High prevalence of capillary abnormalities in patients with diabetes and association with retinopathy

Nailfold videocapillaroscopy as a non-invasive tool for the assessment of peripheral microangiopathy in cardiovascular diseases

Cardiovascular disease (CVD) remains the main cause of morbidity and mortality worldwide. Accumulating evidence supports the presence of endothelial and microvascular dysfunction in CVD, which can be assessed using several methods in peripheral organs and tissues. Naifold videocapillaroscopy (NVC) is an established, noninvasive, easily applicable technique for the assessment of peripheral microcirculation. There is limited capillaroscopic data in the field of CVD, though, and the diagnostic or possible prognostic significance of the capillaroscopic alterations in this population is still a matter of research. This review aims to summarize the current knowledge on the capillaroscopic findings in patients with cardiovascular risk factors or established atherosclerotic and nonatherosclerotic CVD, focusing on the possible correlations of these alterations with clinical and laboratory markers of cardiac function.

Gender-Related Difference in Skin Oxygenation in Young Patients with Uncomplicated Type 1 Diabetes

Gender, through genetic, epigenetic and hormonal regulation, is an important modifier of the physiological mechanisms and clinical course of diseases. In diabetes mellitus, there are gender differences in incidence, prevalence, morbidity, and mortality. This disease also has an impact on the microvascular function. Therefore, this cross-sectional study was designed to investigate how gender affects the cutaneous microcirculation. We hypothesized that gender should be an important factor in the interpretation of capillaroscopy and transcutaneous oxygen saturation results. The study group consisted of 42 boys and 55 girls, uncomplicated diabetic pediatric patients. Females (F) and males (M) did not differ in terms of age, age at onset of diabetes, or diabetes duration. Furthermore, they did not differ in metabolic parameters. The comparison showed that group F had lower BP, higher pulse, and higher HR than group M. Group F had significantly lower creatinine and hemoglobin levels than group M. In children and adolescents with type 1 diabetes without complications, there was a gender difference in microcirculatory parameters. The resting transcutaneous partial pressure of oxygen was significantly higher in females than in males. However, there were no gender-related differences in basal capillaroscopic parameters or vascular reactivity during the PORH test. Our results indicate that studies investigating the structure and function of the microcirculation should consider the role of gender in addition to known cofactors such as puberty, body mass index, physical activity, and cigarette smoking.

Evaluation of nail fold capillaroscopy changes in patients with diabetic retinopathy and healthy controls, and its correlation with disease duration, HbA1c levels and severity of diabetic retinopathy: An observational study

Background Diabetic retinopathy (DR) is an important microvascular complication of long-term type 2 diabetes mellitus (T2DM) leading to blindness if not properly diagnosed and managed. It can develop as early as 7 years before the diagnosis of diabetes. Nail fold capillaroscopy (NFC) is a non-invasive technique for observing capillary microvasculature and there are few studies which have explored the use of NFC in diabetes mellitus patients. Objective To study the nail fold capillaroscopic alterations in patients with T2DM having diabetic retinopathy and compare them to healthy controls. The secondary objective was to correlate the NFC findings with the duration of diabetes, haemoglobin A1c (HbA1c) levels and the severity of DR. Materials and methods This cross-sectional observational study enrolled 200 patients - 100 cases with T2DM having diabetic retinopathy (as per the American Diabetes Association criteria and Diabetic Retinopathy Disease Severity Scale) and 100 healthy age and sex-matched controls. All patients were subjected to NFC and ophthalmological assessment. Results NFC revealed that patients with DR showed significantly higher frequencies of tortuous, dilated, bushy, meandering, angulated capillaries, avascular areas and micro-haemorrhages as compared to healthy controls (p < 0.05). In proliferative DR (PDR), the frequency of tortuous, bushy capillaries, and avascular areas was statistically high and the capillary density was reduced as compared to non-proliferative DR. The DR patients with longer disease duration (>20) years had a significantly higher frequency of tortuous capillaries, avascular areas, meandering, angulated and dilated capillaries. The frequency of tortuosity, avascular areas, and bushy areas was significantly higher in patients with poor glycaemic control (HbA1c >11). Limitations A larger sample size study with different demographic populations could have provided a broader picture of NFC changes in T2DM patients with DR. Discussion NFC may act as a surrogate marker of retinal involvement in patients with DM and should be performed at regular intervals. Conclusion NFC is a quick, simple, safe, and non-invasive method to assess the capillaroscopic alterations in diabetic patients which inturn can help in assessing the severity of DR.

Beneficial Effect of Sirolimus-Pretreated Mesenchymal Stem Cell Implantation on Diabetic Retinopathy in Rats

BACKGROUND

Diabetic retinopathy (DR) is a vision-threatening complication that affects virtually all diabetic patients. Various treatments have been attempted, but they have many side effects and limitations. Alternatively, stem cell therapy is being actively researched, but it faces challenges due to a low cell survival rate. In this study, stem cells were pretreated with sirolimus, which is known to promote cell differentiation and enhance the survival rate. Additionally, the subconjunctival route was employed to reduce complications following intravitreal injections.

METHODS

Diabetes mellitus was induced by intraperitoneal injection of 55 mg/kg of streptozotocin (STZ), and DR was confirmed at 10 weeks after DM induction through electroretinogram (ERG). The rats were divided into four groups: intact control group (INT), diabetic retinopathy group (DR), DR group with subconjunctival MSC injection (DR-MSC), and DR group with subconjunctival sirolimus-pretreated MSC injection (DR-MSC-S). The effects of transplantation were evaluated using ERG and histological examinations.

RESULTS

The ERG results showed that the DR-MSC-S group did not significantly differ from the INT in b-wave amplitude and exhibited significantly higher values than the DR-MSC and DR groups (p < 0.01). The flicker amplitude results showed that the DR-MSC and DR-MSC-S groups had significantly higher values than the DR group (p < 0.01). Histological examination revealed that the retinal layers were thinner in the DR-induced groups compared to the INT group, with the DR-MSC-S group showing the thickest retinal layers among them.

CONCLUSIONS

Subconjunctival injection of sirolimus-pretreated MSCs can enhance retinal function and mitigate histological changes in the STZ-induced DR rat model.

Non-invasive detection of early microvascular changes in juveniles with type 1 diabetes

AIMS/HYPOTHESIS

The study aimed to assess the usefulness of capillaroscopy and photoplethysmography in the search for early vascular anomalies in children with type 1 diabetes.

METHODS

One hundred sixty children and adolescents aged 6-18, 125 patients with type 1 diabetes, and 35 healthy volunteers were enrolled in the study. We performed a detailed clinical evaluation, anthropometric measurements, nailfold capillaroscopy, and photoplethysmography.

RESULTS

Patients with diabetes had more often abnormal morphology in capillaroscopy (68.60%, p = 0.019), enlarged capillaries (32.6%, p = 0.006), and more often more over five meandering capillaries (20.90%, p = 0.026) compared to healthy controls. Meandering capillaries correlated with higher parameters of nutritional status. In a photoplethysmography, patients with diagnosed neuropathy had a higher percentage of flow disturbance curves (p < 0.001) with a reduced frequency of normal curves (p = 0.050).

