Introducing extended consultations for patients with severe mental illness in general practice: Results from the SOFIA feasibility study

BACKGROUND

People with a severe mental illness (SMI) have shorter life expectancy and poorer quality of life compared to the general population. Most years lost are due to cardiovascular disease, respiratory disease, and various types of cancer. We co-designed an intervention to mitigate this health problem with key stakeholders in the area, which centred on an extended consultations for people with SMI in general practice. This study aimed to1) investigate general practitioners' (GPs) experience of the feasibility of introducing extended consultations for patients with SMI, 2) assess the clinical content of extended consultations and how these were experienced by patients, and 3) investigate the feasibility of identification, eligibility screening, and recruitment of patients with SMI.

METHODS

The study was a one-armed feasibility study. We planned that seven general practices in northern Denmark would introduce extended consultations with their patients with SMI for 6 months. Patients with SMI were identified using practice medical records and screened for eligibility by the patients' GP. Data were collected using case report forms filled out by practice personnel and via qualitative methods, including observations of consultations, individual semi-structured interviews, a focus group with GPs, and informal conversations with patients and general practice staff.

RESULTS

Five general practices employing seven GPs participated in the study, which was terminated 3 ½ month ahead of schedule due to the COVID-19 pandemic. General practices attempted to contact 57 patients with SMI. Of these, 38 patients (67%) attended an extended consultation, which led to changes in the somatic health care plan for 82% of patients. Conduct of the extended consultations varied between GPs and diverged from the intended conduct. Nonetheless, GPs found the extended consultations feasible and, in most cases, beneficial for the patient group. In interviews, most patients recounted the extended consultation as beneficial.

DISCUSSION

Our findings suggest that it is feasible to introduce extended consultations for patients with SMI in general practice, which were also found to be well-suited for eliciting patients' values and preferences. Larger studies with a longer follow-up period could help to assess the long-term effects and the best implementation strategies of these consultations.

Understanding primary care transformation and implications for ageing populations and health inequalities: a systematic scoping review of new models of primary health care in OECD countries and China

BACKGROUND

Many countries have introduced reforms with the aim of primary care transformation (PCT). Common objectives include meeting service delivery challenges associated with ageing populations and health inequalities. To date, there has been little research comparing PCT internationally. Our aim was to examine PCT and new models of primary care by conducting a systematic scoping review of international literature in order to describe major policy changes including key 'components', impacts of new models of care, and barriers and facilitators to PCT implementation.

METHODS

We undertook a systematic scoping review of international literature on PCT in OECD countries and China (published protocol: https://osf.io/2afym ). Ovid [MEDLINE/Embase/Global Health], CINAHL Plus, and Global Index Medicus were searched (01/01/10 to 28/08/21). Two reviewers independently screened the titles and abstracts with data extraction by a single reviewer. A narrative synthesis of findings followed.

RESULTS

A total of 107 studies from 15 countries were included. The most frequently employed component of PCT was the expansion of multidisciplinary teams (MDT) (46% of studies). The most frequently measured outcome was GP views (27%), with  < 20% measuring patient views or satisfaction. Only three studies evaluated the effects of PCT on ageing populations and 34 (32%) on health inequalities with ambiguous results. For the latter, PCT involving increased primary care access showed positive impacts whilst no benefits were reported for other components. Analysis of 41 studies citing barriers or facilitators to PCT implementation identified leadership, change, resources, and targets as key themes.

CONCLUSIONS

Countries identified in this review have used a range of approaches to PCT with marked heterogeneity in methods of evaluation and mixed findings on impacts. Only a minority of studies described the impacts of PCT on ageing populations, health inequalities, or from the patient perspective. The facilitators and barriers identified may be useful in planning and evaluating future developments in PCT.

The SOFIA pilot trial: a cluster-randomized trial of coordinated, co-produced care to reduce mortality and improve quality of life in people with severe mental illness in the general practice setting

Background

People with severe mental illness (SMI) have an increased risk of premature mortality, predominantly due to somatic health conditions. Evidence indicates that primary and tertiary prevention and improved treatment of somatic conditions in patients with SMI could reduce this excess mortality. This paper reports a protocol designed to evaluate the feasibility of a coordinated co-produced care program (SOFIA model, a Danish acronym for Severe Mental Illness and Physical Health in General Practice) in the general practice setting to reduce mortality and improve quality of life in patients with severe mental illness.

