Hypertensive retinopathy: there's more than meets the eye

Optical coherence tomography as a potential surrogate marker of dopaminergic modulation across the life span

The retina has been considered a "window to the brain" and shares similar innervation by the dopaminergic system with the cortex in terms of an unequal distribution of D1 and D2 receptors. Here, we provide a comprehensive overview that Optical Coherence Tomography (OCT), a non-invasive imaging technique, which provides an "in vivo" representation of the retina, shows promise to be used as a surrogate marker of dopaminergic neuromodulation in cognition. Overall, most evidence supports reduced retinal thickness in individuals with dopaminergic dysregulation (e.g., patients with Parkinson's Disease, non-demented older adults) and with poor cognitive functioning. By using the theoretical framework of metacontrol, we derive hypotheses that retinal thinning associated to decreased dopamine (DA) levels affecting D1 families, might lead to a decrease in the signal-to-noise ratio (SNR) affecting cognitive persistence (depending on D1-modulated DA activity) but not cognitive flexibility (depending on D2-modulated DA activity). We argue that the use of OCT parameters might not only be an insightful for cognitive neuroscience research, but also a potentially effective tool for individualized medicine with a focus on cognition. As our society progressively ages in the forthcoming years and decades, the preservation of cognitive abilities and promoting healthy aging will hold of crucial significance. OCT has the potential to function as a swift, non-invasive, and economical method for promptly recognizing individuals with a heightened vulnerability to cognitive deterioration throughout all stages of life.

Subclinical retinal microvascular alterations assessed by optical coherence tomography angiography in children with systemic hypertension

PURPOSE

To compare the foveal avascular zone (FAZ) macular and peripapillary vessel density between children with high blood pressure and healthy subjects.

METHODS

A total of 40 eyes of 20 children with hypertension and 40 eyes of 20 age- and sex-matched healthy controls were included. Capillary vessel density (CVD) in superficial (SCP) and deep (DCP) retinal capillary plexus, peripapillary region, and FAZ were analyzed by optical coherence tomography angiography.

RESULTS

The mean ages were 15.2 ± 1.5 years (range, 10-18) in patients with hypertension and 14.4 ± 2.8 years (range, 10-18) in healthy controls (P = 0.742). The mean FAZ area measured 0.25 ± 0.10 mm² in children with hypertension and 0.25 ± 0.09 mm² in healthy controls (P = 0.765). There was no significant difference between study groups in any measure of the macular SCP (P > 0.05 for all); however, the mean whole image, inferior hemisphere, and para- and perifoveal measurements of the macular DCP were significantly lower in children with hypertension than in controls (P < 0.05 for all).

CONCLUSIONS

Although there was no evidence of hypertensive retinopathy, subthreshold microvascular alterations were found in the DCP of the retinal circulation in pediatric hypertensives. These alterations should be considered as prognostic cues when defining whole systemic response to high blood pressure in childhood.

Retinal structural changes in systemic arterial hypertension: an OCT study

PURPOSE

To assess retinal nerve fiber layer (RNFL), ganglion cell complex (GCC), and macular thickness changes in young adults with systemic arterial hypertension.

METHODS

This study included 80 young patients (age 23.8 ± 2.8 years) with systemic hypertension (sHT) without any known systemic or ocular disease and 80 age-matched (23.5 ± 2.1 years) healthy controls. Retinal nerve fiber layer thickness, macular thickness, and GCC thickness were measured with spectral-domain optical coherence tomography.

RESULTS

Mean disease duration was 3.45 ± 1.48 years (range 2-10). Differences in intraocular pressure, body mass index, axial length, and spherical equivalent between the groups were insignificant (p&gt;0.05). The differences in RNFL thickness did not differ between the groups. Patients with sHT had significantly lower central macular thickness (p = 0.037), inner superior macular thickness (p = 0.045), and outer temporal superior and outer temporal inferior GCC (p&lt;0.001 for both). The RNFL thickness did not differ significantly in all quadrants between the groups (p&gt;0.05). Systolic and diastolic blood pressure were significantly correlated with inner temporal superior and inner temporal inferior GCC thickness in a negative manner (p&lt;0.05 for all).