CONCLUSIONS

Capillaroscopic and photoplethysmographic examinations are non-invasive, painless, fast, and inexpensive. They are devoid of side effects, and there are no limitations in the frequency of their use and repetition. The usefulness of capillaroscopy and photoplethysmography in the study of microcirculation in diabetic patients indicates the vast application possibilities of these methods in clinical practice.

Opening a window to skin biomarkers for diabetes stage with optoacoustic mesoscopy

Being the largest and most accessible organ of the human body, the skin could offer a window to diabetes-related complications on the microvasculature. However, skin microvasculature is typically assessed by histological analysis, which is not suited for applications to large populations or longitudinal studies. We introduce ultra-wideband raster-scan optoacoustic mesoscopy (RSOM) for precise, non-invasive assessment of diabetes-related changes in the dermal microvasculature and skin micro-anatomy, resolved with unprecedented sensitivity and detail without the need for contrast agents. Providing unique imaging contrast, we explored a possible role for RSOM as an investigational tool in diabetes healthcare and offer the first comprehensive study investigating the relationship between different diabetes complications and microvascular features in vivo. We applied RSOM to scan the pretibial area of 95 participants with diabetes mellitus and 48 age-matched volunteers without diabetes, grouped according to disease complications, and extracted six label-free optoacoustic biomarkers of human skin, including dermal microvasculature density and epidermal parameters, based on a novel image-processing pipeline. We then correlated these biomarkers to disease severity and found statistically significant effects on microvasculature parameters as a function of diabetes complications. We discuss how label-free RSOM biomarkers can lead to a quantitative assessment of the systemic effects of diabetes and its complications, complementing the qualitative assessment allowed by current clinical metrics, possibly leading to a precise scoring system that captures the gradual evolution of the disease.

Qualitative analysis of nailfold capillaries in diabetes and diabetic retinopathy using dermatoscope in patients with coloured skin

Introduction

Diabetes mellitus (DM) is associated with significant morbidity and mortality due to vascular complications. Diabetic retinopathy (DR) is the most common microvascular complication of diabetes. Videocapillaroscope has been the predominant tool for nailfold capillary analysis. We aimed at using the commonly available handheld dermatoscope and observe changes in the nailfold capillaries as a part of evaluating diabetic microvascular involvement.

Materials and methods

A cross-sectional observational study involving 262 patients of diabetes mellitus and 150 controls was conducted for nailfold capillaroscopic changes using a hand-held dermatoscope over a period of 1 year.

Results

All the capillaroscopic variables like tortuosity, increased capillary density, neoangiogenesis, microhaemorrhages, avascular areas, crossing and meandering capillaries and receding capillaries were significantly more among diabetic than healthy controls. Patients with diabetic retinopathy had significant nailfold capillaroscopic features as compared to patients without DR (P value < 0.001). Neoangiogenesis, receding capillaries and avascular area were significantly higher in proliferative DR as against nonproliferative DR (P < 0.001). A positive association was found between the duration of DM and HbA1c values and NFC features. A decrease in the visualisation of NFC features was noted with increasing skin tone. The difference was significantly more between Fitzpatrick skin phototypes 4 and 5.

Limitations

The study was limited by its qualitative nature of accessing parameters as precise quantitative assessment of various findings cannot be done by a hand-held dermatoscope.

Conclusion

Nailfold capillaroscopy is a quick, cost-effective screening tool for identifying patients at high risk of DR in patients with skin of colour. NFC findings may mirror DR changes. The qualitative findings of NFC using a hand-held dermatoscope were comparable to other modes of nailfold capillaroscopy.

Nailfold capillaroscopy and deep learning in diabetes

OBJECTIVE

To determine whether nailfold capillary images, acquired using video capillaroscopy, can provide diagnostic information about diabetes and its complications.

RESEARCH DESIGN AND METHODS

Nailfold video capillaroscopy was performed in 120 adult patients with and without type 1 or type 2 diabetes, and with and without cardiovascular disease. Nailfold images were analyzed using convolutional neural networks, a deep learning technique. Cross-validation was used to develop and test the ability of models to predict five5 prespecified states (diabetes, high glycosylated hemoglobin, cardiovascular event, retinopathy, albuminuria, and hypertension). The performance of each model for a particular state was assessed by estimating areas under the receiver operating characteristics curves (AUROC) and precision recall curves (AUPR).

RESULTS

A total of 5236 nailfold images were acquired from 120 participants (mean 44 images per participant) and were all available for analysis. Models were able to accurately identify the presence of diabetes, with AUROC 0.84 (95% confidence interval [CI] 0.76, 0.91) and AUPR 0.84 (95% CI 0.78, 0.93), respectively. Models were also able to predict a history of cardiovascular events in patients with diabetes, with AUROC 0.65 (95% CI 0.51, 0.78) and AUPR 0.72 (95% CI 0.62, 0.88) respectively.

CONCLUSIONS

This proof-of-concept study demonstrates the potential of machine learning for identifying people with microvascular capillary changes from diabetes based on nailfold images, and for possibly identifying those most likely to have diabetes-related complications.

[Evaluation of the diagnostic capabilities of nailfold capillaroscopy in diabetic retinopathy]

PURPOSE

This study evaluates the diagnostic capabilities and the prognostic value of nailfold capillaroscopy data of patients with diabetic retinopathy (DR) to develop an algorithm of monitoring patients with type 2 diabetes mellitus.

MATERIAL AND METHODS

The study involved 90 patients (mean age 67 years), among them 31 with nonproliferative diabetic retinopathy, 29 patients with proliferative DR and 30 patients without retinopathy. In addition to conventional ophthalmological examination, optical coherence tomography angiography (OCTA) on the Optovue RTVue-100 device (USA) was performed using en face vessel density protocol to examine the state of the microvasculature of the superficial and deep layers of the vascular plexus of the central retinal zone, as well as nailfold capillaroscopy using computerized capillaroscope KK-01 (ZAO Centr Analiz veshhestv, Russia).

RESULTS

The cut-off points for detecting the presence of non-proliferative DR (capillary network density below 38.4%, arterial velocity below 512 mm/s and venous blood flow below 585 mm/s), and the presence of proliferative DR (capillary network density below 30.4%, the arterial velocity below 451 mm/s and the venous blood flow below 441 mm/s) were identified according to ROC-analysis of nailfold capillaroscopy data. In the diagnosis of proliferative DR the capillary network density parameter has a slightly higher diagnostic information value (AUC=0.963) than arterial blood flow velocity (AUC=0.941) or venous blood flow velocity (AUC=0.909). Using the identified critical parameters for predicting the initial and proliferative DR, we created a diagnostic algorithm involving a comprehensive assessment of all characteristics.

CONCLUSION

The study revealed that nailfold capillaroscopy indicators (capillary network density, velocity of arterial and venous blood flow) have high diagnostic information value for detecting both non-proliferative and proliferative retinopathy. We constructed mathematical models for predicting DR with an accuracy of predicting the presence of a non-proliferative stage in 92.2% of cases and a proliferative stage in 94.4% of cases. For practical use in clinical environment, we created a computer program calculating the results of DR predictions according to nailfold capillaroscopy data.