Methods

The SOFIA pilot trial is designed as a cluster randomized controlled trial targeting general practices in two regions in Denmark. We aim to include 12 practices, each of which is instructed to recruit up to 15 community-dwelling patients aged 18 and older with SMI. Practices will be randomized by a computer in a ratio of 2:1 to deliver a coordinated care program or usual care during a 6-month study period. A randomized algorithm is used to perform randomization. The coordinated care program includes educational training of general practitioners and their clinical staff educational training of general practitioners and their clinical staff, which covers clinical and diagnostic management and focus on patient-centered care of this patient group, after which general practitioners will provide a prolonged consultation focusing on individual needs and preferences of the patient with SMI and a follow-up plan if indicated. The outcomes will be parameters of the feasibility of the intervention and trial methods and will be assessed quantitatively and qualitatively. Assessments of the outcome parameters will be administered at baseline, throughout, and at end of the study period.

Discussion

If necessary the intervention will be revised based on results from this study. If delivery of the intervention, either in its current form or after revision, is considered feasible, a future, definitive trial to determine the effectiveness of the intervention in reducing mortality and improving quality of life in patients with SMI can take place. Successful implementation of the intervention would imply preliminary promise for addressing health inequities in patients with SMI.

Trial registration

The trial was registered in Clinical Trials as of November 5, 2020, with registration number NCT04618250.

Protocol version: January 22, 2021; original version

The association between secondary care multimorbidity in mid-life and premature mortality

Background

Multimorbidity (MM) is the co-existence of two or more health conditions. Whilst its prevalence is higher in older adults, in absolute numbers there are more multimorbid young people. Recently, the trends for increasing life expectancy observed in high income countries have stalled or reversed. The relationship between MM and premature mortality requires exploration. We assessed the prevalence of secondary care MM in mid-life and its association with premature mortality in the Scottish Aberdeen Children of the 1950s (ACONF) cohort.

Methods

Prospective cohort study. ACONF members were linked to electronic hospital records and mortality records. Secondary care MM was assessed using hospital records in 2001 when participants were aged 45-51 years. The association between MM and mortality over 15 years (to age 60-66 years) was assessed using Cox proportional hazards regression. There was adjustment for key covariates: age, gender, social class at birth, childhood intelligence, educational attainment, alcohol, smoking, body mass index and adult social class.

Results

Of 9,625 participants (51% male), 3% had MM. Higher childhood intelligence and adult social class were associated with reduced MM. In relation to the reference group (no MM), those with MM had a mortality hazard ratio of 4.5 (95% CI 3.4-6.0) over 15 years. The association remained when adjusted for the covariates (2.5 [95% CI 1.5-4.0]).

Conclusions

Secondary care MM prevalence was 3% in mid-life and associated with premature mortality. Younger adults with MM are an important group at risk of premature mortality which should be the focus of public health action. This includes reducing the impact of social inequality and reconfiguring secondary care services to offer comprehensive management of younger multimorbid adults.

Key messages

Multimorbidity in mid-life is associated with premature mortality and may be an important influence on reducing life expectancy trends. Much focus is upon multimorbidity in older adults, however younger adults with multimorbidity are at risk of premature mortality, requiring public health action.

The association between psychological distress in mid-life and hospital-based multimorbidity

Background

Mental ill-health is common with significant impact on individuals and services. Using healthcare records to identify poor mental health missed individuals who do not seek healthcare treatment. A screening questionnaire (General Health Questionnaire (GHQ)) can detect psychological distress. However, before considering implementing such a screening tool, we need to understand if it detects those at high risk of experiencing poorer outcomes. Hospital-based multimorbidity is a rising healthcare challenge. The aim was to assess the prevalence of psychological distress in mid-life and its influence on hospital-based multimorbidity by older age in the Aberdeen Children of the 1950s (ACONF) cohort.

Methods

Prospective cohort study using ACONF. GHQ-4 was measured in mid-life from questionnaire. Multimorbidity (2 or more co-existing conditions) was measured using linked hospital records in older age (15 years after the questionnaire). The relationship between psychological distress (GHQ-4 score of 1 or more) and multimorbidity was assessed using logistic regression with adjustment for key life-course variables.

Results

Of 5,839 individuals (48% male, mean age 48), psychological distress prevalence was 20% and was associated with being female, lower childhood cognition, lower educational attainment, lower adult social class, unemployment, higher adult body mass index, smoking and alcohol misuse. In comparison to the asymptomatic reference group, the odds ratio for multimorbidity in older age in those with psychological distress was 2.2 (95% CI 1.8-2.7) in the unadjusted model. In the adjusted model this was 1.4 (95% CI 1.1-1.8).

