Metabolic flexibility in postmenopausal women: Hormone replacement therapy is associated with higher mitochondrial content, respiratory capacity, and lower total fat mass

AIM

To investigate effects of hormone replacement therapy in postmenopausal women on factors associated with metabolic flexibility related to whole-body parameters including fat oxidation, resting energy expenditure, body composition and plasma concentrations of fatty acids, glucose, insulin, cortisol, and lipids, and for the mitochondrial level, including mitochondrial content, respiratory capacity, efficiency, and hydrogen peroxide emission.

METHODS

22 postmenopausal women were included. 11 were undergoing estradiol and progestin treatment (HT), and 11 were matched non-treated controls (CONT). Peak oxygen consumption, maximal fat oxidation, glycated hemoglobin, body composition, and resting energy expenditure were measured. Blood samples were collected at rest and during 45 min of ergometer exercise (65% VO2peak). Muscle biopsies were obtained at rest and immediately post-exercise. Mitochondrial respiratory capacity, efficiency, and hydrogen peroxide emission in permeabilized fibers and isolated mitochondria were measured, and citrate synthase (CS) and 3-hydroxyacyl-CoA dehydrogenase (HAD) activity were assessed.

RESULTS

HT showed higher absolute mitochondrial respiratory capacity and post-exercise hydrogen peroxide emission in permeabilized fibers and higher CS and HAD activities. All respiration normalized to CS activity showed no significant group differences in permeabilized fibers or isolated mitochondria. There were no differences in resting energy expenditure, maximal, and resting fat oxidation or plasma markers. HT had significantly lower visceral and total fat mass compared to CONT.

CONCLUSION

Use of hormone therapy is associated with higher mitochondrial content and respiratory capacity and a lower visceral and total fat mass. Resting energy expenditure and fat oxidation did not differ between HT and CONT.

Co-Occurrence of Prevalent Symptoms in Patients Receiving Hemodialysis - A Cross-Sectional Survey

Patients with chronic kidney disease undergoing hemodialysis generally have a significant symptom burden, which may interfere with their quality of life. The aim of this study was to identify the prevalence of fatigue, pain, anxiety, and depression in patients on hemodialysis and analyze their co-occurrence. A cross-sectional study used self-reported measures. A total of 242 patients aged 18 years or older were initially screened; 141 were included in the study; 129 answered the questionnaires (response rate 91%). Preva lences were 24.8% had moderate to severe fatigue, 38.0% had pain, 32.6% had anxiety, and 29.5% had depression. The prevalence of coexistent moderate to severe symptoms ranged from 15.5% to 25.6%. Further research is needed to better understand the symptom burden and their co-occurrence in patients receiving hemodialysis.

The impact of caring on caregivers of patients with life-threatening organ failure

OBJECTIVES

This study aimed at characterizing 3 populations of family/friend caregivers of patients with different life-threatening organ failure regarding health-related quality of life, caregiver burden, and dyadic coping.

METHODS

Three cross-sectional (population) studies were conducted at a tertiary hospital in Denmark (2019-2020). Patients with renal failure (RF), cystic fibrosis (CF), and intestinal failure (IF) were asked to designate the closest person with ≥18 years old involved in the care (caregiver) to participate in this study. Number of caregivers included were RF = 78, CF = 104, and IF = 73. Electronic questionnaires were filled in by caregivers to assess health-related quality of life and caregiver burden and by caregivers and respective patients to assess dyadic coping.

RESULTS

The 3 caregiver groups had self-perception of poor health and energy; however, caregivers of CF patients perceived their physical role functioning better than those caregiving for RF and IF patients (p = 0.002). The level of caregiver burden was reported as not high, but caregivers used in average 13 hours/day for caring. Moreover, cleaning tasks (p = 0.005) and personal care (p = 0.009) were more demanding in RF and IF patients. Caregivers also did not differ regarding dyadic coping. When comparing patients and caregivers, stress communication by oneself and the partner differed (p < 0.001).

SIGNIFICANCE OF RESULTS

Caregivers spent many hours in the care role, they reported poor health, and dyadic coping may be improved. Interventions in caregivers of patients with life-threatening organ failure could help to improve care management at home, caregiver's health, and dyadic coping between caregiver and patient and consequently reduce caregiver burden.

The influence of age, sex and cardiorespiratory fitness on maximal fat oxidation rate

Fat oxidation decreases with age, yet no studies have previously investigated if aging affects the maximal fat oxidation rate (MFO) during exercise in men and women differently. We hypothesized that increased age would be associated with a decline in MFO and this would be more pronounced in women due to menopause, compared with men. In this cross-sectional study design, 435 (247/188, male/female) subjects of varying ages performed a DXA scan, a submaximal graded exercise test and a maximal oxygen uptake test, to measure MFO and cardiorespiratory fitness (CRF) by indirect calorimetry. Subjects were stratified into 12 groups according to sex (male/female), age (<45, 45-55 and >55 years), CRF (below average and above average). Women aged <45 years had a higher MFO relative to fat free mass (FFM) (mg/min/kg) compared with men, regardless of CRF. However, there were no differences in MFO (mg/min/kg FFM) between men and women, in the groups aged between 45-55 and >55 years. In summary, we found that women aged <45 years display a higher MFO (mg/min/kg FFM) compared with men and that this sexual divergence is abolished after the age of 45 years. Novelty: Maximal fat oxidation rate is higher in young women compared with men. This sex-related difference is attenuated after the age of 45 years. Cardiorespiratory fitness does not influence this sex-related difference.

