Automated evaluation of parapapillary choroidal microvasculature in crowded optic discs:a controlled,optical coherence tomography angiography study

AIM:To compare superficial and deep vascular properties of optic discs between crowded discs and controls using optical coherence tomography angiography(OCT-A).METHODS:Thirty patients with crowded discs,and 47 control subjects were enrolled in the study.One eye of each individual was included and OCT-A scans of optic discs were obtained in a 4.5×4.5 mm^(2) rectangular area.Radial peripapillary capillary(RPC)density,peripapillary retinal nerve fiber layer(pRNFL)thickness,cup volume,rim area,disc area,cup-to-disc(c/d)area ratio,and vertical c/d ratio were obtained automatically using device software.Automated parapapillary choroidal microvasculature(PPCMv)density was calculated using MATLAB software.When the vertical c/d ratio of the optic disc was absent or small cup,it was considered as a crowded disc.RESULTS:The mean signal strength index of OCT-A images was similar between the crowded discs and control eyes(P=0.740).There was no difference in pRNFL between the two groups(P=0.102).There were no differences in RPC density in whole image(P=0.826)and peripapillary region(P=0.923),but inside disc RPC density was higher in crowded optic discs(P=0.003).The PPCMv density in the inner-hemisuperior region was also lower in crowded discs(P=0.026).The pRNFL thickness was positively correlated with peripapillary RPC density(r=0.498,P<0.001).The inside disc RPC density was negatively correlated with c/d area ratio(r=-0.341,P=0.002).CONCLUSION:The higher inside disc RPC density and lower inner-hemisuperior PPCMv density are found in eyes with crowded optic discs.

Effects of obstructive sleep apnea on retinal microvasculature

AIM:To detect retinal microvascular variations in obstructive sleep apnea syndrome patients.METHODS:This prospective,observational case-control study included healthy controls and patients with mild,moderate,and severe obstructive sleep apnea syndrome.Vascular parameters,foveal avascular area,and flow areas in macula-centered,6.00×6.00 mm2 scan size optical coherence tomography angiography images were compared.RESULTS:The control group had the highest whole image,parafoveal,and perifoveal vessel density among the groups in both superficial and the deep capillary plexus(all P<0.05).Rapid eye movement sleep apnoea-hypopnoea index was reversely correlated with whole(Rho=-0.195,P=0.034),parafoveal(Rho=-0.242,P=0.008),perifoveal(Rho=-0.187,P=0.045)vessel density in the superficial capillary plexus,and whole(Rho=-0.186,P=0.046),parafoveal(Rho=-0.260,P=0.004),perifoveal(Rho=-0.189,P=0.043)vessel density in the deep capillary plexus,though the mean and non-rapid eye movement sleep apnoeahypopnoea index related with only parafoveal vessel density in the superficial capillary plexus(Rho=-0.213,P=0.020;Rho=-0.191,P=0.038)and the deep capillary plexus(Rho=-0.254,P=0.005;Rho=-0.194,P=0.035).CONCLUSION:This study shows decreased vessel density and its reverse correlation with the apnoea-hypopnoea index in patients with obstructive sleep apnea syndrome.

Characteristics of macular microvasculature before and after idiopathic macular hole surgery

AIM:To evaluate the macular microvasculature before and after surgery for idiopathic macular hole(MH)and the association of preoperative vascular parameters with postoperative recovery of visual acuity and configuration.METHODS:Twenty eyes from 20 patients with idiopathic MH were enrolled.Optical coherence tomography angiography(OCTA)images were obtained before,2 wk,1,and 3 mo after vitrectomy with internal limiting membrane peeling.Preoperative foveal avascular zone(FAZ)area and perimeter and regional vessel density(VD)in both layers were compared according to the 3-month best-corrected visual acuity(BCVA).RESULTS:The BCVA improved from 0.98±0.59(log MAR,Snellen 20/200)preoperatively to 0.30±0.25(Snellen 20/40)at 3 mo postoperatively.The preoperative deep VD was smaller and the FAZ perimeter was larger in the 3-month BCVA<20/32 group(all P<0.05).A significant reduction was observed in FAZ parameters and all VDs 2 wk postoperatively.Except for deep perifoveal VD,all VDs recovered only to their preoperative values.The postoperative FAZ parameters were lower during follow-up.Decreases in preoperative deep VDs were correlated with worse postoperative BCVA(Pearson’s r=-0.667 and-0.619,respectively).A larger FAZ perimeter(Spearman’s r=-0.524)and a lower deep perifoveal VD preoperatively(Pearson’s r=0.486)were associated with lower healing stage.CONCLUSION:The status of the deep vasculature may be an indicator of visual acuity in patients with a closed MH.Except for the deep perifoveal region,VD recovers only to preoperative levels.