Capillary microarchitectural changes are independent of disease activity in acromegaly

OBJECTIVE

Although atherosclerosis-related macrovascular complications are well known in acromegaly, studies on endothelial function and arteriolar level are contradictory. In order to test the hypothesis, microvascular changes associated with macrovascular changes in acromegaly, we aimed to evaluate microvascular changes in nailfold capillaries and carotid intima-media thickness (CIMT) in patients with acromegaly.

DESIGN

In this cross-sectional observation study, of total 70 patients with acromegaly [ten (14.3 %) were active acromegaly (AA), 60 (85.7 %) were controlled acromegaly (CA)] and 74 healthy controls were enrolled. Microvascular structure was evaluated using the nailfold video capillaroscopy, and CIMT was measured using ultrasonography.

RESULTS

The median number of capillaries was less [10 no./mm (min-max: 5-16) vs. 11 no./mm (min-max: 9-15); p = 0.001] in the acromegaly group than in the controls. Capillaries below 6-8 per/mm was more common in the acromegaly patients [six (8.6 %) vs. one (1.4 %); p = 0.046]. All capillaroscopic parameters were similar among the patients with CA or AA. CIMT levels were higher in the acromegaly group than in the control group [0.60 mm (0.43-0.86) vs. 0.38 mm (0.27-0.59); p < 0.001], and AA patients had higher CIMT than CA patients (p = 0.037). None of the clinical or laboratory parameters including growth hormone and IGF-1 were related to capillaroscopic parameters or CIMT.

CONCLUSION

Decreased capillary number was the major capillaroscopic finding in acromegaly and there was no significant difference between active and controlled cases, but CIMT was found to be higher in the active group. Increased CIMT levels in acromegaly were not associated with capillary changes. Large-scale, prospective studies are needed to make a definite conclusion about the effect of the disease activity on nailfold capillaries and its association with macrovascular changes.

Nail fold microangiopathy in adolescents with type 1 diabetes: Relation to diabetic vascular complications

OBJECTIVES

Microangiopathy is implicated in the pathogenesis of diabetic vascular complications. Nail fold videocapillaroscopy (NVC) is an easy non-invasive tool of microvasculature assessment. This study compares the NVC changes in adolescents with Type1 diabetes (T1D) to healthy controls and correlates them to diabetic vascular complications.

METHODS

Hundred thirty-five adolescents with T1D (disease duration 5 years) were compared to 135 matched controls. Diabetes duration, insulin therapy, fundus, and Toronto clinical scoring system (TCSS) were assessed. Fasting lipids, fraction-C of glycosylated hemoglobin (HbA1C), urinary albumin creatinine ratio (UACR), nerve conduction velocity, and NVC were performed.

RESULTS

NVC changes were found in 120 adolescents with T1D (88.8%). These changes were significantly higher in adolescents with T1D than controls (p < .001). Significant positive relation was found between NVC changes and TCSS (p = .006), diabetes duration (p = .001), HbA1C (0.008), cholesterol (p = .011), LDL (0.016), UACR (p < .001), and nerve conduction velocity (p < .001). Multivariate logistic regression study revealed that diabetic nephropathy and neuropathy were independently associated with NVC changes (p < .001 and p = .007, respectively).

CONCLUSION

Adolescents with T1D have significantly higher NVC changes than controls. These changes were more evident in those having vascular complications than those without. Thus, NVC can be a potential non-invasive tool for early assessment and follow-up of the microvasculature among adolescents with T1D.

Nailfold capillaroscopy in diabetes mellitus: a case of neo-angiogenesis after achieving normoglycemia

Diabetes mellitus (DM) is a disease process characterized by a chronic hyperglycemic milieu that leads to micro and macrovascular complications, including diabetic retinopathy, diabetic nephropathy and diabetic neuropathy. During the last decade, researchers have used nail-fold capillaroscopy to study the microvascular alterations in rheumatologic diseases; however, the technology is gaining momentum in other disease processes that alter microvascular architecture. We observed a drastic improvement in the nail-fold capillary architecture in a patient with uncontrolled DM. After achieving excellent glycemic control 6 months after diagnosis, increased capillary density and evident rearrangement of the capillaries replaced the avascular areas and giant capillaries found at the time of diagnosis.

A pilot study of nailfold capillaroscopy in hereditary transthyretin amyloidosis

Nailfold capillaroscopy (NFC) is a safe and non-invasive imaging tool for evaluating microvascular abnormalities. This retrospective cross-sectional study aimed to analyze the NFC outcomes and clinical characteristics in patients and an asymptomatic carrier with transthyretin (TTR) gene mutation. The participants consist of eight patients with genetically and clinically confirmed hereditary amyloidogenic transthyretin (ATTRv) amyloidosis and one asymptomatic carrier. The TTR gene mutant forms of six male and three female participants from six families were Asp38Ala (five patients), Lys35Asn (three patients), and Ala36Pro (one patient). All participants showed decreased capillary density, dilatated capillaries, and destructed architecture in NFC. Early progression identification of a carrier to patients with symptoms is a major concern from a therapeutic viewpoint in ATTRv amyloidosis. Therefore, further studies with a larger number of subjects will be needed to determine the use of NFC as an early detection tool.

Capillaroscopic appearance of nailfold vasculature of diabetic nephropathy patients

Objective

Diabetic nephropathy is a microvascular complication of diabetes and the most common cause of end-stage renal failure throughout the world. Videocapillaroscopy is a simple and noninvasive method that can display capillaries in the nail bed at the micron level. A few studies have been conducted on detecting retinopathy, another important diabetic microvascular complication, with videocapillaroscopy; however, no comprehensive study has been performed on diabetic nephropathy. We aimed to determine the relationship between nephropathy and capillaroscopic changes.

Methods

Capillaroscopic findings of 144 patients with type 2 diabetes and 88 healthy controls were assessed prospectively by nailfold videocapillaroscopy. Twelve capillaroscopic findings were evaluated in all subjects.

Results

Patients with albuminuria had more capillary aneurysms (15.5%), more microhemorrhages (15.5%), greater tortuosity (76.3%), more neoformations (29.9%), more bizarre capillaries (49.5%) and more bushy capillaries (20.6%) than the control group. In logistic regression analysis, tortuosity was significantly correlated with albuminuria (OR: 2.451, p = 0.048).

Conclusion

Our findings show that the application of nailfold videocapillaroscopy can detect microvascular abnormalities in the nail bed that occur in diabetes mellitus patients compared to healthy people. Although there was no difference in the microvascular changes among the stages of diabetic nephropathy, a relationship between tortuosity and albuminuria was identified by logistic regression analysis. Nailfold videocapillaroscopy may be a new application that can be used to screen the microvascular changes that occur in diabetes mellitus.

Capillary microarchitectural changes in Cushing's syndrome

PURPOSE

Macrovascular alterations are prominent in Cushing's syndrome (CS). Microvascular abnormalities are yet to be established. This cross-sectional observational study aimed to evaluate microvascular changes in nailfold capillaries and their association with disease status and carotid intima-media thickness (CIMT) as a marker of atherosclerosis.

METHODS

A total of 70 patients with CS [46 (65.7%) ACTH-dependent pituitary adenoma and 24 (34.3%) adrenocortical adenomas] and 100 healthy controls were enrolled. The microvascular structure was evaluated using nailfold video-capillaroscopy (NVC).

