Matthew E. Hyndman

The T-786→C Mutation in Endothelial Nitric Oxide Synthase Is Associated With Hypertension

Although the pathogenic mechanisms involved in predisposing individuals to hypertension are not well defined, evidence is accumulating that suggests a strong genetic transmission. Animal studies and some clinical investigations have revealed that aberrant NO production may be an important contributing factor. Indeed, a missense mutation in the endothelial NO gene caused by a Glu298Asp alteration has been strongly associated with essential hypertension, coronary artery spasm, and myocardial infarction. Recently, another point mutation caused by a T-786→C transition in the 5′-flanking region of the endothelial NO synthase gene has been identified and, like the Glu298Asp mutation, is associated with coronary artery spasm. The present study was conducted to determine the effect of the T-786→C point mutation on hypertension. We investigated the interaction between the endothelial NO synthase T-786→C polymorphism and blood pressure in a large (n=705) clinically healthy population. Allele frequencies for the T and C alleles were 62% and 38%, translating into 39%, 46% and 15% of the population having the T/T, T/C, and C/C genotypes, respectively, for the T-786→C point mutation. Subjects with the C/C genotype had significantly higher systolic blood pressures and were 2.16(95% confidence interval, 1.3 to 3.7) more likely to be hypertensive. Therefore, the −786 C/C genotype in NO synthase is a significant contributing factor for increasing the risk of essential hypertension.

Hyperhomocyst(e)inemia and the prevalence of atherosclerotic vascular disease in patients with end-stage renal disease

Hyperhomocyst(e)inemia is now recognized as an independent risk factor for atherosclerotic cardiovascular disease in patients with normal renal function. Hyperhomocyst(e)inemia is common in patients with chronic renal failure. This study is designed to look for an association between hyperhomocyst(e)inemia and atherosclerotic vascular disease in patients with end-stage renal disease (ESRD). Two hundred eighteen patients undergoing hemodialysis were enrolled onto the study and had predialysis bloodwork performed for total homocyst(e)ine, red blood cell folate, and vitamin B(12) levels. A history of clinically significant atherosclerotic vascular disease (ischemic heart disease, cerebrovascular disease, or peripheral vascular disease) was elicited by patient questionnaire and verified by careful inpatient and outpatient chart review. Atherosclerotic vascular disease was present in 45.9% of patients. Mean homocyst(e)ine concentration was 26.7 micromol/L (95% confidence interval [CI], 25.0 to 28.4) overall. Mean homocyst(e)ine concentration was 28.6 micromol/L (95% CI, 25.6 to 31.7) and 25.0 micromol/L (95% CI, 23.2 to 26.8) in patients with and without atherosclerotic disease, respectively (P = 0.036). The adjusted odds ratio for atherosclerotic disease was 2.12 (95% CI, 1.03 to 4.39) for those subjects with a homocyst(e)ine level in the highest quartile compared with the lowest 3 quartiles. In the 126 men, the adjusted odds ratio for atherosclerotic disease was 3.4 (95% CI, 1. 24 to 9.42) for those with homocyst(e)ine levels in the highest quartile compared with the lowest 3 quartiles. No association was found between homocyst(e)ine level and atherosclerotic disease in women. In conclusion, there is an association between hyperhomocyst(e)inemia and atherosclerotic vascular disease in patients undergoing dialysis. Prospective studies need to further examine the relationship between homocyst(e)ine level and atherosclerosis in women with ESRD.

