CX3CL1-Fc treatment prevents atherosclerosis in Ldlr KO mice

OBJECTIVE

Atherosclerosis is a major cause of cardiovascular disease. Monocyte-endothelial cell interactions are partly mediated by expression of monocyte CX3CR1 and endothelial cell fractalkine (CX3CL1). Interrupting the interaction between this ligand-receptor pair should reduce monocyte binding to the endothelial wall and reduce atherosclerosis. We sought to reduce atherosclerosis by preventing monocyte-endothelial cell interactions through use of a long-acting CX3CR1 agonist.

METHODS

In this study, the chemokine domain of CX3CL1 was fused to the mouse Fc region to generate a long-acting soluble form of CX3CL1 suitable for chronic studies. CX3CL1-Fc or saline was injected twice a week (30 mg/kg) for 4 months into Ldlr knockout (KO) mice on an atherogenic western diet.

RESULTS

CX3CL1-Fc-treated Ldlr KO mice showed decreased en face aortic lesion surface area and reduced aortic root lesion size with decreased necrotic core area. Flow cytometry analyses of CX3CL1-Fc-treated aortic wall cell digests revealed a decrease in M1-like polarized macrophages and T cells. Moreover, CX3CL1-Fc administration reduced diet-induced atherosclerosis after switching from an atherogenic to a normal chow diet. In vitro monocyte adhesion studies revealed that CX3CL1-Fc treatment caused fewer monocytes to adhere to a human umbilical vein endothelial cell monolayer. Furthermore, a dorsal window chamber model demonstrated that CX3CL1-Fc treatment decreased in vivo leukocyte adhesion and rolling in live capillaries after short-term ischemia-reperfusion.

CONCLUSION

These results indicate that CX3CL1-Fc can inhibit monocyte/endothelial cell adhesion as well as reduce atherosclerosis.

Publisher Correction: Oxidized phospholipids are proinflammatory and proatherogenic in hypercholesterolaemic mice

In this Letter, affiliation number 1 was originally missing from the HTML; the affiliations were missing for author Ming-Yow Hung in the HTML; and the Fig. 4 legend erroneously referred to panels a-h, instead of a-g. These errors have been corrected online.

Oxidized phospholipids are proinflammatory and proatherogenic in hypercholesterolaemic mice

Oxidized phospholipids (OxPL) are ubiquitous, are formed in many inflammatory tissues, including atherosclerotic lesions, and frequently mediate proinflammatory changes ¹ . Because OxPL are mostly the products of non-enzymatic lipid peroxidation, mechanisms to specifically neutralize them are unavailable and their roles in vivo are largely unknown. We previously cloned the IgM natural antibody E06, which binds to the phosphocholine headgroup of OxPL, and blocks the uptake of oxidized low-density lipoprotein (OxLDL) by macrophages and inhibits the proinflammatory properties of OxPL^2-4. Here, to determine the role of OxPL in vivo in the context of atherogenesis, we generated transgenic mice in the Ldlr^-/- background that expressed a single-chain variable fragment of E06 (E06-scFv) using the Apoe promoter. E06-scFv was secreted into the plasma from the liver and macrophages, and achieved sufficient plasma levels to inhibit in vivo macrophage uptake of OxLDL and to prevent OxPL-induced inflammatory signalling. Compared to Ldlr^-/- mice, Ldlr ^-/- E06-scFv mice had 57-28% less atherosclerosis after 4, 7 and even 12 months of 1% high-cholesterol diet. Echocardiographic and histologic evaluation of the aortic valves demonstrated that E06-scFv ameliorated the development of aortic valve gradients and decreased aortic valve calcification. Both cholesterol accumulation and in vivo uptake of OxLDL were decreased in peritoneal macrophages, and both peritoneal and aortic macrophages had a decreased inflammatory phenotype. Serum amyloid A was decreased by 32%, indicating decreased systemic inflammation, and hepatic steatosis and inflammation were also decreased. Finally, the E06-scFv prolonged life as measured over 15 months. Because the E06-scFv lacks the functional effects of an intact antibody other than the ability to bind OxPL and inhibit OxLDL uptake in macrophages, these data support a major proatherogenic role of OxLDL and demonstrate that OxPL are proinflammatory and proatherogenic, which E06 counteracts in vivo. These studies suggest that therapies inactivating OxPL may be beneficial for reducing generalized inflammation, including the progression of atherosclerosis, aortic stenosis and hepatic steatosis.