Estimation of minimum tolerated milk temperature for feeding dairy calves with small- and large-aperture teat bottles: A complementary dose-response study

At birth, calves are functionally monogastric and remain so for the first weeks of life. Milk in the rumen may cause indigestion, diarrhea, and reduced growth. Calves are often fed cold milk from a large-aperture teat, but warm milk and sucking behavior are believed to trigger the esophageal reflex. The aim of this study was to use radiography to estimate the lowest milk temperature that can be given to dairy calves at high and low intake rates without causing milk in the rumen. Our hypothesis was that cold milk drunk at high speed would cause insufficient closure of the esophageal groove and hence milk in the rumen. Fifteen Norwegian Red calves, 9 to 27 d of age, weighing between 45.5 and 71.0 kg, were tested according to the response surface pathway design. Each calf was offered 4 L of milk from both a small- (2 mm) and a large-aperture (19 mm) teat. The milk contained barium sulfate, and radiography was applied before, during, and after the milk meal. Following radiography, the calves were returned to a group pen and observed for 2 h using continuous live behavioral observation to detect signs of abdominal pain or discomfort. Starting with a low number of subjects and increasing this number with increasing design levels reduces the sample size without reducing the statistical power. The minimum milk temperature was estimated to be 8°C. No behavioral signs of pain or discomfort were observed, but shivering was noted in several calves drinking 8°C milk. These results strengthen the argument that calves can be fed large milk meals without risk of causing milk in the rumen, even cold milk drunk at high speed.

P3487Pre-ischemic succinate dehydrogenase inhibition is protective against ischemia-reperfusion injury in rat and human myocardium with and without diabetes mellitus

Background

Ischemia-reperfusion (IR) injury can be attenuated through modulation of mitochondrial metabolism with succinate dehydrogenase (SDH) inhibition by dimethyl malonate (DiMAL). However, it is unknown whether SDH inhibition yields protection in aged, diabetic individuals and whether protection translate into human cardiac tissue.

Purpose

We wished to evaluate if SDH inhibition can be protective in aged, diabetic rat hearts and could be translated to the human myocardium.

Methods

We studied infarct size in aged non-diabetic and diabetic rat hearts subjected to isolated, retrograde perfusion and global ischemia and reperfusion. The hearts were randomized to: Sham hearts, IR injured hearts and IR injured hearts co-perfused with 0.1 mM or 0.6 mM DiMAL. Infarct size and mitochondrial respiratory capacity were evaluated post-ischemic. To translate our findings into human cardiac tissue, we tested the efficacy of DiMAL treatment in human atrial trabeculae from patients with and without diabetes mellitus undergoing cardiac surgery. We randomized atrial trabeculae to: IR injury, IR injury treated with ischemic preconditioning (IPC) and IR injury treated with 5 mM DiMAL. Contractile force recovery and mitochondrial respiratory capacity were evaluated post-ischemic.

Results

In non-diabetic rat hearts, DiMAL 0.1 mM reduced infarct size/area-at-risk (IS/AAR) compared to IR hearts (53±7% vs. 69±6% of IS/AAR; p<0.05). In diabetic hearts, an increased concentration of 0.6 mM DiMAL was required to confer protection (62±13% vs. 80±8% of IS/AAR; p<0.05). Mitochondrial complex I linked respiratory capacity was higher in both Sham and DiMAL 0.1 mM groups than with DiMAL 0.6 mM in non-diabetic hearts (157.4±26.5 and 140.0±35.3 vs. 81.8±42.4 pmol O2/(s*mg); p<0.01 and p<0.05). In trabeculae from humans without diabetes mellitus, IPC and DiMAL improved contractile force recovery compared to IR (43±12% and 43±13% vs. 23±13%, p<0.05). In trabeculae from patients with diabetes, IPC but not DiMAL administration improved contractile force recovery compared to IR (48±16% and 19±7% vs. 25±13%, p<0.01 and p>0.99). Mitochondrial complex I linked respiration capacity did not improve by IPC or DiMAL compared to IR in non-diabetic trabeculae (p>0.99).

Conclusion

Inhibition of the SDH by DiMAL protects the aged non-diabetic and diabetic heart from IR injury but the threshold for cardioprotection is increased in diabetic rat hearts. DiMAL provides cardioprotection similar to IPC in non-diabetic trabeculae but does not protect the human diabetic myocardium when given in identical concentrations. SDH inhibition can provide protection in both animal and human tissue and may provide a new target for pharmacologic conditioning in patients.

Mitochondrial respiratory capacity remains stable despite a comprehensive and sustained increase in insulin sensitivity in obese patients undergoing gastric bypass surgery

AIM

It has been proposed, but not yet demonstrated by convincing evidence in published articles, that insulin resistance and mitochondrial respiratory function are causally related physiological phenomena. Here, we tested the prediction that weight loss-induced increase in insulin sensitivity will correlate with a corresponding change in mitochondrial respiratory capacity over the same time period.

METHODS

Insulin sensitivity was evaluated using the hyperinsulinaemic-euglycaemic clamp technique, and skeletal muscle mitochondrial respiratory capacity was evaluated by high-resolution respirometry in 26 patients with obesity. Each experiment was performed ~2 months and 1-2 weeks before, and ~4 and ~19 months after Roux-en-Y gastric bypass (RYGB) surgery.

RESULTS

A substantial weight loss was observed in all patients, and insulin sensitivity increased in all patients over the 21-months time period of the study. In contrast, skeletal muscle mitochondrial respiratory capacity, intrinsic mitochondrial respiratory capacity and mitochondrial content remained unchanged over the same time period.

CONCLUSION

Among obese patients with and without type 2 diabetes undergoing RYGB surgery, intrinsic mitochondrial respiratory capacity in skeletal muscle is not correlated with insulin sensitivity before or after the surgical intervention. Mitochondrial respiratory function may not be germane to the pathophysiology and/or aetiology of obesity and/or type 2 diabetes.

High-intensity interval training improves insulin sensitivity in older individuals

AIM

Metabolic health may deteriorate with age as a result of altered body composition and decreased physical activity. Endurance exercise is known to counter these changes delaying or even preventing onset of metabolic diseases. High-intensity interval training (HIIT) is a time efficient alternative to regular endurance exercise, and the aim of this study was to investigate the metabolic benefit of HIIT in older subjects.

METHODS

Twenty-two sedentary male (n = 11) and female (n = 11) subjects aged 63 ± 1 years performed HIIT training three times/week for 6 weeks on a bicycle ergometer. Each HIIT session consisted of five 1-minute intervals interspersed with 1½-minute rest. Prior to the first and after the last HIIT session whole-body insulin sensitivity, measured by a hyperinsulinaemic-euglycaemic clamp, plasma lipid levels, HbA1c, glycaemic parameters, body composition and maximal oxygen uptake were assessed. Muscle biopsies were obtained wherefrom content of glycogen and proteins involved in muscle glucose handling were determined.

