Publications by authors named "Jan Carstens"

7 Publications

  • Page 1 of 1

Aortoduodenal fistulas after endovascular abdominal aortic aneurysm repair and open aortic repair.

J Vasc Surg 2021 Mar 5. Epub 2021 Mar 5.

Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of vascular surgery, Berlin, Germany.

Objective: In the present study, we have reported and compared aortoduodenal fistulas (ADFs) after endovascular abdominal aortic aneurysm repair (EVAR) vs after open aortic repair (OAR).

Methods: We retrospectively analyzed the data from patients treated for ADFs from January 2015 to May 2020 in our hospital. The clinical data, diagnostic procedures, and surgical options were evaluated. The primary endpoints of the present study were 30-day and 1-year mortality. The secondary endpoints were major postoperative complications.

Results: A total of 24 patients (20 men; median age, 69 years; range, 53-82 years) were admitted with ADFs after EVAR (n = 9) or OAR (n = 15). These patients accounted for ∼4.3% of all abdominal aortic aneurysm repairs in our hospital. The median interval from the initial aortic repair and the diagnosis of ADF was 68 months (range, 6-83 months) for the ADF-EVAR group and 80 months (range, 1-479 months) for the ADF-OAR group. Three patients in the ADF-EVAR group had refused surgical treatment owing to their high surgical risk. One patient in the ADF-OAR group had undergone removal of the aortic prosthesis without replacement. Of the remaining 20 patients, 12 (ADF-EVAR group, n = 4; ADF-OAR group, n = 8) had undergone in situ replacement of the aorta and 8 (ADF-EVAR group, n = 2; ADF-OAR group, n = 6) had undergone extra-anatomic reconstruction with aortic ligation. After a mean follow-up of 26 months, no patient had experienced early limb loss. However, one case of rupture of the venous graft (ADF-EVAR), one case of aortic stump blowout (ADF-OAR), and one case of a ureteroarterial fistula with a homograft (ADF-OAR) had occurred. Overall, the incidence of postoperative complications was significantly greater after ADF-OAR (93% vs 33%; P = .036). The most frequent bacteria involved in the blood cultures were Escherichia coli (25% of patients), and Candida spp. (61%) were the predominant pathogens found on intra-abdominal smears. The in-hospital mortality rates for the ADF-EVAR and ADF-OAR group were 22% and 13%, respectively. The corresponding 1 -year mortality rates were 22% and 33%.

Conclusions: Patients with ADFs after EVAR or OAR have limited overall survival. In addition to the similar therapeutic approaches, we found no significant differences in postoperative mortality between these two uncommon pathologic entities. In our study, the overall postoperative morbidity seemed greater for the ADF-OAR group.
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March 2021

Ostarine and Ligandrol Improve Muscle Tissue in an Ovariectomized Rat Model.

Front Endocrinol (Lausanne) 2020 17;11:556581. Epub 2020 Sep 17.

Department of Trauma Surgery, Orthopaedics and Plastic Surgery, University of Göttingen, Göttingen, Germany.

In postmenopausal women, hormonal decline changes muscle function and structure. The non-steroidal selective androgen receptor modulators (SARMs) Ostarine (OS) and Ligandrol (LG) have been shown to increase muscle mass and physical function while showing a relative low risk profile. Information about their effects on muscle structure and metabolism is lacking. To analyze this, two experiments were performed using ovariectomized rats as a standard model for postmenopausal conditions. In each experiment, 3-month old Sprague-Dawley rats were divided into five groups ( = 12 to 15). One group remained intact (Non-OVX), the other four groups were ovariectomized (OVX) and remained untreated for eight (OS Experiment) or nine (LG Experiment) weeks. Thereafter, rats of three of the four OVX groups were treated with OS or LG (with doses of 0.04, 0.4, or 4 mg/kg body weight/day) for 5 weeks. Then, uterus, gastrocnemius, and soleus muscles were weighed, fiber size, capillary density, and enzyme activity (lactate dehydrogenase [LDH], citrate synthase [CS], and complex I) were analyzed. In the LG experiment, intramuscular fat content was determined in the quadriceps femoris muscle. All OS treatments resulted in a higher capillary density in the gastrocnemius and longissimus muscles compared with the Non-OVX and the OVX rats, whereas all LG treatments showed a higher capillary density compared with the Non-OVX group. Muscle fiber size and distribution patterns were not changed under either SARM. The CS activity was higher in the longissimus muscle under OS treatment. LG resulted in a higher activity of CS in the gastrocnemius and of LDH in the longissimus muscle. Both SARMs showed an uterotrophic effect, OS at 4 and 0,4 mg dosages, LG at 4 mg dosage. In sum, beneficial effect on muscle vascularization was observed for both SARMs with a stronger impact for OS. LG showed more effect on muscle metabolism. However, a higher muscle weight and intramuscular fat content observed after LG treatment (4 mg) as well as an uterotrophic effect of both SARMs at higher dosages could be considered as an unfavorable side effects and might be a limitation for their application at these dosages.
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May 2021

Relative and absolute cancer risks among Nordic kidney transplant recipients-a population-based study.