Microvasculature of the esophagus and gastroesophageal junction: Lesson learned from submucosal endoscopy

Advanced therapeutic endoscopy,in particular endoscopic mucosal resection,endoscopic submucosal dissection,per-oral endoscopic myotomy,submucosal endoscopic tumor resection opened a new era where direct esophageal visualization is possible.Combining these information with advanced diagnostic endoscopy,the esophagus is organized,from the luminal side to outside,into five layers(epithelium,lamina propria with lamina muscularis mucosa,submucosa,muscle layer,adventitia).A specific vascular system belonging to each layer is thus visible: Mucosa with the intra papillary capillary loop in the epithelium and the sub-epithelial capillary network in the lamina propria and,at the lower esophageal sphincter(LES) level with the palisade vessels; submucosa with the drainage vessels and the spindle veins at LES level; muscle layer with the perforating vessels; periesophageal veins in adventitia.These structures are particularly important to define endoscopic landmark for the gastro-esophageal junction,helpful in performing submucosal therapeutic endoscopy.

Decreased retinal microvasculature densities in pterygium

AIM:To investigate the retinal vascular network alterations in eyes of patients with pterygium.METHODS:Totally 18 left eyes from 18 female pterygium patients and 18 left eyes from 18 female healthy control subjects were enrolled.Optical coherence tomography angiography(OCTA)images were generated of the superficial retinal layer and deeper retinal layer of the macular retina for each eye.The microvascular(MIR)and macrovascular(MAR)densities were calculated and MIR,MAR,and total microvascular(TMI)density was compared in the healthy control and pterygium groups.RESULTS:In pterygium group,in the superficial retinal layer,the vascular density in superficial MIR,superior right(SR),inferior right(IR),right(R),superficial central annuli(SC)1,SC2,and SC3 decreased significantly in the macular area(P<0.05).Furthermore,the vascular density in all those decreased regions except R,was significantly and negatively correlated with the disease course(r=-0.6038 to-0.7762,P=0.0008),and the area size of pterygium(r=-0.6043 to-0.9508,P<0.05).For the deeper retinal layer,the density of deep total microvessel(DTMI),deeper MIR,SR,IR,R,DC2,and DC3 decreased significantly in macular area of pterygium patients(P<0.05).Furthermore,the vascular density in all those decreased regions was significantly and negatively correlated with the disease course(r=-0.6901 to-0.7795,P=0.0015),and the area size of pterygium(r=-0.6043 to-0.9563,P<0.05).No statistically significant differences and correlation was found in other region density(|r|<0.47,P>0.05).CONCLUSION:OCTA findings suggest that pterygium patients present with decreased retinal MIR density,and the major vascular alterations occurr mainly on the bitamporal side.The vascular density of the superficial SC1,SC2,SC3 adjacent to the foveal and deep layer of DC2,DC2 regions,significantly decreased.