Conclusions

1 in 5 individuals in the general population in mid-life had psychological distress. This was associated with hospital-based multimorbidity by older age. Intervening early could reduce costs to both individuals and healthcare services. The next step is research of the cost-effectiveness of population screening for psychological distress.

Key messages

Psychological distress in mid-life is associated with hospital-based multimorbidity by older age. Screening for psychological distress early in life should be explored as an intervention to reduce costs to individuals and healthcare services.

Patients with more comorbidities have better detection but poorer management of chronic diseases

Background

The burden of non-communicable diseases (NCDs) is rising rapidly in middle-income countries (MICs), where NCDs are often undiagnosed, untreated and uncontrolled. How comorbidity impacts diagnosis, treatment, and control of NCDs is an emerging area of research inquiry and have significant clinical implications as highlighted in the recent National Institute for Care Excellence (NICE) guidelines for treating patients suffering from multiple NCDs. This is the first study to examine the association between increasing numbers of comorbidities with being undiagnosed, intreated, and uncontrolled for NCDs, in six large MICs.

Methods

Cross-sectional analysis of WHO SAGE Wave 1 (2007-10), which consisted of adults aged ≥18 years from six populous MICs including, China, Ghana, India, Mexico, Russia and South Africa (overall n = 41, 557).

Results

Higher number of comorbidities was associated with better detection of hypertension, angina and arthritis, and better odds of having treatment for hypertension and angina. However, increasing comorbidity had the opposite effect on being uncontrolled, and was associated with increased odds of uncontrolled hypertension, angina, arthritis, and asthma. Comorbidity with concordant conditions was associated with improved diagnosis and treatment of hypertension and angina. Comorbidity with concordant conditions was not associated with decreased nor increased odds of being uncontrolled for all NCDs.

Conclusions

Patients with more comorbidities have better diagnosis of chronic conditions, but this does not translate into better management and control of these conditions. Improving continuity of care and monitoring treatment are priorities for health systems with ageing populations.

Key messages

Patients with more comorbidities have better diagnosis of chronic conditions. but this does not translate into better management and control of these conditions.

Multimorbidity and functional impairment-bidirectional interplay, synergistic effects and common pathways

This review discusses the interplay between multimorbidity (i.e. co-occurrence of more than one chronic health condition in an individual) and functional impairment (i.e. limitations in mobility, strength or cognition that may eventually hamper a person's ability to perform everyday tasks). On the one hand, diseases belonging to common patterns of multimorbidity may interact, curtailing compensatory mechanisms and resulting in physical and cognitive decline. On the other hand, physical and cognitive impairment impact the severity and burden of multimorbidity, contributing to the establishment of a vicious circle. The circle may be further exacerbated by people's reduced ability to cope with treatment and care burden and physicians' fragmented view of health problems, which cause suboptimal use of health services and reduced quality of life and survival. Thus, the synergistic effects of medical diagnoses and functional status in adults, particularly older adults, emerge as central to assessing their health and care needs. Furthermore, common pathways seem to underlie multimorbidity, functional impairment and their interplay. For example, older age, obesity, involuntary weight loss and sedentarism can accelerate damage accumulation in organs and physiological systems by fostering inflammatory status. Inappropriate use or overuse of specific medications and drug-drug and drug-disease interactions also contribute to the bidirectional association between multimorbidity and functional impairment. Additionally, psychosocial factors such as low socioeconomic status and the direct or indirect effects of negative life events, weak social networks and an external locus of control may underlie the complex interactions between multimorbidity, functional decline and negative outcomes. Identifying modifiable risk factors and pathways common to multimorbidity and functional impairment could aid in the design of interventions to delay, prevent or alleviate age-related health deterioration; this review provides an overview of knowledge gaps and future directions.

Multimorbidity and mortality: A 15-year longitudinal registry-based nationwide Danish population study

BACKGROUND

Knowledge about prevalent and deadly combinations of multimorbidity is needed.

OBJECTIVE

To determine the nationwide prevalence of multimorbidity and estimate mortality for the most prevalent combinations of one to five diagnosis groups. Furthermore, to assess the excess mortality of the combination of two groups compared to the product of mortality associated with the single groups.

