Hormetic modulation of angiogenic factors by exercise-induced mechanical and metabolic stress in human skeletal muscle

This study used an integrative experimental model in humans to investigate whether muscle angiogenic factors are differentially modulated by exercise stimuli eliciting different degrees of mechanical and metabolic stress. In a randomized crossover design, 12 men performed two low-volume high-intensity exercise regimens, including short sprint intervals (SSI) or long sprint intervals (LSI) inducing pronounced mechanical/metabolic stress, and a high-volume moderate-intensity continuous exercise protocol (MIC) inducing mild but prolonged mechanical/metabolic stress. Gene and protein expression of angiogenic factors was determined in vastus lateralis muscle samples obtained before and after exercise. Exercise upregulated muscle VEGF mRNA to a greater extent in LSI and MIC compared with SSI. Analysis of angiogenic factors sensitive to shear stress revealed more marked exercise-induced VEGF receptor 2 (VEGF-R2) mRNA responses in MIC than SSI, as well as greater platelet endothelial cell adhesion molecule (PECAM-1) and endothelial nitric oxide synthase (eNOS) mRNA responses in LSI than SSI. No apparent exercise-induced phosphorylation of shear stress-sensory proteins VEGF-R2^Tyr1175, PECAM-1^Tyr713, and eNOS^Ser1177 was observed despite robust elevations in femoral artery shear stress. Exercise evoked greater mRNA responses of the mechanical stretch sensor matrix metalloproteinase-9 (MMP9) in SSI than MIC. Exercise-induced mRNA responses of the metabolic stress sensor hypoxia-inducible factor-1α (HIF-1α) were more profound in LSI than SSI. These results suggest that low-volume high-intensity exercise transcriptionally activates angiogenic factors in a mechanical/metabolic stress-dependent manner. Furthermore, the angiogenic potency of low-volume high-intensity exercise appears similar to that of high-volume moderate-intensity exercise, but only on condition of eliciting severe mechanical/metabolic stress. We conclude that the angiogenic stimulus produced by exercise depends on both magnitude and protraction of myocellular homeostatic perturbations.NEW & NOTEWORTHY Skeletal muscle capillary growth is orchestrated by angiogenic factors sensitive to mechanical and metabolic signals. In this study, we employed an integrative exercise model to synergistically target, yet to different extents and for different durations, the mechanical and metabolic components of muscle activity that promote angiogenesis. Our results suggest that the magnitude of the myocellular perturbations incurred during exercise determines the amplitude of the angiogenic molecular signals, implying hormetic modulation of skeletal muscle angiogenesis by exercise-induced mechanical and metabolic stress.

Metabolic stress-dependent regulation of the mitochondrial biogenic molecular response to high-intensity exercise in human skeletal muscle

KEY POINTS

Low-volume high-intensity exercise training promotes muscle mitochondrial adaptations that resemble those associated with high-volume moderate-intensity exercise training. These training-induced mitochondrial adaptations stem from the cumulative effects of transient transcriptional responses to each acute exercise bout. However, whether metabolic stress is a key mediator of the acute molecular responses to high-intensity exercise is still incompletely understood. Here we show that, by comparing different work-matched low-volume high-intensity exercise protocols, more marked metabolic perturbations were associated with enhanced mitochondrial biogenesis-related muscle mRNA responses. Furthermore, when compared with high-volume moderate-intensity exercise, only the low-volume high-intensity exercise eliciting severe metabolic stress compensated for reduced exercise volume in the induction of mitochondrial biogenic mRNA responses. The present results, besides improving our understanding of the mechanisms mediating exercise-induced mitochondrial biogenesis, may have implications for applied and clinical research that adopts exercise as a means to increase muscle mitochondrial content and function in healthy or diseased individuals.

