LPS-induced microvascular leukocytosis can be assessed by blue-field entoptic phenomenon

Administration of low doses of Escherichia coli endotoxin [a lipopolysaccharide (LPS)] to humans enables the study of inflammatory mechanisms. The purpose of the present study was to investigate whether the blue-field entoptic technique may be used to quantify the increase in circulating leukocytes in the ocular microvasculature after LPS infusion. In addition, combined laser Doppler velocimetry and retinal vessel size measurement were used to study red blood cell movement. Twelve healthy male volunteers received 20 IU/kg iv LPS as a bolus infusion. Outcome parameters were measured at baseline and 4 h after LPS administration. In the first protocol (n = 6 subjects), ocular hemodynamic effects were assessed with the blue-field entoptic technique, the retinal vessel analyzer, and laser Doppler velocimetry. In the second protocol (n = 6 subjects), white blood cell (WBC) counts from peripheral blood samples and blue-field entoptic technique measurements were performed. LPS caused peripheral blood leukocytosis and increased WBC density in ocular microvessels (by 49%; P = 0.036) but did not change WBC velocity. In addition, retinal venous diameter was increased (by 9%; P = 0.008), but red blood cell velocity remained unchanged. The LPS-induced changes in retinal WBC density and leukocyte counts were significantly correlated (r = 0.87). The present study indicates that the blue-field entoptic technique can be used to assess microvascular leukocyte recruitment in vivo. In addition, our data indicate retinal venous dilation in response to endotoxin.     

Regulation of endotoxin-induced proinflammatory activation in human coronary artery cells: expression of functional membrane-bound CD14 by human coronary artery smooth muscle cells

Low-level endotoxemia has been identified as a powerful risk factor for atherosclerosis. However, little is known about the mechanisms that regulate endotoxin responsiveness in vascular cells. We conducted experiments to compare the relative responses of human coronary artery endothelial cells (HCAEC) and smooth muscle cells (HCASMC) to very low levels of endotoxin, and to elucidate the mechanisms that regulate endotoxin responsiveness in vascular cells. Endotoxin (10-fold higher in magnitude at >10-fold lower threshold concentrations (10-30 pg/ml) compared with HCAEC. This remarkable sensitivity of HCASMC to very low endotoxin concentrations, comparable to that found in circulating monocytes, was not due to differential expression of TLR4, which was detected in HCAEC, HCASMC, and intact coronary arteries. Surprisingly, membrane-bound CD14 was detected in seven different lines of HCASMC, conferring responsiveness to endotoxin and to lipoteichoic acid, a product of Gram-positive bacteria, in these cells. These results suggest that the low levels of endotoxin associated with increased risk for atherosclerosis are sufficient to produce inflammatory responses in coronary artery cells. Because CD14 recognizes a diverse array of inflammatory mediators and functions as a pattern recognition molecule in inflammatory cells, expression of membrane-bound CD14 in HCASMC implies a potentially broader role for these cells in transducing innate immune responses in the vasculature.     

Endotoxemia causes central downregulation of sympathetic vasomotor tone in healthy humans

Experimental endotoxemia as a model of the initial septic response affects the autonomic nervous system with profound cardiovascular sequelae. Whether the postsynaptic sympathoneural activity to the muscle vascular bed is altered in the early septic phase remains to be determined. The present study aimed to elucidate the early effects of LPS on muscle sympathetic nerve activity (MSNA) and cardiovascular regulation in healthy humans. Young, healthy volunteers randomly received either an LPS bolus (4 ng/kg body wt, n = 11) or placebo (saline; n = 7). Experimental baroreflex assessment (baseline measurements followed by infusion of vasoactive drugs nitroprusside/phenylephrine) was done prior to and 90 min following LPS or placebo challenge. MSNA, heart rate, blood pressure, and blood levels of catecholamines, TNF-alpha and IL-6 were measured sequentially. Endotoxin but not placebo-induced flu-like symptoms and elevated cytokine levels. In contrast to placebo, LPS significantly suppressed MSNA burst frequency 90 min after injection [mean +/- SE: 12.1 +/- 2.9 vs. 27.5 +/- 3.3 burst/min (post- vs. pre-LPS); P < 0.005] but increased heart rate [78.4 +/- 3.1 vs. 60.6 +/- 2.0 beats/min (post- vs. pre-LPS); P < 0.001]. Baseline blood pressure was not altered, but baroreflex testing demonstrated a blunted MSNA response and uncoupling of heart rate modulation to blood pressure changes in the endotoxin group. We conclude that endotoxin challenge in healthy humans has rapid suppressive effects on postsynaptic sympathetic nerve activity to the muscle vascular bed and alters baroreflex function which may contribute to the untoward cardiovascular effects of sepsis.     

