An Analysis of Cost-Effectiveness and Clinical Outcomes of a Comprehensive Aortic Service in a Tertiary Center over One Year.

BACKGROUND: Endovascular aortic repair (EVAR) is an established and attractive alternative to open surgical repair (OSR) of abdominal aortic aneurysms (AAA) due to its superior short-term safety profile. However, opinions are divided regarding its long-term cost-effectiveness. We compared the total yearly cost of running endovascular and OSR services in a single tertiary center to determine whether fenestrated EVAR (FEVAR) represents a clinically efficacious, affordable treatment option. METHODS: A single-center retrospective review was performed on 109 patients undergoing a procedure related to index or previous abdominal aortic repair, with 1 year follow-up. Data was collected from the National Vascular Registry and hospital records. The primary outcome was cost per quality-adjusted life year. Secondary outcomes included 30-day mortality and morbidity, reintervention rates, length of hospital stay, aneurysm, and all-cause mortality at 1 year for elective index procedures. RESULTS: The average cost per patient of all FEVAR was £16,041.53 (±8,857.54), £13,893.51 (±£21,425.25) for standard EVAR, and £15,357.22 (±£15,904.49) for OSR (FEVAR versus EVAR P = 0.55, FEVAR versus OSR P = 0.83, OSR versus EVAR P = 0.76). Of the secondary outcomes, significant findings included increased length of stay and respiratory morbidity for patients undergoing open versus endovascular repair. There was no significant difference in 30-day or 1-year mortality between groups. CONCLUSIONS: FEVAR, EVAR, and OSR all represent cost-effective options for aortic repair with similar outcomes. Our data highlights the potential for FEVAR to present a viable alternative to open repair, particularly in higher-risk groups, when performed in specialist centers.

Does Modified Rankin Score (mRS) Matter? The Impact of Stroke Severity on Carotid Artery Endarterectomy (CEA) Outcomes.

BACKGROUND: Carotid artery endarterectomy (CEA) is recommended to reduce stroke risk in patients following nondisabling ischemic stroke (modified Rankin Score mRS<3). We reviewed CEA outcomes in patients after more devastating strokes (mRS≥3). METHODS: An observational cohort study was performed, and data were collected from 1013 CEA cases over 15 years. Patient demographics, comorbidities and postoperative outcomes were compared between preoperative mRS<3 (Group 1) and mRS≥3 (Group 2). Statistical significance was determined by P < 0.05. RESULTS: Ninety-one (9%) patients were mRS ≥3. There was no significant difference between age, gender, and operated side. Group 2 had significantly higher rates of diabetes and frailty. There was no significant difference in anesthetic type. Group 2 spent longer in High Dependency. Return to theater and postoperative complications were similar. Incidence of perioperative stroke, mortality, and readmission rates were not significant at 30 days postoperation between the 2 groups. CONCLUSIONS: Patients with a higher mRS have more preoperative comorbidities but short-term perioperative complication rate is not significantly different. Patient selection should be undertaken with care.

A Retrospective Cohort Study of Cerebrovascular Fibromuscular Dysplasia.

