The effect of lymphocytes secretome on skeletal muscle stem cells regeneration with ageing

Older people experience skeletal muscle wasting, in part due to impaired proliferative capacity of quiescent skeletal muscle satellite cells and. The work presented in this thesis set out to examine the hypothesis that microenvironment of skeletal muscles can be influenced by immune cell secretions, which affect satellite cell proliferation, and that beneficial immune-muscle interactions in young people are blunted in elderly. The aim of this research was to investigate the role of ageing human lymphocytes on skeletal muscle cell behaviour. For this purpose, lymphocytes were isolated from whole blood of young (aged 18-25 years) and older (aged 78-85 years) healthy volunteers and older healthy volunteers. All the participants were healthy, with no history of muscle disease and not on immunosuppressant or corticosteroids treatment that affect immune function. Lymphocytes were cultured with, or without, anti-CD3/CD28 activators for 4 days to induce release of cytokines, interleukins and growth factors into the media. The secreted proteins were used to prepare conditioned media that were used to culture C2C12 myoblasts. Secretomes were analysed and fifteen secreted Th1/Th2 cytokines and IGF-I were quantified by multiplex immunoassay. The gene expression and protein concentrations of amphiregulin were determined from T-lymphocytes lysates by real-time PCR and ELISA respectively. The levels of CD25 and FoxP3 expression in lymphocytes were examined using flow cytometry. The expression of muscle transcription factors, MyoD and Myogenin were determined by real- time PCR. Activated Mek1/Erk1/2 and Akt/mTOR were measured by multiplex immunoassay. Our results demonstrate for the first time that a decrease in the levels of amphiregulin and CD25 coincides with the increase in FoxP3 with ageing, which may be involved in suppression of lymphocytes. Seven cytokines were differentially secreted by the young- compared with the old-activated lymphocytes. The secretome from young-activated lymphocytes had 30% (P<0.005) higher IGF-I concentrations compared with old and control treatments. The conditioned media from young -activated lymphocytes increased the rate of proliferation of myoblasts by ~3-fold (P<0.005) and caused an approximate 4-fold (P<0.005) increase in migration compared with non-activated lymphocyte control media. These responses were characterised the extended proliferation of young -treated myoblasts was also associated with a decrease in MyoD and Myogenin and an increase in mediators of proliferation Mek1/Erk1/2and a decrease in the key proteins for differentiation, Akt/mTOR. In contrast, myoblasts treated with conditioned media from old-activated lymphocytes exhibited a high degree of differentiation

Reconciliation or Alienation: The Representation of the Syrian Refugee Crisis in the Jordanian Print Media: Al-Ghad Newspaper as a Case Study

The influx of Syrian refugees to Jordan is considered one of the most serious social events that the country has witnessed in decades. The unprecedented flow of refugees that received extensive coverage by the Jordanian print media played an instrumental role in shaping the representation of both the event and the actors involved in the crisis. This paper departs from the premise that news reports are “elements of social events” and as such employ language to change, maintain or inculcate the knowledge, beliefs and social relations shared by members of a society. To this end, Critical Discourse Analysis (CDA) is adopted to investigate how Al-Ghad Newspaper uses language to represent and frame the Syrian refugee crisis and the Syrian refugees and considers whether this portrayal has contributed to the reconciliation or alienation of the Syrian refugees in the Jordanian society

Regenerative function of immune system: Modulation of muscle stem cells

Ageing is characterised by progressive deterioration of physiological systems and the loss of skeletal muscle mass is one of the most recognisable, leading to muscle weakness and mobility impairments. This review highlights interactions between the immune system and skeletal muscle stem cells (widely termed satellite cells or myoblasts) to influence satellite cell behaviour during muscle regeneration after injury, and outlines deficits associated with ageing. Resident neutrophils and macrophages in skeletal muscle become activated when muscle fibres are damaged via stimuli (e.g. contusions, strains, avulsions, hyperextensions, ruptures) and release high concentrations of cytokines, chemokines and growth factors into the microenvironment. These localised responses serve to attract additional immune cells which can reach in excess of 1 × 105 immune cell/mm3 of skeletal muscle in order to orchestrate the repair process. T-cells have a delayed response, reaching peak activation roughly 4 days after the initial damage. The cytokines and growth factors released by activated T-cells play a key role in muscle satellite cell proliferation and migration, although the precise mechanisms of these interactions remain unclear. T-cells in older people display limited ability to activate satellite cell proliferation and migration which is likely to contribute to insufficient muscle repair and, consequently, muscle wasting and weakness. If the factors released by T-cells to activate satellite cells can be identified, it may be possible to develop therapeutic agents to enhance muscle regeneration and reduce the impact of muscle wasting during ageing and disease