Abstract 361: Oxidized Phospholipids Are Proinflammatory and Proatherogenic

Oxidized phospholipids (OxPL) are ubiquitously generated during inflammation, and found on apoptotic cells, OxLDL, and Lp(a). They facilitate uptake of OxLDL by macrophages (Mac) and mediate cellular inflammatory responses. The E06 natural IgM binds to the PC of OxPL, neutralizing biological effects and inhibiting OxLDL uptake by Mac. To determine the role of OxPL in atherogenesis, we generated transgenic mice expressing a single chain variant (scFv) of E06 in Ldlr background (E06-Tg). E06-scFv was secreted into plasma, bound to OxLDL and had sufficient titer to inhibit OxLDL uptake into Mac. E06-Tg or Ldlr mice were fed 1% Chol diet for 4, 7 or 12 months (n=12-15 mice/group). Plasma Chol was ~ 1600 mg/dL in all mice. Atherosclerosis decreased in E06-Tg mice: En face lesions decreased 57%, 34% and 28%, and aortic root lesions decreased 55%, 41% and 26% at 4, 7 and 12-months, respectively. OxLDL uptake by Macs was decreased: Thus, in E06-Tg mice, the uptake by peritoneal Mac of fluorescently-labeled OxLDL injected ip was decreased ~ 50%, as was peritoneal Mac Chol content. As Macs secrete E06-scFv, we performed BMT from E06-Tg donors into irradiated Ldlr recipients (n=10-12): This also decreased lesions 31% compared to BMT from control donors, even though plasma titers of E06-scFv were ~10% of Tg mice. Overexpression of E06-scFv was anti-inflammatory: Thus, in E06-Tg mice, both peritoneal and aortic wall resident macrophages exhibited decreased inflammatory gene expression, and phenotypic switches from M1 to M2 analyzed by RNAseq and FACS. Further, in E06-Tg mice, plasma SAA levels were reduced 32%, and hepatic steatosis was also decreased (-50% in both TG and Chol), as was hepatic inflammatory gene expression. Finally, E06-scFv attenuated both a progressive increase in aortic valve gradient (via echocardiography) and calcification in aged Ldlr mice. The E06-scFv lacks functional effects of an intact antibody other than the ability to “neutralize” OxPL. Thus, these data demonstrate that OxPL are profoundly proatherogenic and proinflammatory, which E06 counteracts in vivo . Neutralizing OxPL may therefore reduce the progression of atherosclerosis and cardiovascular events and more generally, represents a novel strategy to safely attenuate inflammation.

Intermittent hypoxia and hypercapnia induce pulmonary artery atherosclerosis and ventricular dysfunction in low density lipoprotein receptor deficient mice

Patients with obstructive sleep apnea, who experience episodic hypoxia and hypercapnia during sleep, often demonstrate increased inflammation, oxidative stress, and dyslipidemia. We hypothesized that sleep apnea patients would be predisposed to the development of atherosclerosis. To dissect the mechanisms involved, we developed an animal model in mice whereby we expose mice to intermittent hypoxia/hypercapnia (IHH) in normobaric environments. Two- to three-month-old low-density lipoprotein receptor deficient (Ldlr(-/-)) mice were fed a high-fat diet for 8 or 16 wk while being exposed to IHH for either 10 h/day or 24 h/day. Plasma lipid levels, pulmonary artery and aortic atherosclerotic lesions, and cardiac function were then assayed. Surprisingly, atherosclerosis in the aorta of IHH mice was similar compared with controls. However, in IHH mice, atherosclerosis was markedly increased in the trunk and proximal branches of the pulmonary artery of exposed mice; even though plasma cholesterol and triglycerides were lower than in controls. Hemodynamic analysis revealed that right ventricular maximum pressure and isovolumic relaxation constant were significantly increased in IHH exposed mice and left ventricular % fractional shortening was reduced. In conclusion, 1) Intermittent hypoxia/hypercapnia remarkably accelerated atherosclerotic lesions in the pulmonary artery of Ldlr(-/-) mice and 2) increased lesion formation in the pulmonary artery was associated with right and left ventricular dysfunction. These findings raise the possibility that patients with obstructive sleep apnea may be susceptible to atherosclerotic disease in the pulmonary vasculature, an observation that has not been previously recognized.