DESIGN

A prospective cohort study using Danish registries and including 3.986.209 people aged ≥18 years on 1 January, 2000. Multimorbidity was defined as having diagnoses from at least 2 of 10 diagnosis groups: lung, musculoskeletal, endocrine, mental, cancer, neurological, gastrointestinal, cardiovascular, kidney, and sensory organs. Logistic regression (odds ratios, ORs) and ratio of ORs (ROR) were used to study mortality and excess mortality.

RESULTS

Prevalence of multimorbidity was 7.1% in the Danish population. The most prevalent combination was the musculoskeletal-cardiovascular (0.4%), which had double the mortality (OR, 2.03) compared to persons not belonging to any of the diagnosis groups but showed no excess mortality (ROR, 0.97). The neurological-cancer combination had the highest mortality (OR, 6.35), was less prevalent (0.07%), and had no excess mortality (ROR, 0.94). Cardiovascular-lung was moderately prevalent (0.2%), had high mortality (OR, 5.75), and had excess mortality (ROR, 1.18). Endocrine-kidney had high excess mortality (ROR, 1.81) and cancer-mental had low excess mortality (ROR, 0.66). Mortality increased with the number of groups.

CONCLUSIONS

All combinations had increased mortality risk with some of them having up to a six-fold increased risk. Mortality increased with the number of diagnosis groups. Most combinations did not increase mortality above that expected, that is, were additive rather than synergistic.

Comorbidities in adults with asthma: Population-based cross-sectional analysis of 1.4 million adults in Scotland

BACKGROUND

Comorbidity in people with asthma can significantly increase asthma morbidity and lower adherence to asthma guidelines.

OBJECTIVE

The objective of this study was to comprehensively measure the prevalence of physical and mental health comorbidities in adults with asthma using a large nationally representative population.

METHODS

Cross-sectional analysis of routine primary care electronic medical records for 1 424 378 adults in the UK, examining the prevalence of 39 comorbidities in people with and without asthma, before and after adjustment for age, sex, social deprivation and smoking status using logistic regression.

RESULTS

Of 39 comorbidities measured, 36 (92%) were significantly more common in adults with asthma; 62.6% of adults with asthma had ≥1 comorbidity vs 46.2% of those without, and 16.3% had ≥4 comorbidities vs 8.7% of those without. Comorbidities with the largest absolute increase in prevalence in adults with asthma were as follows: chronic obstructive pulmonary disease (COPD) (13.4% vs 3.1%), depression (17.3% vs 9.1%), painful conditions (15.4% vs 8.4%) and dyspepsia (10.9% vs 5.2%). Comorbidities with the largest relative difference in adults with asthma compared to those without were as follows: COPD (adjusted odds ratio [aOR] 5.65, 95% CI 5.52-5.79), bronchiectasis (aOR 4.65, 95% CI 4.26-5.08), eczema/psoriasis (aOR 3.30, 95% CI 3.14-3.48), dyspepsia (aOR 2.20, 95% CI 2.15-2.25) and chronic sinusitis (aOR 2.12, 95% CI 1.99-2.26). Depression and anxiety were more common in adults with asthma (aOR 1.60, 95% CI 1.57-1.63, and aOR 1.53, 95% CI 1.48-1.57, respectively).

CONCLUSIONS AND CLINICAL RELEVANCE

Physical and mental health comorbidities are the norm in adults with asthma. Appropriate recognition and management should form part of routine asthma care.

Mindfulness-based stress reduction in Parkinson's disease: a systematic review

BACKGROUND

Mindfulness based stress reduction (MBSR) is increasingly being used to improve outcomes such as stress and depression in a range of long-term conditions (LTCs). While systematic reviews on MBSR have taken place for a number of conditions there remains limited information on its impact on individuals with Parkinson's disease (PD).

METHODS

Medline, Central, Embase, Amed, CINAHAL were searched in March 2016. These databases were searched using a combination of MeSH subject headings where available and keywords in the title and abstracts. We also searched the reference lists of related reviews. Study quality was assessed based on questions from the Cochrane Collaboration risk of bias tool.

RESULTS

Two interventions and three papers with a total of 66 participants were included. The interventions were undertaken in Belgium (n = 27) and the USA (n = 39). One study reported significantly increased grey matter density (GMD) in the brains of the MBSR group compared to the usual care group. Significant improvements were reported in one study for a number of outcomes including PD outcomes, depression, mindfulness, and quality of life indicators. Only one intervention was of reasonable quality and both interventions failed to control for potential confounders in the analysis. Adverse events and reasons for drop-outs were not reported. There was also no reporting on the costs/benefits of the intervention or how they affected health service utilisation.