RESULTS

The median number of capillaries was less [10 mm (IQR: 2, min-max:7-14) vs. 11 mm (IQR: 2, min-max:9-19) (p < 0.001)], the median limb diameter and capillary width were wider in the CS group than in the controls (p = 0.016 and p = 0.002, respectively). Microhemorrhages within limited areas were more frequent in the CS group than in the controls (p = 0.046). Observed capillary changes were similar among the patients with CS with remission or active disease. CIMT levels were higher in the CS group than in the controls and similar in subjects with active disease and remission. Univariate logistic regression analyses revealed that the number of capillaries and capillary widths were associated with body mass index (BMI), the presence of type 2 diabetes mellitus, HbA1c, and CIMT.

CONCLUSION

Morphologic alterations present similarly in nailfold capillaries in subjects with CS regardless of disease status, resembling changes in chronic atherosclerotic diseases. Microvascular changes in nailfold capillaries measured using NVC can be used as a marker in the assessment of cardiovascular risk in patients with CS.

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.

Nail-fold capillaroscopy for the dermatologists

Nail fold is one of the most accessible sites for studying changes in the microcirculation in various microangiopathies. The characterization of changes in microvasculature can provide useful clues towards the diagnosis and prognosis of a disease. The diagnostic utility of nail fold capillaroscopy has improved and expanded over the past couple of decades. Beyond connective tissue diseases, it is now explored for its role in various systemic and dermatological diseases. Incorporation of nail-fold capillaroscopy in the diagnostic criteria of systemic sclerosis has generated interest among dermatologists. The current review is aimed at providing knowledge about nail-fold capillaroscopy to dermatologists. For the purpose of review, a PubMed search was done using the keywords "nail fold capillaries" and "nail fold capillaroscopy". All the articles were retrieved and classified into reviews and clinical studies of various types. The final data were then analyzed and presented in a narrative fashion.

Skin microvascular function and renal hemodynamics in overweight patients with type 2 diabetes: A cross-sectional study

OBJECTIVE

Diabetic kidney disease is a microvascular complication of diabetes. Here, we assessed the association between skin microvascular function and renal hemodynamic function in a cohort of well-phenotyped adults with type 2 diabetes (T2D).

METHODS

We included 81 overweight/obese adults (age: 62 ± 8 years; BMI: 32 ± 4 kg/m² ) with well-controlled T2D and no renal impairment. Skin microvascular function was assessed by nailfold capillary density in rest and after arterial occlusion (ie, peak capillary density). Renal hemodynamic functions (ie, measured glomerular filtration rate [mGFR], effective renal blood flow [ERBF], filtration fraction [FF], and effective renal vascular resistance [ERVR]) were assessed by combined inulin and para-aminohippurate clearances and blood pressure measurements.

RESULTS

Skin capillary density was 45 ± 10 capillaries/mm² at baseline and 57 ± 11 capillaries/mm² during post-occlusive peak; mGFR averaged 108 ± 20 ml/min. In multivariable regression analyses, positive associations between capillary density during post-occlusive peak and mGFR (β = 0.224; p = 0.022) and ERBF (β = 0.203; p = 0.020) and a positive trend for hyperemia and mGFR (β = 0.391; p = 0.053) were observed, while a negative association for post-occlusive capillary density with ERVR (β = -0.196; p = 0.027) was found.

CONCLUSION

These findings indicate that microvascular dysfunction in overweight adults with T2D is associated with lower mGFR and ERPF and higher ERVR. We hypothesize that increased renal vascular resistance may contribute to glomerular dysfunction due to impaired renal perfusion.

Association of Nailfold Capillary Abnormalities With Primary Open-angle Glaucoma and Glaucomatous Visual Field Loss

PRECIS

Nailfold capillary abnormalities are associated with primary open-angle glaucoma (POAG) and increased severity of global and central glaucomatous visual field (VF) loss.

PURPOSE

The purpose of this study was to investigate whether nailfold capillary abnormalities are associated with POAG and the severity of glaucomatous VF loss.

MATERIALS AND METHODS

A cross-sectional study of 83 POAG cases and 40 controls was conducted. Nailfold capillaroscopy images were assessed by masked graders for dilated capillaries >50 μm, crossed capillaries, tortuous capillaries, hemorrhages, avascular zones >100 μm, capillary density, and capillary distribution. VF loss in glaucoma cases was quantified using mean deviation and mean central pattern standard deviation (PSD) from the worst-affected eye.

RESULTS

Logistic regression analyses of cases and controls showed that avascular zones [odds ratio (OR)=1.24; 95% confidence interval (CI): 1.06, 1.47; P=0.005], capillary density (OR=0.63; 95% CI: 0.46, 0.83; P<0.001), and capillary distribution (OR=7.88; 95% 95% CI: 2.53, 28.40; P=0.001) were associated with POAG. Simple linear regression analysis of cases only showed that nailfold hemorrhages were associated with mean deviation (β=-5.10; 95% CI: -9.20, -1.01; P=0.015) and mean central PSD (β=-4.37; 95% CI: -8.18, -0.57; P=0.025), and this remained significant in the multiple linear regressions. After controlling for demographic and clinical factors, avascular zones were associated with both mean deviation (β=-0.76; 95% CI: -1.48, -0.04; P=0.040) and mean central PSD (β=-0.78; 95% CI: -1.45, -0.10; P=0.024), whereas capillary distribution was only associated with mean deviation (β=-4.67; 95% CI: -7.92, -1.43; P=0.017).

CONCLUSION

Nailfold capillary abnormalities are associated with POAG as well as increased global and central vision loss.

Association of abdominal obesity with crossing capillaries in the finger nailfold in type 2 diabetes mellitus

Aim

Increased crossing of finger nailfold capillaries could be a novel visual marker of early microvascular damage among type 2 diabetes mellitus patients. Although abdominal obesity is an important driver of early microvascular damage, its association with an increase in the percentage of crossing capillaries remains uncertain. We investigated the association between abdominal obesity and an increase in the percentage of crossing capillaries in the finger nailfold in patients with type 2 diabetes mellitus.

Methods

This cross-sectional study enrolled 123 type 2 diabetes mellitus patients (age 40-75 years) who visited the outpatient diabetic clinic at Osaka University Hospital between May and October 2019. Abdominal obesity was defined as a waist circumference ≥ 90 cm in women and ≥ 85 cm in men. Capillary morphology was assessed by nailfold capillaroscopy based on the simple capillaroscopic definitions of the European League Against Rheumatism Study Group. The association between abdominal obesity and a high percentage of crossing capillaries in the finger nailfold (defined as the highest tertile of crossing capillaries) was analyzed using multivariable logistic regression.

Results

After adjusting for age, sex, smoking status, regular exercise, duration of diabetes, glycated hemoglobin, hypertension, and dyslipidemia, abdominal obesity was significantly associated with a high percentage of crossing capillaries (multivariable-adjusted odds ratios [95% confidence interval] = 2.70 [1.05-6.90], p = 0.038).

Conclusions

Abdominal obesity may play an important role in the increase in the percentage of crossing capillaries in the finger nailfold in patients with type 2 diabetes mellitus.