ABSTRACT

The aim of the present study was to examine the impact of exercise-induced metabolic stress on regulation of the molecular responses promoting skeletal muscle mitochondrial biogenesis. Twelve endurance-trained men performed three cycling exercise protocols characterized by different metabolic profiles in a randomized, counter-balanced order. Specifically, two work-matched low-volume supramaximal-intensity intermittent regimes, consisting of repeated-sprint (RS) and speed endurance (SE) exercise, were employed and compared with a high-volume continuous moderate-intensity exercise (CM) protocol. Vastus lateralis muscle samples were obtained before, immediately after, and 3 h after exercise. SE produced the most marked metabolic perturbations as evidenced by the greatest changes in muscle lactate and pH, concomitantly with higher post-exercise plasma adrenaline levels in comparison with RS and CM. Exercise-induced phosphorylation of CaMKII and p38 MAPK was greater in SE than in RS and CM. The exercise-induced PGC-1α mRNA response was higher in SE and CM than in RS, with no difference between SE and CM. Muscle NRF-2, TFAM, MFN2, DRP1 and SOD2 mRNA content was elevated to the same extent by SE and CM, while RS had no effect on these mRNAs. The exercise-induced HSP72 mRNA response was larger in SE than in RS and CM. Thus, the present results suggest that, for a given exercise volume, the initial events associated with mitochondrial biogenesis are modulated by metabolic stress. In addition, high-intensity exercise seems to compensate for reduced exercise volume in the induction of mitochondrial biogenic molecular responses only when the intense exercise elicits marked metabolic perturbations.

Accuracy of GPS devices for measuring high-intensity running in field-based team sports

We compared the accuracy of 2 GPS systems with different sampling rates for the determination of distances covered at high-speed and metabolic power derived from a combination of running speed and acceleration. 8 participants performed 56 bouts of shuttle intermittent running wearing 2 portable GPS devices (SPI-Pro, GPS-5 Hz and MinimaxX, GPS-10 Hz). The GPS systems were compared with a radar system as a criterion measure. The variables investigated were: total distance (TD), high-speed distance (HSR>4.17 m·s(-1)), very high-speed distance (VHSR>5.56 m·s(-1)), mean power (Pmean), high metabolic power (HMP>20 W·kg(-1)) and very high metabolic power (VHMP>25 W·kg(-1)). GPS-5 Hz had low error for TD (2.8%) and Pmean (4.5%), while the errors for the other variables ranged from moderate to high (7.5-23.2%). GPS-10 Hz demonstrated a low error for TD (1.9%), HSR (4.7%), Pmean (2.4%) and HMP (4.5%), whereas the errors for VHSR (10.5%) and VHMP (6.2%) were moderate. In general, GPS accuracy increased with a higher sampling rate, but decreased with increasing speed of movement. Both systems could be used for calculating TD and Pmean, but they cannot be used interchangeably. Only GPS-10 Hz demonstrated a sufficient level of accuracy for quantifying distance covered at higher speeds or time spent at very high power.

Are all cases of low-grade mosaic trisomy 13 in amniotic fluid with no fetal malformation in fact confined placental mosaicism? A case report

We report on a case of true prenatal mosaic trisomy 13 on amniotic fluid associated with a normal phenotype at the age of 6 years. The amniocentesis was performed because of advanced maternal age and was controlled by a second sample. Morphological and cardiac ultrasonography did not reveal any fetal malformations. No trisomic cells were found in the fetal blood and a nuclear magnetic resonance imaging (IRM) of the brain was performed during the third trimester found no abnormality of the brain. Finally, at birth cytogenetic analysis was performed on two placental samples for chromosomal analysis: one in an area where the placenta seemed normal, and the other one in an area with infarcted and hemorrhagic aspect. We found a high rate of trisomic cells in the sample with abnormal aspect. Furthermore, no trisomic cell was observed by fluorescent in situ hybridation (FISH) on the buccal smears of the baby. We concluded to a confined placental mosaicism. The good outcome of the child aged 6 years confirms this diagnosis. So in the aim to predict a good development for the child in case of low rate mosaic trisomy 13 in amniotic fluid, we propose at birth: i) to take several samples from the placenta to confirm placental mosaicism; ii) to label by FISH buccal smears with a LSI 13 probe to prove that the baby is not a carrier of the trisomy.

