Charles Laurent

Charles Laurent, Ph.D., Director, In Vivo Pharmacology.

Charles earned his B.Sc. in Biochemistry at the Université du Québec à Montréal, his M.Sc. in Pharmacology and his Ph.D. in Pharmacology with Cardiovascular Applications at the Université de Montréal. He completed four years of post-doc studies in Molecular Biology at the University of Pittsburgh Medical Center.

“I like designing new projects for clients with special needs – validating each protocol to reflect the specific requirements of their projects.”

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Articles:

Dual antiplatelet and anticoagulant APAC prevents experimental ischemia–reperfusion-induced acute kidney injury

  • Raimo Tuuminen Affiliated with Transplantation Laboratory Haartman Institute, University of HelsinkiDepartment of Cardiothoracic Surgery, Helsinki University Hospital
  • Annukka Jouppila Affiliated with Helsinki University Hospital Research Institute
  • Dan Salvail Affiliated with IPS Therapeutique
  • Charles-E. Laurent Affiliated with IPS Therapeutique
  • Marie-Claude Benoit Affiliated with IPS Therapeutique
  • Simo Syrjälä Affiliated with Transplantation Laboratory Haartman Institute, University of HelsinkiDepartment of Cardiothoracic Surgery, Helsinki University Hospital
  • Heikki Helin Affiliated with Division of Pathology, HUSLAB and Helsinki University Hospital
  • Karl Lemström Affiliated with Transplantation Laboratory Haartman Institute, University of HelsinkiDepartment of Cardiothoracic Surgery, Helsinki University Hospital

The article – in its entirety – is available online at: http://link.springer.com/article/10.1007/s10157-016-1308-2

Background

Renal ischemia–reperfusion predisposes to acute kidney injury (AKI) and mortality. APAC, mast cell heparin proteoglycan mimetic is a potent dual antiplatelet and anticoagulant inhibiting thrombosis in several vascular models.

Methods

Clinically relevant (0.06 and 0.13 mg/kg) and high (0.32 and 7.3 mg/kg) heparin doses of APAC and unfractionated heparin (UFH) were administered i.v. in pharmacological studies. Antithrombotic action of APAC and UFH was assessed with platelet aggregation to collagen, activated partial thromboplastin (APTT) and prothrombin (PT) times. Pharmacodynamics of [64Cu]-APAC or -UFH were monitored by PET/CT. Next, APAC and UFH doses (0.06 and 0.13 mg/kg) were i.v. administered 10 min prior to renal ischemia–reperfusion injury (IRI) in rats.

Results

APAC in contrast to UFH inhibited platelet aggregation. During 0.06 and 0.13 mg/kg dose regimens APTT and PT remained at baseline, but at the high APTT prolonged fourfold to sixfold. Overall bio-distribution and clearance of APAC and UFH were similar. After bilateral 30-min renal artery clamping, creatinine, urea nitrogen and neutrophil gelatinase-associated lipocalin concentrations and histopathology indicated faster renal recovery by APAC (0.13 mg/kg). APAC, unlike UFH, prevented expression of innate immune ligand hyaluronan and tubulointerstitial injury marker Kim-1. Moreover, in severe bilateral 1-h renal artery clamping, APAC (0.13 mg/kg) prevented AKI, as demonstrated both by biomarkers and survival. Compatible with kidney protection APAC reduced the circulating levels of vascular destabilizing and pro-inflammatory angiopoietin-2 and syndecan-1. No tissue bleeding ensued.

Conclusion

APAC and UFH were similarly eliminated via kidneys and liver. In contrast to UFH, APAC (0.13 mg/kg) was reno-protective in moderate and even severe IRI by attenuating vascular injury and innate immune activation.

Keywords

Ischemia–reperfusion injury Acute kidney injury Unfractionated heparin APAC


Laurent C-E, Dupre E and Salvail D IPS Therapeutique, Sherbrooke, Canada. Journal of Thrombosis and Haemostasis, Special Issue: Abstracts of the 62nd Annual Meeting of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis May 25–28, 2016, 14 (Suppl. 1) (2016) 1–168.