BACKGROUND: Fibromuscular dysplasia (FMD) is a rare vasculopathy for which limited data are available particularly from Europe. Our aim was to study the clinical characteristics of a regional cohort of carotid fibromuscular dysplasia patients to assess their clinical outcomes and the rate of vascular complications. METHODS: A retrospective cohort study of all cases of carotid/cerebrovascular FMD presenting to our regional vascular service (catchment population approximately 2 million), between 1998 and 2020. Imaging reports and patient case notes were screened using the keywords "FMD", "Fibromuscular Dysplasia", and "carotid". From case-note and imaging review, all relevant clinical data were extracted and the anatomical extent of vascular disease recorded. RESULTS: Eighty six patients with a diagnosis of cerebrovascular fibromuscular dysplasia were identified on imaging (31 computed tomography angiography, 46 magnetic resonance angiography, and 9 digital subtraction angiography) by a neurovascular radiologist. The mean age was 64 years, 78 (90%) patients were female, and 45/59 (75%) were Caucasian. Presenting clinical syndromes were Stroke/transient ischemic attack in 54 (63%) patients, symptomatic intracranial aneurysm in 6 (10%), and other neurological symptoms (headache/migraine, tinnitus) in 14 (16%), with 11 (13%) presenting incidentally. Six patients (7%) had a positive family history of FMD (2 patients) or other cerebrovascular event (4 patients: carotid dissection, intracerebral bleed, or stroke). Eight patients (9%) had a known or suspected hereditary connective tissue disorder (2 Ehlers-Danlos syndrome). Involved vessels were as follows: Carotid (mainly extracranial) in 79 (92%), vertebral 19 (22%), and a combination of these in 15 (17%) patients. Fifty eight (67%) patients had bilateral disease. Cerebrovascular complications were observed in 35 (41%) patients as follows: carotid dissection 11 (23%), carotid stenosis or occlusion 8 (9%), carotid aneurysm 8 (9%), cerebral aneurysm 9 (11%), vertebral aneurysm/dissection 2 (2%), and carotid-cavernous fistula 2 (2%). Of the 22 patients who had extracranial imaging, 14 (60%) had FMD affecting other beds-renal artery in 8 (36%) patients, other visceral arteries in 4 (18%), and aorta in 2 (9%). In addition, 4 (18%) patients had aneurysm or dissection affecting renal, splenic, and lower limb arteries. Overall, 67 (80%) patients had FMD affecting more than 1 vessel and 50 (58%) had multisite FMD (>/ = 2 vascular beds involved). Fifty nine (68%) patients were managed conservatively on close surveillance. Nineteen (21%) patients required carotid/cerebrovascular intervention and 9 (10%) required vascular intervention at other sites. Recurrent cerebrovascular events (stroke/transient ischemic attack, symptomatic Berry aneurysm) were seen in 20 (23%) patients. Overall mortality was 7% over a median follow-up period of 47 months. CONCLUSIONS: Carotid FMD patients have a high rate of multisite involvement, extracerebral vascular complications, and evidence of hereditary vasculopathy, requiring careful screening and surveillance.

Infective Native Extracranial Carotid Artery Aneurysms: A Systematic Review.

BACKGROUND: Infective native extracranial carotid artery aneurysms are rare, and their management is variable due to a lack of evidence assessing outcomes. METHODS: We performed a systematic literature review following PRISMA guidelines to identify all reported cases of infective native extracranial carotid artery aneurysms between January 1970 and March 2021. RESULTS: This study identified 193 infective native aneurysms of the extracranial carotid artery from 154 sources. Patients were predominantly male (71.4%), and age ranged from 6 months to 89 years old. The most common presenting features were a neck mass and fever, but also included hemorrhage, respiratory distress, and neurological symptoms. Most aneurysms were located in the internal carotid artery (47.4%). Staphylococcus (23.3%) was the most commonly identified causative pathogen, followed by Mycobacterium tuberculosis (20.9%). Most appeared to become infected by direct local spread. Treatment strategies involved open surgical methods in 101 cases and an endovascular approach in 41 cases. In 4 cases, a hybrid method involving concurrent endovascular and open surgical management was undertaken. In 5 cases, there was antibiotic treatment alone. In the open surgery-treated group, the complication rate was 20.8% compared to 13.2% in the endovascular group. Mortality rate was 5.6%. CONCLUSIONS: Our review identified 193 cases of infective native extracranial carotid artery aneurysms. Direct local spread of a staphylococcus infection was the commonest cause. Endovascular management was associated with fewer early complications than open surgical management.

A Stepwise Haemostasis Intraoperative Protocol Driven Reduction of Haematoma Rate Following Symptomatic Carotidendarterectomy.