Verkürzte Inspirationszeit während der Beatmung eines ungeschützten Atemweges

BACKGROUND

In an unprotected airway during cardiopulmonary resuscitation, two ventilations with an inspiratory time of 2 s after 15 chest compressions are recommended. Therefore, approximately 30% of the resuscitation attempt is spent on ventilation. Since survival rates did not decrease sharply when minute ventilation levels were relatively low, and uninterrupted chest compressions with a constant rate of approximately 100/min have been shown to be lifesaving, it may be beneficial to decrease the time spent on ventilation and instead, increase the time for chest compressions.

METHODS

In an established bench model of a simulated, unprotected airway with increased airway resistance, we evaluated if inspiratory time can be decreased from 2 to 1 s at different lower oesophageal sphincter pressure (LOSP) levels during ventilation with a bag-valve-mask device.

RESULTS

An inspiratory time of 2 vs. 1 s resulted in significantly lower peak airway pressure, while lung tidal volume was significantly higher at an inspiratory time of 2 s and a LOSP of 5 cm H(2)O (480+/-20 vs. 380+/-30 ml) and 10 cm H(2)O (630+/-50 vs. 440+/-20 ml) and significantly lower at a LOSP of 15 cm H(2)O (470+/-70 vs. 540+/-20 ml). While neither ventilation strategy produced stomach inflation at 20 cm H(2)O LOSP, 1 vs. 2 s inspiratory time produced significantly higher stomach inflation at 15 cm H(2)O LOSP (8+/-11 vs. 0 ml) and significantly lower stomach inflation at a LOSP of 5 cm H(2)O (359+/-31 vs. 375+/-29 ml) and 10 cm H(2)O (28+/-13 vs. 36+/-12 ml) per breath.

CONCLUSION

In this model of a simulated, unprotected airway, a reduction of inspiratory time from 2 to 1 s resulted in a significant increase of peak airway pressure, while lung tidal volumes and stomach inflation volumes were statistically different but clinically comparable.

Intravenous immunoglobulin (IVIg) for therapy-resistant cutaneous lupus erythematosus (LE)

BACKGROUND

A group of patients exists with predominantly cutaneous lupus erythematosus (LE) who do not respond to standard oral therapies. There has been interest in the role of intravenous immunoglobulin (IVIg) in a number of connective tissue diseases, and its role in some circumstances has been proven. In the case of LE, there are suggestions that the use of IVIg for cutaneous and more systemic disease may be of value.

OBJECTIVE

To investigate the use of low dose IVIg for therapy-resistant cutaneous disease.

METHODS

Twelve patients with histologically confirmed cutaneous LE were given IVIg, with starting doses of 1 g/kgx2, followed by 400 mg/kg monthly until disease resolution or for 6 months. Disease assessment was by scoring erythema, induration, scaling and the extent before and at the end of therapy. Immunological parameters indicating systemic disease activity were measured before and after therapy.

RESULTS

One patient became pregnant, five patients had complete or near complete clearing of their skin disease (>75%), two had partial but helpful improvement (>50%) and three had limited responses (<50%). One patient developed acute cutaneous vasculitis and received no further therapy.

CONCLUSION

Overall, therapy was well tolerated and side effects were limited. A formal study of IVIg for cutaneous disease would be valuable, but evidence indicates that IVIg may be a useful therapy for cutaneous disease in lupus erythematosus.

Long-term effect of sodium hyaluronate (Hyalgan) on osteoarthritis progression in a rabbit model

BACKGROUND

Intra-articular (IA) hyaluronan (HA) injections are approved for the treatment of knee osteoarthritis (OA) pain. One of the currently available products is approved for repeat treatment courses. While HA is classed as a symptom-modifying agent, there is substantial evidence that this therapeutic modality also possesses disease-modifying activity.

OBJECTIVE

A rabbit model of OA, anterior cruciate ligament transection (ACLT), was used to investigate the long-term effects of single and sequential courses of HA therapy on OA progression.