Phosphorylation of 5-lipoxygenase at ser523 by protein kinase A determines whether pioglitazone and atorvastatin induce proinflammatory leukotriene B4 or anti-inflammatory 15-epi-lipoxin a4 production

The 5-lipoxygenase (5LO) produces leukotriene B(4) and 15-epilipoxin-A(4) (15-epi-LXA(4)). Phosphorylation at Ser(523) by protein kinase A (PKA) prevents 5LO shift to the perinuclear membrane. Atorvastatin and pioglitazone up-regulate 15-epi-LXA(4) production in the heart. We assessed whether phosphorylation of 5LO by PKA determines whether 5LO interacts with the membranous cytosolic phospholipase A(2) (cPLA(2)) to produce leukotriene B(4) or with cyclooxygenase-2 (COX2) to produce 15-epi-LXA(4). Rats received either pioglitazone, atorvastatin, pioglitazone plus atorvastatin, vehicle, or LPS. Rat myocardial cells were incubated with pioglitazone plus atorvastatin, pioglitazone plus atorvastatin plus H-89 (PKA inhibitor), H-89, or vehicle for 8 h. Pioglitazone and atorvastatin did not affect total 5LO expression. However, both increased 5LO levels in the cytosolic fraction. H-89 caused a shift of 5LO to the membranous fraction in atorvastatin- and pioglitazone-treated rats. Pioglitazone and atorvastatin increased phospho-5LO levels. H-89 attenuated this increase. Both pioglitazone and atorvastatin increased COX2 levels in the cytosolic fraction and the membranous fraction. H-89 prevented this increase. Pioglitazone and atorvastatin increased cPLA(2) expression in the membranous fraction. This effect was not attenuated by H-89. Pioglitazone plus atorvastatin increased 15-epi-LXA(4) levels. H-89 attenuated the effect of pioglitazone plus atorvastatin. Pioglitazone plus atorvastatin plus H-89 increased leukotriene B(4) levels. Coimmunoprecipitation showed that without H-89, atorvastatin and pioglitazone induced an interaction between 5LO and COX2 in the cytosolic fraction, whereas when H-89 was added, 5LO interacted with cPLA(2) on the membranous fraction. The 5LO phosphorylation determines whether 15-epi-LXA(4) (anti-inflammatory) or leukotriene B(4) (inflammatory mediator) is produced.     

Mild endotoxemia, NF-kappaB translocation, and cytokine increase during exertional heat stress in trained and untrained individuals