The lymphocyte secretome from young adults enhances skeletal muscle proliferation and migration, but effects are attenuated in the secretome of older adults.

Older people experience skeletal muscle wasting, in part due to impaired proliferative capacity of quiescent skeletal muscle satellite cells which can be reversed by exposure to young blood. To investigate the role of immune cells in muscle regeneration, we isolated lymphocytes from whole blood of young and older healthy volunteers and cultured them with, or without, anti-CD3/CD28 activators to induce release of cytokines, interleukins, and growth factors into the media. The secreted proteins were collected to prepare a conditioned media, which was subsequently used to culture C2C12 myoblasts. The conditioned media from the activated young lymphocytes increased the rate of proliferation of myoblasts by around threefold (P < 0.005) and caused an approximate fourfold (P < 0.005) increase in migration compared with nonactivated lymphocyte control media. These responses were characterized by minimal myotube formation (2%), low fusion index (5%), low myosin heavy chain content, and substantial migration. In contrast, myoblasts treated with conditioned media from activated old lymphocytes exhibited a high degree of differentiation, and multi-nucleated myotube formation that was comparable to control conditions, thus showing no effect on proliferation or migration of myoblasts. These results indicate that secreted proteins from lymphocytes of young people enhance the muscle cell proliferation and migration, whereas secreted proteins from lymphocytes of older people may contribute to the attenuated skeletal muscle satellite cell proliferation and migration

Soluble factors released from activated T-lymphocytes regulate C2C12 myoblast proliferation and cellular signalling, but effects are blunted in the elderly.

The key objective of this work was to investigate the impact of young and old human lymphocyte secretomes on C2C12 myoblasts regeneration. Conditioned media (CMs) were harvested from isolated young and older lymphocytes treated with (activated AC), or without (non-activated NA), anti-CD3/CD28 activators for 4 days. AC conditioned media from older lymphocytes had decreased levels of amphiregulin (367±208pg/ml vs. 904±323pg/ml; p=0.018) and IGF-I (845±88ng/ml vs. 1100±48ng/ml; p=0.032) compared with younger AC. AC older vs younger lymphocytes had reduced expression of CD25 (24.6±5.5%; p=0.0003) and increased expression of FoxP3 (35±15.7%; p=0.032). Treatment of C2C12 myoblasts with young AC resulted in decreased expression of MyoD (0.46±0.12; p=0.004) and Myogenin (0.34±0.05; p=0.010) mRNA, increased activation of MEk1 (724±140 MFI; p=0.001) and ERK1/2 (3768±314 MFI; p=0.001) and a decreased activation of Akt (74.5±4 MFI; p=0.009) and mTOR (61.8±7 MFI; p=0.001) compared with old AC. By contrast, C2C12 myoblasts treated with older AC displayed increased expression of MyoD (0.7±0.08; p=0.004) and Myogenin (0.68±0.05; p=0.010) mRNA, decreased phosphorylation of MEk1 and ERK1/2 (528±80 MFI; p=0.008, and 1141±668 MFI; p=0.001, respectively) and increased Akt/mTOR activation (171±35 MFI; p=0.009, and 184±33 MFI; p=0.001, respectively). These data provide new evidence that differences between older and younger lymphocyte secretomes contribute to differential responses of C2C12 myoblasts in culture

Evaluation of a task-based community oriented teaching model in family medicine for undergraduate medical students in Iraq