DESIGN

One or two courses of five weekly IA injections of sodium hyaluronate (Hyalgan) average molecular weight, MW, of 500-730 kDa, or vehicle were administered to rabbits (N=10 per group), initiated 4 and 13 weeks (for groups that received a second course) after ACLT. Gross morphological and histomorphometric evaluations were performed on harvested knee joints following sacrifice at 26 weeks after surgery.

RESULTS

All the rabbits exhibited the characteristic pathologic changes of OA. Rabbits that received one or two courses of HA injections showed less disease progression than rabbits treated with ACLT alone or with 10 vehicle injections. However, rabbits that received five vehicle injections also showed improved morphology compared with those given no injections. Rabbits that received 10 HA injections showed significantly less surface roughness of the femoral cartilage compared with rabbits treated with ACLT, 5 HA injections, or 10 vehicle injections, and showed significantly less surface roughness of the tibial plateau compared with all other treatment groups (P<0.05).

CONCLUSIONS

Repeat courses of HA injections reduced the degree of articular degeneration in a rabbit ACLT model of OA. Sequential courses of HA therapy may be advantageous in the long-term management of OA.

The provision of clinical psychology services within a general hospital: an analysis and interpretation of referral rates

A semi-structured interview was administered to fifteen hospital based medical and surgical consultants. This aimed to assess the level of knowledge and understanding regarding the activities of clinical psychologists and to evaluate the perception of need for the clinical psychology service within a general hospital in Central Scotland. Differences between high/regular and occasional/non-referring departments were examined. Results indicated that high/regular referring departments displayed a greater level of knowledge and understanding of clinical psychology practice than occasional/non-referring departments. The occasional/non-referring departments demonstrated more cautious attitudes regarding psychological input to the care of patients than high/regular referring departments. This study suggests that lower referral rates were more likely to be a result of generally low levels of awareness and understanding of psychological issues rather than mistrust of psychological methods. This highlights the need for education about the role of clinical psychology in general hospitals and improved communication between the psychology service and other departments in the hospital.

Managing up to maximize medicare reimbursement for outpatient care

An example of managing up through participation in a multidisciplinary team tasked with maximizing reimbursement under the Medicare ambulatory patient classification (APC) system is described. Medicare's new system of payment for hospital outpatient services replaces the cost-based reimbursement model of the past with a technical payment based on the outpatient evaluation and management level. Individual institutions are responsible for developing criteria for defining technical visit levels. Managers at the New England Medical Center formed a team to develop these criteria. The team outlined components of the patient visit that qualified as technical costs, such as the use of space at a facility, medical and surgical supplies, and nonphysician professional services. Team members then contacted each of the center's clinics to identify specific services that met these criteria. After formulating the technical visit level criteria, the team determined who would assign the technical visit level, wrote policies and procedures, and trained staff. The APC team also assessed billing procedures, focusing particularly on the accuracy of the charge master and the use of proper codes and billing units for pass-through drugs. The team continues to monitor its results by reviewing payments received from Medicare and auditing high-risk areas. The APC team used the principles of managing up to maximize Medicare reimbursement for outpatient visits.

An immortalized myocyte cell line, HL-1, expresses a functional delta -opioid receptor

The present study characterizes opioid receptors in an immortalized myocyte cell line, HL-1. Displacement of [(3)H]bremazocine by selective ligands for the mu (mu), delta (delta), and kappa (kappa) receptors revealed that only the delta -selective ligands could fully displace specific [(3)H]bremazocine binding, indicating the presence of only the delta -receptor in these cells. Saturation binding studies with the delta -antagonist naltrindole afforded a B(max)of 32 fmols/mg protein and a K(D)value for [(3)H]naltrindole of 0.46 n M. The binding affinities of various delta ligands for the receptor in HL-1 cell membranes obtained from competition binding assays were similar to those obtained using membranes from a neuroblastomaxglioma cell line, NG108-15. Finally, various delta -agonists were found to stimulate the binding of [(35)S]GTP gamma S, confirming coupling of the cardiac delta -receptor to G-protein. DADLE (D-Ala-D-Leu-enkephalin) was found to be the most efficacious in this assay, stimulating the binding of [(35)S]GTP gamma S to 27% above basal level. The above results indicate that the HL-1 cell line contains a functionally coupled delta -opioid receptor and therefore provides an in vitro model by which to study the direct effects of opioids on cardiac opioid receptors.