CONCLUSION

This systematic review found limited and inconclusive evidence of the effectiveness of MBSR for PD patients. Both of the included interventions claimed positive effects for PD patients but significant outcomes were often contradicted by other results. Further trials with larger sample sizes, control groups and longer follow-ups are needed before the evidence for MBSR in PD can be conclusively judged.

Vascular comorbidities in younger people with dementia: a cross-sectional population-based study of 616 245 middle-aged people in Scotland

INTRODUCTION

There is growing evidence of an aetiological relationship between vascular risk factors and the development of dementia in later life. Dementia in the under-65s has historically been considered to be more driven by genetic factors, but previous epidemiological studies in the young have been relatively small. This study aims to determine the prevalence of vascular comorbidity in people aged <65 with dementia in comparison to the general population.

METHODS

Analysis of routine clinical data from 314 (30%) general medical practices in Scotland.

RESULTS

From an overall population of 616 245 individuals, 1061 cases of 'all-cause' dementia were identified (prevalence 172/100 000 population, 95% CI 161 to 182). The prevalence of dementia was higher in people with vascular morbidities, and prevalence progressively increased from 129/100 000 in people with no vascular comorbidity to 999/100 000 in people with four or more (p=0.01). The strength of association was greatest with a previous transient ischaemic attack (TIA) or stroke and chronic kidney disease (adjusted OR=3.1 and 2.9, respectively). Statistically significant, but smaller associations were seen with the presence of hypertension, diabetes, ischaemic heart disease and peripheral vascular disease (adjusted OR=1.4, 2.0, 1.9 and 2.2, respectively).

DISCUSSIONS

Vascular comorbid diseases were more commonly recorded in people aged 40-64 with dementia than those without. This finding indicates that vascular disease may be more important in the aetiology of young-onset dementia than previously believed, and is of concern given the continuing rise in obesity and diabetes internationally.

A comparison of general practitioners prescribing of gluten-free foods for the treatment of coeliac disease with national prescribing guidelines

BACKGROUND

Coeliac disease is an autoimmune disorder that is considered to affect approximately one in 100 people. In the UK, gluten-free (GF) foods can be prescribed by general practitioners (GPs) to treat this condition and there are national guidelines on the quantities of GF food an individual should receive on prescription. Information on actual prescribing behaviour by GPs, and how this compares with guideline recommendations, is scarce. The present study aimed to describe GPs prescribing practice of GF foods, within one locality in the UK, comparing this with national guidelines.

METHODS

A retrospective evaluation of GP electronic medical records for all patients with a gluten-sensitive enteropathy diagnosis and/or those prescribed GF food between April 2010 and March 2011 was carried out in 16 GP practices in the west of Scotland, serving a total of 85 667 patients.

RESULTS

Of 175 (0.18% of the total practice population) patients, 152 were identified with coeliac disease, eight with dermatitis herpetiformis and six with both conditions. A further nine patients received GF foods on prescriptions with no recorded diagnosis. There was a positive association between adherence to the prescribing guidelines and female sex (P < 0.0001) and (for those with a recorded diagnosis) increasing age (P = 0.001). There was no significant association between either socio-economic deprivation or co-morbidities and adherence to the prescribing guidelines.

CONCLUSIONS

There was significant under prescribing of GF foods in those identified. Further research is required to establish whether these results are representative of wider practice in the UK.

Does vocational training in family medicine have an impact on antibiotic prescribing pattern?

BACKGROUND

Antibiotics overuse is common and is the major cause of antibiotic resistance. Rational use of antibiotics by GPs is essential as most health problems are exclusively dealt within primary care. Postgraduate family medicine (FM) training has become established in various countries over the last few decades but little is known about the effect of FM training on antibiotic prescribing.

OBJECTIVE

To determine whether GPs with FM training prescribe less antibiotics than those without training.

METHODS

GPs working in a pluralistic primary health care system took part in the 2007-08 primary care morbidity and management survey in Hong Kong and collected information of all consecutive patient encounters during predetermined weeks of data collection. Characteristics of GPs, training status, patient morbidity and antibiotic prescribing pattern were compared using multivariate regression analyses.