Nailfold capillaroscopy : a comprehensive review on common findings and clinical usefulness in non-rheumatic disease

Nailfold video-capillaroscopy (NVC) is a useful diagnostic tool, used to early detect abnormalities in micro-circulation, providing a qualitative description of microvascular anomalies in Raynaud's phenomenon. NVC role in the diagnosis of Systemic Sclerosis is well known. In other rheumatic conditions such as connective tissue diseases, vasculitis, and arthritis, the NVC anomalies are often included in a scleroderma like pattern. The use of NVC in non-rheumatic diseases (NRD), with remarkable microvascular damage, as diabetes, is not standardized yet, although several research studies are carrying on. The aim of this article is to provide a resume of published results in order to lay the groundwork for the employment of NVC both in the diagnosis and follow up of microvascular complication in NRD. Furthermore, we mention NVC findings in pathologies without well recognize microvascular damages in their pathogenesis : micro-vessels abnormalities may suggest a different point of view. J. Med. Invest. 68 : 6-14, February, 2021.

Biophotonics methods for functional monitoring of complications of diabetes mellitus

The prevalence of diabetes complications is a significant public health problem with a considerable economic cost. Thus, the timely diagnosis of complications and prevention of their development will contribute to increasing the length and quality of patient life, and reducing the economic costs of their treatment. This article aims to review the current state-of-the-art biophotonics technologies used to identify the complications of diabetes mellitus and assess the quality of their treatment. Additionally, these technologies assess the structural and functional properties of biological tissues, and they include capillaroscopy, laser Doppler flowmetry and hyperspectral imaging, laser speckle contrast imaging, diffuse reflectance spectroscopy and imaging, fluorescence spectroscopy and imaging, optical coherence tomography, optoacoustic imaging and confocal microscopy. Recent advances in the field of optical noninvasive diagnosis suggest a wider introduction of biophotonics technologies into clinical practice and, in particular, in diabetes care units.

Biologic Therapy and Treatment Options in Diabetic Retinopathy with Diabetic Macular Edema

Proliferative diabetic retinopathy and diabetic macular edema can be a potentially sightthreatening disease if not treated correctly. It is directly correlated to the duration of diabetes and how well managed the patients' diabetes is. In the last 15 years, the treatment of diabetic eye disease has taken a quantum leap in methodology due to the group of biological agents named antivascular endothelial growth factor (anti-VEGF). The introduction of the first biological agent has revolutionized the treatment, not only in diabetic eye disease but also across most inflammatory eye diseases, causing leakage of fluid from the blood vessels i.e., in age-related macular degeneration. The availability of these biological agents, despite their considerable costs, have significantly improved the outcomes measured in visual acuity compared to more traditional treatments of diabetic retinopathy in the form of sole laser treatment and glycemic control. The agents demonstrate a favorable safety profile, but if the rarest and most severe side effects occur, there is a potential total loss of vision. This review aims to make an overview of the current pharmaceutical therapeutic options in the treatment of diabetic macular edema. This includes laser therapy, intravitreal steroids, and a primary focus on intravitreal antivascular endothelial growth factors.

Nailfold capillaroscopy in common non-rheumatic conditions: A systematic review and applications for clinical practice

OBJECTIVE

The role of nailfold capillaroscopy (NC) in common non-rheumatic conditions has not been systematically reported. The aim of this review is to outline NC features observed in frequent non-rheumatic conditions, providing a practical tool to support rheumatologists for the interpretation of capillaroscopic abnormalities in patients with no established connective tissue disease (CTD).

METHODS

We undertook a systematic search in PubMed and Web of Science databases. Studies reporting adults or children with common non-rheumatic diseases or conditions in which quantitative and/or qualitative assessment of morphological nailbed capillary findings was obtained, were included. The presence of a control group composed by subjects not affected by the studied condition and direct comparison of findings between groups were needed.

RESULTS

We included 25 articles. Diabetes mellitus (11 studies), glaucoma (7 studies) and essential hypertension (3 studies) were the most represented diseases. Reduced capillary density, tortuosity, dilated capillaries, microhaemorrhages, ramified capillaries and avascular areas can be observed in diabetic patients. Association was reported between poor glycaemic control or longer duration of diabetes, or presence of microvascular complications as retinopathy and neuropathy, and more severe capillaroscopic abnormalities. Decreased capillary density, tortuosity, microhaemorrhages, dilated capillaries, avascular areas and ramifications might also be present in glaucoma, while in essential hypertension a reduced capillary density might be expected.

CONCLUSION

Abnormal capillaroscopic findings are not uncommon even in individuals with no CTD. Therefore, presence of comorbidities known to potentially affect the microvascular array should always be investigated in patients undergoing NC and the interpretation of findings might be weighted accordingly.

Prevalence and diagnostic value of nail fold capillary microscopy in hereditary hemorrhagic telangiectasia: A retrospective study

Abnormal vasculature is a key feature of hereditary hemorrhagic telangiectasia (HHT) and can also present in the nail fold capillary beds. However, the exact prevalence and the clinical diagnostic value in HHT are still largely unknown. The nail fold can be easily and noninvasively inspected with a capillary microscope. We therefore retrospectively assessed the prevalence and diagnostic value of abnormal nail fold capillaries in all patients who were screened between January 2000 and July 2017 for the presence of HHT and underwent capillary microscopy in St Antonius Hospital, The Netherlands. Capillary microscopy results and clinical characteristics were extracted from medical files and the prevalence of abnormal nail fold capillaries was calculated and the diagnostic value of the Curaçao criteria with and without capillary microscopy results was assessed. Of the 1761 individuals screened, 923 (52%) were diagnosed with a clinical and/or genetic HHT diagnosis. In these patients, capillary microscopy was normal in 23% (n = 218), enlarged loops were seen in 11% (n = 99), and giant loops in 66% (n = 606). The sensitivity and specificity of the Curaçao criteria for the diagnosis of HHT without capillary microscopy results were 96% and 90%, respectively. The addition of the presence of giant loops to the Curaçao criteria led to a small increase in sensitivity to 97% without affecting the specificity. In conclusion, the prevalence of nail fold abnormalities in patients with HHT is high. Capillary microscopy can be a useful, easy, and noninvasive diagnostic tool in HHT.

Nailfold Capillary Morphology in Alzheimer's Disease Dementia

BACKGROUND

Cerebrovascular disease (CVD) is highly comorbid with Alzheimer's disease (AD), yet its role is not entirely understood. Nailfold video capillaroscopy (NVC) is a noninvasive method of live imaging the capillaries near the fingernail's cuticle and may help to describe further vascular contributions to AD.

OBJECTIVE

To examine finger nailfold capillary morphology using NVC in subjects with AD dementia, mild cognitive impairment (MCI), and normal cognition (NC).

METHODS

We evaluated nailfold capillary hemorrhages, avascular zones ≥100 microns, and degree of tortuosity in 28 NC, 15 MCI, and 18 AD dementia subjects using NVC. Tortuosity was measured with a semi-quantitative rating scale. To assess the relation between nailfold capillary morphological features and diagnostic grouping, univariate and multivariable logistic regression models were fit to the data.

