Metformin (MET) is the drug of choice for patients with type 2 diabetes and has been proposed for use in cancer therapy and for treating other metabolic diseases. More than 14,000 studies have been published addressing the cellular mechanisms affected by MET. However, several in vitro studies have used concentrations of the drug 10-100-fold higher than the plasmatic concentration measured in patients. Here, we evaluated the biochemical, metabolic, and morphologic effects of various concentrations of MET. Moreover, we tested the effect of MET on Fanconi Anemia (FA) cells, a DNA repair genetic disease with defects in energetic and glucose metabolism, as well as on human promyelocytic leukemia (HL60) cell lines. We found that the response of wild-type cells to MET is concentration dependent. Low concentrations (15 and 150 µM) increase both oxidative phosphorylation and the oxidative stress response, acting on the AMPK/Sirt1 pathway, while the high concentration (1.5 mM) inhibits the respiratory chain, alters cell morphology, becoming toxic to the cells. In FA cells, MET was unable to correct the energetic/respiratory defect and did not improve the response to oxidative stress and DNA damage. By contrast, HL60 cells appear sensitive also at 150 μM. Our findings underline the importance of the MET concentration in evaluating the effect of this drug on cell metabolism and demonstrate that data obtained from in vitro experiments, that have used high concentrations of MET, cannot be readily translated into improving our understanding of the cellular effects of metformin when used in the clinical setting.

Emerging evidence demonstrates that targeting energy metabolism is a promising strategy to fight cancer. Here we show that combining metformin and short-term starvation markedly impairs metabolism and growth of colon and breast cancer. The impairment in glycolytic flux caused by starvation is enhanced by metformin through its interference with hexokinase II activity, as documented by measurement of 18F-fluorodeoxyglycose uptake. Oxidative phosphorylation is additively compromised by combined treatment: metformin virtually abolishes Complex I function; starvation determines an uncoupled status of OXPHOS and amplifies the activity of respiratory Complexes II and IV thus combining a massive ATP depletion with a significant increase in reactive oxygen species. More importantly, the combined treatment profoundly impairs cancer glucose metabolism and virtually abolishes lesion growth in experimental models of breast and colon carcinoma. Our results strongly suggest that energy metabolism is a promising target to reduce cancer progression.

Exosomes are secreted nanovesicles that are able to transfer RNA and proteins to target cells. The emerging role of mesenchymal stem cell (MSC) exosomes as promoters of aerobic ATP synthesis restoration in damaged cells, prompted us to assess whether they contain an extramitochondrial aerobic respiration capacity. Exosomes were isolated from culture medium of human MSC from umbilical cord of ≥37-wk-old newborns or between 28- to 30-wk-old newborns (i.e., term or preterm infants). Characterization of samples was conducted by cytofluorometry. Oxidative phosphorylation capacity was assessed by Western blot analysis, oximetry, and luminometric and fluorometric analyses. MSC exosomes express functional respiratory complexes I, IV, and V, consuming oxygen. ATP synthesis was only detectable in exosomes from term newborns, suggestive of a specific mechanism that is not completed at an early gestational age. Activities are outward facing and comparable to those detected in mitochondria isolated from term MSC. MSC exosomes display an unsuspected aerobic respiratory ability independent of whole mitochondria. This may be relevant for their ability to rescue cell bioenergetics. The differential oxidative metabolism of preterm vs. term exosomes sheds new light on the preterm newborn's clinical vulnerability. A reduced ability to repair damaged tissue and an increased capability to cope with anoxic environment for preterm infants can be envisaged.-Panfoli, I., Ravera, S., Podestà, M., Cossu, C., Santucci, L., Bartolucci, M., Bruschi, M., Calzia, D., Sabatini, F., Bruschettini, M., Ramenghi, L. A., Romantsik, O., Marimpietri, D., Pistoia, Vi., Ghiggeri, G., Frassoni, F., Candiano, G. Exosomes from human mesenchymal stem cells conduct aerobic metabolism in term and preterm newborn infants.