INTRODUCTION: Carotid endarterectomy (CEA) for symptomatic stenosis reduces further stroke risk. Post-CEA haematoma increases the risk of complications including stroke. There are few studies considering protocols aimed at reducing post-CEA haematoma rates. Presented are the outcomes of a protocol developed to reduce this surgical complication. METHOD: The protocol was implemented in 112 consecutive CEA. It involves stepwise additional measures to ensure haemostasis before wound closure. Attention to bleeding points is followed by light compression for 10 min. Protamine is then given if haemostasis has not been achieved. If after 20 min the problem persists Tranexamic acid is given. Following a further 20 min if haemostasis is not yet achieved a platelet transfusion is undertaken. Haematoma rates, return to theatre for post-operative haematoma and other complications were compared with 100 consecutive pre-protocol introduction CEA cases. RESULTS: Of 112 CEA patients, 19 received protamine, 8 protamine and tranexamic acid. One case required platelet transfusion. Neck haematoma rate fell from 10 to 3 cases (P = .02, OR: 0.25 [95% CI .07-.94]), of which returned to theatre for haematoma evacuation fell from 6 to 1 case (P = .03, OR: 0.14 [95% CI .02-1.19]). 30 day stroke and death rate reduced from 5% to 1.8% (P = .11, OR: 0.35 [95% CI .07-1.82]). CONCLUSION: The stepwise haemostasis intraoperative protocol can reduce post-CEA haematoma rates.

Toll-like receptors 2 and 6 mediate apoptosis and inflammation in ischemic skeletal myotubes.

Critical limb ischemia (CLI) is associated with skeletal muscle damage. However, the pathophysiology of the muscle damage is poorly understood. Toll-like receptors (TLR) have been attributed to play a role in ischemia-induced tissue damage but their role in skeletal muscle damage in CLI is unknown. TLR2 and TLR6 expression was found to be upregulated in skeletal muscle of patients with CLI. In vitro, ischemia led to upregulation of TLR2 and TLR6 by myotubes, and activation of the downstream TLR signaling pathway. Ischemia-induced activation of the TLR signaling pathway led to secretion of the pro-inflammatory cytokine interleukin-6 and muscle apoptosis, which were abrogated by neutralising TLR2 and TLR6 antibodies. Our study demonstrates that TLR2 and TLR6 are upregulated in ischemic muscle and play a role in ischemia-induced muscle damage. Thus, manipulating the TLR pathway locally may be of potential therapeutic benefit.

Role of surgical thoracic sympathetic interruption in treatment of facial blushing: a systematic review.

OBJECTIVES: This paper aims to review the evidence to support the effectiveness of sympathectomy as a treatment for facial blushing in terms of relief of facial blushing, patient satisfaction, recurrence of blushing, patients regretting treatment and its associated complications. METHODS: A systematic search strategy was performed in Ovid-Medline, Embase, Cochrane library and NICE. Studies reporting outcomes of sympathetic interruption in the treatment of facial blushing were retrieved. RESULTS: Nine studies met the inclusion criteria with 1369 patients included in the final analysis. The age range of patients was 8 to 74 years (from 7 studies) with 56% females. Mean follow up was 21 months in 8 studies (range 6 to 30 months). The pooled proportion of patients who had good relief of facial blushing was 78.30% (95% C.I. 58.20% - 98.39%). Complete satisfaction was reported in 84.02% (95% C.I. 71.71% - 96.33%). Compensatory sweating and gustatory sweating were the commonest complications occurring in 74.18% (95% C.I. 58.10% - 90.26%) and 24.42% (95% C.I. 12.22% - 36.61%) respectively. The estimated proportion of patients regretting surgery was 6.79% (C.I 2.08% 11.50%). CONCLUSION: Sympathetic interruption at T2 or T2-3 ganglia appears to be an effective treatment for facial blushing. However, lack of randomized trials comparing sympathetic interruption with non-surgical methods of treatment and heterogeneity of included studies with respect to assessment of outcome measures preclude strong evidence and definitive recommendations.

Stem cells of the lower limb: their role and potential in management of critical limb ischemia.