Antioxidant-induced reductive stress has untoward consequences on the brain microvasculature

All cells in the body metabolize oxygen in a series of reactions in the mitochondria to generate energy.A by-product of these reactions is the production of highly reactive oxygen radicals which have the potential to cause irreparable damage to cellular components,and have been linked to mutagenic and neurotoxicity of the nervous system.Under normal conditions,innate molecular systems,glutathione,superoxide dismutases,

High-speed high-resolution laser diode-based photoacoustic microscopy for in vivo microvasculature imaging

Laser diodes(LDs)have been considered as cost-effective and compact excitation sources to overcome the requirement of costly and bulky pulsed laser sources that are commonly used in photoacoustic microscopy(PAM).However,the spatial resolution and/or imaging speed of previously reported LD-based PAM systems have not been optimized simultaneously.In this paper,we developed a high-speed and high-resolution LD-based PAM system using a continuous wave LD,operating at a pulsed mode,with a repetition rate of 30 kHz,as an excitation source.A hybrid scanning mechanism that synchronizes a one-dimensional galvanometer mirror and a two-dimensional motorized stage is applied to achieve a fast imaging capability without signal averaging due to the high signal-to-noise ratio.By optimizing the optical system,a high lateral resolution of 4.8μm has been achieved.In vivo microvasculature imaging of a mouse ear has been demonstrated to show the high performance of our LD-based PAM system.

Retinal microvasculature is a potential biomarker for acute mountain sickness

Increased cerebral blood flow resulting from altered capillary level autoregulation at high altitudes leads to capillary overperfusion and then vasogenic cerebral edema,which is the leading hypothesis of acute mountain sickness(AMS).However,studies on cerebral blood flow in AMS have been mostly restricted to gross cerebrovascular endpoints as opposed to the microvasculature.This study aimed to investigate ocular microcirculation alterations,the only visualized capillaries in the central neural system(CNS),during early-stage AMS using a hypobaric chamber.This study found that after high altitude simulation,the optic nerve showed retinal nerve fiber layer thickening(P=0.004–0.018)in some locations,and the area of the optic nerve subarachnoid space(P=0.004)enlarged.Optical coherence tomography angiography(OCTA)showed increased retinal radial peripapillary capillary(RPC)flow density(P=0.003–0.046),particularly on the nasal side of the nerve.The AMSpositive group had the largest increases in RPC flow density in the nasal sector(AMS-positive,?3.21±2.37;AMS-negative,?0.01±2.16,P=0.004).Among multiple ocular changes,OCTA increase in RPC flow density was associated with simulated early-stage AMS symptoms(beta=0.222,95%CI,0.009–0.435,P=0.042).The area under the receiver operating characteristics curve(AUC)for the changes in RPC flow density to predict early-stage AMS outcomes was 0.882(95%CI,0.746–0.998).The results further confirmed that overperfusion of microvascular beds is the key pathophysiologic change in early-stage AMS.RPC OCTA endpoints may serve as a rapid,noninvasive potential biomarker for CNS microvascular changes and AMS development during risk assessment of individuals at high altitudes.

Increased retinal venule diameter as a prognostic indicator for recurrent cerebrovascular events:a prospective observational study

Microvasculature of the retina is considered an alternative marker of cerebral vascular risk in healthy populations.However,the ability of retinal vasculature changes,specifically focusing on retinal vessel diameter,to predict the recurrence of cerebrovascular events in patients with ischemic stroke has not been determined comprehensively.While previous studies have shown a link between retinal vessel diameter and recurrent cerebrovascular events,they have not incorporated this information into a predictive model.Therefore,this study aimed to investigate the relationship between retinal vessel diameter and subsequent cerebrovascular events in patients with acute ischemic stroke.Additionally,we sought to establish a predictive model by combining retinal veessel diameter with traditional risk factors.We performed a prospective observational study of 141 patients with acute ischemic stroke who were admitted to the First Affiliated Hospital of Jinan University.All of these patients underwent digital retinal imaging within 72 hours of admission and were followed up for 3 years.We found that,after adjusting for related risk factors,patients with acute ischemic stroke with mean arteriolar diameter within 0.5-1.0 disc diameters of the disc margin(MAD_(0.5-1.0DD))of≥74.14μm and mean venular diameter within 0.5-1.0 disc diameters of the disc margin(MVD_(0.5-1.0DD))of≥83.91μm tended to experience recurrent cerebrovascular events.We established three multivariate Cox proportional hazard regression models:model 1 included traditional risk factors,model 2 added MAD_(0.5-1.0DD)to model 1,and model 3 added MVD0.5-1.0DD to model 1.Model 3 had the greatest potential to predict subsequent cerebrovascular events,followed by model 2,and finally model 1.These findings indicate that combining retinal venular or arteriolar diameter with traditional risk factors could improve the prediction of recurrent cerebrovascular events in patients with acute ischemic stroke,and that retinal imaging could be a useful and non-invasive method for identifying high-risk patients who require closer monitoring and more aggressive management.

