aortic augmentation index (AIx) corrected for a heart rate of 75 beats per minute (AIx-75), and carotid-femoral pulse wave velocity (PWV) were also performed to assess macrovascular function. Cardiovascular risk disease (CVD) algorithms were also calculated and included in the analysis.

RESULTS

A total of 81 patients (6 males) were studied with mean age 55.44 ± 13.40 years. Reduced capillary density was inversely correlated with arterial stiffness (Alx-75) and augmentation pressure (r =  - 0.262, p = 0.018, and r =  - 0.249, p = 0.025 respectively). Alx was significantly lower in the early compared to late pattern (28.24 ± 11.75 vs 35.63 ± 10.47, p = 0.036). A significant trend was found among NVC patterns with Alx-75 values being higher with the progression of microangiopathy towards the "late" group (26.36 ± 10.90 vs 30.81 ± 11.59 vs 35.21 ± 7.90, p = 0.027 for trend). Similarly, Framingham risk score and Atherosclerotic Cardiovascular Disease score were progressively higher across the worsening NVC patterns (4.10 ± 4.13 vs 2.99 ± 2.72 vs 6.36 ± 5.65, p = 0.023, and 6.99 ± 7.18 vs 5.63 ± 4.41 vs 12.09 ± 9.90, p = 0.019, respectively, for trends). Finally, QRISK3 (10-year cardiovascular disease risk) and ASCVD (Atherosclerotic Cardiovascular Disease) scores were inversely correlated with the number of capillaries (r =  - 0.231, p = 0.048, and r =  - 0.260, p = 0.038 respectively).

CONCLUSION

These data suggest that CVD risk scores and macrovascular parameters are strongly correlated with microvasculopathy in patients with SSc. Key Points • Microangiopathy is the hallmark of SSc, but the relationship between subclinical atherosclerosis and small vessel disease remains unknown. • Arterial stiffening and CVD risk scores are positively associated with the degree of progression of peripheral microvasculopathy assessed with NVC. • The results of the study suggest an association between NVC abnormalities and higher CVD risk in SSc patients.

Vascular endothelial injury assessed with functional techniques in systemic sclerosis patients with pulmonary arterial hypertension versus systemic sclerosis patients without pulmonary arterial hypertension: a systematic review and meta-analysis

Microvascular dysfunction is one of the hallmarks of systemic sclerosis (SSc). The presence of pulmonary-arterial-hypertension (PAH) in SSc-patients is associated with poor prognosis. This is a systematic review and meta-analysis of studies assessing microvascular and endothelial injury with functional techniques in SSc-patients with PAH (SSc-PAH) compared to those without PAH (SSc-non-PAH) (PROSPERO: CRD42021236212). Literature search involved PubMed, the-Cochrane-Library, Web-of-Science, Scopus and manual search of article references. Studies assessing microvascular function by all available functional methods were considered eligible. Preclinical studies and studies using structural nailfold-videocapillaroscopy or biomarkers were excluded. Newcastle-Ottawa-Scale (NOS) was applied to evaluate the quality of retrieved studies. From a total of 602 retrieved articles, four studies (n = 159 participants) were included in meta-analysis; three studies were of high quality (NOS ≥ 7). In pooled analysis, a marginally significant impaired microvascular function was observed in SSc-PAH compared to SSc-non-PAH patients [SMD - 0.71, 95% CI (- 1.53, 0.12)], with significant between-study heterogeneity (I² = 80%, p = 0.002). Among the studies examining endothelium-dependent and -independent vasodilation with LDF-iontophoresis, SSc-PAH subjects had significantly impaired endothelium-dependent-vasodilation [Ach-stimulated %change WMD - 216.79, 95% CI (- 337.87, - 95.71), I² = 0%, p = 0.40], but no significant differences in endothelium-independent-vasodilation [SNP-stimulated %change WMD 90.84, 95% CI (- 82.52, 264.19), I² = 44%, p = 0.18] compared with SSc-non-PAH subjects. In sensitivity analysis including only studies where SSc-PAH patients were diagnosed by right-heart-catheterization, a borderline difference between the two groups was noted [SMD - 1.09, 95% CI (- 2.30, 0.13), I² = 82%, p = 0.004]. SSc-PAH patients showed marginally impaired microvascular function in the pooled analysis, as well as impaired endothelium-dependent-vasodilation in subgroup analysis compared with SSc-non-PAH patients. Vascular endothelial dysfunction could be involved in high cardiovascular risk of patients with SSc and PAH.