RESULTS

56% of subjects with AD dementia compared to 14% with NC and 13% with MCI displayed moderate to severe tortuosity. Greater severity of tortuosity was associated with 10.6-fold (95% confidence interval [CI]: 2.4, 46.2; p = 0.0018) and 7.4-fold (95% CI: 1.3, 41.3; p = 0.023) increased odds of AD dementia relative to NC and MCI, respectively, after adjusting for multiple covariates.

CONCLUSION

Greater nailfold capillary tortuosity was found in participants with AD dementia compared to those with MCI or NC. These data provide preliminary evidence of a systemic microvasculopathy in AD that may be noninvasively and inexpensively evaluated through NVC.

Cutaneous microangiopathy in patients with type 2 diabetes: Impaired vascular endothelial growth factor expression and its correlation with neuropathy, retinopathy and nephropathy

AIMS/INTRODUCTION

To examine the three-dimensional morphology and vascular endothelial growth factor (VEGF) expression of skin microvasculature in patients with type 2 diabetes in relation to neuropathy, retinopathy and nephropathy.

MATERIALS AND METHODS

The present study enrolled 17 individuals with type 2 diabetes and 16 without. Skin sections were double-immunostained for type IV collagen and VEGF-A or protein gene product 9.5. Projected images from confocal microscopy served to quantify the occupancy rate of subepidermal type IV collagen-immunoreactive microvascular basement membrane area (OR-T4MBM), subepidermal VEGF-A-immunoreactive area and the VEGF/T4MBM ratio, as well as the protein gene product 9.5-immunoreactive intraepidermal nerve fiber density. Reduced intraepidermal nerve fiber density was applied for the diagnosis of neuropathy, fundic ophthalmoscopy and fluorescein angiography for retinopathy, and microalbuminuria or persistent proteinuria for nephropathy.

RESULTS

A total of 12 patients with diabetes had neuropathy, 10 had retinopathy and eight had nephropathy. Regardless of the presence or absence of neuropathy, retinopathy or nephropathy, OR-T4MBM was significantly increased in patients with diabetes compared with individuals without diabetes. In contrast, VEGF/T4MBM ratio was significantly decreased in those with neuropathy and retinopathy, as well as in those with and without nephropathy, whereas a trend toward a decreased VEGF/T4MBM ratio was seen in patients without retinopathy, as compared with individuals without diabetes.

CONCLUSIONS

The present study is the first report to show that cutaneous microangiopathy, as indicated by subepidermal microvascular proliferation and impaired VEGF expression, appears to occur before the development of overt clinical neuropathy, retinopathy or nephropathy in patients with type 2 diabetes.

Nailfold capillary morphology and platelet function in patients with exfoliative glaucoma

Purpose

The purpose of the present study was to evaluate the nailfold capillary morphological features in patients with exfoliative glaucoma (XFG) and compare them with those pertaining to primary open-angle glaucoma (POAG), normal controls and subjects with exfoliation syndrome (XFS). The second purpose was to investigate all parameters related to platelet function on the hemogram, including the platelet count (PLT), the mean platelet volume (MPV), platelet distribution width (PDW), and plateletcrit (PCT) in patients with XFG. These parameters were subsequently compared with those belonging to normal controls, POAG and XFS subjects.

Methods

This case control study involved 152 consecutive patients that were examined at the Glaucoma Department of Clinic for Eye Diseases, Clinical Centre of Serbia, as the referral center for glaucoma in Serbia, between June 2016 and December 2017.

Results

Regarding capillaroscopic characteristics, statistically significant difference was found in capillary diameter and tortuosity between the XFG and POAG group (p = 0.050 and p = 0.035) and the XFG and NC group (p = 0.003 and p = 0.044), as well as in the distribution of capillary loops and avascular zones between the XFG and NC group (p = 0.014 and p = 0.004). The subjects with XFG had lower PLT values compared to POAG patients (p = 0.022).

Conclusions

In conclusion, to the best of our knowledge, this study marks the first attempt to evaluate capillary morphology as well as to investigate all parameters related to platelet function on the hemogram, in patients with newly diagnosed XFG. Our findings revealed nailfold capillary morphological vascular changes in XFG patients. The subjects with XFG had lower PLT values and a higher MPV serum parameter compared to normal controls and patients with POAG. Further research in this field should therefore aim to evaluate the consequences of the aforementioned microvascular abnormalities in patients with XFG.

The evaluation of nailfold videocapillaroscopy findings in patients with type 2 diabetes with and without diabetic retinopathy

OBJECTIVE:

Diabetes mellitus (DM) is a chronic hyperglycemic state and is associated with microvascular structural alterations. This study aimed to investigate the diameters of capillary loops and morphostructural changes using nailfold video capillaroscopy (NVC) in patients with type 2 DM with and without diabetic retinopathy (DR).

METHODS:

This cross-sectional, single-center study was conducted in patients with type 2 DM who were followed in outpatient clinics of ophthalmology and internal medicine. General demographic data were collected from patients. An ophthalmologist examined all patients in terms of DR. A rheumatologist blinded to the clinical data performed NVC. The diameters of apical, arterial, and venous loop of capillaries were measured, and the microvascular changes of capillaries were scored.

RESULTS:

In this study, 44 patients with type 2 DM with DR (47.7% males) and 20 patients with type 2 DM without DR (55% males) were included. In our study, patients with type 2 DM with DR had more frequent capillary hemorrhage, more frequent ectasia, more frequent giant capillary, and more frequent neo-angiogenesis than patients with type 2 DM without DR. However, these findings were not statistically significant.

CONCLUSION:

Further controlled studies with large sample size are needed to determine the characteristic NVC findings of DR in patients with type 2 DM.

Early vascular parameters in the micro- and macrocirculation in type 2 diabetes

BACKGROUND

Diabetes converts from a metabolic disorder into a predominantly vascular disease, once its duration extends over several years or/and when additional cardiovascular risk factors such as hypertension coexist. In a cross-sectional analysis we analyzed various vascular parameters in the renal, retinal and systemic circulation, with the goal to identify which vascular parameter of early organ damage is the earliest that can be clinically detected.

METHODS

In 111 patients with type 2 diabetes (T2DM) (off any anti-diabetic medication for at least 4 weeks) and 54 subjects without T2DM we compared various parameters of early vascular remodeling in the same patient: urinary albumin creatinine ratio ([UACR], early morning spot urine) and estimated glomerular filtration rate (eGFR), retinal capillary flow (RCF) and intercapillary distance (ICD) as parameters of capillary rarefaction, wall-to-lumen ratio (WLR) of the retinal arterioles [all assessed by Scanning Laser Doppler Flowmetry], and central systolic pressure (cSBP) and central pulse pressure (cPP) [measured by pulse wave analysis, Syphygmocor] both reflecting vascular stiffness of large arteries.