Pelvic Lymph Node Dissection is Associated With Symptomatic Venous Thromboembolism Risk During Laparoscopic Radical Prostatectomy

PURPOSE Venous thromboembolism is a potentially catastrophic complication of radical prostatectomy. It is unknown whether pelvic lymph node dissection is related to the development of venous thromboembolism. We hypothesized that omitting pelvic lymph node dissection may be associated with a decreased incidence of venous thromboembolism. MATERIALS AND METHODS The records of 773 consecutive patients who underwent laparoscopic radical prostatectomy by a single surgeon from 2001 to 2009 were reviewed for postoperative venous thromboembolism. All patients underwent laparoscopic radical prostatectomy with or without pelvic lymph node dissection and had at least 3 months of followup. Generally only patients at increased risk for lymph node metastasis received pelvic lymph node dissection. Diagnostic studies were not routinely performed but were initiated for clinical symptoms of venous thromboembolism. Separately a meta-analysis of radical prostatectomy studies with or without pelvic lymph node dissection was performed to evaluate associations with venous thromboembolism. RESULTS Of the 773 patients 468 (60.8%) underwent laparoscopic radical prostatectomy plus pelvic lymph node dissection, 302 (39.2%) underwent laparoscopic radical prostatectomy without pelvic lymph node dissection, and 3 were missing preoperative data and were excluded from study. Patients in the laparoscopic radical prostatectomy plus pelvic lymph node dissection and laparoscopic radical prostatectomy only groups were similar in age, body mass index and prostate volume, although they differed in pathological characteristics and operative time. Venous thromboembolism occurred in 7 of 468 (1.5%) patients who underwent laparoscopic radical prostatectomy plus pelvic lymph node dissection and in 0 of 302 (0%) who underwent laparoscopic radical prostatectomy only (p = 0.047). Patients in whom venous thromboembolism developed had greater body mass index (30.8 vs 27.1 kg/m(2), p = 0.015) than those in whom venous thromboembolism did not develop. No patient had a symptomatic lymphocele. Meta-analysis of the literature demonstrated a significant association between venous thromboembolism and radical prostatectomy plus pelvic lymph node dissection compared to radical prostatectomy only (RR 2.15, CI 1.14-4.04, p = 0.018). CONCLUSIONS Pelvic lymph node dissection during radical prostatectomy increases the risk of venous thromboembolism. In carefully selected low risk patients omitting pelvic lymph node dissection may decrease the incidence of venous thromboembolism.

Pelvic node dissection in prostate cancer: extended, limited, or not at all?

Purpose of review Pelvic lymph node dissection in patients with clinically localized prostate cancer has long been an established part of radical prostatectomy that provides prognostic information in men with locally metastatic disease. However, given downward stage migration over the last 25 years, it is no longer clear that pelvic lymphadenectomy is pertinent for most men diagnosed today. In men in whom it is pertinent, it is unclear how extensive a lymphadenectomy should be performed. Recent findings Computed tomography and magnetic resonance imaging alone are not accurate for detecting nodal metastases, but new modalities such as magnetic resonance lymphography have great apparent potential. Until these become widely available, pelvic lymph node dissection remains the modality of choice for detecting lymph node metastasis. A variety of predictive nomograms exists to predict lymph node involvement. As a pelvic lymphadenectomy has complications that generally increase with extent of dissection, lymphadenectomy should be limited to patients at an increased risk of nodal metastasis. Summary There is good evidence that a pelvic lymph node dissection limited to the external iliac vein nodes is unnecessary in men with low-risk prostate cancer. A standard external iliac and obturator lymph node dissection, with or without extension to hypogastric nodes, makes sense in cases of intermediate and high risk. Harvesting a greater number of lymph nodes adds prognostic and even therapeutic benefit in many cases, including in some men with no obvious nodal metastases.

Incidence and risk factors for inguinal and incisional hernia after laparoscopic radical prostatectomy