Development and Innovation of Modern Microvascular Anastomoses

High-quality microvascular anastomosis is the foundation of successful microsurgery and one of the most important basic skills for microsurgeons. The traditional manual suture is recognized as the “gold standard” for microvascular anastomosis, but it still has problems such as long operation time and easy to cause vascular damage. In order to improve the success rate of microvascular anastomosis, reduce surgical complications and make the prognosis of patients better. In order to improve the success rate of microvascular anastomosis and reduce the surgical complications, scholars at home and abroad have developed some new vascular anastomosis techniques that are simple, fast and minimally invasive while improving the traditional surgical suturing methods. In this paper, we review the microvascular anastomosis, and its application research in two methods of traditional hand suture and non-suture anastomosis, in order to promote the application development of microvascular anastomosis.

Effects of Huanshuai Recipe Oral Liquid (缓衰口服液) on Restructuring Glomerular Microvasculature and Expression of Vascular Endothelial Growth Factor in Subtotal Nephrectomized Rats

Objectives：To explore the effects and significance of Huanshuai Recipe Oral Liquid（缓衰口服液,HSR）,a formula with supplementing qi,nourishing blood and activating blood on restructuring glomerular microvasculature and expression of vascular endothelial growth factor（VEGF）in subtotal nephrectomized（SNX） rats.Methods：A total of 76 male Wistar rats were randomly divided into four groups：16 in the sham-operated group and fed with tap water 10 mL/kg per day; 20 in the model group were operated with 5/6 SNX and fed with tap water 10 mL/kg per day; 20 SNX rats in the HSR group were treated with HSR 10 mL/kg per day; 20 SNX rats in the losartan group were treated with losartan 40 mg/kg per day.Serum creatinine（SCr）and urinary protein excretion（Upro）were examined at the 2nd,4th,8th,and 12th weeks of the treatment,and the remnant kidneys were harvested.Changes in histological microstructure were evaluated using light microscopy,and the expression of VEGF was detected by using ELISA.Results：Upro,microvasculature injury and glomerulosclerosis were found to be alleviated in HSR and Losartan groups,respectively.The change of VEGF expression showed positive correlation with glomerular capillary area and peritubular capillary number（r=0.448,r=0.422,P〈0.01）, but negative correlation with that of SCr and Upro（r=-0.592,r=-0.481,P〈0.01）.Conclusions：HSR could regulate the VEGF expression,reduce the loss of microvasculature,which demonstrated similar renal protective effects to losartan in SNX rats.Examination of Chinese herbal medicine influence on VEGF signaling and restructuring renal microvasculature may elucidate the molecular mechanism of renal protection to a certain degree.

Retinal nerve fiber layer (RNFL) integrity and its relations to retinal microvasculature and microcirculation in myopic eyes

Background:The aim was to determine retinal nerve fiber layer function and its relations to retinal microvasculature and microcirculation in patients with myopia.Method:Polarization-sensitive optical coherence tomography(PS-OCT)was used to measure phase retardation per unit depth(PR/UD,proportional to the birefringence)of the retinal nerve fiber layer(RNFL).Optical coherence tomography angiography(OCTA)was used to measure macular vessel density analyzed using fractal analysis.In addition,a retinal function imager(RFI)was used to measure macular blood flow velocities in arterioles and venules.Twenty-two patients with moderate myopia(MM,refraction>3 and<6 diopters),seventeen patients with high myopia(HM,≥6 D)and 29 healthy control subjects(HC,≤3.00 D)were recruited.One eye of each patient was imaged.Results:Although the average PR/UD of the RNFL in the HM group did not reach a significant level,the birefringence of the inferior quadrant was significantly lower(P<0.05)in the HM group compared to the HC group.Significant thinning of the average RNFL and focal thinning of RFNL in temporal,superior and inferior quadrants in the HM group were found,compared to the HC group(P<0.05).There were no significant differences of retinal blood flow velocities in arterioles and venules among groups(P>0.05).The macular vessel density in both superficial and deep vascular plexuses was significantly lower in the HM group than in the other two groups(P<0.05)as well as in the MM group than in the HC group(P<0.05).The average PR/UD and PR/UD in the inferior quadrant were not related to refraction,axial length,blood flow velocities and macular vessel densities(r ranged from−0.09 to 0.19,P>0.05).Conclusions:The impairment of the retinal nerve fiber birefringence in the HM group may be one of the independent features in high myopic eyes,which appeared not to relate to macular microvascular density and blood flow velocity.