RESULTS

Compared to subjects without T2DM, patients with T2DM (diabetes duration: median 48 months, interquartile range 24-88 months) were older (59.8 ± 7.3 vs 43.4 ± 12.9 years, p < 0.001), more females (33.3 vs 20.4%, p < 0.001), but 24-h systolic and diastolic blood pressure did not differ between the two groups. The analysis adjusted for age, gender and cardiovascular risk factors revealed that ICD (23.9 ± 5.1 vs 20.8 ± 3.5 µm, p value = 0.001) and cPP (41.8 ± 11.7 vs 34.8 ± 10.6 mmHg, p value < 0.001) were significantly higher and eGFR (91.7 ± 9.9 vs 95.9 ± 17.3 ml/min/1.73 m², p value < 0.001) was significantly lower in patients with T2DM than in subjects without T2DM.

CONCLUSION

These data suggest that at similar blood pressure capillary rarefaction in the retinal circulation (ICD), decreased eGFR in the renal circulation and increased central pulse pressure (cPP) of large arteries are earlier detectable than other vascular remodeling parameters of the micro- (WLR, RCF, UACR) and macrocirculation (cSBP) in patients with T2DM. Trial registration Trial registration number: NCT02471963, Date of registration: June 15, 2015, retrospectively registered; Trial registration number: NCT01319357, Date of registration: March 21, 2011, retrospectively registered; Trial registration number: NCT02383238, Date of registration: March 9, 2015, retrospectively registered; Trial registration number: NCT00152698, Date of registration: September 9, 2005, prospectively registered; Trial registration number: NCT00136188, Date of registration: August 26, 2005, prospectively registered.

Somatolactogens and diabetic retinopathy

IMPORTANCE

Diabetic retinopathy (DR) is one of the most common of all diabetic complications. The number of people with DR in the United States is expected to increase to 16 million by 2050. DR is the leading cause of blindness among working-age adults in many different countries, including the United States. In later DR stages, neovascularization is associated with extensive retinal capillary non-perfusion and vitreo-proliferation leading to retinal detachment. This neovascularization is orchestrated by an imbalance of growth factors in the retina from which somatolactogens (pituitary growth hormone, GH-N; placental growth hormone, GH-V; prolactin, PRL; and placental lactogen, PL, also referred as chorionic somatomammotropin, CSH), may play an important role.

OBSERVATIONS

Somatolactogens are a group of hormones that share many structural and functional features. They are important for physiological changes in pregnancy, for adequate development of the fetus, and in the case of GH-N, for promoting growth after birth. GH-N is synthesized by the anterior pituitary, GH-V and PL are secreted by the placenta, whereas, PRL is synthesized by the anterior pituitary and uterine decidua. However, in recent years the expression of GH-N and PRL and their receptors have been detected in other tissues including the retina, acting as neuroprotective and pro-angiogenic agents. The relationship of GH-N and diabetic retinopathy (DR) was established many years ago when it was observed that its deficiency was related to regression of DR while an increase in serum levels of GH-N, GH-V, and PL promoted DR. While more studies are needed to define the potential implications of GH-V and PL in DR pathogenesis, it has been demonstrated that GH-N and PRL participate in DR by enhancing neovascularization. Some PRL isoforms, however, have shown an anti-angiogenic activity rather than pro-angiogenesis and appears to be PRL's main role in the regulation of retinal vasculature.

CONCLUSIONS

Somatolactogens are a group of hormones with a significant role in neuroprotection and angiogenesis regulation in the eye. Understanding the mechanisms of angiogenesis regulation by somatolactogens will potentially lead to the development of new drugs for DR.

Current Advances in Pharmacotherapy and Technology for Diabetic Retinopathy: A Systematic Review

Diabetic retinopathy (DR) is classically defined by its vascular lesions and damage in the neurons of the retina. The cellular and clinical elements of DR have many features of chronic inflammation. Understanding the individual cell-specific inflammatory changes in the retina may lead to novel therapeutic approaches to prevent vision loss. The systematic use of available pharmacotherapy has been reported as a useful adjunct tool to laser photocoagulation, a gold standard therapy for DR. Direct injections or intravitreal anti-inflammatory and antiangiogenesis agents are widely used pharmacotherapy to effectively treat DR and diabetic macular edema (DME). However, their effectiveness is short term, and the delivery system is often associated with adverse effects, such as cataract and increased intraocular pressure. Further, systemic agents (particularly hypoglycemic, hypolipidemic, and antihypertensive agents) and plants-based drugs have also provided promising treatment in the progression of DR. Recently, advancements in pluripotent stem cells technology enable restoration of retinal functionalities after transplantation of these cells into animals with retinal degeneration. This review paper summarizes the developments in the current and potential pharmacotherapy and therapeutic technology of DR. Literature search was done on online databases, PubMed, Google Scholar, clinitrials.gov, and browsing through individual ophthalmology journals and leading pharmaceutical company websites.

Clinical usefulness of videocapillaroscopy and selected endothelial cell activation markers in people with Type 1 diabetes mellitus complicated by microangiopathy

PURPOSE

Microvascular abnormalities are one of the most important causes of persistent diabetic complications. The aim of our study was to compare microvascular changes examined by nailfold videocapillaroscopy (NVC) examination with serum concentrations of vascular endothelial growth factor (VEGF), soluble thrombomodulin (sTM) and endothelin-1 (ET-1) in people with Type 1 diabetes with and without microangiopathy.

MATERIAL/METHODS

The study included 106 people with Type 1 diabetes and 40 healthy controls. All participants were evaluated by extensive clinical, laboratory and capillaroscopic studies. NVC was performed using a stereomicroscope SZ 4045 (Olympus, Germany). The intensity of morphological changes was graded from 0 to 3. Serum levels of VEGF, sTM and ET-1 were determined by an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Morphological changes were observed by NVC in 86 out of 106 (81%) people with Type 1 diabetes mellitus. Severe capillaroscopic changes (score 3) were seen in 32 out of 54 (59%) people with microangiopathy, but in only seven out of 52 (13%) individuals without microangiopathy. Higher serum concentration of VEGF (p<0.001), ET-1 (p<0.001) and sTM (p<0.05) were demonstrated in people with diabetes complicated with microangiopathy compared to healthy controls. Moreover, comparison between people with and without microangiopathic complications showed a significantly higher capillaroscopic score and sTM serum concentration in the group with retinopathy (p<0.001) nephropathy (p<0.001) and neuropathy (p<0.01).

CONCLUSIONS

Our results suggest that abnormalities in NVC may reflect the extent of microvascular involvement and associated with higher VEGF, sTM and ET-1 serum levels, as well as with microangiopathic complications in diabetic people.

Compliance with dietary guidelines affects capillary recruitment in healthy middle-aged men and women

PURPOSE

Healthy microcirculation is important to maintain the health of tissues and organs, most notably the heart, kidney and retina. Single components of the diet such as salt, lipids and polyphenols may influence microcirculation, but the effects of dietary patterns that are consistent with current dietary guidelines are uncertain. It was hypothesized that compliance to UK dietary guidelines would have a favourable effect on skin capillary density/recruitment compared with a traditional British diet (control diet).

METHODS

A 12-week randomized controlled trial in men and women aged 40-70 years was used to test whether skin microcirculation, measured by skin video-capillaroscopy on the dorsum of the finger, influenced functional capillary density (number of capillaries perfused under basal conditions), structural capillary density (number of anatomical capillaries perfused during finger cuff inflation) and capillary recruitment (percentage difference between structural and functional capillary density).