RESULTS

Insulin sensitivity (P = .011) and maximal oxygen uptake increased (P < .05) in both genders, while plasma cholesterol (P < .05), low-density lipoprotein (P < .05), visceral fat mass (P < .05) and per cent body fat (P < .05) decreased after 6 weeks of HIIT. HbA1c decreased only in males (P = .001). Muscle glycogen content increased in both genders (P = .001) and in line GLUT4 (P < .05), glycogen synthase (P = .001) and hexokinase II (P < .05) content all increased.

CONCLUSION

Six weeks of HIIT significantly improves metabolic health in older males and females by reducing age-related risk factors for cardiometabolic disease.

Exercise training increases skeletal muscle mitochondrial volume density by enlargement of existing mitochondria and not de novo biogenesis

AIMS

(i) To determine whether exercise-induced increases in muscle mitochondrial volume density (Mito_VD ) are related to enlargement of existing mitochondria or de novo biogenesis and (ii) to establish whether measures of mitochondrial-specific enzymatic activities are valid biomarkers for exercise-induced increases in Mito_VD .

METHOD

Skeletal muscle samples were collected from 21 healthy males prior to and following 6 weeks of endurance training. Transmission electron microscopy was used for the estimation of mitochondrial densities and profiles. Biochemical assays, western blotting and high-resolution respirometry were applied to detect changes in specific mitochondrial functions.

RESULT

Mito_VD increased with 55 ± 9% (P < 0.001), whereas the number of mitochondrial profiles per area of skeletal muscle remained unchanged following training. Citrate synthase activity (CS) increased (44 ± 12%, P < 0.001); however, there were no functional changes in oxidative phosphorylation capacity (OXPHOS, CI+II_P ) or cytochrome c oxidase (COX) activity. Correlations were found between Mito_VD and CS (P = 0.01; r = 0.58), OXPHOS, CI+CIIP (P = 0.01; R = 0.58) and COX (P = 0.02; R = 0.52) before training; after training, a correlation was found between Mito_VD and CS activity only (P = 0.04; R = 0.49). Intrinsic respiratory capacities decreased (P < 0.05) with training when respiration was normalized to Mito_VD. This was not the case when normalized to CS activity although the percentage change was comparable_. CONCLUSIONS: Mito_VD was increased by inducing mitochondrial enlargement rather than de novo biogenesis. CS activity may be appropriate to track training-induced changes in Mito_VD.

Resection of synchronous liver metastases between radiotherapy and definitive surgery for locally advanced rectal cancer: short-term surgical outcomes, overall survival and recurrence-free survival

AIM

There is debate as to the correct treatment algorithm sequence for patients with locally advanced rectal cancer with liver metastases. The aim of the study was to assess safety, resectability and survival after a modified 'liver-first' approach.

METHOD

This was a retrospective study of patients undergoing preoperative radiotherapy for the primary rectal tumour, followed by liver resection and, finally, resection of the primary tumour. Short-term surgical outcome, overall survival and recurrence-free survival are reported.

RESULTS

Between 2009 and 2013, 45 patients underwent liver resection after preoperative radiotherapy. Thirty-four patients (76%) received neoadjuvant chemotherapy, 24 (53%) concomitant chemotherapy during radiotherapy and 17 (43%) adjuvant chemotherapy. The median time interval from the last fraction of radiotherapy to liver resection and rectal surgery was 21 (range 7-116) and 60 (range 31-156) days, respectively. Rectal resection was performed in 42 patients but was not performed in one patient with complete response and two with progressive metastatic disease. After rectal surgery three patients did not proceed to a planned second stage liver (n = 2) or lung (n = 1) resection due to progressive disease. Clavien-Dindo ≥Grade III complications developed in 6.7% after liver resection and 19% after rectal resection. The median overall survival and recurrence-free survival in the patients who completed the treatment sequence (n = 40) were 49.7 and 13.0 months, respectively. Twenty of the 30 patients who developed recurrence underwent further treatment with curative intent.

CONCLUSION

The modified liver-first approach is safe and efficient in patients with locally advanced rectal cancer and allows initial control of both the primary tumour and the liver metastases.

Gentamicin Nephropathy and Contrast Media

Urine profiles were followed for 3 or 9 days after intravenous injection of diatrizoate, iohexol or saline in 30 rats, where a tubulointerstitial nephropathy was induced by gentamicin given over a 14-day period. Another 10 rats who had an injection of saline served as controls. Iohexol increased the excretion of lactate dehydrogenase significantly more than both saline and diatrizoate for the first 3 days, whereas diatrizoate had no effect. Both media caused significantly increased excretion of L-gamma-glutamyltransferase compared with saline, but iohexol significantly more than diatrizoate. Compared with saline S-creatinine was significantly increased following iohexol at 24 h, 3 and 9 days, and following diatrizoate only at 9 days. Among rats having gentamicin light microscopy revealed more severe changes in kidneys exposed to iohexol than to either diatrizoate or saline 3 days after their injection. Six days later no obvious differences were found between the 3 groups. In conclusion, iohexol induced more renal dysfunction than diatrizoate in this animal model of gentamicin induced nephropathy.

Adriamycin Nephrosis and Contrast Media

Urine profiles (albumin, glucose, NAG, LDH, GGT and sodium) were followed for 9 days after intravenous injection of either diatrizoate, iohexol, or saline in 27 Wistar rats with nephrosis induced by Adriamycin 42 days before. Another 9 rats exposed to neither Adriamycin nor contrast media served as controls. None of the contrast media caused further increased albuminuria of significance, whereas both induced significantly increased excretion of all 5 tubular components. The excretion of NAG and sodium was significantly higher following diatrizoate than following iohexol. From 24 h post injection there was no significantly greater excretion of any of the components after either diatrizoate or iohexol than after saline among the rats given Adriamycin. At the end of day 9 after contrast medium injection neither serum sodium, potassium, glucose, urea, creatinine, nor albumin revealed any contrast media related changes. Kidney histology showed quantitatively larger lesions in kidneys exposed to Adriamycin and contrast media than in kidneys exposed to Adriamycin and saline. There were no differences between the two contrast media groups. It is thus concluded, that both high osmolar ionic and low osmolar non-ionic contrast media cause temporary tubular dysfunction but no further glomerular dysfunction in rats with nephrosis induced by Adriamycin. The histologic findings indicate that both media may worsen non-reversible renal lesions.

