Prophylactic cefazolin concentrations in morbidly obese patients undergoing sleeve gastrectomy: do we achieve targets?

Morbid obesity is known to increase the risk of surgical site infections. Optimal concentrations of prophylactic antibacterial drugs are required. Using Monte Carlo simulations, the aim of this work was to build a population pharmacokinetics model for a morbidly obese population to assess a 4000-mg dose of cefazolin recommended by the guidelines and to propose new administration schemes. One hundred and seventeen morbidly obese patients (mean body mass index, 46.95 kg/m2) received 4000 mg of cefazolin intravenously before sleeve gastrectomy. Using population pharmacokinetics modelling and Monte Carlo simulations, probabilities of target attainment (PTAs) (subcutaneous tissue concentration of cefazolin above the minimum inhibitory concentration (MIC) throughout the surgical procedure was targeted) were determined. For Staphylococcus spp. and Streptococcus spp., which are the most frequent species isolated from post-surgical infections in bariatric surgery (MIC usually ≤2 mg/L), PTA remains greater than 0.9 until 2 h after administration of 4000 mg of cefazolin. For MIC up to 4 mg/L, efficient prophylaxis was checked until 1 h after the initial administration. A 3000-mg regimen followed by a continuous infusion (1000 mg/h) achieves these two targets until 4 h after the loading dose. A 2000-mg and a 3000-mg regimen do not achieve sufficient concentrations. According to the duration of surgery and MIC values, an initial administration of 4000 mg should be sufficient, but for extended surgeries continuous infusion can be considered.

Once versus twice daily injection of enoxaparin for thromboprophylaxis in bariatric surgery: effects on antifactor Xa activity and procoagulant microparticles. A randomized controlled study.

BACKGROUND: The optimal scheme of thromboprophylaxis in bariatric surgery remains uncertain, because clinical practice is different between countries and randomized trials are lacking. OBJECTIVES: The primary objective of this randomized multicenter study was to determine the optimal regimen of enoxaparin providing an antifactor Xa peak activity between .3 and .5 IU/mL at equilibrium and to evaluate the course of procoagulant microparticles (MPs). SETTING: University hospital. METHODS: A total of 164 patients scheduled for gastric bypass were allocated to 3 groups (A, B, and C) of enoxaparin treatment (4000, 6000, or 2×4000 IU, respectively). Antifactor Xa activity was measured before and 4 hours after each injection from D0 to D2. Doppler screening of the lower limbs was performed at D1, D9, and D30. Bleeding (BE) and thrombotic events (TE) were recorded during the first postoperative month. Total MPs were measured at D0, D9, and D30. MPs of leucocyte, platelet, and granulocyte origin were assessed in one third of the patients from each group. The 3 groups were compared by ANOVA. RESULTS: A total of 135 patients were analyzed. The equilibrium of antifactor Xa peak levels was obtained 52 hours after the presurgery injection and 12.8%, 56.4%, and 27.3% of the patients reached the target in groups A, B, and C, respectively (P<.001). No TE was detected. BE occurred in 1, 2, and 6 patients in groups A, B, and C, respectively). Total MPs remained unchanged over time. While no significant variation was observed in the other groups, platelet GP1 b(+)-MPs increased (P = .01) at D9 in group C, suggesting an incomplete control of anticoagulation leading to cell activation and procoagulant MP release that was confirmed by the higher MP levels measured at D30 (P = .04). CD66(+)-MPs were also highly elevated at J9 and D30 in group C indicating a granulocyte contribution. CONCLUSIONS: This study shows that a single dose of enoxaparin 6000 IU/d allowed most of the patients to reach the target range of antifactor Xa activity without increasing the bleeding risk, with the most likely efficient reduction of procoagulant MPs. (Surg Obes Relat Dis 2015;0:000-000.) © 2015 American Society for Metabolic and Bariatric Surgery. All rights reserved.

Laparoscopic Gastric Banding in Obese Patients with Sleep Apnea: A 3-Year Controlled Study and Follow-up After 10 Years.

