Tiffany T. Fancher

Limb ischemia after iliac ligation in aged mice stimulates angiogenesis without arteriogenesis

OBJECTIVE Older patients are thought to tolerate acute ischemia more poorly than younger patients. Since aging may depress both angiogenesis and arteriogenesis, we determined the effects of age on both angiogenesis and arteriogenesis in a model of severe acute limb ischemia. METHODS Young adult (3-months-old) and aged (18-months-old) C57BL/6 mice underwent right common iliac artery and vein ligation and transection. Data were collected on days 0, 7, and 14. Perfusion was measured with a laser Doppler scan and compared to the contralateral limb. Functional deficits were evaluated with the Tarlov scale. Capillary density and endothelial progenitor cell (EPC) number were determined by direct counting lectin-positive/alpha-actin-negative cells and VEGFR2/CXCR4 dually-positive cells, respectively; angiography was performed to directly assess arteriogenesis. RESULTS Young adult and aged mice had a similar degree of decreased perfusion after iliac ligation (young, n = 15: 20.4 +/- 1.9%, vs aged, n = 20: 19.6 +/- 1.3%; P = .72, analysis of variance [ANOVA]); however, young mice recovered faster and to a greater degree than aged mice (day 7, 35 +/- 6% vs 17 +/- 4%, P = .046; day 14, 60 +/- 5% vs 27 +/- 7%, P = .0014). Aged mice had worse functional recovery by day 14 compared to young mice (2.3 +/- 0.3 vs 4.3 +/- 0.4; P = .0021). Aged mice had increased capillary density (day 7, 12.9 +/- 4.4 vs 2.8 +/- 0.3 capillaries/hpf; P = .02) and increased number of EPC incorporated into the ischemic muscle (day 7, 8.1 +/- 0.9 vs 2.5 +/- 1.9 cells; P = .007) compared to young mice, but diminished numbers of collateral vessels to the ischemic limb (1 vs 9; P = .01), as seen on angiography. CONCLUSION After severe hind limb ischemia, aged animals become ischemic to a similar degree as young animals, but aged animals have significantly impaired arteriogenesis and functional recovery compared to younger animals. These results suggest that strategies to stimulate arteriogenesis may complement those that increase angiogenesis, and may result in improved relief of ischemia.

Eph-B4 prevents venous adaptive remodeling in the adult arterial environment

Stimulation of Eph-B4 prevents adaptive remodeling and preserves venous identity when veins are surgically placed into an arterial environment.

Laminar shear stress stimulates vascular smooth muscle cell apoptosis via the Akt pathway.

Vascular smooth muscle cells (SMC) may be directly exposed to blood flow after an endothelial‐denuding injury. It is not known whether direct exposure of SMC to shear stress reduces SMC turnover and contributes to the low rate of restenosis after most vascular interventions. This study examines if laminar shear stress inhibits SMC proliferation or stimulates apoptosis. Bovine aortic SMC were exposed to arterial magnitudes of laminar shear stress (11 dynes/cm2) for up to 24 h and compared to control SMC (0 dynes/cm2). SMC density was assessed by cell counting, DNA synthesis by 3[H]‐thymidine incorporation, and apoptosis by TUNEL staining. Akt, caspase, bax, and bcl‐2 phosphorylation were assessed by Western blotting; caspase activity was also measured with an in vitro assay. Analysis of variance was used to compare groups. SMC exposed to laminar shear stress had a 38% decrease in cell number (n = 4, P = 0.03), 54% reduction in 3[H]‐thymidine incorporation (n = 3, P = 0.003), and 15‐fold increase in TUNEL staining (n = 4, P < 0.0001). Akt phosphorylation was reduced by 67% (n = 3, P < 0.0001), whereas bax/bcl‐2 phosphorylation was increased by 1.8‐fold (n = 3, P = 0.01). Caspase‐3 activity was increased threefold (n = 5, P = 0.03). Pretreatment of cells with ZVAD‐fmk or wortmannin resulted in 42% increased cell retention (n = 3, P < 0.01) and a fourfold increase in apoptosis (n = 3, P < 0.04), respectively. Cells transduced with constitutively‐active Akt had twofold decreased apoptosis (n = 3, P < 0.002). SMC exposed to laminar shear stress have decreased proliferation and increased apoptosis, mediated by the Akt pathway. These results suggest that augmentation of SMC apoptosis may be an alternative strategy to inhibit restenosis after vascular injury. J. Cell. Physiol. 216: 389–395, 2008.