Nephropathy Induced by Intramuscularly Administered Glycerol and Contrast Media in Rats

Urine profiles (albumin, glucose, NAG, LDH, GGT, sodium, and phosphate) were followed for 14 days after intravenous injection of either diatrizoate, iohexol, ioxilan, or saline in 24 Wistar rats with a glomerular and tubular dysfunction induced by intramuscularly (i.m.) administered glycerol. Another 6 rats exposed to neither glycerol nor contrast media served as controls. The effect of ioxilan and saline on the albumin excretion was similar, whereas diatrizoate and iohexol increased it significantly. The contrast media had no further inhibitory effect on the reabsorption of glucose. Iohexol caused significantly increased excretion of all three enzymes, ioxilan of NAG and LDH, whereas diatrizoate only increased the excretion of LDH. The sodium excretion was further increased by ioxilan and diatrizoate, whereas none of the contrast media affected the phosphaturia. Both ioxilan and iohexol caused a round cell response around the tubules shown by light microscopy whereas diatrizoate caused no further changes. It is concluded that diatrizoate and iohexol increase glomerular dysfunction induced by glycerol i.m.; all three contrast media cause some further increase in the tubular dysfunction. Neither diatrizoate, iohexol nor ioxilan prolong nephropathy induced by glycerol i.m. determined by the chemical analyses. The histologic finding indicates a direct toxic effect of non-ionic low osmolar contrast media in this animal model of nephropathy.

Intravenous Injection of Ioxilan, Iohexol and Diatrizoate

Effects of intravenous ioxilan, a new third generation non-ionic contrast medium, diatrizoate, iohexol and saline on urine profiles were compared. Albumin, glucose, sodium, phosphate, and the enzymes NAG, LDH and GGT were followed in 24 normal rats over 7 days. Diatrizoate significantly affected all profile components during the first two hours. Albuminuria was significantly greater after diatrizoate than after iohexol or ioxilan, and excretion of glucose, LDH and GGT was significantly higher than after ioxilan. Both iohexol and ioxilan increased the excretion of albumin, LDH and GGT, while iohexol also significantly increased excretion of glucose and sodium. There was a greater excretion of glucose and GGT after iohexol than after ioxilan. Saline did not induce any changes. At day 7, serum sodium, urea, creatinine, and albumin were normal for all test substances, and kidney histology revealed no difference between the groups of animals. It is thus concluded that both high osmolar ionic and low osmolar non-ionic contrast media may cause temporary glomerular and tubular dysfunction in rats. In this model, the kidney is affected most by diatrizoate, less by iohexol, and least by ioxilan.

Low Sodium Diet, Indomethacin, and Contrast Media

Urine profiles were followed for 3 or 9 days after intravenous injection of diatrizoate, iohexol, or saline in 30 adult Wistar rats, which received a low sodium diet for 14 days, and indomethacin intravenously 2 hours and immediately before contrast medium or saline injection. A control group of 10 rats, which also received low sodium diet, got saline alone and no indomethacin or contrast medium. Diatrizoate increased albuminuria during the first 22 hours after its injection whereas iohexol did not have any significant effect on albuminuria. Both contrast media caused tubular dysfunction, but there was significant difference between them during the first 2 hours after injection. Compared to the effect of saline, iohexol but not diatrizoate caused increased excretion of lactate dehydrogenase and N-acetyl-beta-glucosaminidase for 2 days. Iodine measurements showed delayed excretion of both media. Light microscopy showed focal location of dilated tubular profiles with hydrophia, which were only present in kidneys exposed to contrast media. It is concluded that in rats fed on a low sodium diet administration of indomethacin in relation to iohexol has a greater tubular cell effect than diatrizoate, which in turn has a greater effect on the glomerular permeability. The excretion of both media is delayed.

Effects of Intravenous Injection of Diatrizoate, Iohexol or Ioxilan on Renal Size, Urine Profiles and Blood Profiles in the Rabbit

Diatrizoate, iohexol or ioxilan were injected intravenously in 18 rabbits. The contrast medium passage through the kidneys was recorded on digital subtraction images for the first 50 s followed by 100 mm exposures up to 15 min after injection. The renal area was measured planimetrically. Urine profiles (glucose, phosphate, LDH, GGT, NAG), blood profiles (potassium, urea) and the relative clearance of albumin and sodium were followed for 5 days and compared with a control group injected with saline. All kidneys were examined by light and immunofluorescence microscopy. All three contrast media produced excellent arteriograms and urograms. The three different contrast media caused a rapid increase of the kidney area within the first minute, reaching an average maximum of 10 to 12 per cent after 5 min, followed by a gradual decline. Contrary to expectations the increase in renal area was similar for all three contrast media, so hyperosmolality is no likely explanation of this phenomenon. None of the contrast agents caused significant changes in any of the profile components with one exception: the GGT excretion was significantly elevated during the first 24 h after diatrizoate administration as compared with the effect of saline. Light and immunofluorescence microscopy revealed no differences.

Nephrotoxicity of Cyclosporin a and Contrast Media

Urine profiles (albumin, glucose, NAG, LDH, GGT and sodium) were followed for 22 h or 8 days after intravenous injection of diatrizoate, iohexol or saline in 30 adult Wistar rats in which nephrotoxicity was induced by daily peroral administration of 25 mg/kg body weight cyclosporin A over a 14-day period. Another 10 rats which had the vehicle of the cyclosporin A solution (placebo) and saline injected intravenously served as controls. The effect of iohexol and saline on the albumin excretion was similar, whereas diatrizoate increased it significantly. Both contrast media caused significantly increased excretion of all three enzymes. The contrast media had no effect on the excretion of glucose and sodium. Except for the fact that the excretion of NAG was significantly higher following iohexol than following diatrizoate 24 to 46 h after injection no significant differences between the two media were found from 24 h after injection among the rats given cyclosporin A. No contrast medium related changes were found by light microscopy of the kidneys. Neither iohexol nor diatrizoate potentiate acute cyclosporin A nephrotoxcity.