Quantitative analysis of conjunctival microvasculature imaged using optical coherence tomography angiography

Background:The goal was to quantitatively analyze the bulbar conjunctival microvascular density using optical coherence tomography angiography(OCTA)and compare it to the vessel density using functional slit-lamp biomicroscopy(FSLB).Methods:Temporal bulbar conjunctiva of 20 eyes(10 healthy subjects)was imaged using both OCTA and FSLB.Image processing was performed including equalization,de-noising,thresholding,and skeletonization.The vessel density was measured by fractal analysis(box counting,Dbox)and pixel counting(%).Results:Vessel density(Dbox)of the bulbar conjunctiva obtained using OCTA was 1.28±0.01 Dbox,which was significantly lower than the result(1.32±0.01 Dbox,P<0.001)obtained using FSLB.Furthermore,the vessel density(%)obtained using OCTA was 3.31±0.12%,which was also significantly lower than the result(3.69±0.16%,P<0.001)obtained using FSLB.No significant correlations(r ranged from 0.21 to 0.32,P>0.05)between both instruments were found in both vessel density methods(Dbox and percentage).However,in each of the devices,vessel density in Dbox was significantly correlated with the vessel density in percentage(r=1.0 for FSLB and r=0.98 for OCTA,both P<0.001).Conclusion:This study demonstrated that the vessel density of the bulbar conjunctiva obtained using OCTA can be quantified,and the results were not compatible with that obtained using slit-lamp biomicroscopy photography.

Advances in cellular and molecular mechanisms of oral submucosal fibrosis

Oral submucosal fibrosis(OSF)is a pathological process in which the oral mucosa forms abnormal repair in persistent chronic injury.It is characterized by inflammatory reactions,massive extracellular matrix deposition and vascular loss,ultimately leading to structural and functional damage of the oral mucosa.The infiltration of inflammatory cells is the fuse of oral submucosal fibrosis,suggesting that the immune microenvironment of local tissues plays an important role in its occurrence and development.Activated myofibroblasts can secrete large amounts of extracellular matrix,which reassemble and remodel,thereby resisting collagenase degradation,while the loss of blood vessels can significantly aggravate the progression of fibrosis.This article reviews the etiology of oral submucosal fibrosis and the effects of local tissue immune environment imbalance,extracellular matrix deposition and vascular loss on the progression of oral submucosal fibrosis.

Endothelial dysfunction in inflammatory bowel diseases:Pathogenesis,assessment and implications