CONCLUSIONS

Ganglion cell complex thickness decrease is possibly a better retinal marker for hypertensive changes with respect to RNFL and macular thickness.

Relationship of Hypertensive Retinopathy with Mean Platelet Volume Among Hypertensive Patients

Background The pathophysiological mechanism of hypertensive retinopathy (HR) is not fully understood, although it is thought that increased platelet activation may have a pivotal role. This study was designed to investigate this possibility by determining the frequency and magnitude of mean platelet volume (MPV), a marker of platelet activation, in HR.

Methods One hundred and thirty-eight patients, aged 31 to 80 years, who had essential hypertension with HR were enrolled in the study. The patients who presented at the emergency and outpatient medical department of the Capital Development Authority (CDA) Hospital, Islamabad, Pakistan, from March 2013 to February 2014 were selected for this study. All patients were analyzed for grading of HR according to the Keith-Wagener-Barker (KWB) classification criteria. A direct ophthalmoscopic examination was performed in all the subjects, together with an assessment of MPV.

Results The mean age of the patients was 54.1 ± 11.7 years. Normal MPV was found in 97 (70.2%) patients, 53 males and 44 females. Elevated levels of MPV were found in 41 (29.7%)  patients, 19 males and 22 females. In patients with Grade 1 HR, the MPV was 10.6 ± 0.6 femtoliters (fl). In Grades 2, 3, and 4 HR, the values of MPV were 11.1± 0.5 fl, 11.6 ± 0.3 fl, and 12.2 ± 0.6 fl, respectively, which were greater than the normal range (> 10 fl) of MPV values. In addition, the frequency of elevated MPV significantly (P < 0.001) and linearly (r = 0.998) increased with increasing HR grade.

Conclusion It is concluded that the frequency of elevated MPV is increased in patients with HR and strongly correlates to grade. In addition, the magnitude of the elevated MPV increased with the severity of the retinopathy. Thus, abnormally elevated MPV may be an etiological factor for HR in hypertensive patients.

Accumulation of microvascular target organ damage in newly diagnosed hypertensive patients

Early identification of hypertensive target organ damage (TOD) emerges as important for global cardiovascular risk assessment. Retinal vascular alterations, capillary rarefaction, and microalbuminuria represent different forms of microvascular TOD. However, data regarding their concomitant presence in the early stages of hypertension, the association of the number of affected organs with cardiovascular risk, and aldosterone effect on multiple TOD are lacking. We studied naïve, never-treated patients with recent duration of hypertension and healthy volunteers. Innovative software was developed to estimate retinal vascular diameters and capillary density. Biochemical parameters including microalbuminuria and serum aldosterone were derived. Framingham Risk Score was used to determine cardiovascular risk. In total 103 subjects, 66 hypertensives and 37 normotensives, were included. Hypertensive patients exhibited a greater number of affected target organs compared with normotensives (P = .014), with retinopathy and capillary rarefaction (40.9%) representing the most common TOD among hypertensives. The number of affected organs was linearly correlated with increased Framingham score and serum aldosterone, analyzed with univariate (P < .001 and P = .002) and multivariate analysis (P = .025 and P = .004), respectively. Physicians dealing with hypertensive patients should be aware of the possibility of diffuse microvascular impairment and seek multiple TOD even in the early stages of hypertension.

[Hypertension-related eye disorders]

Hypertension affects a significant proportion of the population, however, it is often diagnosed with a delay. The aim of this article is to review the well known and less known eye abnormalities related to hypertension, and place them in the context of population based studies. Hypertension affects various parts of the eye. The originally classified hypertensive retinopathy (retinal microvascular changes) is still relevant, but new features are visible in cases of controlled hypertension. Signs of mild hypertensive retinopathy are more common than expected occurring in nearly 10-15% of the adult non-diabetic population. Hypertensive retinopathy can be an indicator of other hypertensive complications such as neurologic and cardiac complications. Microvascular changes are reversible in well controlled hypertension. Proper treatment of hypertension can reduce the development and progression of diabetic retinopathy and, thus, visual loss due to severe retinal diseases such as retinal vascular occlusion (artery and vein), retinal arteriolar emboli, macroaneurysm, ischemic optic neuropathy and age-related macular degeneration.