This study examined endotoxin-mediated cytokinemia during exertional heat stress (EHS). Subjects were divided into trained [TR; n=12, peak aerobic power (VO2peak)=70+/-2 ml.kg lean body mass(-1).min(-1)] and untrained (UT; n=11, VO2peak=50+/-1 ml.kg lean body mass(-1).min(-1)) groups before walking at 4.5 km/h with 2% elevation in a climatic chamber (40 degrees C, 30% relative humidity) wearing protective clothing until exhaustion (Exh). Venous blood samples at baseline and 0.5 degrees C rectal temperature increments (38.0, 38.5, 39.0, 39.5, and 40.0 degrees C/Exh) were analyzed for endotoxin, lipopolysaccharide binding protein, circulating cytokines, and intranuclear NF-kappaB translocation. Baseline and Exh samples were also stimulated with LPS (100 ng/ml) and cultured in vitro in a 37 degrees C water bath for 30 min. Phenotypic determination of natural killer cell frequency was also determined. Enhanced blood (104+/-6 vs. 84+/-3 ml/kg) and plasma volumes (64+/-4 vs. 51+/-2 ml/kg) were observed in TR compared with UT subjects. EHS produced an increased concentration of circulating endotoxin in both TR (8+/-2 pg/ml) and UT subjects (15+/-3 pg/ml) (range: not detected to 32 pg/ml), corresponding with NF-kappaB translocation and cytokine increases in both groups. In addition, circulating levels of tumor necrosis factor-alpha and IL-6 were also elevated combined with concomitant increases in IL-1 receptor antagonist in both groups and IL-10 in TR subjects only. Findings suggest that the threshold for endotoxin leakage and inflammatory activation during EHS occurs at a lower temperature in UT compared with TR subjects and support the endotoxin translocation hypothesis of exertional heat stroke, linking endotoxin tolerance and heat tolerance.     

Structural and functional analysis of pancreatic islets preserved by pioglitazone in db/db mice

To evaluate preventive effects of pioglitazone on pancreatic beta-cell damage in C57BL/KsJ db/db mice, an obese diabetic animal model, the pancreatic islets were compared morphologically between pioglitazone-treated (100 mg/kg daily po) and untreated db/db mice (n = 7 for each) after a 12-wk intervention (6-18 wk of age). The fasting blood glucose level was significantly improved by the treatment with pioglitazone (260 +/- 12 vs. 554 +/- 62 mg/dl, P < 0.05). The islet mass in the pancreas was significantly greater in pioglitazone-treated mice than in untreated mice (10.2 +/- 1.1 vs. 4.6 +/- 0.2 mg, P < 0.01). Subsequently, biochemical and physiological analyses of the beta-cell function were employed using pioglitazone-treated and untreated db/db mice (n = 6 for each) and pioglitazone-treated and untreated db/+ mice (n = 6 for each). After 2 wk of treatment (10-12 wk of age), the plasma levels of triglyceride and free fatty acid were significantly decreased, whereas the plasma adiponectin level increased significantly compared with the untreated group (65.2 +/- 18.0 vs. 18.3 +/- 1.3 microg/ml, P < 0.05). Pioglitazone significantly reduced the triglyceride content in the islets (43.3 +/- 3.6 vs. 65.6 +/- 7.6 ng/islet, P < 0.05) with improved glucose-stimulated insulin secretion. Pioglitazone showed no significant effects on the biochemical and physiological parameters in db/+ mice. The present study first demonstrated that pioglitazone prevents beta-cell damage in an early stage of the disease progression in db/db mice morphologically and physiologically. Our results suggest that pioglitazone improves glucolipotoxicity by increasing insulin sensitivity and reducing fat accumulation in the pancreatic islets.     

Insulin at physiological concentrations increases microvascular perfusion in human myocardium

Vascular endothelium regulates vascular tone and tissue perfusion in response to various physiological and pathological stimuli. Insulin and meal feeding increase microvascular perfusion and thus oxygen, nutrient, and hormone delivery to human skeletal muscle. Meal feeding also increases cardiac microvascular perfusion in healthy humans. To examine whether insulin at physiological concentrations increases microvascular perfusion in human myocardium, we studied 13 healthy, overnight-fasted, lean, young human volunteers by using myocardial contrast echocardiography (MCE) and insulin-clamp techniques. We measured cardiac microvascular blood volume (MBV), microvascular flow velocity (MFV), and microvascular blood flow (MBF) at baseline, 60 min, and 120 min after initiating insulin infusion at 1 mU.kg(-1).min(-1). MBF is the product of MBV and MFV and represents microvascular perfusion. Insulin increased myocardial MBV by 23% at 60 min (P < 0.01) and by 41% at 120 min (P = 0.001) without changing MFV. As a result, insulin-mediated myocardial MBF increased significantly at both 60 min (P < 0.01) and 120 min (P < 0.0005). Insulin also significantly increased brachial artery diameter, flow velocity, and total blood flow at 60 and 120 min (P < 0.05 for all). The changes in cardiac MBV correlated positively with quantitative insulin sensitivity check index (QUICKI) and negatively with body mass index but not with the steady-state glucose-infusion rates or the changes in brachial artery parameters. We conclude that insulin, at physiologically relevant concentrations, increases microvascular perfusion in human heart muscle by increasing cardiac MBV in healthy, insulin-sensitive adults. This insulin-mediated cardiac microvascular perfusion may play an important role in normal human myocardial oxygen and substrate physiology.     