Angiography in Non-Functioning Renal Allografts Receiving Cyclosporin A

During a two-year period angiography was performed in 10 out of 40 initially perfused kidney allografts within the first 3 postoperative weeks. Immunosuppression was in all cases performed with cyclosporin A. The indication for angiography was mainly deterioration in the graft function as judged from the renograms or inadequate demonstration of the graft during intravenous radionuclide angiography. At angiography, neither arterial nor venous occlusion was found, and it was normal in 5 patients. It is concluded that during cyclosporin A treatment angiography cannot be recommended on the above mentioned indications in the early postoperative period. A graft biopsy seems sufficient.

Tolerability and pharmacokinetic profile of a novel benzene-poly-carboxylic acids complex with cis-diammineplatinum (II) dichloride in dogs with malignant mammary tumours

The pharmacokinetic profile, tolerability and efficacy of benzene-poly-carboxylic acids complex with cis-diammineplatinum (II) dichloride (BP-C1) were studied in dogs with mammary cancer. A three-level response surface pathway designed trial was performed on seven dogs. At each level BP-C1 was administered subcutaneously daily for 7 days followed by a 7-day rest period in a dose escalating manner. Adverse events according to VCOG-CTCAE, performance status and tumour progression were recorded. The pharmacokinetic profile followed a two-compartment model with rapid absorption, short distribution, and a slow elimination phase. The overall elimination half-life was 125 h. The maximum tolerated dose of BP-C1 was estimated to be above 0.46 mg kg^-1 . A significant reduction in VCOG-CTCAE toxicity which correlated negatively with increasing dose was found. The dogs' general performance status remained unchanged. No decrease in total tumour burden was found, although temporary tumour reduction was seen in some target tumours.

Genetic and environmental influences in Dupuytren's disease: a study of 30,330 Danish twin pairs

We aimed to assess the relative contribution of genes and environment in the aetiology of Dupuytren's disease by studying Danish twins born between 1870 and 2000. Twins with a diagnosis (n = 365) and the subgroup who also had an operation (n = 259) after 1977 were identified through linkage with a nationwide hospital registry among 30,330 monozygotic and same-sexed dizygotic twin pairs. Since monozygotic twins share all their genes and dizygotic twins share on average half of their genetic material, greater phenotypic similarity is expected in monozygotic than in dizygotic twins if a genetic component is involved. The number of concordant male twin pairs with Dupuytren's disease was 17 and 7 (monozygotic and dizygotic pairs, respectively), compared with 60 and 174 discordant monozygotic and dizygotic pairs, yielding probandwise concordance rates of 0.37 (95% confidence interval (CI): 0.26 to 0.50) and 0.07 (95% CI: 0.04 to 0.14), respectively. The heritability of Dupuytren's disease was approximately 80%. We conclude that genetic factors play a major role in the development of Dupuytren's disease.

Three-dimensional reconstruction of the human skeletal muscle mitochondrial network as a tool to assess mitochondrial content and structural organization

AIM

Mitochondria undergo continuous changes in shape as result of complex fusion and fission processes. The physiological relevance of mitochondrial dynamics is still unclear. In the field of mitochondria bioenergetics, there is a need of tools to assess cell mitochondrial content. To develop a method to visualize mitochondrial networks in high resolution and assess mitochondrial volume.

METHODS

Confocal fluorescence microscopy imaging of mitochondrial network stains in human vastus lateralis single muscle fibres and focused ion beam/ scanning electron microscopy (FIB/SEM) imaging, combined with 3D reconstruction was used as a tool to analyse mitochondrial morphology and measure mitochondrial fractional volume.

RESULTS

Most type I and type II muscle fibres have tubular highly interconnected profusion mitochondria, which are thicker and more structured in type I muscle fibres (Fig. 1). In some muscle fibres, profission-isolated ellipsoid-shaped mitochondria were observed. Mitochondrial volume was significantly higher in type I muscle fibres and showed no correlation with any of the investigated molecular and biochemical mitochondrial measurements (Fig. 2). Three-dimensional reconstruction of FIB/SEM data sets shows that some subsarcolemmal mitochondria are physically interconnected with some intermyofibrillar mitochondria (Fig. 3).

CONCLUSION

Two microscopy methods to visualize skeletal muscle mitochondrial networks in 3D are described and can be used as tools to investigate mitochondrial dynamics in response to life-style interventions and/or in certain pathologies. Our results question the classification of mitochondria into subsarcolemmal and intermyofibrillar pools, as they are physically interconnected.

A maximal cycle test with good validity and high repeatability in adults of all ages

In 11 680 individuals (18-85 years) maximal oxygen consumption (VO2max) was estimated indirectly in a maximal cycle test using a prediction model developed in a young population (15-28 years). A subsample of 182 individuals (23-77 years) underwent 2 maximal cycle tests with VO2max estimated indirectly in both tests and measured directly in one test. Agreement between the direct measurement and the indirect estimate of VO2max and repeatability of the indirect estimates of VO2max were examined by Bland-Altman plots, limits of agreement (LOA) and coefficient of repeatability (CR). The indirect method (mean VO2max=3 132 ml · min(-1)) underestimated VO2max as compared to the direct method (mean VO2max=3 190 ml · min(-1)) in men (bias: 58 ml · min(-1) (95% LOA-450 and 565)) and overestimated VO2max in women (mean VO2max=2 328 vs. 2 258 ml · min(-1), bias: - 70 ml · min(-1) (95% LOA-468 and 328)). The mean difference between the 2 indirect estimates was non-significant (men: - 11.9 ml · min(-1), women: 18.3 ml · min(-1)) with a CR of 279 ml · min(-1) (8.9%) in men and 274 ml · min(-1) (11.7%) in women. The validity of the indirect method was good despite minor sex-specific bias. Owing to this bias we suggest a new prediction model of VO2max. The maximal cycle test was highly repeatable.

Decreased plasma chemerin levels in women with gestational diabetes mellitus

AIMS

To evaluate fasting and post-prandial serum chemerin levels in pregnant women with and without gestational diabetes, and again following delivery when normal glucose homeostasis is re-established.

