Potent inhibition by ropivacaine of metastatic colon cancer SW620 cell invasion and NaV1.5 channel function.

BACKGROUND: Metastatic breast and colon cancer cells express neonatal and adult splice variants of NaV1.5 voltage-activated Na(+) channels (VASCs). Block of VASCs inhibits cell invasion. Local anaesthetics used during surgical tumour excision inhibit VASC activity on nociceptive neurones providing regional anaesthesia. Inhibition of VASCs on circulating metastatic cancer cells may also be beneficial during the perioperative period. However, ropivacaine, frequently used to provide analgesia during tumour resection, has not been tested on colon cancer cell VASC function or invasion. METHODS: We used reverse transcription-polymerase chain reaction and sequencing to identify NaV1.5 variants in the SW620 metastatic colon cancer cell line. Recombinant adult and neonatal NaV1.5 variants were expressed in human embryonic kidney cells. Voltage-clamp recordings and invasion assays were used to examine the effects of ropivacaine on recombinant NaV1.5 channels and the metastatic potential of SW620 cells, respectively. RESULTS: SW620 cells expressed adult and neonatal NaV1.5 variants, which had similar steady-state inactivation profiles, but distinctive activation curves with the neonatal variant having a V1/2 of activation 7.8 mV more depolarized than the adult variant. Ropivacaine caused a concentration-dependent block of both NaV1.5 variants, with IC50 values of 2.5 and 3.9 µM, respectively. However, the reduction in available steady-state current was selective for neonatal NaV1.5 channels. Ropivacaine inhibited SW620 invasion, with a potency similar to that of inhibition of NaV1.5 channels (3.8 µM). CONCLUSIONS: Ropivacaine is a potent inhibitor of both NaV1.5 channel activity and metastatic colon cancer cell invasion, which may be beneficial during surgical colon cancer excision.

When rectal bleeding is serious: anal squamous cell carcinoma in two intravenous cyclophosphamide treated systemic lupus erythematosus patients with human papilloma virus infection.

Anal squamous cell carcinoma is a potentially fatal disease. Human papilloma virus (HPV) is the most common sexually transmitted disease worldwide and is responsible for almost all cases of anal cancer. Immunocompromised patients are at increased risk of developing anal dysplasia and malignancies. A lack of awareness of HPV-associated anal malignancies in the immunocompromised may lead to a delay in diagnosis and confer a poor prognosis.

Metabolic effects of insulin and insulin-like growth factor-I in endotoxemic rats during total parenteral nutrition feeding.

The effects of insulin and insulin-like growth factor-I (IGF-I) on protein, energy, and glucose metabolism were examined in endotoxemic rats receiving total parenteral nutrition (TPN) for 3 days. The endotoxemic model was induced by constant infusion of lipopolysaccharide (1 mg/kg x d) for 3 days. The TPN regimen provided 200 kcal/kg x d and 1.5 g protein/kg x d. The dosage of insulin (5 mU/kg x h) and IGF-I (20 microg/kg x h), either alone or in combination, was chosen to maintain normal levels of leucine and glucose in plasma during feeding. One normal control and 4 endotoxemic groups with different treatments (saline, IGF-I, insulin, or IGF-I and insulin) were included. The effects of endotoxin were compared between the group receiving endotoxin alone and normal controls, and the effects of insulin and IGF-I were compared within the endotoxemic groups. The results show that endotoxin significantly increased the mortality and induced a hypermetabolic state, and nutrition alone could not overcome the catabolism induced by endotoxin. However, administration of insulin and IGF-I enhanced protein preservation in muscle tissue in endotoxemic rats during TPN. This effect was greater for insulin either alone or in combination with IGF-I. Insulin also significantly reduced the mortality. There were no additive effects of these two anabolic hormones on any measured parameter in these experimental conditions.

Effect of short-term enteral feeding with eicosapentaenoic and gamma-linolenic acids on alveolar macrophage eicosanoid synthesis and bactericidal function in rats.