Although almost 90% of the world population of children and adolescents live in low-and middle-income countries, few trials of psychosocial interventions to prevent child mental health problems have been conducted in these countries. 1 Early-onset conduct problems are the most common mental health concern in childhood, affecting 5-8% of the population at the severity level for an ICD-10 diagnosis. 2 Long-term outcomes are very poor, with three-to sixfold increases in the prevalence of adult criminal violence, drug misuse, school failure, teenage pregnancy and unemployment. 3 Although proven preventative interventions exist, they reach few children, even in high-income countries. This problem is amplified in low-and middle-income countries where child mental health services are extremely limited. 4,5 Schools offer a logical setting for interventions for children, and school-based violence prevention programmes in high-income countries have shown significant reductions to children's aggressive and disruptive behaviour and increases in child competencies. Universal interventions promote the mental health of all children, avoid stigmatisation and generally attract community support. 6 However, there is limited information on the effectiveness of these programmes in low-and middle-income countries where schools often have few resources and poor conditions. In Jamaica, violence among youth and adults is particularly prevalent. 7 However, there are good opportunities for early intervention as 98% of 3-to 6-year-old children attend pre-schools so there is potential for almost universal coverage. In pilot studies we implemented the Incredible Years Teacher Training programme and showed large benefits to teachers' practices and to class-wide measures of child behaviour, 8 and also demonstrated that the intervention was acceptable, feasible and relevant. 9 The aim of this study was to evaluate on a larger scale the effect of the intervention on the behaviour of high-risk children at home and at school. Method Study design and participants A cluster randomised trial was conducted in the school year in 24 community pre-schools in inner-city areas of Kingston, Jamaica. Over 75% of preschool children in Jamaica attend community pre-schools, which are provided through community organisations with government oversight. Parents pay a small fee and also provide school materials such as books and pencils. Most teachers are paraprofessionals and the schools generally have poor physical conditions, including overcrowding and few teaching and learning materials. We used 'pre-school' as the unit of randomisation to prevent contamination among teachers. Inclusion criteria for pre-schools were: three to four classes of children, at least 20 children per class, situated in a specified geographical area and all teachers consented to the trial. In total, 50 pre-schools were approached and 24 meeting the inclusion criteria were recruited (Fig. 1). Children at high risk for subsequent externalising problems were selected for evaluation. 2 An interviewer-administered screening questionnaire was conducted with each teacher. Teachers rated each child on ten items from the ICD-10 Diagnostic Criteria for Research 10 for conduct disorder (loses temper, back chats, disobedient/breaks rules, annoys others, blames others, easily annoyed, often angry, spiteful to others, fights or bullies and destroys property), using a four-point scale. The three children from each class with the highest scores were enrolled. Background There is an urgent need for effective, affordable interventions to prevent child mental health problems in low-and middle-income countries.

Cancer metabolism is characterized by an accelerated glycolytic rate facing reduced activity of oxidative phosphorylation. This "Warburg effect" represents a standard to diagnose and monitor tumor aggressiveness with (18)F-fluorodeoxyglucose whose uptake is currently regarded as an accurate index of total glucose consumption. Studying cancer metabolic response to respiratory chain inhibition by metformin, we repeatedly observed a reduction of tracer uptake facing a marked increase in glucose consumption. This puzzling discordance brought us to discover that (18)F-fluorodeoxyglucose preferentially accumulates within endoplasmic reticulum by exploiting the catalytic function of hexose-6-phosphate-dehydrogenase. Silencing enzyme expression and activity decreased both tracer uptake and glucose consumption, caused severe energy depletion and decreased NADPH content without altering mitochondrial function. These data document the existence of an unknown glucose metabolism triggered by hexose-6-phosphate-dehydrogenase within endoplasmic reticulum of cancer cells. Besides its basic relevance, this finding can improve clinical cancer diagnosis and might represent potential target for therapy.

Aging is a physiological process in which multifactorial processes determine a progressive decline. Several alterations contribute to the aging process, including telomere shortening, oxidative stress, deregulated autophagy and epigenetic modifications. In some cases, these alterations are so linked with the aging process that it is possible predict the age of a person on the basis of the modification of one specific pathway, as proposed by Horwath and his aging clock based on DNA methylation. Because the energy metabolism changes are involved in the aging process, in this work, we propose a new aging clock based on the modifications of glucose catabolism. The biochemical analyses were performed on mononuclear cells isolated from peripheral blood, obtained from a healthy population with an age between 5 and 106 years. In particular, we have evaluated the oxidative phosphorylation function and efficiency, the ATP/AMP ratio, the lactate dehydrogenase activity and the malondialdehyde content. Further, based on these biochemical markers, we developed a machine learning-based mathematical model able to predict the age of an individual with a mean absolute error of approximately 9.7 years. This mathematical model represents a new non-invasive tool to evaluate and define the age of individuals and could be used to evaluate the effects of drugs or other treatments on the early aging or the rejuvenation.