Transpl Int 2020 12 25;33(12):1700-1710. Epub 2020 Sep 25.

Clinical Epidemiology Division, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.

Kidney transplant recipients (KTRs) have an increased cancer risk compared to the general population, but absolute risks that better reflect the clinical impact of cancer are seldom estimated. All KTRs in Sweden, Norway, Denmark, and Finland, with a first transplantation between 1995 and 2011, were identified through national registries. Post-transplantation cancer occurrence was assessed through linkage with cancer registries. We estimated standardized incidence ratios (SIR), absolute excess risks (AER), and cumulative incidence of cancer in the presence of competing risks. Overall, 12 984 KTRs developed 2215 cancers. The incidence rate of cancer overall was threefold increased (SIR 3.3, 95% confidence interval [CI]: 3.2-3.4). The AER of any cancer was 1560 cases (95% CI: 1468-1656) per 100 000 person-years. The highest AERs were observed for nonmelanoma skin cancer (838, 95% CI: 778-901), non-Hodgkin lymphoma (145, 95% CI: 119-174), lung cancer (126, 95% CI: 98.2-149), and kidney cancer (122, 95% CI: 98.0-149). The five- and ten-year cumulative incidence of any cancer was 8.1% (95% CI: 7.6-8.6%) and 16.8% (95% CI: 16.0-17.6%), respectively. Excess cancer risks were observed among Nordic KTRs for a wide range of cancers. Overall, 1 in 6 patients developed cancer within ten years, supporting extensive post-transplantation cancer vigilance.
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December 2020

Calcineurin inhibitors acutely improve insulin sensitivity without affecting insulin secretion in healthy human volunteers.

Br J Clin Pharmacol 2012 Apr;73(4):536-45

Department of Nephrology, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 100, Aarhus, Denmark.

What Is Already Known About This Subject: New onset diabetes after transplantation is related to treatment with immunosuppressive medications. Clinical studies have shown that risk of new onset diabetes is greater with tacrolimus compared with ciclosporin. The diabetogenicity of ciclosporin and tacrolimus has been attributed to both beta cell dysfunction and impaired insulin sensitivity.

What This Study Adds: This is the first trial to investigate beta cell function and insulin sensitivity using gold standard methodology in healthy human volunteers treated with clinically relevant doses of ciclosporin and tacrolimus. We document that both drugs acutely increase insulin sensitivity, while first phase and pulsatile insulin secretion remain unaffected. This study demonstrates that ciclosporin and tacrolimus have similar acute effects on glucose metabolism in healthy humans. AIM The introduction of calcineurin inhibitors (CNIs) ciclosporin (CsA) and tacrolimus (Tac) has improved the outcome of organ transplants, but complications such as new onset diabetes mellitus after transplantation (NODAT) cause impairment of survival rates. The relative contribution of each CNI to the pathogenesis and development of NODAT remains unclear. We sought to compare the impact of CsA and Tac on glucose metabolism in human subjects.

Methods: Ten healthy men underwent 5 h infusions of CsA, Tac and saline in a randomized, double-blind, crossover study. During infusion glucose metabolism was investigated using following methods: a hyperinsulinaemic-euglycemic clamp, an intravenous glucose tolerance test (i.v.GTT), glucose-stimulated insulin concentration-time series and indirect calorimetry.

Results: Clamp derived insulin sensitivity was increased by 25% during CsA (P < 0.0001) and 13% during Tac administration (P = 0.047), whereas first phase and pulsatile insulin secretion were unaffected. Coinciding with the CNI induced improved insulin sensitivity, glucose oxidation rates increased, while insulin clearance rates decreased, only non-significantly. Tac singularly lowered hsCRP concentrations, otherwise no changes were observed in circulating glucagon, FFA or adiponectin concentrations. Mean blood concentrations of CNIs were 486.9 ± 23.5 µg l(-1) for CsA and 12.8 ± 0.5 µg l(-1) for Tac.

Conclusions: Acute effects of i.v. CsA, and to a lesser degree Tac infusions, in healthy volunteers include increased insulin sensitivity, without any effect on first phase or pulsatile insulin secretion.
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April 2012

Three-years experience with Neoral C2 monitoring adjusted to a target range of 500-600 ng/ml in long-term renal transplant recipients receiving dual immunosuppressive therapy.

Jan Carstens

Scand J Urol Nephrol 2008 ;42(3):286-92

Department of Renal Medicine, Skejby Sygehus, Aarhus University Hospital, Aarhus, Denmark.

Objective: There is little knowledge about the optimal 2-h post-dose concentration (C(2) level) of cyclosporin A (CsA) in renal transplant recipients beyond 1 year post-transplant. The aim of this study was to investigate the effects of C(2)-CsA monitoring on Neoral dose, renal graft function and systemic blood pressure in long-term renal transplant recipients, who had previously been monitored by means of trough levels (C(0)).