BACKGROUND: The purpose of this study was to compare the effects of intensive nutritional care (INC) and laparoscopic adjustable gastric banding (LAGB) on nocturnal non-invasive ventilation (NIV) requirement in obese patients using short-, medium-, and long-term follow-up data. METHODS: This prospective randomized controlled trial included obese patients with obstructive sleep apnea (OSA) treated by NIV. Patients were randomized to the INC and LAGB groups. The primary endpoint was the theoretical rate of weaning from NIV at years 1 and 3. Data were also collected from patients 10 years after randomization. RESULTS: Sixty-three patients were randomized. The rate of weaning from NIV did not differ significantly between the LAGB and INC groups at year 1 (35 vs. 13%) or year 3 (14 vs. 21%). Percentages of excess weight loss were greater in the LAGB group than in the INC group at years 1 (33 vs. 15%, p = 0.002) and 3 (27 vs. 8%, p = 0.014). Decreases in the apnea-hypopnea index were observed in the LAGB group from baseline to year 1 (-44%, p = 0.001) and from baseline to year 3 (-26%, p = 0.044). After 10 years, the weaning rate was low and similar between groups. CONCLUSION: LAGB was not superior to INC for weaning from NIV at 1 and 3 years in obese patients with OSA.

Transintestinal cholesterol excretion is an active metabolic process modulated by PCSK9 and statin involving ABCB1.

OBJECTIVE: Transintestinal cholesterol excretion (TICE) is an alternate pathway to hepatobiliary secretion. Our study aimed at identifying molecular mechanisms of TICE. APPROACH AND RESULTS: We studied TICE ex vivo in mouse and human intestinal explants, and in vivo after bile diversion and intestinal cannulation in mice. We provide the first evidence that both low-density lipoprotein (LDL) and high-density lipoprotein deliver cholesterol for TICE in human and mouse jejunal explants at the basolateral side. Proprotein convertase subtilisin kexin type 9 (PCSK9)(-/-) mice and intestinal explants show increased LDL-TICE, and acute injection of PCSK9 decreases TICE in vivo, suggesting that PCSK9 is a repressor of TICE. The acute repression was dependent on the LDL receptor (LDLR). Further, TICE was increased when mice were treated with lovastatin. These data point to an important role for LDLR in TICE. However, LDLR(-/-) mice showed increased intestinal LDL uptake, contrary to what is observed in the liver, and tended to have higher TICE. We interpret these data to suggest that there might be at least 2 mechanisms contributing to TICE; 1 involving LDL receptors and other unidentified mechanisms. Acute modulation of LDLR affects TICE, but chronic deficiency is compensated for most likely by the upregulation of the unknown mechanisms. Using mice deficient for apical multidrug active transporter ATP-binding cassette transporter B1 a and b, and its inhibitor, we show that these apical transporters contribute significantly to TICE. CONCLUSIONS: TICE is operative in human jejunal explants. It is a metabolically active process that can be acutely regulated, inversely related to cholesterolemia, and pharmacologically activated by statins.

Endoscopic removal of a migrating polyester band using argon plasma coagulation.

A case is reported of a 40-year-old woman with a past history of bariatric surgery with vertical banding gastroplasty. Migrating band was observed during upper GI endoscopy performed for pyrosis. Before undergoing another bariatric intervention, migrated band had to be removed. This procedure was successfully performed endoscopically using argon plasma coagulation. No complication occurred. This case highlights that migrated band could be easily and safely removed without the need of specific or dedicated endoscopic tool.

Characterisation of early mucosal and neuronal lesions following Shigella flexneri infection in human colon.

BACKGROUND: Shigella, an enteroinvasive bacteria induces a major inflammatory response responsible for acute rectocolitis in humans. However, early effect of Shigella flexneri (S. flexneri) infection upon the human mucosa and its microenvironement, in particular the enteric nervous system, remains currently unknown. Therefore, in this study, we sought to characterize ex vivo the early events of shigellosis in a model of human colonic explants. In particular, we aimed at identifying factors produced by S. flexneri and responsible for the lesions of the barrier. We also aimed at determining the putative lesions of the enteric nervous system induced by S. flexneri. METHODOLOGY/PRINCIPAL FINDINGS: We first showed that, following 3 h of infection, the invasive but not the non-invasive strain of S. flexneri induced significant desquamation of the intestinal epithelial barrier and a reduction of epithelial height. These changes were significantly reduced following infection with SepA deficient S. flexneri strains. Secondly, S. flexneri induced rapid neuronal morphological alterations suggestive of cell death in enteric submucosal neurones. These alterations were associated with a significant increase in the proportion of vasoactive intestinal peptide (VIP) immunoreactive (IR) neurons but not in total VIP levels. The NMDA receptor antagonist MK-801 blocked neuronal morphological changes induced by S. flexneri, but not the increase in the proportion of VIP-IR. CONCLUSIONS/SIGNIFICANCE: This human explant model can be used to gain better insight into the early pathogenic events following S. flexneri infection and the mechanisms involved.