Peripheral arterial occlusive disease (PAOD) contributes to decreased exercise tolerance, poor balance, impaired proprioception, muscle atrophy and weakness, with advanced cases resulting in critical limb ischemia (CLI) where the viability of the limb is threatened. Patients with a diagnosis of CLI have a poor life expectancy due to concomitant cardio and cerebrovascular diseases. The current treatment options to avoid major amputation by re-establishing a blood supply to the limb generally have poor outcomes. Human skeletal muscle contains both multipotent stem cells and progenitor cells and thus has a capacity for regeneration. Phase I and II studies involving transplantation of bone marrow-derived progenitor cells into CLI limbs show positive effects on wound healing and angiogenesis; the increase in quiescent satellite cell numbers observed in CLI muscle may also provide a sufficient in vivo source of resident stem cells. These indigenous cells have been shown to be capable of forming multiple mesodermal cell lineages aiding the repair and regeneration of chronically ischemic muscle. They may also serve as a repository for autologous transplantation. The behavior and responses of the stem cell population in CLI is poorly understood and this review tries to elucidate the potential of these cells and their future role in the management of CLI.

Isolated endarterectomy of femoral bifurcation in critical limb ischemia: is restoration of inline flow essential?

This retrospective study reviews clinical outcomes of isolated common femoral endarterectomy (CFE) for critical limb ischemia (CLI), in particular whether poor runoff and inability to restore inline flow has negative impact. In 30 patients, runoff was assessed on preoperative angiograms and categorized into groups based on Society of Vascular Surgery criteria. Data were evaluated using Cox Regression survival analysis. Freedom from secondary revascularization was not affected by runoff score (hazard ratio for compromised and poor groups being 1.8 (95% CI 0.16 to 20.8) and 1.47 (95% CI 0.09 to 24.3), respectively; P = .894). Distal inline flow was not achieved in 25 (83%) patients, but this was not associated with significantly worse outcome (P = .295, log-rank test). In conclusion, CFE can be performed in CLI with high technical success and there is no significant effect of runoff score on recurrence of symptoms. Limb salvage can be achieved even if options to restore inline flow are limited.

Review of the role of erythropoietin in critical leg ischemia.

There is a need to develop alternative treatment strategies for the 30% of patients with critical leg ischemia (CLI) for whom conventional modes of revascularization fail. The efficacy erythropoietin (EPO) in this regard has been verified in preclinical models. Erythropoietin receptors are expressed in the human skeletal muscle and possibly, upregulated in CLI. Furthermore, EPO induces angiogenesis and prevents apoptosis in the ischemic skeletal muscle. The use of EPO in conjunction with autologous bone marrow cells or gene-induced angiogenesis with vascular endothelial growth factor may be more effective in inducing angiogenesis and protecting the critically ischemic leg than EPO alone. The recently synthesized nonhemopoietic derivatives of EPO (eg, asialo erythropoietin and carbamylated erythropoietin) allow higher doses to be administered to achieve tissue protective effects, without an unwanted increase in hematocrit. This may allow translation of preclinical studies into clinical trials.

Angiogenic effects of stromal cell-derived factor-1 (SDF-1/CXCL12) variants in vitro and the in vivo expressions of CXCL12 variants and CXCR4 in human critical leg ischemia.

PURPOSE: Critical leg ischemia (CLI) is associated with a high morbidity and mortality. Therapeutic angiogenesis is still being investigated as a possible alternative treatment option for CLI. CXCL12, a chemokine, is known to have two spliced variants, CXCL12alpha and CXCL12beta, but the significance remains unknown. The study investigated the angiogenic effects of CXCL12, protein expressions of CXCL12, and the receptor CXCR4 in human CLI. METHODS: In vitro, human microvascular endothelial cells (HMEC-1) were used. Cell proliferation was assessed using methylene blue assay and cell count method. Apoptosis was determined by counting the pyknotic nuclei after 4'-6-diamidino-2-phenylindole staining and confirmed by caspase-3 assay. We employed matrigel as capillary tube formation assay. The activity of signaling pathways was measured using Western blotting. In vivo, gastrocnemius biopsies were obtained from the lower limbs of patients with CLI and controls (n = 12 each). Immunohistochemistry, double immunofluorescence labeling, and Western blotting were then performed. RESULTS: CXCL12 attenuated HMEC-1 apoptosis (P < .01), stimulated cell proliferation (P < .05) and capillary tube formation (P < .01). Compared with CXCL12alpha, CXCL12beta has a greater effect on apoptosis and cell proliferation (P < .01). Treatment with both variants resulted in time-dependent activation of PI3K/Akt and p44/42 but not p38 MAP kinase. In CLI, CXCL12alpha was expressed by skeletal muscle fibers with minimal expression of CXCL12beta. CXCR4 was extensively expressed and colocalized to microvessels. A significant 2.6-fold increase in CXCL12alpha and CXCR4 expressions (P < .01) were noted in CLI but not for CXCL12beta (P > .05). CONCLUSIONS: The study showed that CXCL12beta had more potent angiogenic properties but was not elevated in human CLI biopsies. This provided an interesting finding on the role of CXCL12 variants in pathophysiologic angiogenic response in CLI.