Endothelial dysfunction is considered one of the etiological factors of inflammatory bowel disease(IBD). An inflammatory process leads to functional and structural changes in the vascular endothelium. An increase of leukocyte adhesiveness and leukocyte diapedesis, as well as an increased vascular smooth muscle tone and procoagulant activity is observed. Structural changes of the vascular endothelium comprise as well capillary and venule remodeling and proliferation of endothelial cells. Hypoxia in the inflammatory area stimulates angiogenesis by upregulation of vascular endothelial growth factor, fibroblast growth factor and tumor necrosis factor-α. Inflammatory mediators also alter the lymphatic vessel function and impair lymph flow, exacerbating tissue edema and accumulation of dead cells and bacteria. The endothelial dysfunction might be diagnosed by the use of two main methods: physical and biochemical. Physical methods are based on the assessment of large arteries vasodilatation in response to an increased flow and receptors stimulation. Flowmediated vasodilatation(FMD) is the method that is the most widely used; however, it is less sensitive in detecting early changes of the endothelium function. Most of the studies demonstrated a decrease of FMD in IBD patients but no changes in the carotic intima-media thickness. Biochemical methods of detecting the endothelial dysfunction are based on the assessment of the synthesis of compounds produced both by the normal and damaged endothelium. The endothelial dysfunction is considered an initial step in the pathogenesis of atherosclerosis in the general population. In IBD patients, the risk of cardiovascular diseases is controversial. Large, prospective studies are needed to establish the role of particular medications or dietary elements in the endothelial dysfunction as well to determine the real risk of cardiovascular diseases.

Role of the endothelium in inflammatory bowel diseases

Inflammatory bowel diseases(IBD) are a complex group of diseases involving alterations in mucosal immunity and gastrointestinal physiology during both initiation and progressive phases of the disease.At the core of these alterations are endothelial cells,whose continual adjustments in structure and function coordinate vascular supply,immune cell emigration,and regulation of the tissue environment.Expansion of the endothelium in IBD(angiogenesis),mediated by inflammatory growth factors,cytokines and chemokines,is a hallmark of active gut disease and is closely related to disease severity.The endothelium in newly formed or inflamed vessels differs from that in normal vessels in the production of and response to inflammatory cytokines,growth factors,and adhesion molecules,altering coagulant capacity,barrier function and blood cell recruitment in injury.This review examines the roles of the endothelium in the initiation and propagation of IBD pathology and distinctive features of the intestinal endothelium contributing to these conditions.

Effectiveness of narrow-band imaging magnification for invasion depth in early colorectal cancer

AIM: To evaluate the surface microvascular patterns of early colorectal cancer (ECC) using narrow-band imaging (NBI) with magnification and its effectiveness for invasion depth diagnosis. METHODS: We studied 112 ECC lesions [mucosal/ submucosal superficial (m/sm-s), 69; sm-deep (sm-d), 43] ≥ 10 mm that subsequently underwent endoscopic or surgical treatment at our hospital. We compared microvascular architecture revealed by NBI with magnification to histological findings and then to magnifi- cation colonoscopy pit pattern diagnosis. RESULTS: Univariate analysis indicated vessel density: non-dense (P < 0.0001); vessel regularity: negative (P < 0.0001); caliber regularity: negative (P < 0.0001); vessel length: short (P < 0.0001); and vessel meandering: positive (P = 0.002) occurred significantly more often with sm-d invasion than m/sm-s invasion. Multivariate analysis showed sm-d invasion was independently associated with vessel density: non-dense[odds ratio (OR) = 402.5, 95% confidence interval (CI): 12.4-13 133.1] and vessel regularity: negative (OR = 15.9, 95% CI: 1.2-219.1). Both of these findings when combined were an indicator of sm-d invasion with sensitivity, specificity and accuracy of 81.4%, 100% and 92.9%, respectively. Pit pattern diagnosis sensitivity, specificity and accuracy, meanwhile, were 86.0%, 98.6% and 93.8%, respectively, thus, the NBI with magnification findings of non-dense vessel density and negative vessel regularity when combined together were comparable to pit pattern diagnosis. CONCLUSION: Non-dense vessel density and/or negative vessel regularity observed by NBI with magnification could be indicators of ECC sm-d invasion.