The effect of immunoglobulin immunadsorptions on delayed xenograft rejection of human CD55 transgenic pig kidneys in baboons.

Delayed xenograft rejection (DXR) remains a major obstacle in discordant xenotransplantation. As strategies of complement inhibition and xenogeneic natural antibody (Ab) removal have been shown to give prolonged xenograft survival, we endeavored to determine whether combining these two strategies would lead to an additive effect in terms of graft survival. The study was initiated with two groups, A and B, where group A received normal kidneys and group B received hCD55 transgenic kidneys. Both groups underwent pre-transplant (day-1) total immunoglobulin (Ig) immunoadsorption (IA) and received an immunosuppression of cyclophosphamide, cyclosporine A, mycophenolate mofetil and corticosteroids. Two subsequent groups (C and D) receiving hCD55 transgenic pig kidneys were then performed with an 'optimized' immunosuppression (Cyclophosphamide starting 1 day earlier) but only group D recipients were immunoadsorbed. Biopsies taken during the post-transplantation period were analyzed for Ab deposition, compliment activation and cellular infiltration. No hyperacute rejection was observed. In the initial immunoadsorbed groups A and B, all baboons underwent DXR, which started surprisingly early (day 5 in most cases. In the subsequent two groups, the immunoadsorbed group D baboons also underwent DXR, again as early as day 5. In contrast, group C baboons did not show any signs of DXR on their day 6 biopsy or at their time of death. Analysis of graft biopsies from the kidneys undergoing rejection or with stable function showed strong deposition of anti-Gal IgM in all cases whereas strong complement C5b-9 deposits were only observed in biopsies at rejection. Cellular infiltration consisted mostly of monocytes/macrophages, was more pronounced in biopsies taken at rejection and was associated with a pro-inflammatory environment involving interleukins 1alpha, 6 and 8. Our findings suggest non-specific Ig (anti-Gal and non-Gal Ig of all isotypes) IA or even incomplete IA in immunosuppressed baboon recipients of transgenic pig kidneys is detrimental to graft survival by being associated with an Ab and compliment driven rejection. We speculate that the IA were insufficient in terms of Ig depletion or frequency inducing an Ab rebound or that this total Ig depletion also removed components facilitating graft survival.

Rapid failure of pig islet transplantation in non human primates.

We have previously demonstrated that adult pig islets of Langerhans are not destroyed in vitro by primate sera. Whether these islets can function when placed into the liver of non-human primates is not known. We now report on the outcome of pig islet xenotransplantation into five non diabetic primates (four baboons and one macacus fascicularis) receiving intraportally purified adult pig islets. The average number of islet-equivalent per graft was 110,000 (60-180,000). All animals received associations of ATG, cyclosporine or LF 195 (a deoxyspergualin analog), mycophenolate mofetil and corticosteroids. A specific porcine C-peptide (C-pep) RIA test was used to monitor insulin secretion. Two hours after grafting, porcine C-peptide was positive (from 0.37 to 4.25 ng/ml) in all monkeys except one. Primate C-pep was normal in all cases. Only two monkeys had detectable levels of porcine C-pep on day 1 or 2 with undetectable levels thereafter, even after glucagon challenge between days 6 and 10. Several normal islets with moderate inflammatory infiltration were observed in one animal liver on day 2 (the time of necropsy) as well as islets with IgM and complement deposition. Among animals sacrificed on days 14, 16 and 38, some residual islet cells could be identified only in livers collected on day 14. Partial glycaemic control was achieved in some rats receiving islets from the same preparations. In conclusion, adult pig islets are not able to maintain insulin secretion for more than 24 h when injected intraportally into non diabetic immunosuppressed monkeys. suggesting immediate islet xenograft destruction.