Background: Activated factor XI (FXIa) has been identified as the probable causative agent associated with thromboembolic events (TEE) following intravenous (IV) IgG (IVIG) product administration. Although there is no official method required by the regulator to validate the therapeutic safety of new batches of IVIG, the rabbit venous stasis assay, a prothrombogenic model, remains the model of choice for in vivo assessment of potential TEE.

Aims: This study aimed at standardizing the in vivo venous stasis rabbit model and quantifying the formed thrombi on a ranking system to evaluate the amount of FXIa in new batches of IVIG, in order to predict potential TEE. Methods: Anesthetized rabbits (2.5 to 3 kg) were infused with 10 ml/kg of 200 mM glycine, 5% BSA (Gycine-BSA) solution spiked with increasing doses of FXIa followed by a jugular venous stasis of 2-cm long for 15-min. The formed thrombus was scored according to a ranking system from 0 to 4.

Results: Spiked Glycine-BSA solution with 4 increasing doses of FXIa (0, 1, 1.5, 2 and 7 mU/mL) showed a dose-dependent clot formation response of 0, 0.5, 1.0, 2.33, and 3.75 respectively. The IVIG Gamunex and spiked Gamunex with 1.5 mU/mL of FXIa scored 0.8 and 3.5 respectively. Concomitantly, the bleeding time in rabbits treated with the spiked Glycine-BSA decreased from 220 s to 130 s with increasing doses of FXIa.

Conclusions: The current study demonstrates that the standardized venous stasis rabbit model is very sensitive to FXIa and that the thrombus score correlates with the amount of FXIa present in the test solution. Furthermore, this standardized model can be used to predict the potential for a TEE in batches of IVIG.


Pharmacokinetics and pharmacodynamics of APAC, a dual novel anticoagulant and antiplatelet heparin complex.

Jouppila Annukka, MSc, Marie-Claude Benoit, Charles Laurent, Dany Salvail, Lassila Riitta, MD, PhD. Helsinki University Central Hospital and Aplagon, Helsinki Finland, and IPS Therapeutique, Sherbrooke, Quebec. Presented at the XXV Congress of the International Society on Thrombosis and Haemostatis & 61st Annual SSC Meeting, June 20-25, 2015 in Toronto, Ontario.

Keywords. APAC2, UFH, antiplatelet, anticoagulant.

Background. APAC2 heparin-protein complex is inspired by mast cell-derived heparin proteoglycans which attenuate platelet-collagen interactions under blood flow and reduce platelet thrombosis. In addition of inhibiting platelets APAC2 is an anticoagulant and arrests thrombus growth in two arterial baboon models (Lassila and Jouppila, STH 2014).. Upon local administration APAC2 targets and remains at vascular injury site. In vitro, APAC2 inhibits collagen-induced platelet aggregation and procoagulant activity in CAT.

Aim. To study the pharmacokinetics (PK) and pharmacodynamics of APAC2 in rats.

Methods. Male Sprague-Dawley rats were dosed APAC2 or UFH at 0.13 or 7.3 mg/Kg. Blood samples were drawn pre- and post-dose (PD) at 60min, 90min, 6h, 24h and 48h for APTT and PT analysis. Distribution and retention were studied with 64Cu-labeled APAC2 or UFH and measured by gamma counter and corrected for 64Cu decay. Two rats per dose were scanned by PET. At 48h rats were euthanized and kidneys, liver, lungs and spleen harvested for 64Cu radioactivity.

Results. At both 0.13 and 7.3 mg/Kg (15-fold above target dose), APAC2 and UFH were mainly distributed to kidneys and liver and lesser extent to other organs or blood. APAC2 clearance (T1/2) was rapid, 15 min at 0.13 mg/Kg and 1 h at 7.3 mg/Kg while UFH T1/2 was 23-28 min at both doses. At 0.13 mg/Kg, APAC2 or UFH had no effect on APTT, but both prolonged APTT dose dependently and at 7,3 mg/Kg by 6- and 4-fold, respectively. APAC2 and UFH prolonged PT by only 1.5-fold at 7.3 mg/Kg. At the highest dose APTT remained elevated at 90min while PT reverted. Controlled at 6h APTT and PT were normal.

Conclusions. APAC2 and UFHwere mainly detected in kidney and liver following the heparin elimination route. APAC2 had 2.5-fold clearance time over UFH suggesting some retention.APAC2 prolonged APTT, while PT only modestly elevated referring to minimal role on extrinsic pathway. The PK profile of APAC2 appears beneficial.