Endothelial Nitric Oxide Synthase Stimulates Aneurysm Growth in Aged Mice

Background/Aims: Age-associated changes in endothelial nitric oxide synthase (eNOS) expression have not been definitively linked to the pathophysiology of aortic aneurysms. We examined the role of eNOS in human patients and an age-appropriate mouse model. Methods: eNOS transcripts and immunodetectable protein were assessed by quantitative PCR and immunohistochemistry in human ascending thoracic aneurysms (n = 29) and referent aortae (n = 31). Carotid aneurysms were induced with CaCl2 in young adult (3 months) and aged (18 months) C57BL/6 and eNOS-knockout (eNOS-KO) mice. Results: eNOS transcripts and protein were reduced in human aneurysms compared with controls, although aortic eNOS expression also decreased with patient age. Aged wild-type mice had significantly larger aneurysm diameter than young adult mice. Aged wild-type mice had reduced eNOS transcripts and protein compared with young adult mice. Aged eNOS-KO mice had smaller aneurysms compared with aged wild-type mice but similar size aneurysms compared with young eNOS-KO and young wild-type mice. Conclusion: eNOS expression is reduced in both aged human and aged mouse endothelium and eNOS expression is linked to aneurysm expansion in aged but not young adult mice. These findings support the relevance of age-associated changes in eNOS expression in clinical aneurysmal disease.

Control of Blood Vessel Identity: From Embryo to Adult

Arteries and veins have been historically defined by the direction of blood flow and oxygen tension within the vessel, in addition to their functional, hemodynamic, and anatomical differences. It is now known that the molecular identity of these vessels is genetically predetermined, with specific molecular pathways activated during the development of arteries and veins. Eph-B4 is a determinant of venous differentiation and Ephrin-B2 is a determinant of arterial differentiation. Placement of a vein into the higher pressure and flow of the arterial circulation results in adaptation of the vein to the arterial environment. There is selective loss of Eph-B4 expression without induction of Ephrin-B2 expression during vein graft adaptation. These findings suggest that loss of venous identity is the crucial mechanism in vein graft adaptation and that developmentally critical determinants of vessel identity are plastic during adult life.

A Woman's Influence to Choose Mastectomy as Treatment for Breast Cancer

INTRODUCTION Over a 10-y period at our community hospital, more than 50% of women 40 y of age and younger underwent a mastectomy as first line breast cancer treatment. These results catapulted a study to identify personal and physical implications of a mastectomy and to determine if, in women of all ages, breast conservation therapy with close follow-up is a better alternative to mastectomy. METHODS Six hundred eight women underwent a mastectomy for breast cancer from 1989 to 2005 at our teaching institution; 77% (n = 120) of 156 successfully contacted women agreed to participate in the study, and 70% (n = 84) of them completed a questionnaire. RESULTS Most women discovered their breast cancer through mammography or self breast examination, 31% and 28%, respectively. Five patients were diagnosed at Stage 0, 35 at Stage 1, 26 at Stage 2, 8 at Stage 3, 1 at Stage 4, and 9 patients had an unknown stage of disease. Sixty-three patients primarily discussed their treatment plan with a surgeon; 80 were satisfied with the time spent discussing their treatment. Twenty-four patients underwent various reconstruction procedures; most (75%) were satisfied with their treatment and reconstruction choices. CONCLUSIONS Mastectomy as a treatment choice for breast cancer did not have the negative personal and physical outcome that we had predicted. Personal choice and a surgeons advice were the primary influencing factors on the womens treatment choice of mastectomy. Adequate preoperative discussion time and a multimodality cancer team can be most helpful in providing comprehensive treatment options for all women with breast cancer.

Is Gender Related to the Stage of Colorectal Cancer at Initial Presentation in Young Patients

BACKGROUND The incidence of colorectal cancer (CRC) in young adults is rising, and young age is a predictor of poor survival. The purpose of this study was to examine factors leading to increased mortality in patients ≤ 50 years of age, and to examine this population for characteristics that could lead to benefit from CRC screening. METHODS Charts of patients 50 years of age and under, diagnosed with CRC from 1998 through 2007, at our community teaching hospital, were reviewed retrospectively. Demographics, social and family history, staging, treatment and death were evaluated. Mann Whitney, Fisher Exact, and χ(2) tests were used with P <0.05 considered statistically significant. RESULTS Forty-five young patients with CRC were identified. Twenty-five patients were female and 20 male; the mean age was 43.6 y. Most patients presented with rectal bleeding. Right-sided cancers had a higher presenting stage (P < 0.05). Men had both a higher presenting stage (P = 0.35) and a higher incidence of smoking compared with women (P = 0.001). Female patients were more likely to have left-sided CRC (65%) compared with men (35%). Ninety-six percent of patients underwent surgical resection; 14 patients died. CONCLUSIONS CRC in young adults is not common, but is often advanced when discovered. Diagnostic efforts should be aggressive in young patients who have rectal bleeding, especially young male smokers. Sigmoidoscopy is not adequate for comprehensive diagnosis of CRC in young patients, as the majority have right-sided colon cancers, which often result in subsequent presentation of the disease at a higher stage, risk, and mortality rate.