Pressure-distension relationship in arteries and arterioles in response to 5 wk of horizontal bedrest

We hypothesized that exposure to prolonged recumbency (bedrest), and thus reductions of intravascular pressure gradients, increases pressure distension in arteries/arterioles in the legs. Ten subjects underwent 5 wk of horizontal bedrest. Pressure distension was investigated in arteries and arterioles before and after the bedrest, with the subject seated or supine in a hyperbaric chamber with either one arm or a lower leg protruding through a hole in the chamber door. Increased pressure in the vessels of the arm/leg was accomplished by increasing chamber pressure. Vessel diameter and flow were measured in the brachial and posterior tibial arteries using Doppler ultrasonography. Electrical tissue impedance was measured in the test limb. Bedrest increased (P < 0.01) pressure distension threefold in the tibial artery (from 8 +/- 7% to 24 +/- 11%) and by a third (P < 0.05) in the brachial artery (from 15 +/- 9% to 20 +/- 10%). The pressure-induced increase in tibial artery flow was more pronounced (P < 0.01) after (50 +/- 39 ml/min) than before (13 +/- 23 ml/min) bedrest, whereas the brachial artery flow response was unaffected by bedrest. The pressure-induced decrease in tissue impedance in the leg was more pronounced (P < 0.01) after (16 +/- 7%) than before (10 +/- 6%) bedrest, whereas bedrest did not affect the impedance response in the arm. Thus, withdrawal of the hydrostatic pressure gradients that act along the blood vessels in erect posture markedly increases pressure distension in dependent arteries and arterioles.     

Mixed meal and light exercise each recruit muscle capillaries in healthy humans

Intense exercise and insulin each increases total limb blood flow and recruits muscle capillaries, presumably to facilitate nutrient exchange. Whether mixed meals or light exercise likewise recruits capillaries is unknown. We fed 18 (9 M, 9 F) healthy volunteers a 480-kcal liquid mixed meal. Plasma glucose, insulin, brachial artery flow, and forearm muscle microvascular blood volume were measured before and after the meal. Brachial artery flow and microvascular volume were also examined with light (25% max), moderate (50%), and heavy (80%) forearm contraction every 20 s in 5 (4 M, 1 F) healthy adults. After the meal, glucose and insulin rose modestly (to approximately 7 mM and approximately 270 pM) and peaked by 30 min, whereas brachial artery blood flow (P < 0.05) and the microvascular volume (P < 0.01) each increased significantly by 60 min, and microvascular flow velocity did not change. For exercise, both 50 and 80%, but not 25% maximal handgrip, increased average forearm and brachial artery blood flow (P < 0.01). Flow increased immediately after each contraction and declined toward basal over 15 s. Exercise at 25% max increased microvascular volume threefold (P < 0.01) without affecting microvascular flow velocity or total forearm blood flow. Forearm exercise at 80% maximal grip increased both microvascular volume and microvascular flow velocity (P < 0.05 each). We conclude that light exercise and simple meals each markedly increases muscle microvascular volume, thereby expanding the endothelial surface for nutrient exchange, and that capillary recruitment is an important physiological response to facilitate nutrient/hormone delivery in healthy humans.     

Peripheral vascular resistance increases after termination of obstructive apneas.