Familial 18 centromere variant resulting in difficulties in interpreting prenatal interphase FISH

We report here on a familial case of centromeric heteromorphism of chromosome 18 detected by prenatal interphase fluorescence in situ hybridization (FISH) analysis transmitted by the mother to her fetus, and resulting in complete loss of one 18 signal. The prenatal diagnosis was performed by interphase FISH (AneuVysion probe set, and LSI DiGeorge 22q11.2 kit) because of the presence of an isolated fetal cardiac abnormality, and was first difficult to interpret: only one centromeric 18 signal was detectable on prenatal interphase nuclei, along with one signal for the Y and one for the X chromosome. The LSI DiGeorge 22q11.2 kit also showed the absence of one TUPLE 1 signal on all examined nuclei. In fact, the FISH performed on maternal buccal smear displayed the same absence of one chromosome 18 centromeric signal, combined with the presence of two TUPLE1 signals. All these results led to the diagnosis of an isolated 22q11.2 fetal microdeletion that was confirmed on metaphases spreads. This case illustrates once again that the locus specific (LSI) probes are more effective than the alpha centromeric probes for interphase analysis. The development of high-quality LSI probes for chromosomes 18, X and Y could avoid the misinterpretation of prenatal interphase FISH leading to numerous additional and expensive investigations.

Lymphatic mapping to tailor selective lymphadenectomy in cN0 tongue carcinoma: beyond the sentinel node concept

PURPOSE

Cervical lymph node status is the most important pathological determinant of prognosis and decision making in head and neck squamous cell carcinoma (SCC). The aim of this study was to demonstrate that lymphoscintigraphy (LS) can supply a complete map of the lymphatic drainage before surgery, allowing planning of the type of intervention and serving to guide lymphadenectomy.

METHODS

The study population comprised 14 patients with T2-4 SCCs of the tongue and clinically negative lymph nodes in the neck (cN0) who were scheduled to undergo tumour resection and selective level I-IV neck dissection extended to level V. LS was performed in all patients following the injection of (99m)Tc-colloidal sulphide in three aliquots around the primary lesion. Dynamic, static and tomographic images of the head and neck were acquired. The operative specimens were subjected to lymphoscintigraphic evaluation. Preoperative and postoperative imaging results were compared with the pathological findings. All nodes were examined using haematoxylin-eosin staining.

RESULTS

Preoperative LS was successful in all patients. Preferential pathways of lymphatic drainage were identified: level II of the neck was the most common lymphatic drainage pattern, followed by levels IV and III. Contralateral drainage occurred in 11 patients and in two of them metastatic nodes were found on the contralateral side. Metastases were observed only in radioactive lymph nodes.

CONCLUSION

LS is able to supply a complete map of the lymphatic drainage before surgery, making it possible to tailor selective neck dissection to each individual patient based on the results of preoperative mapping, thereby sparing healthy lymphatic tissue and reducing surgery-related morbidity.

90Y-DOTA-D-Phe1-Try3-octreotide in therapy of neuroendocrine malignancies

Somatostatin receptors type 2 (sst(2)) are expressed in high concentration on numerous neudoendocrine tumors. The successful use of radiolabeled somatostatin analogs in imaging promoted further studies in utilizing them in radiopeptide therapy. The somatostatin analog [(90)Y-DOTA-D-Phe(1)-Try3]octreotide (DOTATOC) (DOTA: 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid) possesses favorable characteristic for its therapeutic use; shows high affinity for sst(2), moderately high affinity for sst(5), and intermediate affinity for sst(3); high hydrophilicity; stable and facile labeling with (111) In and (90) Y. In this article we report our experience with (90)Y-DOTATOC in neuroendocrine tumors. Eighty-seven patients with neuroendocrine tumors were treated with a cumulated activity ranging from 7.4 to 20.2 GBq. Most patients responded with stabilization of disease (48%); however, objective responses were observed in 28% of patients (5% complete response). No major acute reactions were observed up to the activity of 5.55 GBq per cycle. The dose limiting was bone marrow toxicity and the maximal tolerated dose was defined as 5.18 GBq.