BACKGROUND: The inclusion of family medicine in medical school curricula is essential for producing competent general practitioners. The aim of this study is to evaluate a task-based, community oriented teaching model of family medicine for undergraduate students in Iraqi medical schools. METHODS: An innovative training model in family medicine was developed based upon tasks regularly performed by family physicians providing health care services at the Primary Health Care Centre (PHCC) in Mosul, Iraq. Participants were medical students enrolled in their final clinical year. Students were assigned to one of two groups. The implementation group (28 students) was exposed to the experimental model and the control group (56 students) received the standard teaching curriculum. The study took place at the Mosul College of Medicine and at the Al-Hadba PHCC in Mosul, Iraq, during the academic year 1999–2000. Pre- and post-exposure evaluations comparing the intervention group with the control group were conducted using a variety of assessment tools. RESULTS: The primary endpoints were improvement in knowledge of family medicine and development of essential performance skills. Results showed that the implementation group experienced a significant increase in knowledge and performance skills after exposure to the model and in comparison with the control group. Assessment of the model by participating students revealed a high degree of satisfaction with the planning, organization, and implementation of the intervention activities. Students also highly rated the relevancy of the intervention for future work. CONCLUSION: A model on PHCC training in family medicine is essential for all Iraqi medical schools. The model is to be implemented by various relevant departments until Departments of Family medicine are established

Risk factors for pre-term birth in Iraq: a case-control study

BACKGROUND: Preterm birth (PTB)is a major clinical problem associated with perinatal mortality and morbidity. The aim of the present study is to identify risk factors associated with PTB in Mosul, Iraq. METHODS: A case-control study was conducted in Mosul, Iraq, from 1(st )September, 2003 to 28(th )February, 2004. RESULTS: A total of 200 cases of PTB and 200 controls of full-term births were screened and enrolled in the study. Forward logistic regression analysis was used in the analysis. Several significant risk associations between PTB and the following risk factors were identified: poor diet (OR = 4.33), heavy manual work (OR = 1.70), caring for domestic animals (OR = 5.06), urinary tract infection (OR = 2.85), anxiety (OR = 2.16), cervical incompetence (OR = 4.74), multiple pregnancies (OR = 7.51), direct trauma to abdomen (OR = 3.76) and abortion (OR = 6.36). CONCLUSION: The main determinants of PTB in Iraq were low socio-economic status and factors associated with it, such as heavy manual work and caring for domestic animals, in addition to urinary tract infections and poor obstetric history

Treatment outcomes for children with multidrug-resistant tuberculosis: a systematic review and meta-analysis

BACKGROUND: Paediatric multidrug-resistant (MDR) tuberculosis is a public health challenge of growing concern, accounting for an estimated 15% of all global cases of MDR tuberculosis. Clinical management is especially challenging, and recommendations are based on restricted evidence. We aimed to assess existing evidence for the treatment of MDR tuberculosis in children. METHODS: We did a systematic review and meta-analysis of published and unpublished studies reporting treatment outcomes for children with MDR tuberculosis. We searched PubMed, Ovid, Embase, Cochrane Library, PsychINFO, and BioMedCentral databases up to Oct 31, 2011. Eligible studies included five or more children (aged ≤16 years) with MDR tuberculosis within a defined treatment cohort. The primary outcome was treatment success, defined as a composite of cure and treatment completion. RESULTS: We identified eight studies, which reported treatment outcomes for a total of 315 patients. We recorded much variation in the characteristics of patients and programmes. Time to appropriate treatment varied from 2 days to 46 months. Average duration of treatment ranged from 6 months to 34 months, and duration of follow-up ranged from 12 months to 37 months. The pooled estimate for treatment success was 81·67% (95% CI 72·54-90·80). Across all studies, 5·9% (95% CI 1·3-10·5) died, 6·2% (2·3-10·2) defaulted, and 39·1% (28·7-49·4) had an adverse event. The most common drug-related adverse events were nausea and vomiting. Other serious adverse events were hearing loss, psychiatric effects, and hypothyroidism. INTERPRETATION: The treatment of paediatric MDR tuberculosis has been neglected, but when children are treated outcomes can be achieved that are at least as good as those reported for adults. Programmes should be encouraged to report outcomes in children to improve the knowledge base for care, especially as new drugs become available. FUNDING: None