METHODS

Chemerin levels were measured in serum from nine women with gestational diabetes, and from eight age- and BMI-matched pregnant women with normal glucose tolerance during two meal tests: in the third trimester and 3-4 months post partum. All women with gestational diabetes re-established normal glucose tolerance after delivery.

RESULTS

Meal intake did not affect serum chemerin levels. The group with gestational diabetes had lower mean serum chemerin levels during the third trimester compared with the group with normal glucose tolerance (28 ± 1.3 vs. 88 ± 3.5 ng/ml, P < 0.0001). In the group with normal glucose tolerance, mean serum chemerin levels decreased significantly post partum to 57 ± 2.8 ng/ml (P = 0.0001), but remained significantly (P = 0.0003) higher than post-partum levels in the group with gestational diabetes (31 ± 1.9 ng/ml), which did not differ significantly from third trimester levels (P = 0.31).

CONCLUSIONS

Normal pregnancy is associated with increased circulating chemerin levels, which may act to reduce pregnancy-induced insulin resistance and prevent glucose intolerance. Women with gestational diabetes, however, have severely reduced chemerin levels that remain low after delivery, which may contribute to the insulin resistance, glucose intolerance and high type 2 diabetes risk associated with gestational diabetes.

Depletion of penicillin G residues in heavy sows after intramuscular injection. Part I: tissue residue depletion

Heavy sows (n = 126) were treated with penicillin G procaine at a 5× label dose (33 000 IU/kg) for 3 consecutive days by intramuscular (IM) injection using three patterns of drug administration. Treatments differed by injection pattern and injection volume. Sets of sows were slaughtered 5, 10, 15, 20, 25, 32, and 39 days after the last treatment; skeletal muscle, kidney, serum, and urine were collected for penicillin G analysis by LC-MS/MS. Penicillin G at withdrawal day 5 averaged 23.5 ± 10.5 and 3762 ± 1932 ng/g in muscle and kidney, respectively. After 15 days of withdrawal, muscle penicillin G residues were quantifiable in only one treated hog (3.4 ng/g) but averaged 119 ± 199 ng/g in kidneys. Using a hypothetical tolerance of 50 ng/g and a natural log-linear depletion model, the withdrawal period required for penicillin depletion to 50 ng/g was 11 days for skeletal muscle and 47 days for kidney.

Invasive pneumococcal disease following adult allogeneic hematopoietic stem cell transplantation

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (alloHSCT) recipients are at high risk of invasive pneumococcal disease (IPD). We investigated the incidence and risk factors of IPD in alloHSCT recipients from 4 regional transplant centers over an 11-year period. This study aimed to inform future improvements in post-transplant care.

METHODS

We conducted a retrospective nested 1:2 case-control study in patients aged ≥18 years who underwent alloHSCT between 2001 and 2011 in 4 major allogeneic transplant centers. Controls were matched with IPD cases on the basis of conditioning intensity and donor relationship (related or unrelated). Demographics and clinical characteristics of cases and controls were summarized. Univariate analysis of risk factors in matched case-control sets, and multivariate conditional logistic regression to control for confounding, were performed.

RESULTS

In 23 alloHSCT recipients, 26 IPD episodes were identified. The cumulative incidence over 11 years was 2.3% (95% confidence interval [CI] 1.45-3.15) and the incidence density 956 per 100,000 transplant years of follow-up (95% CI 580-1321). Multivariate risk factor analysis and backwards elimination showed a significant positive association between mycophenolate mofetil (MMF), hyposplenism/asplenia, and IPD, whereas trimethoprim-sulfamethoxazole (TMP/SMX) prophylaxis for Pneumocystis jirovecii pneumonia (PJP) was associated with lower odds of IPD cases. Of alloHSCT recipients with IPD, 38.5% required intensive care, and, of deaths documented in cases over the period of review, 30% were attributable to IPD. Serotypes causing IPD matched currently available vaccines in 15/22 (68.1%) episodes.

CONCLUSIONS

The incidence of IPD in alloHSCT recipients is an important cause of morbidity and mortality, with rates of disease being many fold higher than the general population. Patients with evidence of hyposplenism/asplenia define a high-risk group in the alloHSCT population for IPD, and the independent association with IPD and MMF in the adjusted model from this study requires further evaluation. The occurrence of post-transplant IPD may be reduced by measures such as vaccination with both 13-valent and 23-valent pneumococcal vaccines. TMP/SMX prophylaxis for the prevention of PJP may offer incidental protection against IPD in alloHSCT recipients.

Influence of age on leptin induced skeletal muscle signalling

AIM

Age associated fat mass accumulation could be because of dysregulation of leptin signalling in skeletal muscle. Thus, we investigated total protein expression and phosphorylation levels of the long isoform of the leptin receptor (OB-Rb), and leptin signalling through janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3), insulin receptor substrate 1 (IRS-1), AMP-activated protein kinase (AMPK) and acetyl-coenzyme A carboxylase (ACC), combined with the leptin signalling inhibitors suppressor of cytokine signalling 3 (SOCS3) and protein tyrosine phosphatase 1B (PTP1B) in human skeletal muscle of different age.

METHODS

Vastus lateralis muscle biopsies were obtained from 39 men matched for BMI < 30 kg m(-2) and separated into three groups: 13 young (Y, 24 ± 4 years); 14 middle aged (MA, 44 ± 5 years) and 12 aged (A, 58 ± 8 years) subjects.

RESULTS

Whole body fat percentage and plasma leptin were higher (P < 0.05), whereas lean mass, plasma free testosterone and total testosterone were lower (P < 0.05) in A compared to Y. Skeletal muscle OB-Rb (170 KDa) protein expression and pTyr(1141) -OB-R170 were comparable between groups, whereas pTyr(985) -OB-R170 was lower in A compared to Y (P < 0.05). pSTAT3 levels tended (P = 0.09) to be lower (50%) in A compared to Y. In A, muscle PTP1B was greater and IRS-1 lower than Y and MA respectively (P < 0.05). PTyr(612) -IRS-1 tended to be lower in A than in Y (P = 0.09). Suppressor of cytokine signalling 3 (SOCS3) protein expression, pJAK2, pSer(1101) -IRS-1, pAMPKα and pACCβ were similar between groups.