Endovascular aortic aneurysm repair (EVAR) has significantly lower perioperative mortality in comparison to open repair: a systematic review.

OBJECTIVE: The objective of this meta-analysis was to evaluate the effectiveness of endovascular abdominal aortic aneurysm repair (EVAR) in reducing inhospital mortality against open graft replacement for aortic aneurysm. METHODS: Generic terms including EVAR, endovascular aneurysm repair and aortic endografting were used to search a variety of electronic databases. Based on selection criteria, decisions regarding inclusion and exclusion of primary studies were made. RESULTS: A total of three randomized controlled trials on 1,468 patients were included. In the EVAR group, 12 of 759 (1.5%) patients died, compared to 33 of 709 (4.6%) patients who died in the open surgery group. In both the fixed and random effect models, EVAR was associated with statistically significantly lower perioperative mortality when compared to open surgical repair of aortic aneurysm. The risk ratio of 0.33 indicates that mortality is 3.3 times more likely in the open surgery group compared to the EVAR group. CONCLUSION: EVAR carries a threefold lower risk of perioperative death in comparison to open repair of abdominal aortic aneurysm. This early advantage must be offset against the increased need for later re-intervention and probable equivalence of long-term outcome. In older and high operative risk patients, EVAR should be the treatment of choice.

Does diabetes mellitus play a role in restenosis and patency rates following lower extremity peripheral arterial revascularization? A critical overview.

Patients with diabetes mellitus (DM) are at increased risk of developing lower extremity peripheral arterial disease (PAD). The effect of DM on restenosis and patency rates in patients with PAD undergoing surgical revascularization or percutaneous interventions has not been fully clarified. We therefore critically reviewed the role of DM in restenosis, as well as primary and secondary patency rates in these patients. We searched Medline for studies investigating the effect of DM on restenosis (primary and secondary patency) rates in patients undergoing surgical/percutaneous interventions for the treatment of lower extremity PAD. Search terms used were "diabetes and peripheral arterial disease," "angioplasty," "restenosis," "revascularization," "patency rates," and "in-stent restenosis." Diabetic patients with PAD have similar restenosis, primary patency, and secondary patency rates compared with nondiabetic patients. However, mortality and amputation rates are increased in patients with DM. This increased risk of mortality and amputation may distort the estimation of restenosis and patency rates. Strict glucose control should be implemented in diabetic patients. Additionally, the use of antiplatelet agents and statins may have a beneficial effect on restenosis and patency rates. The role of radiation therapy in preventing restenosis remains to be determined. Patients with PAD and DM should receive optimal medical therapy to improve cardiovascular outcome and decrease functional decline. The direct involvement of vascular surgeons in the management of PAD patients is essential to reduce the incidence of cardiovascular events and mortality rates.

The role of fibrinogen and fibrinolysis in peripheral arterial disease.

Peripheral arterial disease (PAD) is associated with high rates of cerebrovascular and cardiovascular events; PAD is a marker of systemic atherosclerosis. As a result, standard therapy for all PAD patients should be directed at both peripheral and systemic atherosclerosis. Modification of established risk factors in the form of smoking cessation, correcting hypertension, optimizing diabetic control and normalizing lipids is essential. Furthermore, novel risk factors have emerged including fibrinogen and other hemostatic factors. Fibrinogen is a coagulation factor and a marker of the acute phase response (inflammation), a platelet activator, a major determinant of plasma viscosity and a component of the atherosclerotic plaque. Fibrinogen appears not only to predict the severity of PAD, but also serves as a marker for future development of PAD. Whether reducing the levels of fibrinogen and other coagulation factors will decrease the incidence and progression of PAD remains to be resolved. This review summarizes the role of fibrinogen in the pathogenesis of PAD and its association with other hemostatic factors. The role of fibrinolysis in patients with PAD is also considered.