Click on the link to download the .pdf file – jouppila et al isth 2015 (2)


Pulmonary Arterial Hypertension is Insulin-Dependent in Type-1 and Type-2 Diabetic Rats.

C.-E. Laurent, Ph.D.; M.-C. Benoit, DEC animal health; S. Baillargeon, DEC animal health; D. Salvail, Ph.D., Sherbrooke QC. Presented at the American Thoracic Society International Conference in Denver CO on Sunday, May 17 2015.

RATIONALE: Clinical evidence suggests that patients with Type-1 or Type-2 diabetes have a higher prevalence of pulmonary arterial hypertension (PAH). Recent preclinical observations have shown that diabetes induces pulmonary artery (PA) dysfunction that can lead to PAH in rats. The present study aimed to determine whether the reduced pulmonary arterial elasticity observed in isolated PA derived from diabetic rats translates into increased pulmonary arterial pressure in anesthetized diabetic animals. METHODS: Twelve (12) adult male Sprague-Dawley rats were randomly divided into control (saline), Type-1 and Type-2 diabetic groups. Type-1 diabetes was induced with dual i.v. injections of 45 mg/kg streptozotocin, and received stabilized insulin via implanted osmotic pumps for 4 weeks. Type-2 diabetes was induced with a single i.v. injection of 25 mg/kg streptozotocin, preceded by 4 weeks of high-fat diet, and followed by 3 weeks of sugar-enriched rat chow. Insulin levels, glycemia, and food/water consumption were monitored daily at first, and then weekly. Diabetic animals had glycemia levels greater than 30 mM. Twenty-eight (28) days post induction, the rats were instrumented and functional hemodynamics measured prior to organ harvesting for histological examination. RESULTS: Both diabetic models exhibited a 5-fold increase in glycemia. Insulin levels were below 5 µU/mL in Type-1, and approximately 20 µU/mL in Type-2 diabetics. Water and food consumption were 2-3-fold greater in diabetic animals than in control. Mean pulmonary arterial pressure (mPAP) was significantly increased in Type-1 rats when compared to control (22±0.21 vs 18±0.56 mmHg respectively, n=4, P≤0.05). Interestingly, no statistical difference in mPAP was calculated in Type-2 rats when compared to control (18±1.27 vs 18±0.56 mmHg, n=4).

Oxygen saturation measured with a pulse oximeter showed a significant decrease in oxygen saturation in Type-1 when compared to control animals (92 vs 96% SO2 respectively, n=4, P≤0.05). Histological examination confirmed vascular remodeling in the lungs, with loss of functional endothelium associated with smooth muscle hypertrophy and hyperplasia. CONCLUSION: These results show that Type-1 diabetes-induced loss of PA elasticity reported from ex vivo experiments translates into PAH in Type-1 diabetic animals, but not in Type-2 animals, suggesting that hypoinsulinemia rather than hyperglycemia plays a major role in regulating PA elasticity in diabetic rats.

Am J Respir Crit Care Med 191;2015:A1964

A 14-Day Assessment of the Tolerability and Pharmacokinetics (Pk) with a Nanoparticle Formulation of Hexadecyl-Treprostinil, a Long-Acting Pulmonary Vasodilator, In Rats, [Publication Number: A1948]

Rationale: Studies in both rats and dogs demonstrate that single dose inhalation with a nanoparticle formulation of the prodrug, hexadecyl-treprostinil (C16TR) is well tolerated, produces long acting pulmonary vasodilation and sustained levels of treprostinil (TRE) in the plasma and C16TR in the lungs. To assess whether repeated dosing with inhaled C16TR is well tolerated and alters PK, rats were exposed to C16TR for 14-consecutive days.

V. Malinin, PhD1, Z. Li, PhD1, R.W. Chapman, PhD1, F. Leifer, PhD1, D. Konicek, PhD1, D. Salvail, PhD2, C. Laurent, PhD2, H. Yin, MS2, W. Perkins, PhD1
1Bridgewater, NJ/US, 2Sherbrooke, QC/CA, Am J Respir Crit Care Med 191;2015:A1948

https://cms.psav.com/cPaper2012/myitinerary/publication-65238.html?congress=ats2015