Hypothalamic obesity in humans: what do we know and what can be done?

CD8 cytotoxic T-cell infiltrates and cellular damage in the hypothalamus in human obesity

Rare cases of paraneoplastic obesity in children suggest sporadic obesity might also arise from an adaptive immune cell-mediated mechanism. Since the hypothalamus is a central regulator of feeding behavior and energy expenditure, we quantified lymphocytic inflammation in this region in a cohort of obese and non-obese human post-mortem brains. We report that CD8-positive cytotoxic T-cells are increased in hypothalamic median eminence/arcuate nucleus (ME/Arc) and bed nucleus of the stria terminalis in 40% of obese compared to non-obese patients, but not in other hypothalamic nuclei or brain regions. CD8 T-cells were most abundant in individuals with concurrent obesity and diabetes. Markers of cytotoxic T-cell induced damage, activated caspase 3 and poly-ADP ribose, were also elevated in the ME/Arc of obese patients. To provoke CD8 cytotoxic T-cell infiltrates in ventromedial region of hypothalamus in mice we performed stereotactic injections of an adeno-associated virus expressing immunogenic green fluorescent protein or saline. AAV but not saline injections triggered hypothalamic CD8 T-cell infiltrates associated with a rapid weight gain in mice recapitulating the findings in human obesity. This is the first description of the neuropathology of human obesity and when combined with its reconstitution in a mouse model suggests adaptive immunity may drive as much as 40% of the human condition.

Herpes Simplex Virus Diencephalitis Leading to Panhypopituitarism

Herpes simplex virus (HSV) is one of the most common causes of viral encephalitis. Hypothalamic-pituitary dysfunction has rarely been reported in HSV encephalitis, with few reports into the longer term outcomes for these patients. A 46-year-old male presented with a 10-day history of delirium, fever, and polydipsia. Initial computed tomography of the brain and cerebrospinal fluid cell counts were normal. Magnetic resonance imaging showed T2-hyperintensity affecting bilateral infundibuli, hypothalami, subthalamic nuclei, and optic radiations. Serial cerebrospinal fluid detected HSV1 DNA and we diagnosed him with HSV diencephalitis. He had marked biochemical abnormalities from the outset, with dramatic changes in serum sodium levels. He was ultimately diagnosed with permanent central diabetes insipidus and panhypopituitarism following evidence of central hypothyroidism, hypogonadotrophic hypogonadism, and a flat cortisol response to an insulin tolerance test. Neurocognitive recovery took several months, but subtle deficits in executive function and information processing remain. Hypothalamic hyperphagia developed as well as temperature dysregulation. He requires lifelong hormonal replacement and is undergoing regular endocrine follow up. This case highlights hypothalamic-pituitary dysfunction as a rare endocrine complication of HSV diencephalitis and illustrates the complexity of managing this in the long term.

Successful Diagnoses and Remarkable Metabolic Disorders in Patients With Solitary Hypothalamic Mass: A Case Series Report

BACKGROUND

Solitary intracranial hypothalamic mass occurs rarely. The etiological diagnosis of solitary hypothalamus lesion is challenging and often unachievable. Although previous studies indicated that lesions affecting the hypothalamus often cause significant metabolic disorders, few reports about the metabolic disturbances of patients with solitary hypothalamic mass have been reported.

METHOD

Twenty-five patients with solitary hypothalamus lesions who had been evaluated and treated in Huashan Hospital from January 2010 to December 2020 were retrospectively enrolled. The clinical manifestations, radiological features, endocrine and metabolic disorders, and pathology were analyzed.

RESULTS

The male to female ratio was 5/20. The median age of onset was 22 (19, 35) years old. The most common initial symptom was polydipsia/polyuria (19/25, 76.0%) and amenorrhea (9/20, 45.0%). A high prevalence of hypopituitarism of different axes was found, with almost all no less than 80%. Central hypogonadism (21/22, 95.5%) and central diabetes insipidus (19/21, 90.5%) were the top two pituitary dysfunctions. Conclusive diagnoses were achieved by intracranial surgical biopsy/resection or stereotactic biopsy in 16 cases and by examining extracranial lesions in 3 cases. The pathological results were various, and the most common diagnoses were Langerhans cell histiocytosis (7/19) and hypothalamitis (5/19). The mean timespan from onset to diagnosis in the 19 cases was 34 ± 26 months. Metabolic evaluations revealed remarkable metabolic disorders, including hyperlipidemia (13/16, 81.3%), hyperglycemia (10/16, 62.5%), hyperuricemia (12/20, 60%), overweight/obesity (13/20, 65.0%), and hepatic adipose infiltration (10/13, 76.6%).

CONCLUSION

Either surgical or stereotactic biopsy will be a reliable and relatively safe procedure to help to confirm the pathological diagnosis of solitary hypothalamic mass. Metabolic disorders were severe in patients with solitary hypothalamic mass. The management of such cases should cover both the treatment of the primary disease, as well as the endocrine and metabolic disorders.