The association between endothelial dysfunction and hypertensive retinopathy in essential hypertension

BACKGROUND

Endothelial dysfunction, which is characterized by an imbalance between relaxing and contracting factors, procoagulant and anticoagulant substances, and between pro-inflammatory mediators, may play a particularly significant role in the pathogenesis of atherosclerosis. Numerous experimental and clinical reports suggest that a high von Willebrand factor (vWF) level reflects endothelial damage or dysfunction. Hypertensive retinopathy (HR) is a condition characterized by a spectrum of retinal vascular signs in people with elevated blood pressure. The pathophysiological mechanism of HR is not completely understood. Elevated blood pressure alone does not fully account for the extent of retinopathy. Endothelial dysfunction and mechanisms known to be involved in vascular lesions may be involved in the pathophysiological mechanism of HR. Therefore, this study was designed to answer the following questions: (i) Do vWf levels change in HR? and (ii) Is there any relation between degree of HR and vWf levels?

MATERIAL AND METHODS

This study included 80 hypertensive patients with HR. Group 1 comprised 40 patients with grade I HR, and group 2 comprised 40 patients with grade II HR. We selected 40 healthy subjects for the control group.

RESULTS

Level of vWf in group 2 was significantly higher than in group 1 (p=0.017) and the control group (p<0.001), and it was also higher in group 1 than in the control group (p<0.005). Also, vWf showed positive correlation with degree of HR in the hypertensive group (r=0.284, p=0.009).

CONCLUSIONS

Our study suggests that endothelial dysfunction, which is a mechanism known to be involved in vascular lesions, may promote the development of HR.

Retinal arteriole-to-venule ratio changes and target organ disease evolution in newly diagnosed hypertensive patients at 1-year follow-up

There is no agreement on the systematic exploration of the fundus oculi (FO) in hypertensive patients, and it is unknown whether the evolution of retinal microcirculatory alterations has prognostic value or not. The aim of this study was to investigate whether the evolution of the arteriole-to-venule ratio (AVR) in newly-diagnosed hypertensive patients is associated with better or worse evolution of target organ damage (TOD) during 1 year. A cohort of 133 patients with newly-diagnosed untreated hypertension was followed for 1 year. At baseline and follow-up, all patients underwent a physical examination, self-blood pressure measurement, ambulatory blood pressure monitoring, blood and urine analysis, electrocardiogram, and retinography. The endpoint was the favourable evolution of TOD and the total amount of TOD, according to the baseline AVR and the baseline and final difference of the AVR. A total of 133 patients were analyzed (mean age, 57 ± 10.7 years; 59% men). No differences were found in the decrease in blood pressure or antihypertensive treatment between quartiles of baseline AVR or baseline-final AVR difference. Patients with a difference between baseline and final AVR in the highest quartile (>0.0817) had a favorable evolution of left ventricular hypertrophy (odds ratio, 14.9; 95% confidence interval, 1.08-206.8) and the amount of TOD (odds ratio, 2.22; 95% confidence interval, 1.03-6.05). No favorable evolution was found of glomerular filtration rate. There is an association between the evolution of the AVR and the favorable evolution of TOD. Patients with greater increase of AVR have significantly better evolution of left ventricular hypertrophy and amount of TOD.

Vildagliptin in addition to metformin improves retinal blood flow and erythrocyte deformability in patients with type 2 diabetes mellitus - results from an exploratory study

Numerous rheological and microvascular alterations characterize the vascular pathology in patients with type 2 diabetes mellitus (T2DM). This study investigated effects of vildagliptin in comparison to glimepiride on retinal microvascular blood flow and erythrocyte deformability in T2DM.