Single-center experience of endovascular abdominal aortic aneurysm repair (EVAR) in patients not participating in the U.K. EVAR trials.

The objective was to evaluate outcomes of a high-risk patient cohort following endovascular abdominal aortic aneurysm repair (EVAR) treatment not entered into the U.K. endovascular stent-graft aortic aneurysm repair trials (EVAR-1 or -2) because of equipoise absence but where EVAR was judged to be the most appropriate intervention option on compassionate grounds. A single-center retrospective analysis was performed involving all patients undergoing compassionate EVAR treatment during the EVAR-1 and -2 trial period. Over an 8-year period, 34 patients underwent compassionate EVAR procedure. The mean (SD) age was 76 (79) years. The mean (SD) preoperative physiology score (P-POSSUM) was 25 (8.3) with a mean (SD) predicted early mortality of 9.9% (16%). The actual early mortality in our study was 2.9% and morbidity was 35%. There were 8 cases of endoleak: type I (n = 2), type II (n = 5), and type IV (n = 1). Aneurysm-related mortality and all-cause mortality after 8 years were 5.8% and 23.5% respectively. Satisfactory outcome with low mortality (2.9%) and morbidity can be achieved in patients with compassionate indications, where clinicians judge EVAR to be an advantage over open abdominal aortic aneurysm repair. Based on our study, the early mortality (2.9%) in our compassionate EVAR group is comparable to EVAR-1 outcomes (1.7%) and better than EVAR-2 mortality results (9%). EVAR should therefore not be denied to a significant number of high-risk abdominal aortic aneurysm patients who fall between the EVAR-1 and EVAR-2 criteria.

Applicability of Glasgow Aneurysm Score and Hardman Index to elective endovascular abdominal aortic aneurysm repair.

OBJECTIVE: This retrospective study aimed to explore the role of Glasgow Aneurysm Score (GAS) and Hardman Index (HI) in predicting outcome after elective endovascular aneurysm repair (EVAR). METHODS: All 71 patients who underwent elective EVAR in a single centre over 9 years were reviewed. Clinical data were used to classify patients into the three standard GAS tertiles and to score patients according to the HI. RESULTS: Fifty-one patients scored > or = 77 according to GAS. Actual and predicted mortality in this group were 3.9% and 9.3%. Seventeen patients scored between 69 and 77 with actual and predicted mortality of 0% and 4.1%. Three patients scored less than 69 with actual and predicted mortality of 0% and 2.4%. Ten patients scored > or = 3 on the HI with actual and predicted mortality of 10% and 100%, respectively. Twenty-four patients scored 2 with actual and predicted mortality of 4.2% and 55%. Twenty-seven patients scored 1 with actual and predicted mortality of 0% and 28%, respectively. Ten patients scored 0 with actual and predicted mortality of 0% and 16%, respectively. The chi(2) test showed extremely significant p value of 0.0001 in case of HI, and p value of 0.0800 for GAS, slightly less significant, probably due to the small sample size. CONCLUSION: Contrary to their role in ruptured and open aortic aneurysm repair, GAS and HI overestimate both mortality and morbidity following EVAR and are poor predictors of outcome.

Hypoxia-inducible factor 1 in lower limb ischemia.