RESULTS

Microvascular measures were available for 137 subjects out of the 165 participants randomized to treatment. There was evidence of compliance to the dietary intervention, and participants randomized to follow dietary guidelines showed significant falls in resting supine systolic, diastolic and mean arterial pressure of 3.5, 2.6 and 2.9 mmHg compared to the control diet. There was no evidence of differences in capillary density, but capillary recruitment was 3.5 % (95 % CI 0.2, 6.9) greater (P = 0.04) on dietary guidelines compared with control.

CONCLUSIONS

Adherence to dietary guidelines may help maintain a healthy microcirculation in middle-aged men and women. This study is registered at www.isrctn.com as ISRCTN92382106.

Nailfold capillary morphology in exfoliation syndrome

PurposeThe purpose of the study was to investigate nailfold microvascular morphology in exfoliation syndrome with or without glaucoma (XFS/XFG) compared with primary open-angle glaucoma (POAG) and control subjects using nailfold capillary videomicroscopy.Patients and methodsWe used a JH-1004 capillaroscope to perform nailfold capillary videomicroscopy on the fourth and fifth digit of the non-dominant hand. We enrolled 56 XFS/XFG patients, 87 POAG patients, and 75 control subjects. Masked observers graded the videos for hemorrhages, avascular zones ≥200 microns (μm), and degree of microvascular tortuosity on a four-point subjective scale. Multivariable odds ratios, 95% confidence intervals and P-for trends for assessing the relation between morphological changes and POAG or XFS/XFG were obtained from logistic regression analyses. We also assessed this relation with XFS/XFG compared with POAG in multivariable models.ResultsAfter adjusting for multiple covariates, nailfold hemorrhages, avascular zones ≥200 μm, and higher degree of vascular tortuosity were more common in XFS/XFG vs controls (P-for trend ≤0.0001) and in POAG vs controls (P-for trend ≤0.01). For each 100 capillaries, the number of hemorrhages was similar (P-for trend=0.91) between XFS/XFG and POAG patients; however, there were more avascular zones per 100 capillaries with borderline significance (P-for trend=0.04) in the XFS/XFG group. XFS/XFG patients had more tortuosity than POAG patients; specifically, having a tortuosity score ≥1.5 was associated with a 4.4-fold increased odds of XFS/XFG (95% confidence interval: 1.5-13.3) relative to a tortuosity score <1.0 (P-for trend=0.005).ConclusionA high degree of nailfold capillary tortuosity is a distinct non-ocular feature associated with XFS/XFG compared with either POAG or controls.

Nailfold capillary abnormalities are associated with type 2 diabetes progression and correlated with peripheral neuropathy

Diabetes mellitus (DM) is associated with a state of chronic hyperglycemia with a highly increased risk of vascular complications. The current study aimed to investigate microcirculation abnormalities in patients with type 2 DM and those with pre-DM using nailfold videocapillaroscopy (NVC) and evaluate the possible correlation with microvascular complications.A total of 115 patients with type 2 DM, 41 patients with pre-DM, and 37 healthy subjects without diabetes were enrolled. All subjects underwent NVC to evaluate capillary density, length, morphology, distribution, presence of enlarged loops or hemorrhages, and blood flow. NVC score was used to quantitate the aforementioned characteristics.Patients with type 2 DM showed significantly increased alterations including reduced capillary length (29.6%), irregular distribution (35.7%), and abnormal morphology (59.1%), while the corresponding NVC scores were comparable to those of control subjects. In addition, subjects with pre-DM had a significantly higher NVC score and greater alterations in distribution (26.8%) and morphology (48.8%) than control subjects. NVC score was positively correlated with diabetic peripheral neuropathy (DPN) and the number of microvascular complications.NVC identified a high frequency of microcirculation abnormalities in subjects with pre-DM or type 2 DM compared to those in the control group. NVC score was also capable of detecting microvascular complications in patients with type 2 DM and was correlated with DPN and the number of microvascular complications.

Assessment of the Relationship between Diabetic Retinopathy and Nailfold Capillaries in Type 2 Diabetics with a Noninvasive Method: Nailfold Videocapillaroscopy

Background and Objectives. Nailfold capillaroscopy is an easy and noninvasive technique used to investigate dermal microvasculature. Traditional investigations of vascularity do not detect changes until they are well-established in type 2 diabetics. The objective of the current study was to evaluate nailfold capillaries in type 2 diabetes mellitus patients and to determine the association of retinopathy with changes in the nailfold capillaries. Materials and Methods. Capillaroscopic findings by nailfold capillaroscopy and fundoscopic examinations were assessed in 216 patients with type 2 diabetes mellitus and 101 healthy controls included in this prospective study. Results. Retinopathy was detected in 43.05% of diabetic patients (n = 93). Capillaroscopic findings including tortuosity (p < 0.001), bushy capillary (p < 0.001), neoformation (p < 0.001), bizarre capillary (p < 0.001), microhemorrhage (p = 0.001), capillary ectasia (p = 0.002), and aneurysm (p = 0.004) were significantly higher in diabetic group than control group. In logistic regression analysis, only tortuosity was shown significant (OR, 2.16; p = 0.036). There was also a significant relation between diabetes duration and most of the capillaroscopic findings. Conclusion. Capillaroscopic changes were found to be correlated with diabetic retinopathy, in particular with longer disease duration in our study. Capillaroscopic imaging could be a useful new technique for assessment of diabetic microvascular changes.

Non-invasive detection of microvascular changes in a paediatric and adolescent population with type 1 diabetes: a pilot cross-sectional study

BACKGROUND

The detection of microvascular damage in type 1 diabetes is difficult and traditional investigations do not detect changes until they are well established. The purpose of this study was to investigate the combined ability of nailfold capillaroscopy, laser Doppler flowmetry, retinal vessel analysis and 24-hr ambulatory blood pressure monitoring to detect early microvascular changes in a paediatric and adolescent population with type 1 diabetes.

METHODS

Patients aged between 8 - 18 years with type I diabetes and no other autoimmune conditions were studied. The participants underwent the above cardiac and vascular investigations in a single three-hour session. Standard parameters including HbA1c were also investigated. Associations between all parameters were described by correlation analysis. Fisher's exact and t-tests determined the association with clinical findings.

RESULTS

26 participants were recruited. The mean HbA1c was 8.1% (SD ± 1.1) with a mean duration of type 1 diabetes of 7.9 years (SD ± 3.4). Three participants had microalbuminuria and one had early signs of retinopathy. Participants with microvascular complications had more avascular areas on nailfold capillaroscopy (p = 0.03). Recent HbA1c was positively associated with the number of nailfold microhaemorrhages (p = 0.03) Decreased baseline perfusion by laser Doppler flowmetry was associated with increased capillary density (p = 0.001) and an increased number of microaneurysms (p = 0.04) on nailfold capillaroscopy.

CONCLUSIONS

This pilot study has shown that in children and adolescents with established type 1 diabetes, abnormal microvasculature can be detected by these investigations. These markers were also positively associated with evidence of suboptimal diabetes control as assessed by HbA1c. Further research will be necessary to determine the practical role of these investigations in the management and progress of the complications of type 1 diabetes.

TRIAL REGISTRATION

Clinical Trial number NCT01279928, ClinicalTrials.gov.