The mechanisms by which obstructive apneas produce intermittent surges in arterial pressure remain poorly defined. To determine whether termination of obstructive apneas produce peripheral vasoconstriction, we assessed forearm blood flow during and after obstructive events in sleeping patients experiencing spontaneous upper airway obstructions. In all subjects, heart rate was monitored with an electrocardiogram and blood pressure was monitored continuously with digital plethysmography. In 10 patients (protocol 1), we used forearm plethysmography to assess forearm blood flow, from which we calculated forearm vascular resistance by performing venous occlusions during and after obstructive episodes. In an additional four subjects, we used simultaneous Doppler and B-mode images of the brachial artery to measure blood velocity and arterial diameter, from which we calculated brachial flow continuously during spontaneous apneas (protocol 2). In protocol 1, forearm vascular resistance increased 71% after apnea termination (29.3 +/- 15.4 to 49.8 +/- 26.5 resistance units, P < 0.05) with all patients showing an increase in resistance. In protocol 2, brachial resistance increased at apnea termination in all subjects (219.8 +/- 22.2 to 358.3 +/- 46.1 mmHg x l(-1) x min; P = 0.01). We conclude that termination of obstructive apneas is associated with peripheral vasoconstriction.     

Effect of bronchial artery blood flow on cardiopulmonary bypass-induced lung injury

Cardiovascular surgery requiring cardiopulmonary bypass (CPB) is frequently complicated by postoperative lung injury. Bronchial artery (BA) blood flow has been hypothesized to attenuate this injury. The purpose of the present study was to determine the effect of BA blood flow on CPB-induced lung injury in anesthetized pigs. In eight pigs (BA ligated) the BA was ligated, whereas in six pigs (BA patent) the BA was identified but left intact. Warm (37 degrees C) CPB was then performed in all pigs with complete occlusion of the pulmonary artery and deflated lungs to maximize lung injury. BA ligation significantly exacerbated nearly all aspects of pulmonary function beginning at 5 min post-CPB. At 25 min, BA-ligated pigs had a lower arterial Po(2) at a fraction of inspired oxygen of 1.0 (52 +/- 5 vs. 312 +/- 58 mmHg) and greater peak tracheal pressure (39 +/- 6 vs. 15 +/- 4 mmHg), pulmonary vascular resistance (11 +/- 1 vs. 6 +/- 1 mmHg x l(-1) x min), plasma TNF-alpha (1.2 +/- 0.60 vs. 0.59 +/- 0.092 ng/ml), extravascular lung water (11.7 +/- 1.2 vs. 7.7 +/- 0.5 ml/g blood-free dry weight), and pulmonary vascular protein permeability, as assessed by a decreased reflection coefficient for albumin (sigma(alb); 0.53 +/- 0.1 vs. 0.82 +/- 0.05). There was a negative correlation (R = 0.95, P < 0.001) between sigma(alb) and the 25-min plasma TNF-alpha concentration. These results suggest that a severe decrease in BA blood flow during and after warm CPB causes increased pulmonary vascular permeability, edema formation, cytokine production, and severe arterial hypoxemia secondary to intrapulmonary shunt.     

VEGF-A stimulation of leukocyte adhesion to colonic microvascular endothelium: implications for inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder characterized by increased leukocyte recruitment and subsequent tissue damage. An increase in the density of the microvasculature of the colon during IBD has been suggested, leading to the concept that angiogenesis may play a pathological role in IBD. Increased tissue and serum levels of the angiogenic cytokine VEGF-A have been reported in cases of active IBD. In this study, we examined the hypothesis that VEGF-A exerts a proinflammatory effect on colon microvascular endothelium that contributes to colonic inflammation. Leukocyte adhesion to VEGF-A-stimulated colon microvascular endothelial cells was examined using a parallel-plate hydrodynamic flow chamber. ICAM-1 adhesion molecule expression on colonic microvascular endothelium also was determined in response to VEGF-A stimulation, along with characterization of leukocyte adhesion molecule expression. High-dose VEGF-A (50 ng/ml) stimulation increased neutrophil and T cell adhesion to and decreased rolling velocities on activated endothelium, whereas low-dose VEGF-A (10 ng/ml) was without effect. Colonic endothelium constitutively expressed ICAM-1, which was significantly increased by treatment with 50 ng/ml VEGF-A or 10 ng/ml TNF-alpha but not 10 ng/ml VEGF-A. T cells expressed CD18 and CD11a with no expression of CD11b, whereas neutrophils expressed CD18, CD11a, and CD11b. Finally, VEGF-A-dependent leukocyte adhesion was found to occur in a CD18-dependent manner. These results demonstrate that VEGF-A levels found in IBD exert a proinflammatory effect similar to other inflammatory agents and suggest that this cytokine may serve as an intermediary between angiogenic stimulation and cell-mediated immune responses.     