Pretargeted adjuvant radioimmunotherapy with yttrium-90-biotin in malignant glioma patients: a pilot study

In a previous study we applied a three-step avidin-biotin pretargeting approach to target 90Y-biotin to the tumour in patients with recurrent high grade glioma. The encouraging results obtained in this phase I-II study prompted us to apply the same approach in an adjuvant setting, to evaluate (i) time to relapse and (ii) overall survival. We enrolled 37 high grade glioma patients, 17 with grade III glioma and 20 with glioblastoma, in a controlled open non-randomized study. All patients received surgery and radiotherapy and were disease-free by neuroradiological examinations. Nineteen patients (treated) received adjuvant treatment with radioimmunotherapy. In the treated glioblastoma patients, median disease-free interval was 28 months (range=9-59); median survival was 33.5 months and one patient is still without evidence of disease. All 12 control glioblastoma patients died after a median survival from diagnosis of 8 months. In the treated grade III glioma patients median disease-free interval was 56 months (range=15-60) and survival cannot be calculated as only two, within this group, died. Three-step radioimmunotherapy promises to have an important role as adjuvant treatment in high grade gliomas, particularly in glioblastoma where it impedes progression, prolonging time to relapse and overall survival. A further randomized trial is justified.

Dosimetry in radionuclide therapies with 90Y-conjugates: the IEO experience

The basis for a successful radionuclide therapy is a high and stable uptake of the radiopharmaceutical in the target tissue along with low activity concentration in other normal organs. The contribution of dosimetry in radionuclide therapy is to predict before the treatment the absorbed doses in tumor and normal organs, to identify the critical organs, to minimize any possible toxicity and to evaluate the maximum tolerated dose. We report our experience concerning pharmacokinetics and dosimetry of two 90Y-therapeutic protocols: 3-step pretargeting radioimmunotherapy (RIT) according to the biotin-avidin system and receptor mediated radionuclide therapy with the somatostatin analogue [DOTA-D-Phe1-Tyr3] octreotide named DOTATOC. For the dosimetric analysis, analogous approaches for the two radiolabeled compounds due to the similar pharmacokinetic characteristics were adopted; the MIRD formalism was applied, taking into account both the physical and the biological characteristics of the radioconjugate and patients' metabolism. In order to determine biological clearance, serial blood samples and complete urine collection were obtained up to 48 hours after injection; to evaluate biodistribution, several whole body scans were acquired. Both therapies showed the advantageous characteristics of a fast blood clearance and a predominantly renal excretion of the radiopharmaceuticals thus lowering the irradiation of the total body. Although pharmacokinetic characteristis were similar, different critical organs were found for the two therapies; in particular, some considerations regarding red marrow, spleen and kidneys were required. The results of our studies indicate that high activities of 90Y-biotin (3-step RIT) and 90Y-DOTATOC can be administered with acceptable radiation doses to normal organs.

Sentinel node biopsy in early vulvar cancer

Lymph node pathologic status is the most important prognostic factor in vulvar cancer; however, complete inguinofemoral node dissection is associated with significant morbidity. Lymphoscintigraphy associated with gamma-probe guided surgery reliably detects sentinel nodes in melanoma and breast cancer patients. This study evaluates the feasibility of the surgical identification of sentinel groin nodes using lymphoscintigraphy and a gamma-detecting probe in patients with early vulvar cancer. Technetium-99m-labelled colloid human albumin was administered perilesionally in 37 patients with invasive epidermoid vulvar cancer (T1-T2) and lymphoscintigraphy performed the day before surgery. An intraoperative gamma-detecting probe was used to identify sentinel nodes during surgery. A complete inguinofemoral node dissection was then performed. Sentinel nodes were submitted separately to pathologic evaluation. A total of 55 groins were dissected in 37 patients. Localization of the SN was successful in all cases. Eight cases had positive nodes: in all the sentinel node was positive; the sentinel node was the only positive node in five cases. Twenty-nine patients showed negative sentinel nodes: all of them were negative for lymph node metastases. Lymphoscintigraphy and sentinel-node biopsy under gamma-detecting probe guidance proved to be an easy and reliable method for the detection of sentinel node in early vulvar cancer. This technique may represent a true advance in the direction of less aggressive treatments in patients with vulvar cancer.