RESULTS

One hundred and nine GPs, of whom 67 had FM training, participated in the study and recorded 69 973 health problems. The overall antibiotic prescribing rate was 8.5% and that of GPs with FM training was 5.4% compared with the 13.3% among those without. Multivariate logistic regression showed that GPs with FM training were less likely to prescribe antibiotics (odds ratio 0.68, P < 0.05). They had lower antibiotic prescribing rates when managing upper respiratory tract infections, acute bronchitis and cough but higher in treating infective conjunctivitis and acute laryngitis.

CONCLUSIONS

Postgraduate FM training in Hong Kong is associated with significantly lower antibiotic prescribing rates. This supports the importance of FM training in rationalizing the use of antibiotics in Hong Kong.

A qualitative study of general practitioners' and practice nurses' attitudes to obesity management in primary care

OBJECTIVES

To examine general practitioners' (GPs) and practice nurses' (PNs) perceptions of obesity, their strategies and attitudes towards weight management, and their views on the major obstacles to (and need for) better weight management in primary care.

METHOD

A qualitative study was carried out using semi-structured interviews with GPs and PNS within the Greater Glasgow Healthboard area.

RESULTS

GPs and PNs understood the problem of obesity but generally had little enthusiasm for weight management. Most of the GPs felt it was an inappropriate use of their time and passed obese patients onto the PNs; the PNs felt that obese patients were "off-loaded" onto them. Stated management objectives were aimed at "healthy lifestyle" rather than "unrealistic" weight loss, yet frustration at "lack of success" was a major theme. Lack of motivation on the part of the patient was seen as the major problem. GPs were keener to be directly involved when a concomitant disease was present. Suggested requirements to improve weight management at the level of primary care included more time, better facilities, community dieticians and more training courses. However, many felt that Government, media and public health had to take a leading role in order to deal with the problem effectively.

CONCLUSIONS

A comprehensive and integrative primary care-led approach to weight management may be possible but will need substantial shifts of resources, organisation, training and attitudes in order to maximise its potential impact.

The development of resistance to the lipogenic effects of insulin in brown and white adipose tissue of spontaneously type II diabetic male CBA/Ca mice

1. Lipogenesis in brown adipose tissue and white adipose tissue (WAT) was measured in vivo in spontaneously type II diabetic male CBA/Ca mice. 2. Lipogenic rates rose sharply in brown adipose tissue between the third and fourth month of life, concomitant with the onset of hyperinsulinaemia. However, lipogenic rates fell between the fourth and fifth month of age, and remained low, despite increasing circulating insulin concentrations. 3. Lipogenesis in white adipose tissue showed a modest response to hyperinsulinaemia followed by increasing resistance to elevated insulin concentrations after 5 months of age. 4. Studies involving either the injection of insulin or the intubation of glucose provided further evidence for the development of insulin resistance in both brown and white adipose tissue.

The influence of starvation and natural refeeding on the rate of triacylglycerol/fatty acid substrate cycling in brown adipose tissue and different white adipose sites of the rat in vivo. The role of insulin and the sympathetic nervous system

Triacylglycerol/fatty acid substrate cycling was measured in vivo in brown adipose tissue (BAT) and white adipose tissue (WAT) of fed, starved and refed rats. Starvation (24h) significantly decreased the rate of cycling in BAT, and refeeding chow diet led to a rapid, 6-fold increase in cycling. Cycling rate in WAT was much lower than in BAT, and was not influenced by fasting or refeeding. Similar rates of cycling were found in epididymal, mesenteric, subcutaneous, and scapular WAT depots. Sympathetic denervation of interscapular BAT abolished the response of the tissue to refeeding, as did acute suppression of insulin secretion. Similarly, rats fasted for 3 days showed no acute increase in the activity of the cycle following refeeding.

Rapid inhibition by intragastric triolein of the re-activation of glucose utilization and lipogenesis in the mammary gland during the starved-refed transition in lactating rats. Evidence for a direct effect of oral lipid on mammary tissue