OBJECTIVES: Because vasoactive eicosanoids derived from arachidonic acid present in immune cell phospholipids promote lung inflammation in critically ill patients, novel experimental diets containing eicosapentaenoic acid from fish oil and gamma-linolenic acid from borage oil have been designed to limit arachidonic acid metabolism. However, excess dietary eicosapentaenoic acid impairs superoxide formation and bacterial killing by immune cells. The present study determined whether short-term enteral feeding with diets enriched with either eicosapentaenoic acid alone or in combination with gamma-linolenic acid would modulate alveolar macrophage eicosanoid synthesis without compromising bactericidal function. DESIGN: Prospective, randomized, controlled, blinded study. SETTING: University medical center. SUBJECTS: Adult male Sprague-Dawley rats. INTERVENTIONS: Rats underwent surgical placement of a gastroduodenal feeding catheter and were randomly assigned to receive one of three high-fat (55.2% of total calories), low-carbohydrate diets containing isocaloric amounts of lipids for 4 days. The control diet was enriched with linoleic acid, whereas the two test diets were low in linoleic acid and enriched with either 5 mole % eicosapentaenoic acid alone or in combination with 5 mole % gamma-linolenic acid. Alveolar macrophages were then procured to assess phospholipid fatty acid composition, eicosanoid synthesis after stimulation with endotoxin, superoxide formation and phagocytosis by flow cytometry, and killing of Staphylococcus aureus MEASUREMENTS AND MAIN RESULTS: Alveolar macrophage levels of arachidonic acid were significantly (p < .01) lower and levels of eicosapentaenoic and dihomo-gamma-linolenic acids were higher after feeding the eicosapentaenoic and gamma-linolenic acid diet vs. the linoleic acid diet. Ratios of thromboxane B2,/B3, leukotriene B4/B5, and prostaglandin E2/E1 were reduced in the macrophages from rats given either the eicosapentaenoic acid or eicosapentaenoic acid with gamma-linolenic acid diet compared with ratios from rats given the linoleic acid diet. Macrophages from rats given the eicosapentaenoic with gamma-linolenic acid diet released 35% or 24% more prostaglandin E1 than macrophages from rats given either the linoleic acid or the eicosapentaenoic acid diet, respectively. Macrophage superoxide generation, phagocytosis of opsonized zymosan, and killing of S. aureus were similar irrespective of dietary treatment. CONCLUSION: Short-term enteral feeding with an eicosapentaenoic acid-enriched or eicosapentaenoic with gamma-linolenic acid-enriched diet rapidly modulated the fatty acid composition of alveolar macrophage phospholipids, promoted a shift toward formation of less inflammatory eicosanoids by stimulated macrophages, but did not impair alveolar macrophage bactericidal function relative to responses observed after feeding a linoleic acid diet.

Cyclic vs continuous enteral feeding with omega-3 and gamma-linolenic fatty acids: effects on modulation of phospholipid fatty acids in rat lung and liver immune cells.

UNLABELLED: Arachidonic acid (AA) present in lung and liver immune cell phospholipids is the precursor of eicosanoids that promote neutrophil margination, leading to tissue injury and inflammation. Administration of novel enteral formulations low in linoleic acid (LA) and containing eicosapentaenoic acid (EPA) from fish oil and gamma-linolenic acid (GLA) from borage oil displaces AA and promotes cell formation of eicosanoids with reduced inflammatory potential. The present study was undertaken to determine whether or not short-term provision of enteral diets containing GLA, EPA, or both in a cyclic fashion modulated the fatty acid composition of rat alveolar macrophage (AM) and liver Kupffer and endothelial (K&E) cell phospholipids in vivo to the extent achieved during continuous feeding. METHODS: Rats were isocalorically fed through a gastrostomy catheter for 3 or 6 days with high-fat, low-carbohydrate diets that were enriched with either LA (diet A), EPA (diet B), or EPA + GLA (diet C). The rats were randomized by infusion modality, ie, continuous vs cyclic (14 hours feeding with 10 hours fasting daily) feeding. AM and K&E were isolated and phospholipid fatty acid profiles were determined by gas chromatography. RESULTS: The dietary effects on AM and K&E cell phospholipid fatty acids for a given feeding period were not significantly influenced by the infusion modality. AM and K&E cells from rats receiving either diet B or diet C for 3 days had significantly lower AA and LA and higher EPA and dihomo-GLA (DHGLA), respectively, than rats given diet A regardless of the infusion modality. The mole % of EPA and DHGLA in K&E cells were higher after 6 vs 3 days of cyclic feeding with diet C. Using the eicosanoid precursor ratio (EPA + DHGLA/AA), the potential for generation of AA-derived eicosanoids was lower in rats given die B or C vs diet A regardless of infusion modality. DISCUSSION: Given the rapid changes in lung and liver immune cell phospholipid fatty acids, short-term provision of EPA and GLA-enriched diets cyclically or continuously may prove clinically relevant for modulating the fatty acid composition and potential eicosanoid formation by these cells.