Fourty-four patients with T2DM on metformin monotherapy were included in this randomized, exploratory study over 24 weeks. Patients were randomized to receive either vildagliptin (50 mg twice daily) or glimepiride individually titrated up to 4 mg in addition to ongoing metformin treatment. Retinal microvascular blood flow (RBF) and the arteriolar wall to lumen ratio (WLR) were assessed using a laser doppler scanner. In addition, the erythrocyte elongation index (EI) was measured at different shear stresses using laserdiffractoscopy.

Both treatments improved glycaemic control (p < 0.05 vs. baseline; respectively). While only slight changes in RBF and the WLR could be observed during treatment with glimepiride, vildagliptin significantly increased retinal blood flow and decreased the arterial WLR (p < 0.05 vs. baseline respectively). The EI increased during both treatments over a wide range of applied shear stresses (p < 0.05 vs. baseline). An inverse correlation could be observed between improved glycaemic control (HbA1c) and EI (r = −0.524; p < 0.0001) but not with the changes in retinal microvascular measurements.

Our results suggest that vildagliptin might exert beneficial effects on retinal microvascular blood flow beyond glucose control. In contrast, the improvement in erythrocyte deformability observed in both treatment groups, seems to be a correlate of improved glycaemic control.

The association of oxidative stress with hypertensive retinopathy

This study was designed to answer the following questions: (i) Do levels of serum gamma-glutamyl transferase (GGT), a marker of oxidative stress, change in hypertensive retinopathy (HR)? (ii) Is there any relation between degree of HR and GGT levels? This study included 80 hypertensive patients with HR. Group 1 comprised 40 patients with grade I HR, and group 2 comprised 40 patients with grade II HR. We selected 40 healthy subjects for the control group. Level of GGT in group 2 was significantly higher than in group 1 (P = 0.005) and control group (P = 0.001); it was also higher in group 1 than in control group (P = 0.025). Our study suggests that oxidative stress, mechanisms known to be involved in vascular lesions, may promote the development of HR.

The association of low-grade systemic inflammation with hypertensive retinopathy

High-sensitivity C-reactive protein (hs-CRP) is a marker of systemic low-grade inflammation. The pathophysiologic mechanism of hypertensive retiopathy (HR) is not fully established. Elevated blood pressure (BP) alone does not fully account for the extent of retinopathy, other pathogenic mechanisms may be involved, such as low-grade inflammation. Therefore, this study was designed to answer the following questions. (i) Do hs-CRP levels change in HR? (ii) Is there any relation between degree of HR and hs-CRP levels? This study included 84 hypertensive patients with HR. The hypertensive patients were divided into two groups according to the Keith-Wagener classification. Group 1 comprised 42 patients with grade I HR, and Group 2 comprised 42 patients with grade II HR. We selected 42 healthy subjects matched for age, sex, and body mass index (BMI) for control group. The level of hs-CRP in group 2 was significantly higher than in group 1 group (p = 0.018) and control group (p = 0.001), it was also higher in group 1 than in control group (p = 0.002). Also, hs-CRP showed positive correlations with degree of HR (r = 0.29, p = 0.017). Our study suggests that there is a relationship between HR and hs-CRP levels, which may be associated with systemic low- grade inflammation.

Comparison of the retinal microvasculature in European and African-Caribbean people with diabetes

Diabetes aggravates the impact of elevated BP (blood pressure) on the microcirculation, and people of African ancestry with diabetes are more susceptible to microvascular damage than Europeans. In the present study, we investigated possible differences in the retinal microcirculation in people of European and African-Caribbean ethnicity with diabetes that might account for this. A total of 51 subjects with Type 2 diabetes (age 40–65 years; 25 male; 29 African-Caribbean) were studied. Clinic and 24 h ambulatory BP, and fasting glucose, insulin and lipids were measured. Digital retinal images were analysed using custom-written semi-automatic software to determine: LDR (length/diameter ratio) and AVR (arteriolar/venular diameter ratio), branching angles, vessel tortuosity and NT (number of terminal vessel branches). Arterioles were narrower in European people with diabetes than in African-Caribbean people with diabetes [mean (S.D.) arteriolar diameter, 76 (7) compared with 82 (11) μm respectively (P=0.03); arteriolar LDR, 28.1 (8.5) compared with 23.7 (7.0) respectively (P=0.046); and AVR, 0.66 (0.21) compared with 0.90 (0.36) respectively (P=0.028)]. Ethnic differences in arteriolar LDR, arteriolar diameter and AVR were not explained by differences in BP, but were attenuated by adjustment for the duration of diabetes. There was no significant relationship between BP and arteriolar narrowing in the group as a whole, although the relationship between arteriolar LDR and systolic BP was stronger in Europeans than African-Caribbeans [β=0.08 (0.07) compared with β=0.03 (0.06); P=0.03]. In conclusion, in the presence of diabetes, a relationship between BP and retinal arteriolar diameter was not evident and implies impaired small artery remodelling in the presence of diabetes. African-Caribbean people with diabetes have wider retinal arterioles and this could contribute to enhanced microvascular damage in this ethnic group.