CONCLUSION

Age is associated with dysregulation of the leptin signalling and increased PTP1B protein expression in skeletal muscle.

Intra-articular botulinum toxin A for the treatment of osteoarthritic joint pain in dogs: a randomized, double-blinded, placebo-controlled clinical trial

The aim of this study was to investigate the efficacy of intra-articular (IA) botulinum toxin A (IA BoNT A) for the treatment of osteoarthritic joint pain in dogs. The study was a placebo-controlled, randomized, double-blinded clinical trial with parallel group design and 12-week follow-up. Thirty-six dogs with chronic lameness due to stifle, hip or elbow osteoarthritis were randomized to receive an IA injection of 30IU of BoNT A or placebo. The main outcome variables were vertical impulse (VI) and peak vertical force (PVF) measured with a force platform, and Helsinki chronic pain index (HCPI). Subjective pain score and the need for rescue analgesics were secondary variables. The response to treatment was assessed as the change from baseline to each examination week. The variables were analyzed by ANOVA with repeated measurements and results were considered statistically significant if P ⩽ 0.05. The improvement from baseline to 12 weeks after baseline was statistically significant in VI, PVF and HCPI in the treatment group (P=0.001, P=0.054 and P=0.053, respectively). Additionally, there were statistically significant improvements in VI in the treatment group at 2, 4 and 8 weeks after baseline (P=0.037, P=0.016 and P=0.016, respectively). The difference between groups in improvement in VI was statistically significant at 12weeks after baseline (P=0.005). There was no significant change in the subjective pain score or in the requirement for rescue analgesics in either group. No major adverse events thought to be related to trial protocol were detected. These results suggest that IA BoNT A has some efficacy in reducing osteoarthritic pain in dogs.

Reduced postprandial GLP-1 responses in women with gestational diabetes mellitus

AIM

We investigated postprandial glucagon-like peptide-1 (GLP-1) responses in pregnant women with and without gestational diabetes mellitus (GDM) and again following delivery when normal glucose tolerance (NGT) was re-established.

METHODS

Eleven women with GDM [plasma glucose (PG) concentration at 120 min after a 75-g oral glucose tolerance test (OGTT): 10.0 ± 0.9 mM (mean ± SD); age: 31 ± 6 years; body mass index (BMI): 31.6 ± 6.4 kg/m(2) ; haemoglobin A1c (HbA1c): 5.6 ± 0.5%] and eight pregnant women with NGT (PG(120 min), OGTT : 5.7 ± 0.7 mM; age: 28 ± 3 years; BMI: 29.7 ± 5.4 kg/m(2) ; HbA1c: 5.4 ± 0.3%) were investigated with a 4-h liquid meal test during third trimester (TT) and 3-4 months postpartum (PP). All patients with GDM re-established NGT following delivery.

RESULTS

Pregnancy was associated with low postprandial GLP-1 responses. Patients with GDM exhibited reduced postprandial GLP-1 responses compared to their PP levels [area under curve (AUC): 5.5 ± 1.3 vs. 8.4 ± 3.2 nM × min, p=0.005], but the difference among NGT women (7.3 ± 2.8 vs. 8.8 ± 2.0 nM × min, p=0.066) was not statistically significant. Pregnancy did not influence postprandial responses of the other incretin hormone glucose-dependent insulinotropic polypeptide (GIP) in any of the groups, but GDM patients were characterized by greater postprandial GIP responses during both TT and PP compared to NGT subjects.

CONCLUSIONS

Pregnancy is associated with reduced postprandial GLP-1 responses (most pronounced in patients with GDM) that normalize after delivery. In contrast, postprandial GIP responses seem unaffected by pregnancy but is increased in GDM patients.

The influence of age and aerobic fitness: effects on mitochondrial respiration in skeletal muscle

AIM

Mitochondrial function has previously been studied in ageing, but never in humans matched for maximal oxygen uptake ((V)·O2max). Furthermore, the influence of ageing on mitochondrial substrate sensitivity is not known.

METHODS

Skeletal muscle mitochondrial respiratory capacity and mitochondrial substrate sensitivity were measured by respirometry in young (23 ± 3 years) and middle-aged (53 ± 3 years) male subjects with similar (V)·O2max. Protocols for respirometry included titration of substrates for complex I (glutamate), complex II (succinate) and both (octanoyl carnitine) for calculation of substrate sensitivity (C(50) ). Myosin heavy chain (MHC) isoforms, citrate synthase (CS) and β-hydroxy-acyl-CoA-dehydrogenase (HAD) activity, mitochondrial DNA (mtDNA) content, protein levels of complexes I-V and antioxidant defence system [manganese superoxide dismutase (MnSOD)] were measured.

RESULTS

No differences were found in maximal mitochondrial respiration or C(50) with glutamate (2.0 ± 0.3 and 1.8 ± 0.3 mm), succinate (3.7 ± 0.2 and 3.8 ± 0.4 mm) or octanoyl carnitine (47 ± 8 and 56 ± 7 μm) in young and middle-aged subjects respectively. Normalizing mitochondrial respiration to mtDNA young subjects had a higher (P < 0.05) respiratory capacity per mitochondrion compared to middle-aged subjects. HAD activity and mtDNA per mg tissue were higher in middle-aged compared to young subjects. Middle-aged had a higher MHC I isoform and a lower MHC IIX isoform content compared to young subjects.

CONCLUSION

Mitochondrial substrate sensitivity is not affected by ageing. When young and middle-aged men are carefully matched for (V)·O2max, mitochondrial respiratory capacity is also similar. However, per mitochondrion respiratory capacity was lower in middle-aged compared to young subjects. Thus, when matched for (V)·O2max, middle-aged seem to require a higher mitochondrial content than young subjects.

Skeletal muscle mitochondrial respiration in AMPKα2 kinase-dead mice

AIM

To study whether the phenotypical characteristics (exercise intolerance; reduced spontaneous activity) of the AMPKα2 kinase-dead (KD) mice can be explained by a reduced mitochondrial respiratory flux rates (JO(2) ) in skeletal muscle. Secondly, the effect of the maturation process on JO(2) was studied.