In the Western world, peripheral vascular disease (PVD) has a high prevalence and is associated with high morbidity and mortality. More patients are presenting with critical limb ischemia (CLI), the end stage of PVD, because of an increased life expectancy owing to improved medical care. In a large percentage of these patients, lower limb amputation is still required, despite current advances in surgery and interventional radiology. Studies of ischemic skeletal muscles disclosed evidence of endogenous angiogenesis and adaptive skeletal muscle metabolic changes in response to hypoxia. Many of the genes responsible for these responses are regulated by hypoxia-inducible factor (HIF)-1. HIF-1, consisting of HIF-1alpha and HIF-1beta subunits, is a major transcription factor that functions as a master regulator of oxygen homeostasis that plays essential roles in cellular and systemic pathophysiology. HIF-1alpha expression and HIF-1 transcriptional activity increase exponentially as cellular oxygen concentration is decreased. More than 60 target genes that are transactivated by HIF-1 have been identified. Many of the target genes, such as vascular endothelial growth factor, have been studied extensively, especially in tumors. However, only recently that interest in HIF-1 is growing in relation to ischemic diseases. Most of the studies concentrated mainly on the angiogenic property of HIF-1. In contrast, there is a lack of information on the role of HIF-1 in skeletal muscle metabolic adaptive changes as the end-organ in PVD. This review aims to summarize our current understanding of HIF-1 roles and the therapeutic potential in PVD.

Purinoceptor expression on keratinocytes reflects their function on the epidermis during chronic venous insufficiency.

Purines are extracellular nucleotides that have long-term effects on keratinocyte proliferation, differentiation and death through P2Y(1), P2Y(2), P2X(5) and P2X(7) receptors. This study examined changes in expression of these P2 receptors on lower leg epidermal keratinocytes in control and chronic venous insufficiency (CVI) states. Lower limb skin biopsies from CVI (CEAP classification 4a and 4b) and control skin were immunostained for the above P2 receptor subtypes and epidermal area was calculated. Our results with CVI show an increase in P2Y(1) and P2Y(2) receptor expression in basal and spinosal layers of the epidermis and an increase of P2X(5) receptors mainly in the spinosal layer and extending further into the stratum granulosum. In contrast, P2X(7) receptors were reduced in the stratum corneum in CVI. In conclusion, a thinner epidermis was found in CVI, which might be the result of the changes in expression of P2Y and P2X receptors on keratinocytes: that is, increased proliferation via P2Y(1) and P2Y(2) receptors and reduced P2X(7) receptor-mediated cell death opposed by a dominant decrease in cell numbers as a result of increased P2X(5) receptor-mediated differentiation (which is in effect antiproliferative). Thus, increased keratinocyte P2X(5) receptor activity may, in part, be accountable for epidermal thinning in CVI.

Increased endogenous angiogenic response and hypoxia-inducible factor-1alpha in human critical limb ischemia.

OBJECTIVE: The potent physiologic endogenous angiogenic response to ischemic stimuli is often suboptimal, and therefore, a better understanding of the basic mechanisms is essential for the use in therapeutic angiogenesis. Hypoxia-inducible factor-1 (HIF-1) is a major transcription factor that promotes ischemia-driven angiogenesis and is induced when the HIF-1alpha subunit is upregulated. However, little is known about the endogenous angiogenic response and the role of HIF-1alpha in human critical limb ischemia (CLI). We aimed to investigate the extent of the angiogenic response and the expression of HIF-1alpha in the lower limbs of CLI patients. METHOD: Skeletal muscle biopsy specimens were obtained from the lower limbs of 12 patients with CLI and 12 patients without limb ischemia (controls), with ethical committee approval. Microvessel density (MVD) was determined by using endothelial marker anti-CD31, and HIF-1alpha expressions were determined by immunohistochemistry. MVD was measured as the median number of microvessels in x200 magnification fields. Five random fields per section and three sections per biopsy specimen were analyzed. Enzyme-linked immunoabsorbent assay and Western blotting were used to quantify the HIF-1alpha levels. Colocalization between cell-specific antigens was investigated by double immunofluorescence labelling by using confocal microscopy. Statistical analyses were performed with the Mann-Whitney U test. RESULTS: The CLI group have significantly higher MVD, with an increase of 2.7-fold compared with the controls (P < 0.001). HIF-1alpha expression was significantly increased in CLI muscles (P < 0.001) and was localized to vascular endothelial cells. CONCLUSIONS: Our findings suggest that the endogenous angiogenic response occurs in CLI. The increased HIF-1alpha level and colocalization to vascular endothelial cells suggest that HIF-1alpha plays a role in the physiologic endogenous angiogenic response in CLI. Therefore, augmentation of the HIF-1alpha pathway may be an important aspect in therapeutic angiogenesis.