OBJECTIVES To examine the risk of postoperative hernia development in men undergoing transperitoneal and extraperitoneal laparoscopic radical prostatectomy (LRP). Open radical retropubic prostatectomy increases the risk of postoperative inguinal hernia development within the first 2 postoperative years. It is less clear to what extent minimally invasive radical prostatectomy techniques affect the incidence of hernia development. METHODS A total of 651 LRP patients were mailed follow-up surveys regarding hernia development. Of these 651 patients, 378 responded (58%). Of the 378 patients, 308 had complete medical records for review. The mean follow-up for the fully evaluable cohort was 33.9 months (median 29.5, range 3-87). The potential risk factors for hernia (ie, previous hernia, age, surgical approach, pelvic lymph node dissection, bladder neck contracture, and operative time) were evaluated as categorical and/or continuous variables and using the univariate Cox proportional hazard ratio and Kaplan-Meier analyses. Preoperatively diagnosed inguinal hernias were repaired laparoscopically at LRP. RESULTS The incidence of postoperative inguinal hernia was 5.2% (16 of 308). After transperitoneal LRP (n = 122), 7.4% (9/122) reported an inguinal hernia, a few (29%) of which occurred within 2 years after LRP. After extraperitoneal LRP (n = 186), only 3.8% (7/186) reported an inguinal hernia, all of which occurred within 2 years after LRP. Kaplan-Meier analysis, however, demonstrated no effect of the surgical approach on the inguinal hernia incidence (P = .65). No risk factor was significantly associated with the postoperative hernia risk. One incisional hernia was noted (0.3%, 1 of 308), at a 5-mm extraperitoneal port site. Of the 308 men in the present study, 21 (6.8%) had undergone synchronous hernia repair, with no recurrences. CONCLUSIONS The incidence of inguinal hernia after LRP was similar, regardless of the laparoscopic approach, and was comparable or lower than the risk noted in published open radical retropubic prostatectomy series. No specific risk factors for post-LRP inguinal hernia development were identified.

Characteristics of positive surgical margins in robotic-assisted radical prostatectomy, open retropubic radical prostatectomy, and laparoscopic radical prostatectomy: a comparative histopathologic study from a single academic center.

Studies detailing differences in positive surgical margin among open retropubic radical prostatectomy, laparoscopic radical prostatectomy, and robotic-assisted laparoscopic radical prostatectomy are lacking. A retrospective review of all prostatectomies with positive surgical margin performed at our center in 2007 disclosed 99 cases, 6 (5%) of which were reinterpreted cases as having negative margins. Ninety-three cases were, therefore, included, corresponding to 37 retropubic radical prostatectomies, 19 laparoscopic radical prostatectomies, and 37 robotic-assisted laparoscopic radical prostatectomies. The relationship of positive surgical margin characteristics to clinicopathologic parameters and biochemical recurrence was assessed. The most commonly found positive surgical margin site was the apex/distal third in all groups (62% retropubic prostatectomies, 79% laparoscopic prostatectomies, 60% robotic-assisted prostatectomies). Total linear length of positive surgical margin sites was significantly correlated with preoperative prostate-specific antigen, preoperative prostate-specific antigen density, pT stage, and tumor volume (P ≤ .001). We found no significant differences among the 3 groups with respect to total linear length, number of foci, laterality, or location of positive surgical margin. The rate of biochemical recurrence was also comparable in the 3 groups. On univariate analyses, biochemical recurrence was significantly associated with preoperative prostate-specific antigen values, preoperative prostate-specific antigen density, Gleason score, number of positive surgical margins, and total linear length of positive surgical margin (P ≤ .02). Only preoperative prostate-specific antigen density and number of positive surgical margin foci were statistically significant (P ≤ .03) independent predictors of biochemical recurrence. We found no significant difference in positive surgical margin characteristics or biochemical recurrence among the 3 radical prostatectomy modalities. Preoperative prostate-specific antigen density and number of positive surgical margin foci were the only independent predictors of biochemical recurrence.

Metabolomics and bladder cancer

Diagnosis of bladder cancer is primarily made based on clinical presentation and then by direct visualization with cystoscopy. Despite the massive investments recently made to identify urinary-based assays that are able to diagnosis urothelial carcinoma, urine cytology and cystoscopy still remain the gold standard. Recently proof of principle studies have shown that noninvasive urine-based metabolomics, using high pressure liquid chromatography (HPLC) and nuclear magnetic resonance (NMR), may be able to accurately diagnosis bladder cancer. This review discusses the published studies investigating metabolomics and bladder cancer and the future potential of this developing field.