Experiences with Glucagon-Like Peptide-1 Receptor Agonist in Children with Acquired Hypothalamic Obesity

OBJECTIVE

Hypothalamic obesity (HO) in children after treatment for a tumor in the suprasellar region has severe implications. Previous studies have shown various effects of glucagon-like peptide-1 (GLP-1) receptor agonist in acquired HO, but in adults only. We present our experience of GLP-1 receptor agonist (exenatide) treatment during a 1-year period on body mass index (BMI) in children with acquired HO.

PATIENTS AND METHODS

Children with severe weight gain after treatment for suprasellar tumor were given 2 mg exenatide weekly for a 12-month period. All had undergone previous dietary intervention. BMI standard deviation score (SDS), weight change, and adverse effects were assessed.

RESULTS

Five children with a mean age of 15.4 years (range 13-18) and a mean follow-up time of 8.4 years (mean age of 7.0 years at the time of brain tumor diagnosis) were treated with GLP-1 receptor agonist. After 1 year, BMI SDS or absolute weight had not changed significantly compared to the period without treatment (BMI SDS change +0.005, 95% CI -0.07 to 0.08, p = 0.89, and absolute weight change +1.5 kg, 95% CI -0.08 to 3.1, p = 0.061). Only 1 patient experienced weight loss after 1 year (-5.4 kg, BMI SDS -0.33). All patients experienced mild side effects, such as injection pain or nausea, and 2 patients stopped treatment upon their own request after 8 and 11 months, respectively.

CONCLUSIONS

In this small cohort, we found little effect of GLP-1 receptor agonist in the treatment for acquired HO. Future research should focus on the prevention of HO or, if prevention is not possible, on alternative, individualized interventions.

Management of hypothalamic disease in patients with craniopharyngioma

Patients with craniopharyngioma experience excess morbidity and mortality when compared with the background population and with other hypopituitary patients. Large, suprasellar tumours which form micropapillae into surrounding structures can cause hypothalamic damage before any therapeutic intervention; attempted gross total resection can lead to hypothalamic obesity, sleep disorders, thirst disorders and dysregulation of temperature as well as panhypopituitarism. The management of tumour bulk and the pathophysiology of hypothalamic complications have been reviewed extensively. We present a practical, clinical approach to management of hypothalamic disease in a patient with craniopharyngioma and highlight potential targets for future pharmacological or surgical intervention.

Early gestational ethanol exposure in mice: Effects on brain structure, energy metabolism and adiposity in adult offspring

We examined whether an early-life event - ethanol exposure in the initial stages of pregnancy - affected offspring brain structure, energy metabolism, and body composition in later life. Consumption of 10% (v/v) ethanol by inbred C57BL/6J female mice from 0.5 to 8.5 days post coitum was used to model alcohol exposure during the first 3-4 weeks of gestation in humans, when pregnancy is not typically recognized. At adolescence (postnatal day [P] 28) and adulthood (P64), the brains of male offspring were scanned ex vivo using ultra-high field (16.4 T) magnetic resonance imaging and diffusion tensor imaging. Energy metabolism and body composition were measured in adulthood by indirect calorimetry and dual-energy X-ray absorptiometry (DXA), respectively. Ethanol exposure had no substantial impact on white matter organization in the anterior commissure, corpus callosum, hippocampal commissure, internal capsule, optic tract, or thalamus. Whole brain volume and the volumes of the neocortex, cerebellum, and caudate putamen were also unaffected. Subtle, but non-significant, effects were observed on the hippocampus and the hypothalamus in adult ethanol-exposed male offspring. Ethanol exposure was additionally associated with a trend toward decreased oxygen consumption, carbon dioxide production, and reduced daily energy expenditure, as well as significantly increased adiposity, albeit with normal body weight and food intake, in adult male offspring. In summary, ethanol exposure restricted to early gestation had subtle long-term effects on the structure of specific brain regions in male offspring. The sensitivity of the hippocampus to ethanol-induced damage is reminiscent of that reported by other studies - despite differences in the level, timing, and duration of exposure - and likely contributes to the cognitive impairment that characteristically results from prenatal ethanol exposure. The hypothalamus plays an important role in regulating metabolism and energy homeostasis. Our finding of altered daily energy expenditure and adiposity in adult ethanol-exposed males is consistent with the idea that central nervous system abnormalities also underpin some of the metabolic phenotypes associated with ethanol exposure in pregnancy.