Prodrugs. Part 3. 2-Formylphenyl esters of indomethacin, ketoprofen and ibuprofen and 6-substituted 2-formyl and 2-acylphenyl esters of aspirin

The synthesis and study of a novel series of potential prodrugs of indomethacin, ketoprofen, ibuprofen and aspirin are reported. 2-Formylphenyl esters of the NSAIDs, together with two 6-substituted 2-formyl and two 2-acylphenyl aspirins and 4-formylphenyl indomethacin, have been prepared. A study of their alkaline and neutral hydrolysis shows that these compounds, with the exception of 2-acetylphenyl aspirin, act as true prodrugs of the NSAIDs, giving the NSAID and acylphenol. The rates of hydrolysis and activation parameters indicate that the 2-acylphenyl esters employ an intramolecular catalytic route. The 2-formylphenyl esters were more potent as anti-inflammatory agents than the parent compounds in the carragheenan-induced paw oedema test.

Structure-activity relationships of dihydrofolate reductase inhibitors

Structure-activity relationships of antibacterial dihydrofolate reductase inhibitors are reviewed. A short introduction is followed by a more detailed review of developments since 1980. The design of site directed inhibitors based on data from X-ray crystallographic, NMR spectroscopy and molecular graphic studies is discussed. The development of quantitative structure-activity relations is surveyed from a historical point of view and these are contrasted with more recent alternative approaches. Conclusions are reached regarding possible future developments.

The ligamentization process: a 4 year case study following ACL reconstruction with a semitendinosis graft

This study evaluates the histological and biochemical changes that occurred in a semitendinosis autograft 4 years after intraarticular placement as an anterior cruciate ligament (ACL) substitute in a human patient. The graft was harvested during total knee replacement. Comparison to harvested ACL and hamstring tendon was made. Changes in collagen crimp pattern, cell type, glycosaminoglycan composition, and collagen crosslinking were present between the ACL autograft and the hamstring tendon. The appearance and biochemical properties of the semitendinosis autograft and the native ACL were similar 4 years following intraarticular placement. These observed phenomena could be attributed to functional adaptation, supporting the concept of ligamentization.

Antifolate and antibacterial activities of 5-substituted 2,4-diaminoquinazolines

A series of 5-substituted 2,4-diaminoquinazolines (3) has been synthesized and evaluated as inhibitors of the enzyme dihydrofolate reductase (DHFR) from both bacterial and mammalian sources. The best compounds (e.g. 53) show good activity against Escherichia coli DHFR, but there is no significant selectivity for the bacterial over the mammalian enzyme. The structure-activity relationships for enzyme inhibition appear to be complex and not amenable to simple analysis; a hypothesis to explain the observed qualitative structure-activity relationships is proposed. The inhibitory activities of the compounds against the growth of intact bacterial cells in vitro closely parallel those for the inhibition of the isolated bacterial enzymes, suggesting that their antifolate action is responsible for their antibacterial effects. Five of the compounds were tested for their ability to cure a systemic E. coli infection in the mouse, but they showed no therapeutic effects at their maximum tolerated doses.

Interactions between inhibitors of dihydrofolate reductase

The binding of substrates and inhibitors to dihydrofolate reductase was studied by steady-state kinetics and high-field 1H-n.m.r. spectroscopy. A series of 5-substituted 2,4-diaminopyrimidines were examined and were found to be 'tightly binding' inhibitors of the enzyme (Ki less than 10(-9) M). Studies on the binding of 4-substituted benzenesulphonamides and benzenesulphonic acids also established the existence of a 'sulphonamide-binding site' on the enzyme. Subsequent n.m.r. experiments showed that there are two binding sites for the sulphonamides on the enzyme, one of which overlaps the coenzyme (NADPH) adenine-ring-binding site. An examination of the pH-dependence of the binding of sulphonamides to the enzyme indicated the influence of an ionizable group on the enzyme that was not directly involved in the sulphonamide binding. The change in pKa value from 6.7 to 7.2 observed on sulphonamide binding suggests the involvement of a histidine residue, which could be histidine-28.