Comparison between generalized retinal arteriolar narrowing and left ventricular mass in young untreated hypertensive patients

PURPOSE

This study aims to examine the relationship between retinal arteriolar narrowing and left ventricular hypertrophy in hypertensive patients.

METHODS

A total of 30 patients with a recent history of hypertension (22 M, 8 F; 33 +/- 8; BMI 24,96 +/- 2.8;), consecutively referred to the Hypertension Unit by their family doctors, were studied. Generalized retinal arteriolar narrowing was measured by two ophthalmologists from computer-scanned images on retinal photographs, and summarized as arteriole-to-venule ratio (AVR). Left ventricular hypertrophy was evaluated by quantitative M-mode echocardiography.

RESULTS

All patients were stratified according to the 2003 European Society of Hypertension (ESH) guidelines: 20 subjects (66.7%) were affected by hypertension grade 1, and 10 (33.3%) were affected by hypertension grade 2. Retinal vessel diameters did not differ significantly by grade 1 vs grade 2 hypertension. Echocardiographic left ventricular hypertrophy was present in 10 (33%) patients. No significant correlation was shown between arteriole-to-venule ratio (AVR) and left ventricular mass. [Spearman r = 0.22; p = 0.23].

CONCLUSIONS

We suggest some explanations for the fact that we did not find any correlation between AVR and left ventricular mass. Further clinical studies are required for a greater understanding as to whether early microvascular changes relate with other clinical indicators of hypertensive organ damage.

The association of mean platelet volume levels with hypertensive retinopathy

The pathophysiological mechanism of hypertensive retinopathy (HR) is not fully established. Elevated blood pressure alone does not fully account for the extent of retinopathy so other pathogenic mechanisms may be involved, such as increased platelet activation. Mean platelet volume (MPV) is a marker of platelet activation. Therefore, this study was designed to answer the following questions: Do MPV levels change in HR? and is there any relation between degree of HR and MPV levels? This study included newly diagnosed and 57 untreated essential hypertensive patients with HR. The hypertensive patients were divided into two groups according to the Keith, Wagener classification. Group 1 comprised 29 hypertensive patients with grade 1 HR with a mean age of 56.8 +/- 9.7 years. Group 2 comprised 28 hypertensive patients with grade 2 HR with a mean age of 58.1 +/- 10.3 years. Twenty-seven normotensive subjects who were the healthy participants and had undergone the check-up program were used as the control group. Fundoscopic examination, metabolic parameters and MPV levels were measured in all groups. The level of MPV in group 2 was significantly higher than in group 1 (8.9 +/-0 0.8 fl vs. 8.3 +/- 0.8 fl, p = 0.02) and the normotensive control group (8.9 +/- 0.8 fl vs 7.8 +/- 0.7 fl, p < 0.001). It was also higher in group 1 than in normotensive control group (8.3 +/- 0.8 fl vs.7.8 +/- 0.7 fl, p < 0.01). In addition, MPV showed a positive correlation with the degree of HR in the hypertensive group (r = 0.41, p = 0.015). Our study suggests that platelet activation, a mechanism known to be involved in vascular lesions, may promote the development of HR.