Biokinetics and dosimetry in patients administered with (111)In-DOTA-Tyr(3)-octreotide: implications for internal radiotherapy with (90)Y-DOTATOC

Recent advances in receptor-mediated tumour imaging have resulted in the development of a new somatostatin analogue, DOTA-dPhe(1)-Tyr(3)-octreotide. This new compound, named DOTATOC, has shown high affinity for somatostatin receptors, ease of labelling and stability with yttrium-90 and favourable biodistribution in animal models. The aim of this work was to evaluate the biodistribution and dosimetry of DOTATOC radiolabelled with indium-111, in anticipation of therapy trials with (90)Y-DOTATOC in patients. Eighteen patients were injected with DOTATOC (10 microg), labelled with 150-185 MBq of (111)In. Blood and urine samples were collected throughout the duration of the study (0-2 days). Planar and single-photon emission tomography images were acquired at 0.5, 3-4, 24 and 48 h and time-activity curves were obtained for organs and tumours. A compartmental model was used to determine the kinetic parameters for each organ. Dose calculations were performed according to the MIRD formalism. Specific activities of >37 GBq/ micromol were routinely achieved. Patients showed no acute or delayed adverse reactions. The residence time for (111)In-DOTATOC in blood was 0.9+/-0.4 h. The injected activity excreted in the urine in the first 24 h was 73%+/-11%. The agent localized primarily in spleen, kidneys and liver. The residence times in source organs were: 2.2+/-1.8 h in spleen, 1.7+/-1.2 h in kidneys, 2.4+/-1.9 h in liver, 1.5+/-0.3 h in urinary bladder and 9. 4+/-5.5 h in the remainder of the body; the mean residence time in tumour was 0.47 h (range: 0.03-6.50 h). Based on our findings, the predicted absorbed doses for (90)Y-DOTATOC would be 7.6+/-6.3 (spleen), 3.3+/-2.2 (kidneys), 0.7+/-0.6 (liver), 2.2+/-0.3 (bladder), 0.03+/-0.01 (red marrow) and 10.1 (range: 1.4-31.0) (tumour) mGy/MBq. These results indicate that high activities of (90)Y-DOTATOC can be administered with low risk of myelotoxicity, although with potentially high radiation doses to the spleen and kidneys. Tumour doses were high enough in most cases to make it likely that the desired therapeutic response desired would be obtained.

Acquisition protocol for breast cancer imaging with technetium-99m-labeled synthetic peptide and technetium-99m-MDP

Technetium-99m-MDP and, recently, a 99mTc-labeled synthetic decapentapeptide have been shown to localize in breast lesions. Our goal was to develop an acquisition protocol to improve image quality, to improve detection of axillary lymph nodes with disease and to compare the utility of the new radiotracer to 99mTc-MDP.

METHODS

Ninety-three patients with documented breast carcinoma were studied. Thirty-eight patients were studied in the supine position with anterior and lateral views: eight patients were injected intravenously with 600-740 MBq 99mTc-EPPT and 30 patients with the same activity of 99mTc-MDP. A second group of 55 patients was studied using the same total activity: 20 patients were injected with 99mTc-EPPT and 35 patients with 99mTc-MDP. To improve results, patients were positioned standing up with their arm raised. The breast with a marker over the nipple touched the collimator in the oblique-lateral position. Early planar images (2-5 min postinjection) were acquired with this positioning for the healthy and the tumor breast, collecting 1500 K counts in a 256 x 256 matrix. Imaging of the axillary regions was performed while the patients were positioned supine and a frontal image was obtained at 10-15 min postinjection for 1800 K counts.

RESULTS

This diagnostic study produced good quality images, with the breast lesions and axilla visualized. The positions had limitations due to the overlapping of other organs and to the proximity with the chest wall.

CONCLUSION

Using this protocol, all primary lesions and 50% of the axillary lymph nodes with 99mTc-MDP, and 35% with 99mTc-EPPT, were detected as documented by histology. Our protocol may represent an improvement in the diagnosis and staging of breast cancer.

[Pheochromocytoma diagnosed during quinapril therapy]

A hypertensive diabetic woman, who was resistant to any pharmacological therapy, underwent to check for secondary hypertension. The treatment with the particularly active ACE inhibitor quinapril failed but it suggested a procedure for a fast differential diagnosis of disease.

Visual decodification of some facial expressions through microimitation

We examined the level of muscular tension of mentalis muscle of 36 students in graphic design at rest and during the presentation of three slides reproducing facial expressions. Analysis showed an increase in the myographic level of mentalis muscle from the third second of measurement onwards after the presentation of the slide in which contraction of the chin was involved. We interpret this result by hypothesizing that the decodification of some facial expressions is realized through a microreproduction of the stimulus from the decodifying subject.