Elevated Monocytes in Patients with Critical Limb Ischemia Diminish After Bypass Surgery

BACKGROUND Mononuclear cells (MNC) increase neovascularization and ulcer healing after injection into an ischemic extremity. Circulating MNC are composed of lymphocytes (85%), monocytes (15%), and endothelial progenitor cells (EPC; 0.03%). We hypothesized that ischemic limbs secrete paracrine signals to recruit bone marrow-derived monocytes and EPC into the circulation, such that patients with critical limb ischemia (CLI) have increased circulating monocytes compared with control patients. We also hypothesized that circulating monocytes and EPC recruitment decrease after resolution of ischemia with successful revascularization. METHODS We reviewed the records of all patients at the VA Connecticut Healthcare System undergoing primary, functionally successful, lower extremity peripheral bypass surgery between 2002 and 2007, but only including patients with both preoperative and postoperative (>4 mo) complete blood counts with differentials. RESULTS Patients with CLI (n = 24) had elevated preoperative monocyte counts compared with control patients (n = 8) (0.753 ± 0.04 versus 0.516 ± 0.05; P = 0.0046), whereas the preoperative lymphocyte counts were not significantly different. After revascularization, ischemic patients had decreased monocyte counts compared with control patients (-20% versus + 55%; P = 0.0003), although lymphocyte counts were unchanged in both groups. Diabetic patients also had reduced postoperative monocyte counts (-32% versus + 13%; P = 0.035). Multivariable logistic regression demonstrated that the only factor that independently predicted reduced postoperative monocyte count was preoperative CLI (P = 0.038). CONCLUSIONS Patients with CLI have increased numbers of circulating monocytes, and the monocyte number decreases with resolution of ischemia after successful revascularization. Circulating monocytes may be a clinically useful perioperative marker in patients with CLI undergoing vascular surgery.

Endothelial progenitor cells: a primer for vascular surgeons.

Endothelial progenitor cells (EPCs) participate in vascular healing during both acute injury and chronic disease. The quantity and quality of circulating EPCs correlate inversely with the severity of vascular disease, such that reduced number and/or function of EPCs are significant independent risk factors for impaired healing capacity, dysfunctional endothelium, and progression of atherosclerosis and vascular disease. EPC therapy assists healing of cardiac and limb ischemia and has great potential for improving the quality of life and longevity of patients with severe cardiovascular and peripheral vascular disease who are not candidates for conventional revascularization procedures. In addition, EPCs can be used to promote vascular graft patency. This review focuses on the characterization of EPCs, positive and negative regulators of EPCs, the role of EPCs in vascular disease, and the potential for EPC therapy to ameliorate the sequelae of severe peripheral vascular disease.

Cervical spine injuries; an outcome analysis

Cervical spine injury (CSI) in octogenarians continues to carry a high morbidity and mortality rate. The incidence of CSI among individuals who are below the age of 80 is declining, whereas the incidence of CSI for those 80 years and above is rising.The aim of the study was to evaluate outcomes of cervical spine injuries in octogenarians caused by different mechanisms: motor vehicle accidents, compared to a fall.Material and methods. The National Trauma Data Bank (NTDB) was queried for patients ages 80 and above, who sustained a cervical spine injury via motor vehicle collision and falls. Patient demographics, mechanism of injury, Glasgow Coma Score (GCS), injury severity score (ISS), days in Intensive Care Unit, Temperature on arrival, blood pressure on arrival, CT Scan of head results, complications, sex, and mortality.Results. Three-thousand three hundred seventy-five patients, 80 years of age and older with CSI were included in the study; fifteen percent of these octogenarians with cervical spine injuries died. It was observed that patients in the motor vehicle accident (MVA) group have 1.737 (95% CI 1.407, 2.144 p-value < 0.0001) times the odds of dying, compared to those in the fall group. Patients over the age of 80 who were in a MVA have 1.209 (95% CI 0.941, 1.554 p-value = 0.1372) times the odds of having a positive head CT, compared with people over the age of 80 who experienced a fall. Patients involved in a motor vehicle accident with associated CSI were more likely to be a younger age, have a lower GCS on arrival, have a longer length of stay in the Intensive Care Unit, and a higher ISS (p<0.05).Conclusions. Cervical spine injury in octogenarians carries a high mortality regardless of mechanism. Elderly patients who suffer cervical spine injuries in motor vehicle accidents have a lower SBP, a higher ISS and are nearly twice as likely to die as those who were injured in a fall.