Retinopathy in subjects with impaired fasting glucose: the NANSY-Eye baseline report

AIMS

Network for Pharmacoepidemiology (NEPI) Antidiabetes Study-Eye is a randomized placebo-controlled Swedish trial investigating if treatment with sulphonylurea, in addition to dietary regulation and increased exercise, delays the development of retinopathy in subjects with impaired fasting glucose (IFG).

METHODS

Subjects were surveyed in primary care with repeated fasting blood glucose measurements. Those with a mean of two consecutive values >or=5.6 and <6.1 mmol/l were invited to participate. Baseline physical examination included blood pressure and body mass index (BMI). Fundus photos were taken in two fields using 35-mm diafilm. The alternative classification of the Wisconsin Epidemiologic Study of Diabetic Retinopathy was used to classify the retinopathy level.

RESULTS

At baseline, 90 men and 64 women with IFG were photographed. Of these, 16 subjects (10%) had mild or very mild retinopathy. There was no difference in occurrence of retinopathy between subjects with known diagnosis of hypertension or not. However, subjects with retinopathy had significantly higher systolic (154 vs. 141 mmHg, p = 0.013) and diastolic (86 vs. 81 mmHg, p = 0.008) blood pressure levels independent of differences in age, sex and known hypertension. There was a corresponding difference in BMI, being greater in subjects with than in those without retinopathy (32.4 vs. 29.2 kg/m(2), p = 0.013). There were no associations between levels of fasting blood glucose or haemoglobin A1c, on the one hand, and retinopathy, on the other.

CONCLUSION

Retinopathy may be present even before type 2 diabetes is manifest. It is associated with higher blood pressure levels and higher BMI values, that is, with predominant features of the metabolic syndrome.

Usefulness of optic fundus examination with retinography in initial evaluation of hypertensive patients

BACKGROUND

Although international guidelines for management of hypertension recommend optic fundus examination in the initial evaluation of hypertensive patients, there have been no studies to evaluate the usefulness of retinography in this application.

METHODS

Two hundred and fifty consecutive new patients with hypertension but without known cardiovascular disease were studied. The average age was 57.2 years (s.d. 12.9) and 56% were men. The study was conducted in 14 primary care centers. Measurements included target organ damage (TOD) evaluation (electrocardiography, retinography, microalbuminuria, and serum creatinine) and blood pressure (BP) measurements. Outcome measurements were made to risk stratification according to 2003 World Health Organization and International Society of Hypertension (WHO-ISH) and 2007 European Society of Hypertension and European Society of Cardiology (ESH-ESC) guidelines, analyzed first without incorporating the retinography results and then reclassified using the retinography data.

RESULTS

Advanced retinopathy was detected in 10.8%. The risk stratification arrived at as per the WHO-ISH guidelines, and without the retinography data was: 11.4% low risk, 62.4% moderate risk, and 26.2% high risk. When retinography results were taken into account, 8% from the moderate-risk group were reclassified to the high-risk group (11.4, 54.4, and 34.2%, respectively; P < 0.001). Using ESH-ESC guidelines, the risk stratification without the retinography data was 0.9% reference, 11.3% low, 58.8% moderate, 21.7% high, and 7.3% very high risk. With retinography, 10% were reclassified from a lower to a higher risk group (0.9, 10.4, 51.1, 20.4, and 17.2%, respectively; P < 0.001).

CONCLUSIONS

As an alternative to optic fundus examination, retinography enables a more accurate cardiovascular risk stratification in the first evaluation after diagnosis of hypertension. When retinography is included in the assessment of cardiovascular risk, approximately 10% of patients are reclassified to a higher risk group.

Evaluation of retinal digital images by a general practitioner

Diabetes and systemic hypertension are among the most prevalent diseases in developed countries. Since both can produce retinal involvement, they often cause long waiting lists for ophthalmologist consultation. The inspection of digital eye fundus images by a general practitioner would help to divert only those cases with retinal involvement. To evaluate this possibility we studied the agreement between the assessment of digital fundus images made by a general practitioner and an ophthalmologist. A total of 776 fundus images of 194 patients were inspected by both observers looking for retinal lesions consistent with diabetic or hypertensive retinopathy. Contingency tables were made, and the agreement between both observers was assessed by using the kappa index. We found good agreement between the findings reported by the general practitioner and those reported by the ophthalmologist (kappa = 0.80 for patients with only diabetes, 1.00 for patients with only hypertension, and 0.79 for patients with both diseases). Our results suggest that the inspection of digital retinal images by a general practitioner could reduce the number of referred patients for specialist consultation.