Anticancer activities of bovine and human lactoferricin-derived peptides

Lactoferrin (LF) is a mammalian host defense glycoprotein with diverse biological activities. Peptides derived from the cationic region of LF possess cytotoxic activity against cancer cells in vitro and in vivo. Bovine lactoferricin (LFcinB), a peptide derived from bovine LF (bLF), exhibits broad-spectrum anticancer activity, while a similar peptide derived from human LF (hLF) is not as active. In this work, several peptides derived from the N-terminal regions of bLF and hLF were studied for their anticancer activities against leukemia and breast-cancer cells, as well as normal peripheral blood mononuclear cells. The cyclized LFcinB-CLICK peptide, which possesses a stable triazole linkage, showed improved anticancer activity, while short peptides hLF11 and bLF10 were not cytotoxic to cancer cells. Interestingly, hLF11 can act as a cell-penetrating peptide; when combined with the antimicrobial core sequence of LFcinB (RRWQWR) through either a Pro or Gly-Gly linker, toxicity to Jurkat cells increased. Together, our work extends the library of LF-derived peptides tested for anticancer activity, and identified new chimeric peptides with high cytotoxicity towards cancerous cells. Additionally, these results support the notion that short cell-penetrating peptides and antimicrobial peptides can be combined to create new adducts with increased potency.

The Calcium-Dependent Switch Helix of L-Plastin Regulates Actin Bundling.

L-plastin is a calcium-regulated actin-bundling protein that is expressed in cells of hematopoietic origin and in most metastatic cancer cells. These cell types are mobile and require the constant remodeling of their actin cytoskeleton, where L-plastin bundles filamentous actin. The calcium-dependent regulation of the actin-bundling activity of L-plastin is not well understood. We have used NMR spectroscopy to determine the solution structure of the EF-hand calcium-sensor headpiece domain. Unexpectedly, this domain does not bind directly to the four CH-domains of L-plastin. A novel switch helix is present immediately after the calcium-binding region and it binds tightly to the EF-hand motifs in the presence of calcium. We demonstrate that this switch helix plays a major role during actin-bundling. Moreover a peptide that competitively inhibits the association between the EF-hand motifs and the switch helix was shown to deregulate the actin-bundling activity of L-plastin. Overall, these findings may help to develop new drugs that target the L-plastin headpiece and interfere in the metastatic activity of cancer cells.

Urine and Serum Metabolomics Analyses May Distinguish between Stages of Renal Cell Carcinoma

Renal cell carcinoma (RCC) is a heterogeneous disease that is usually asymptomatic until late in the disease. There is an urgent need for RCC specific biomarkers that may be exploited clinically for diagnostic and prognostic purposes. Preoperative fasting urine and serum samples were collected from patients with clinical renal masses and assessed with 1H NMR and GCMS (gas chromatography-mass spectrometry) based metabolomics and multivariate statistical analysis. Alterations in levels of glycolytic and tricarboxylic acid (TCA) cycle intermediates were detected in RCC relative to benign masses. Orthogonal Partial Least Square Discriminant Analysis plots discriminated between benign vs. pT1 (R2 = 0.46, Q2 = 0.28; AUC = 0.83), benign vs. pT3 (R2 = 0.58, Q2 = 0.37; AUC = 0.87) for 1H NMR-analyzed serum and between benign vs. pT1 (R2 = 0.50, Q2 = 0.37; AUC = 0.83), benign vs. pT3 (R2 = 0.72, Q2 = 0.68, AUC = 0.98) for urine samples. Separation was observed between benign vs. pT3 (R2 = 0.63, Q2 = 0.48; AUC = 0.93), pT1 vs. pT3 (R2 = 0.70, Q2 = 0.54) for GCMS-analyzed serum and between benign vs. pT3 (R2Y = 0.87; Q2 = 0.70; AUC = 0.98) for urine samples. This pilot study suggests that urine and serum metabolomics may be useful in differentiating benign renal tumors from RCC and for staging RCC.