1. Oral administration of triacylglycerol (triolein) to starved/chow-refed lactating rats suppressed the lipogenic switch-on in the mammary gland in vivo. 2. A time-course study revealed that triolein, administered at 30 min after the onset of refeeding, had no influence on lipogenic rate in the mammary gland between 30 and 60 min, but markedly decreased it between 60 and 90 min. Glucose uptake by the mammary gland (arteriovenous difference) increased by 30 min of refeeding, as did lactate production. Between 30 and 90 min glucose uptake remained high in the control animals, but glucose uptake and net C3-unit uptake were decreased in the triolein-loaded animals by 90 min. 3. Triolein increased [glucose 6-phosphate] in the gland and simultaneously decreased [fructose 1,6-bisphosphate], indicative of a decrease in phosphofructokinase activity. This cross-over occurred at 60 min, i.e. immediately before the inhibition of lipogenesis, and by 90 min had reached 'starved' values. 4. Triolein had no effect on plasma [insulin] nor on whole-blood [glucose], [lactate] or [3-hydroxybutyrate]; a small increase in [acetoacetate] was observed. 5. Infusion of the lipoprotein lipase inhibitor, Triton WR1339, abolished the suppression of mammary-gland lipogenesis by triolein and the increase in the [glucose 6-phosphate]/[fructose 1,6-bisphosphate] ratio, suggesting a direct influence of dietary lipid on mammary-gland glucose utilization and phosphofructokinase activity.

Effect of high fat diets on energy balance and thermogenesis in brown adipose tissue of lean and genetically obese ob/ob mice

The effects on energy balance and brown adipose tissue thermogenesis of feeding high fat diets of differing fatty acid composition have been investigated in lean and genetically obese (ob/ob) mice. Groups of mice were fed either a low fat diet or a high fat diet based on corn oil or beef tallow for 2 wk. Energy intake and body weight gain were higher in both lean and obese animals fed the high fat diets than in respective mice fed the low fat diets. Carcass energy gain was greater for the obese than for the lean consuming each of the diets. Both lean and obese mice had a higher energy gain when fed the beef tallow diet than when fed the corn oil, despite isoenergetic intakes of the two diets. The thermogenic activity of brown adipose tissue, assessed from measurements of cytochrome oxidase activity and mitochondrial guanosine 5'-diphosphate (GDP) binding, were greater in both lean and obese mice fed the corn oil diet than in those fed the low fat diet. However, GDP binding and cytochrome oxidase activities in lean or obese mice fed the beef tallow diet were not different from those of mice of the same genotype fed the low fat diet. These results indicate that in both lean and obese (ob/ob) mice energy deposition and the stimulation of brown adipose tissue thermogenesis during the voluntary hyperphagia induced by feeding high fat diets are influenced by the fatty acid composition of the diet. A diet rich in polyunsaturated fatty acids appears to result in preferential stimulation of the thermogenic activity of brown adipose tissue, particularly in the ob/ob mouse.

The regulation of lipogenesis in vivo in the lactating mammary gland of the rat during the starved-refed transition. Studies wtih acarbose, a glucosidase inhibitor

Depression of carbohydrate digestion by oral administration of acarbose, a glucosidase inhibitor, led to a 75% inhibition of the re-activation of lipogenesis in vivo in the mammary gland of 18 h-starved lactating rats refed with 5 g of chow diet. Rates of [1-14C]glucose incorporation in vitro into lipid and CO2 in mammary-gland acini isolated from refed animals were elevated compared with acini from starved rats, but acarbose treatment completely prevented this stimulation. Gastric intubation of glucose led to a large stimulation of lipogenesis in the mammary gland of starved lactating rats, similar to that induced by refeeding with chow diet; this was dependent on the amount of glucose given and the time elapsed between glucose administration and injection of 3H2O for the measurement of lipogenesis. The switch-on of lipogenesis in the mammary gland of starved lactating rats, by refeeding or by intubation of glucose, was associated with a decrease in the ratio of [glucose 6-phosphate]/[fructose 1,6-bisphosphate] in the gland, indicative of an increase in phosphofructokinase activity. A time-course study revealed that the ratio decreased rapidly over the first 30 min of chow refeeding, after which a large surge in lipogenesis was seen. Acarbose, given 25 min after the onset of refeeding, led to a stepwise increase in the ratio, in parallel with the observed decrease in lipogenic activity. It is concluded that the control of lipogenesis in the mammary gland is closely linked to the availability of dietary carbohydrate. An important site of regulation of lipogenesis in the gland appears to be at the level of phosphofructokinase. A possible role of insulin in the regulation of phosphofructokinase activity, and the acute modulation of insulin-sensitivity in the gland during the starved-refed transition, are discussed.