METHODS

In tibialis anterior (almost exclusively type 2 fibres) muscle from young (12-17 weeks, n = 7) and mature (25-27 weeks, n = 12) KD and wild-type (WT) (12-17 weeks, n = 9; 25-27 weeks, n = 11) littermates, JO(2) was quantified in permeabilized fibres ex vivo by respirometry, using a substrate-uncoupler-inhibitor-titration (SUIT) protocol: malate, octanoyl carnitine, ADP and glutamate (GMO(3) ), + succinate (GMOS(3) ), + uncoupler (U) and inhibitor (rotenone) of complex I respiration. Citrate synthase (CS) activity was measured as an index of mitochondrial content.

RESULTS

Citrate synthase activity was highest in young WT animals and lower in KD animals compared with age-matched WT. JO(2) per mg tissue was lower (P < 0.05) in KD animals (state GMOS(3) ). No uncoupling effect was seen in any of the animals. Normalized oxygen flux (JO(2) /CS) revealed a uniform pattern across the SUIT protocol with no effect of KD. However, JO(2) /CS was higher [GMO(3) , GMOS(3) , U and rotenone (only WT)] in the mature compared with the young mice - irrespective of the genotype (P < 0.05).

CONCLUSION

Exercise intolerance and reduced activity level seen in KD mice may be explained by reduced JO(2) in the maximally coupled respiratory state. Furthermore, an enhancement of oxidative phosphorylation capacity per mitochondrion is seen with the maturation process.

Cryopreservation of human skeletal muscle impairs mitochondrial function

Previous studies have investigated if cryopreservation is a viable approach for functional mitochondrial analysis. Different tissues have been studied, and conflicting results have been published. The aim of the present study was to investigate if mitochondria in human skeletal muscle maintain functionality after long term cryopreservation (1 year). Skeletal muscle samples were preserved in dimethyl sulfoxide (DMSO) for later analysis. Human skeletal muscle fibres were thawed and permeabilised with saponin, and mitochondrial respiration was measured by high-resolution respirometry. The capacity of oxidative phosphorylation was significantly (P < 0.05) reduced in cryopreserved human skeletal muscle samples. Cryopreservation impaired respiration with substrates linked to Complex I more than for Complex II (P < 0.05). Addition of cytochrome c revealed an increase in respiration indicating cytochrome c loss from the mitochondria. The results from this study demonstrate that normal mitochondrial functionality is not maintained in cryopreserved human skeletal muscle samples.

A serologic study of canine herpes virus-1 infection in the Norwegian adult dog population

Canine herpes virus-1 (CHV1) causes a fatal hemorrhagic disease in neonatal puppies and is associated with reproductive problems in female dogs. This serologic study was conducted to assess the seroprevalence of CHV1 infection in Norway. Blood samples were collected from clinically healthy dogs (n = 436) one yr of age and older of both genders, supplied by four small animal clinics (A, B, C and D) in different parts of the country. The immunoperoxidase monolayer assay was used for testing of CHV1 antibodies. Serum titers were recorded as the reciprocal value of the highest dilution producing specific cell staining. Titers equal to or above 80 were considered positive for exposure to CHV1. In total, 80.0% of the dogs had titers ≥80 and were classified as positive. Mean age for seronegative dogs was 4.7 yrs (95% CI 4.1-5.4) and for seropositive dogs 5.0 yrs (95% CI 4.7-5.4). Of the dogs, 32.8% displayed a weakly positive titer of 80, whereas 41.5 and 5.7% fell into the moderately (titer 160 and 320) and strongly (titer ≥640) positive categories, respectively. No association was demonstrated when comparing CHV1 antibody titers to gender or reproductive parameters like previous matings, pregnancies, births or number of puppies born. Age, visit in foreign countries and clinic explained together 78% of the variation in antibody titer categories. The percentage of positive samples differed significantly between the four clinics (A 98%, B 58.5%, C 74.6%, D 89.5%). A reasonable explanation for this finding has not been established. No information about an ongoing outbreak of CHV1 infection was available. In conclusion, this study strongly indicates that CHV1 infection is endemic in the dog population of Norway. There are significant differences in seroprevalence between geographic regions in the country.

Metformin-treated patients with type 2 diabetes have normal mitochondrial complex I respiration

AIMS/HYPOTHESIS

The glucose-lowering drug metformin has been shown to inhibit complex I of the mitochondrial electron transport chain in skeletal muscle. To investigate this effect in vivo we studied skeletal muscle mitochondrial respiratory capacity and content from patients with type 2 diabetes treated with metformin (n = 14) or sulfonylurea (n = 8) and healthy control (n = 18) participants.

METHODS

Mitochondrial respiratory capacity was measured ex vivo in permeabilised muscle fibres obtained from the vastus lateralis muscle of all participants. The respiratory response to in vitro titration with metformin was measured in controls. Citrate synthase (CS) activity, and fasting plasma glucose, insulin and HbA(1c) levels were measured and body composition was determined.

RESULTS

Participants were matched for age, BMI and percentage body fat. Fasting plasma glucose concentrations were higher (p < 0.05) in those treated with sulfonylureas and metformin than in controls. CS activity was comparable between metformin-treated and control participants, but tended to be lower in those receiving sulfonylureas. Mitochondrial respiratory capacity with substrates for complex I and complex I and II was comparable in the groups, both when estimated per mg of tissue and when normalised to CS activity. In vitro metformin titration demonstrated a dose-dependent inhibitory effect on complex I and II in human skeletal muscle at suprapharmacological concentrations.

CONCLUSIONS/INTERPRETATION

Metformin treatment does not inhibit mitochondrial complex I respiration in the electron transport chain in human skeletal muscle of patients with type 2 diabetes when measured ex vivo. Inhibition of complex I and II respiration in controls was demonstrated by metformin titration in vitro at doses well above those observed during metformin treatment.

Willingness-to-pay for benefits associated with basal insulin treatment of type 2 diabetes

Data from a 20-week trial comparing insulin detemir and neutral protamine Hagedorn (NPH) insulin in insulin-naïve people with type 2 diabetes were analyzed using willingness-to-pay (WTP) data, a proxy for patient preference. The advantages of insulin detemir relative to NPH insulin with respect to a lower hypoglycemia rate and less weight gain were associated with a value of €27.87 per month.