Immune status evaluation of patients with chronic heart failure

Chronic heart failure (CHF) may be considered a state of immune activation and persistent inflammation expressed by increased circulating levels of pro- and anti-inflammatory cytokines. The purpose of the study was to investigate the immune status in patients with CHF compared to normal individuals. We measured serum cytokine levels as well as cytokine production after ex vivo LPS stimulation of whole blood taken from 14 patients with CHF and 14 healthy volunteers. We used 500 pg/ml of LPS for an incubation period of 4h to stimulate 100 microL of whole blood. Patients with CHF had significantly higher levels of TNF-RI, and TNF-RII in serum compared to normal individuals. TNF-alpha, IL-6, and IL-10 did not differ significantly. After LPS stimulation, patients with CHF had significantly higher levels of TNF-alpha and IL-10, and significantly lower IL-6 levels compared to normal individuals. TNF-alpha receptors did not differ significantly. Patients with CHF may be found in a pro- as well as an anti-inflammatory state. They also do not develop endotoxin tolerance in an ex vivo laboratory model using whole blood stimulated with LPS. They may have increased TNF-alpha and IL-10 production after LPS stimulation of whole blood, which may contribute to a worsening of heart function, more severe disease presentation and a worse outcome during infections.     

Studies on the growth of the fetal sheep. Effects of surgical reduction in placental size, or experimental manipulation of uterine blood flow on plasma sulphation promoting activity and on the concentration of insulin-like growth factors I and II

The effect of long- and short-term manipulations of uterine blood flow on fetal plasma levels of IGF-I and -II have been studied in sheep at days 125-139 of pregnancy and compared with those in near term rats and guinea pig. The primary objective is to show that both long- and short-term reduction of uterine blood flow is associated with increase in the fetal plasma concentration of IGF-II while that of IGF-I falls. In the pregnant sheep long-term depression of utero-placental blood flow was caused by surgical reduction in placental mass (carunclectomy) prior to conception. This reduced fetal weight to 2.42 +/- 0.49 kg (SD) compared with 3.41 +/- 0.46 in controls; the respective values for uterine blood flow being 1694 +/- 558 and 913 +/- 324 ml/min respectively. This was associated with a fall in fetal plasma IGF-I concentration from 22.6 +/- 3.4 ng/ml to 14.9 +/- 1.31 ng/ml and a rise in IGF-II from 1952 +/- 284 ng/ml to 3360 +/- 914 ng/ml respectively. Similar changes in the plasma concentrations of IGF peptides were observed in fetal rats and guinea pigs in response to uterine artery ligation. Short-term reduction (60 min) of the uterine blood flow was caused either by compression of the common uterine artery to depress flow from 1491 +/- 375 to 648 +/- 216 ml/min or through intraarterial infusion of adrenaline at 35 ug/min to lower flow from 1628 +/- 339 to 1195 +/- 128 ml/min. Such falls in uterine blood flow had no significant effect on fetal plasma IGF-I levels but increased IGF-II levels by 30 to 60%.     