Hypertension increases retinal inflammation in experimental diabetes: a possible mechanism for aggravation of diabetic retinopathy by hypertension

Inflammation is pivotal to the pathogenesis of diabetic retinopathy (DR). Hypertension is the main secondary risk factor associated with DR. The mechanisms by which hypertension increases the risk for DR are poorly understood. The aim of the current study was to investigate the contribution of genetic hypertension to early retinal inflammation in experimental diabetes. Diabetes was induced in 4-week-old (developing hypertension) and 12-week-old (fully hypertensive) spontaneously hypertensive rats (SHR) and age-matched control normotensive Wistar Kyoto (WKY) rats by administration of streptozotocin (50 mg/kg, i.v); after 20 days the rats were sacrificed and the retinas were collected. ED1 positive cells, ICAM-1 and VEGF levels were significantly higher in diabetic SHR in both prehypertensive and hypertensive ages (p < 0.005). NF-kappaB p65 levels were higher in prehypertensive SHR and in hypertensive diabetic SHR (p < 0.05). Induction of diabetes in normotensive WKY rats did not show any alteration in retinal expression of inflammatory parameters. Therefore, we conclude that the developing hypertension and also the fully developed hypertension lead to earlier development of inflammation in diabetic retina. Aggravation of the inflammatory process may be involved in the mechanism by which essential hypertension exacerbates retinopathy in the presence of diabetes.

The clinical assessment of retinal microvascular structure and therapeutic implications

Examination of the retinal microvasculature is widely used to assess diabetic eye disease and as an indicator of target organ damage in hypertension. The diagnostic value of grading of hypertensive retinopathy is dubious; however, many recent studies have demonstrated that hypertensive retinopathy is associated with a range of risk factors for cardiovascular disease and may predict cardiovascular events independently of blood pressure. Developments in digital imaging and computer-assisted analysis have facilitated the quantitative assessment of microvascular changes in cardiovascular disease. These approaches may be useful for assessing cardiovascular risk and targeting therapeutic intervention.

Hypertensive retinopathy revisited: some answers, more questions

Hypertension is associated with cardiovascular risk and systemic target organ damage. Retinopathy is considered one of the indicators of target organ damage. This review focuses on recent studies on hypertensive retinopathy and their implications for clinical care. Early recognition of hypertensive retinopathy signs remains an important step in the risk stratification of hypertensive patients.

Mechanisms of target organ damage caused by hypertension: therapeutic potential

Hypertension is a major risk factor for cardiovascular mortality and morbidity through its effects on target organs like the brain, heart, and kidney. Structural alterations in the microcirculation form a major link between hypertension and target organ damage. In this review, we describe damages related to hypertension in these target organs and the mechanisms involved in the pathogenesis of hypertension-induced cardiovascular diseases such as dementia, cardiac ischemia and remodeling, or nephropathy. We also focus on the therapeutical potential on the basis of such mechanisms. Several antihypertensive agents like diuretics, angiotensin converting enzyme (ACE) inhibitors, angiotensin II (Ang II) receptor antagonists, beta-blockers, or calcium channel blockers (CCBs) have been shown to reduce effectively hypertension associated cardiovascular events and to improve end organ damage. More recently, aldosterone antagonism has also shown beneficial effects. Part of the favorable effects of these agents is due to blood pressure lowering as such. Other mechanisms such as oxidative stress, inflammation, or endothelial dysfunction have appeared to play a key role in the pathogenesis of target organ damage and therefore represent another important pathway for therapy. In this review, we discuss the different therapeutic approaches aiming at reducing cardiovascular events and damages induced by hypertension.