Altered Expression of Matrix Metalloproteinases and Tight Junction Proteins in Rats following PEMF-Induced BBB Permeability Change

Objective To investigate the expression of occludin,ZO‐1,MMP‐2,and MMP‐9 in cerebral microvasculature following Pulse Electromagnetic Field（PEMF） induced BBB permeability change.Methods Sprague‐Dawley rats were randomized into PEMF and sham exposed groups（n=8）.After exposure to PEMF at 0.5,1,3,6,and 12 h,BBB permeability was measured by Evans‐Blue extravasation.The expression of occludin,ZO‐1,MMP‐2,and MMP‐9 were detected by real‐time quantitative reverse transcriptase PCR and western blotting.MMP‐2 and MMP‐9 activity were detected by EnzChek gelatinase assay.Results Compared with the sham group,PEMF exposure led to increased permeability of the BBB to EB,which was prolonged after exposure.BBB permeability became progressively more severe,and recovered at 6 h.The gene and protein expression of occludin and ZO‐1 were significantly decreased,while MMP‐2 and MMP‐9 expression were significantly increased after exposure to PEMF.All levels of expression recovered 12 h following PEMF.Conclusion Changes to BBB permeability were related to the alteration expression of tight junction proteins and matrix metalloproteinase after exposure to PEMF.

Characterisation of human non-proliferative diabetic retinopathy using the fractal analysis

· AIM: To investigate and quantify changes in the branching patterns of the retina vascular network in diabetes using the fractal analysis method.·METHODS: This was a clinic-based prospective study of 172 participants managed at the Ophthalmological Clinic of Cluj-Napoca, Romania, between January 2012 and December 2013. A set of 172 segmented and skeletonized human retinal images, corresponding to both normal(24 images) and pathological(148 images)states of the retina were examined. An automatic unsupervised method for retinal vessel segmentation was applied before fractal analysis. The fractal analyses of the retinal digital images were performed using the fractal analysis software Image J. Statistical analyses were performed for these groups using Microsoft Office Excel2003 and Graph Pad In Stat software.·RESULTS: It was found that subtle changes in the vascular network geometry of the human retina are influenced by diabetic retinopathy(DR) and can be estimated using the fractal geometry. The average of fractal dimensions D for the normal images(segmented and skeletonized versions) is slightly lower than the corresponding values of mild non-proliferative DR(NPDR) images(segmented and skeletonized versions).The average of fractal dimensions D for the normal images(segmented and skeletonized versions) is higher than the corresponding values of moderate NPDR images(segmented and skeletonized versions). The lowestvalues were found for the corresponding values of severe NPDR images(segmented and skeletonized versions).· CONCLUSION: The fractal analysis of fundus photographs may be used for a more complete understanding of the early and basic pathophysiological mechanisms of diabetes. The architecture of the retinal microvasculature in diabetes can be quantitative quantified by means of the fractal dimension.Microvascular abnormalities on retinal imaging may elucidate early mechanistic pathways for microvascular complications and distinguish patients with DR from healthy individuals.

The Role of Angiopoietin-1 and Thrombospondin-1 in the Kidney of Rats Subject to 5/6 Nephrectomy

The expression of angiopoietin- 1 （Ang- 1） and thrombospondin- 1 （TSP- 1） in 5/6 subtotal nephrectomy （STN） rats model, and its correlation to the renal microvasculature injury were investigated. Rat 5/6 STN model was established in adult male SD rats, and the sham-operated group and 5/6 STN group were set up. The renal function and histopathological changes were examined at the 1st, 2nd, 4th, 8th and 12th week after operation. The expression orAng-1, TSP-1 and CD31 in renal tissues was detected by using immunohistochemistry. From 2nd to 8th week after operation, Ang-1 was significantly expressed in glomeruli of rats with STN. Ang-1 staining in glomeruli of STN group was increased significantly as compared with that in sham-operated group at 4th and 8th week after operation, and subsequently decreased after the 12th week. The expression of TSP-1 was increased significantly in STN group. As compared with sham-operated group, the CD31 expression was significantly down-regulated from the 2nd week. The expression of Ang-1 mRNA was detected by using RT-PCR at the same time points. The expression of Ang-1 mRNA in renal tissue of rats with STN was significantly up-regulated at the 2nd, 4th and 8th week after operation as compared with that in STN group at other time points or in sham-operated group at the same time points, while decreased evidently at the 12th week as compared with that in sham-operated group. It is concluded that there are changes in the mRNA expression of Ang-1, and the significant up-regulation of the expression of TSP-1 in renal tissue of rats with STN, which may be involved in the remnant renal microvasculature injury.