Time course of changes in plasma glucose and insulin concentrations and mammary-gland lipogenesis during re-feeding of starved conscious lactating rats

Temporal changes in circulating insulin concentrations were measured during re-feeding of 18 h-starved lactating rats. Insulin concentrations rose rapidly over the first 20 min of re-feeding with 5 g of chow diet, and then sharply declined between 20-30 min and remained low for the rest of the 90 min experimental period. Lipogenic activity in the mammary gland also exhibited a peak during re-feeding, but there was a clear time lag between the insulin response and the lipogenic response. Blood-flow measurements failed to show any major increase to the tissue during this activation of lipogenesis. Acute suppression of insulin secretion at 30 min (after the initial surge) abolished the switch-on of lipogenesis, suggesting that the insulin-sensitivity of the gland may be acutely enhanced over this period of re-feeding.

Effects of ciglitazone on insulin resistance and thermogenic responsiveness to acute cold in brown adipose tissue of genetically obese (ob/ob) mice

Genetically obese (ob/ob) mice develop a marked insulin resistance in brown adipose tissue soon after weaning, and this is paralleled by a fall in the acute activation of the mitochondrial proton conductance pathway in the tissue on cold exposure. Treatment of ob/ob mice with ciglitazone, a new oral hypoglycaemic, led to a restoration of insulin sensitivity in brown adipose tissue. The amelioration of insulin resistance was accompanied by a normalization of the acute, cold-induced increase in mitochondrial GDP binding. These results support the hypothesis that the development of insulin resistance in brown adipose tissue is an important factor in the impaired thermogenic responsiveness of obese mice.

The development of insulin resistance in brown adipose tissue may impair the acute cold-induced activation of thermogenesis in genetically obese (ob/ob) mice

Genetically obese (ob/ob) mice develop insulin resistance in brown adipose tissue during the fifth week of life. Prior to this, at 26 days of age, ob/ob mice show a substantial increase in GDP binding to brown-adipose-tissue mitochondria during acute cold exposure. When insulin resistance in brown fat develops, by 35 days of age, the increase in GDP binding in response to cold is markedly reduced. Studies with 2-deoxyglucose suggest that insulin resistance in brown adipose tissue could impair thermogenic responsiveness during acute cold exposure by limiting the ability of the tissue to take up glucose.

Effect of high fat diets on the thermogenic activity of brown adipose tissue in cold-acclimated mice

The effects of feeding high fat diets on thermogenesis in brown adipose tissue has been investigated in cold-acclimated mice. Two high fat diets of differing fatty acid composition were used, one of which was based on corn oil and the other on beef tallow. After 3 weeks of feeding the diets there was little difference in the weight, protein content and cytochrome oxidase activity of brown adipose tissue (interscapular plus subscapular) of mice fed the high fat diets from those given the low fat stock diet. However, the mice fed the high fat diets showed marked increases in mitochondrial GDP binding and in mitochondrial respiration, consistent with an augmentation in the activity of the proton conductance pathway. This increase in thermogenesis in brown adipose tissue mitochondria occurred without any elevation in digestible energy intake, and is therefore not a response to overfeeding. It is concluded that the activity of the proton conductance pathway in brown adipose tissue of cold-acclimated mice can be modulated by the level of dietary triglyceride independently of energy intake. We suggest that the effect of high fat diets on thermogenesis in brown adipose tissue may relate to the suppressive effects of dietary lipid on fatty acid synthesis in the tissue.

Developmental changes in fatty acid synthesis in interscapular brown adipose tissue of lean and genetically obese (ob/ob) mice

Fatty acid synthesis was measured in vivo with 3H2O in interscapular brown adipose tissue of lean and genetically obese (ob/ob) mice. At 26 days of age, before the development of hyperphagia, synthesis in brown adipose tissue was higher in the obese than in the lean mice; synthesis was also elevated in the liver, white adipose tissue and carcass of the obese mice. At 8 weeks of age, when hyperphagia was well established, synthesis remained elevated in all tissues of the obese mice, with the exception of brown adipose tissue. Elevated synthesis rates were not apparent in brown adipose tissue of the obese mice at 14 days of age, nor at 35 days of age. These results demonstrate that brown adipose tissue in ob/ob mice has a transitory hyperlipogenesis at, and just after, weaning on to a low-fat/high-carbohydrate diet. Once hyperphagia has developed, by week 5 of life, brown adipose tissue is the only major lipogenic tissue in the obese mice not to exhibit elevated rates of fatty acid synthesis; this suggests that insulin resistance develops much more rapidly in brown adipose tissue than in other lipogenic tissues of the ob/ob mouse.