Material And Methods: Eighty-six patients treated with CsA+prednisolone were reviewed retrospectively during a follow-up period after switching to C(2)-CsA monitoring.

Results: The patients were 6.0 years (3.4, 9.0 years) [median (25% quartile, 75% quartile)] post-transplant at the time of conversion to C(2)-CsA monitoring. They were studied for 3.7 years (3.3, 3.8 years). Baseline C(0)-CsA level was 161 ng/ml (131, 208 ng/ml). The Neoral dose was reduced in 95% of the recipients. The median C(2) level was reduced by 40% to 585 ng/ml (484, 670 ng/ml) and, accordingly, the Neoral dose was reduced by 30% to 2.8 mg/kg/day (2.3, 3.8 mg/kg/day). Overall, plasma creatinine remained stable during the follow-up period. In 48/86 patients (56%), the plasma creatinine level was lower at the end of the study compared to baseline, declining from 163 micromol/l (124, 189 micromol/l) in 2001 to 147 micromol/l (106, 172) in 2005. Three patients (3.5%) had late acute rejections, 14 (16.3%) discontinued CsA, five (5.8%) commenced dialysis and seven (8.1%) died.

Conclusion: Adoption of C(2)-CsA monitoring resulted in a substantial reduction in Neoral dose, while the overall renal graft function remained stable.
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September 2008

Renal effects of urodilatin in healthy subjects are independent of blockade of the cyclooxygenase and angiotensin II receptor.

Scand J Clin Lab Invest 2008 21;68(1):2-10. Epub 2007 Nov 21.

Holstebro Hospital, Aarhus University, Department of Medical Research, Holstebro, Denmark.

Objective: Little is known about the role of the renin-angiotensin-aldosterone system and the renal prostaglandins in modulating the renal vasoconstrictive and natriuretic effects of synthetic urodilatin (URO) in healthy humans.

Material And Methods: Twelve volunteers were pretreated in a randomized, single-blind, crossover study with losartan 50 mg a day or placebo for 5 days. Another 12 healthy subjects received indomethacin 25 mg three times a day or placebo for 4 days and a single dose on day 5. All subjects received a URO infusion (15 ng kg(-1) min(-1)) on day 5. Radioactive tracers and the lithium clearance technique were used.

Results: The effective renal plasma flow (ERPF) decreased significantly during URO infusion: losartan pretreatment 573+/-63 to 461+/-76 mL/min versus placebo 540+/-89 to 432+/-90 mL/min. The urinary sodium excretion rate (UNa) increased significantly during URO infusion: losartan 335+/-115 to 502+/-134 umol/min (micromol/min) (UNa) versus placebo 386+/-142 to 476+/-137 umol/min (micromol/min) (UNa). In the indomethacin pretreated subjects, ERPF decreased significantly from 530+/-109 to 446+/-55 mL/min versus 533+/-89 to 449+/-69 mL/min in the placebo group. UNa increased significantly from 395+/-142 to 768+/-254 umol/min (micromol/min) (UNa) in the indomethacin group versus 282+/-117 to 552+/-242 umol/min (micromol/min) (UNa) in placebo.

Conclusion: The renal vasoconstrictive and natriuretic effects of synthetic URO are not modified by sustained inhibition of the angiotensin II receptor or the cyclooxygenase in man in a sodium replete state.
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May 2008

Effects of urodilatin on natriuresis in cirrhosis patients with sodium retention.

BMC Gastroenterol 2007 Jan 26;7. Epub 2007 Jan 26.

Research Laboratory of Nephrology and Hypertension, Aarhus University Hospital, Aarhus, Denmark.

Background: Sodium retention and ascites are serious clinical problems in cirrhosis. Urodilatin (URO) is a peptide with paracrine effects in decreasing sodium reabsorption in the distal nephron. Our aim was to investigate the renal potency of synthetic URO on urine sodium excretion in cirrhosis patients with sodium retention and ascites.

Methods: Seven cirrhosis patients with diuretics-resistant sodium retention received a short-term (90 min) infusion of URO in a single-blind, placebo-controlled cross-over study. In the basal state after rehydration the patients had urine sodium excretion < 50 mmol/24 h.

Results: URO transiently increased urine sodium excretion from 22 +/- 16 micromol/min (mean +/- SD) to 78 +/- 41 mumol/min (P < 0.05) and there was no effect of placebo (29 +/- 14 to 44 +/- 32). The increase of URO's second messenger after the receptor, cGMP, was normal. URO had no effect on urine flow or on blood pressure. Most of the patients had highly elevated plasma levels of renin, angiotensin II and aldosterone and URO did not change these.

Conclusion: The short-term low-dose URO infusion increased the sodium excretion of the patients. The increase was small but systematic and potentially clinically important for such patients. The small response contrasts the preserved responsiveness of the URO receptors. The markedly activated systemic pressor hormones in cirrhosis evidently antagonized the local tubular effects of URO.
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January 2007