Immunologic effects of acute hyperglycemia in nondiabetic rats.

BACKGROUND: This study was designed to determine the consequences of acute hyperglycemia on the immune function of peripheral neutrophils, peritoneal macrophages, and alveolar macrophages in nondiabetic rats. METHODS: The animals were randomly divided into nonsurgical (normal) and surgical groups. The postoperative rats were further divided into normoglycemic (control) and hyperglycemic (glucose) groups. The hyperglycemic condition was maintained by constant infusion of glucose to raise plasma glucose concentration to 300 mg/dL for 3 hours. The immune cells were then harvested to determine their phagocytic and oxidative capacities via flow cytometry. RESULTS: The results showed that hyperglycemia significantly decreased the respiratory burst of alveolar macrophages (p < .05). In contrast, hyperglycemia enhanced phagocytosis in these cells (p < .002). There was a significant activation of the respiratory burst in peripheral neutrophils by surgery (p < .002), but no effect of hyperglycemia. CONCLUSIONS: We conclude that hyperglycemia itself can influence immune function in some phagocytic cells, which may be an important factor in postsurgical infection.

Rapid modulation of lung and liver macrophage phospholipid fatty acids in endotoxemic rats by continuous enteral feeding with n-3 and gamma-linolenic fatty acids.

Dienoic eicosanoids derived from phospholipid arachidonic acid (AA) in lung and liver macrophages promote leukosequestration, thrombosis, and tissue injury. Current enteral diets (diet A) are enriched with linoleic acid (LA), a precursor of AA. Novel diets low in LA and containing eicosapentaenoic acid (EPA) and gamma-linolenic acid (GLA) foster formation of less inflammatory eicosanoids. The study objective was to assess the rapidity and extent of LA and AA displacement in vivo from alveolar macrophage (AM phi), lung, and liver Kupffer and endothelial (KE) cell phospholipids in rats fed enterally with diets enriched with 5.3% (by wt) EPA and either 1.2% or 4.6% GLA (diets B and C, respectively). After surgical placement of catheters, the rats were fed enterally and co-infused intravenously with either endotoxin or vehicle continuously for 3 or 6 d. Rats given either diet B or C had significantly lower (P < 0.01) relative percentages of AA and LA within the AM phi, lung, and KE cell phospholipids, and concomitantly higher percentages of EPA compared with rats infused with diet A after 3 d of enteral feeding irrespective of endotoxin co-infusion. Incorporation of dihomo-gamma-linolenic acid (DHGLA), the metabolite of GLA, into lung and KE phospholipids was significant in rats given diet C. Most of the changes in fatty acid composition occurred by day 3. The polyunsaturated fatty acid composition of AM phi, lung, and KE cell phospholipids can be rapidly modified by continuous short-term enteral feeding with EPA- and GLA-enriched diets irrespective of concurrent endotoxemia.

Fatty acid composition of lung, macrophage and surfactant phospholipids after short-term enteral feeding with n-3 lipids.

Utilization of enteral feeding modalities may prove clinically relevant for rapid modulation of lung phospholipid polyunsaturated fatty acids (PUFA) that serve as substrates for the formation of vasoactive dienoic eicosanoids. We compared the effects of short-term enteral feeding with formulations enriched with either fish (n-3) or corn (n-6) oil PUFA on the fatty acid composition of rat lung, alveolar macrophage and surfactant phospholipids. The diets were infused continuously for 72 h through a surgically placed gastroduodenal feeding catheter by a syringe pump. The n-3 PUFA derived from the fish oil enriched diet were readily incorporated into the phospholipid membranes of the alveolar macrophages, lung tissue and pulmonary surfactant. The relative percentages of the n-3 PUFA were significantly higher and individual and total n-6 PUFA significantly lower in the macrophage, lung and surfactant phospholipids from the n-3-supplemented rats in comparison with those present in the rats infused enterally with the n-6 diet or untreated, chow-fed rats (baseline). In contrast, there was a significant increase in linoleic acid (18:2n-6) without modification of arachidonic acid (20:4n-6) in the alveolar macrophages, lung tissue and surfactant from rats enterally receiving the n-6 diet relative to levels measured in the rats at baseline. The results suggest that short-term continuous delivery of n-3-enriched enteral preparations can foster rapid modification of membrane phospholipid PUFA composition of lung tissue, alveolar macrophages and lung surfactant.(ABSTRACT TRUNCATED AT 250 WORDS)