Surfactant protein D is expressed and modulates inflammatory responses in human coronary artery smooth muscle cells

Surfactant protein D (SP-D) is a constituent of the innate immune system that plays a role in the host defense against lung pathogens and in modulating inflammatory responses. While SP-D has been detected in extrapulmonary tissues, little is known about its expression and function in the vasculature. Immunostaining of human coronary artery tissue sections demonstrated immunoreactive SP-D protein in smooth muscle cells (SMCs) and endothelial cells. SP-D was also detected in isolated human coronary artery SMCs (HCASMCs) by PCR and immunoblot analysis. Treatment of HCASMCs with endotoxin (LPS) stimulated the release of IL-8, a proinflammatory cytokine. This release was inhibited >70% by recombinant SP-D. Overexpression of SP-D by adenoviral-mediated gene transfer in HCASMCs inhibited both LPS- and TNF-alpha-induced IL-8 release. Overexpression of SP-D also enhanced uptake of Chlamydia pneumoniae elementary bodies into HCASMCs while attenuating IL-8 production induced by bacterial exposure. Both LPS and TNF-alpha increased SP-D mRNA levels by five- to eightfold in HCASMCs, suggesting that inflammatory mediators upregulate the expression of SP-D. In conclusion, SP-D is expressed in human coronary arteries and functions as an anti-inflammatory protein in HCASMCs. SP-D may also participate in the host defense against pathogens that invade the vascular wall.     

Inflammation induces mitochondrial dysfunction and dopaminergic neurodegeneration in the nigrostriatal system

Evidence suggests that chronic inflammation, mitochondrial dysfunction, and oxidative stress play significant and perhaps synergistic roles in Parkinson's disease (PD), where the primary pathology is significant loss of the dopaminergic neurons in the substantia nigra. The use of anti-inflammatory drugs for PD treatment has been proposed, and inhibition of cyclo-oxygenase-2 (COX-2) or activation of peroxisome proliferator-activated receptor gamma (PPAR-gamma) yields neuroprotection in MPTP-induced PD. Lipopolysaccharide (LPS) induces inflammation-driven dopaminergic neurodegeneration. We tested the hypothesis that celecoxib (Celebrex, COX-2 inhibitor) or pioglitazone (Actos, PPAR-gamma agonist) will reduce the LPS-induced inflammatory response, spare mitochondrial bioenergetics, and improve nigral dopaminergic neuronal survival. Rats were treated with vehicle, celecoxib, or pioglitazone and were intrastriatally injected with LPS. Inflammation, mitochondrial dysfunction, oxidative stress, decreased dopamine, and nigral dopaminergic neuronal loss were observed post-LPS. Celecoxib and pioglitazone provided neuroprotective properties by decreasing inflammation and restoring mitochondrial function. Pioglitazone also attenuated oxidative stress and partially restored striatal dopamine as well as demonstrated dopaminergic neuroprotection and reduced nigral microglial activation. In summary, intrastriatal LPS served as a model for inflammation-induced dopaminergic neurodegeneration, anti-inflammatory drugs provided protective properties, and pioglitazone or celecoxib may have therapeutic potential for the treatment of neuro-inflammation and PD.     

Hypoxia increases production of interleukin-1 and tumor necrosis factor by human mononuclear cells

Exposure to hypoxia (PO2 = 9 +/- 1 torr) increased human peripheral blood mononuclear cell production and secretion of interleukin-1 (IL-1)alpha, IL-1 beta, and tumor necrosis factor (TNF) percent of control = 190% for IL-1 alpha, p = 0.014; 219% for IL-1 beta, p = 0.014; and 243% for TNF, p = 0.037) following treatment with endotoxin (1 ng/ml). Hypoxia potentiated the increased production of these inflammatory cytokines at subthreshold levels of endotoxin with potentiation increasing at lower O2 concentrations. Hypoxia also increased cytokine production induced by the tumor promoter phorbol myristate acetate, suggesting a generalized biologic response. We conclude that hypoxia increases IL-1 and TNF production and speculate that this mechanism aggravates a variety of pathologic conditions involving endotoxin such as adult respiratory distress syndrome (ARDS), multiple organ failure, and septic shock.