Pituitary Adenylate-Cyclase Activating Polypeptide Regulates Hunger- and Palatability-Induced Binge Eating

While pituitary adenylate cyclase activating polypeptide (PACAP) signaling in the hypothalamic ventromedial nuclei (VMN) has been shown to regulate feeding, a challenge in unmasking a role for this peptide in obesity is that excess feeding can involve numerous mechanisms including homeostatic (hunger) and hedonic-related (palatability) drives. In these studies, we first isolated distinct feeding drives by developing a novel model of binge behavior in which homeostatic-driven feeding was temporally separated from feeding driven by food palatability. We found that stimulation of the VMN, achieved by local microinjections of AMPA, decreased standard chow consumption in food-restricted rats (e.g., homeostatic feeding); surprisingly, this manipulation failed to alter palatable food consumption in satiated rats (e.g., hedonic feeding). In contrast, inhibition of the nucleus accumbens (NAc), through local microinjections of GABA receptor agonists baclofen and muscimol, decreased hedonic feeding without altering homeostatic feeding. PACAP microinjections produced the site-specific changes in synaptic transmission needed to decrease feeding via VMN or NAc circuitry. PACAP into the NAc mimicked the actions of GABA agonists by reducing hedonic feeding without altering homeostatic feeding. In contrast, PACAP into the VMN mimicked the actions of AMPA by decreasing homeostatic feeding without affecting hedonic feeding. Slice electrophysiology recordings verified PACAP excitation of VMN neurons and inhibition of NAc neurons. These data suggest that the VMN and NAc regulate distinct circuits giving rise to unique feeding drives, but that both can be regulated by the neuropeptide PACAP to potentially curb excessive eating stemming from either drive.

Kumbhakarna: Did he suffer from the disorder of the hypothalamus?

Kumbhakarna was brother of the evil Raavana in the mythological tale of Ramayana. According the legend, Kumbhakarna had an insatiable appetite and thirst and used to sleep for great lengths of time. He also had an uncontrollable temper, which was feared by many. It is our assessment that Kumbhakarna possibly suffered from hypothalamic obesity. Hypothalamic obesity can be defined as significant polyphagia and weight gain that occurs because of structural or function involvement of the ventromedial nucleus of the hypothalamus bilaterally. The characteristic features are obesity associated with polyphagia. Somnolence is present in 40% of cases. Sham rage is a characteristic behavioral abnormality seen in these patients. All these symptoms are described in the mythological text while describing Kumbhakarna. The episodic nature of Kumbhakarna's symptoms can also be explained by another hypothalamic syndrome called Klein-Levine syndrome. This syndrome is characterized by with periodic episodes of somnolence, hyperphagia and hypersexuality along with other behavioral and cognitive difficulties.

Management of craniopharyngiomas

Craniopharyngiomas are rare epithelial tumours arising along the path of the craniopharyngeal duct. Their pathogenesis remains uncertain and they can present with a variety of manifestations attributed to pressure effects to surrounding structures. The optimal management of craniopharyngiomas remains challenging mainly due to their sharp, irregular borders and their tendency to adhere to vital neurovascular structures making surgical manipulations potentially hazardous to vital brain areas. Non-aggressive surgery followed by radiotherapy is currently the most widely used option possibly achieving the most optimal long-term outcome. Other treatment modalities including intracystic irradiation, intracystic instillation of antineoplasmatic agents and stereotactic radiotherapy are also available in our armamentarium. The long-term morbidities related with the craniopharyngiomas and their treatment remain significant, with hypothalamic damage playing the protagonist role and requiring further studies to identify measures that will improve the prognosis of the patients.

The neuropathology of obesity: insights from human disease

Obesity, a pathologic state defined by excess adipose tissue, is a significant public health problem as it affects a large proportion of individuals and is linked with increased risk for numerous chronic diseases. Obesity is the result of fundamental changes associated with modern society including overnutrition and sedentary lifestyles. Proper energy homeostasis is dependent on normal brain function as the master metabolic regulator, which integrates peripheral signals, modulates autonomic outflow and controls feeding behavior. Therefore, many human brain diseases are associated with obesity. This review explores the neuropathology of obesity by examining brain diseases which either cause or are influenced by obesity. First, several genetic and acquired brain diseases are discussed as a means to understand the central regulation of peripheral metabolism. These diseases range from monogenetic causes of obesity (leptin deficiency, MC4R deficiency, Bardet-Biedl syndrome and others) to complex neurodevelopmental disorders (Prader-Willi syndrome and Sim1 deficiency) and neurodegenerative conditions (frontotemporal dementia and Gourmand's syndrome) and serve to highlight the central regulatory mechanisms which have evolved to maintain energy homeostasis. Next, to examine the effect of obesity on the brain, chronic neuropathologic conditions (epilepsy, multiple sclerosis and Alzheimer's disease) are discussed as examples of obesity leading to maladaptive processes which exacerbate chronic disease. Thus, obesity is associated with multiple pathways including abnormal metabolism, altered hormonal signaling and increased inflammation which act in concert to promote downstream neuropathology. Finally, the effect of anti-obesity interventions is discussed in terms of brain structure and function. Together, understanding human diseases and anti-obesity interventions leads to insights into the bidirectional interaction between peripheral metabolism and central brain function, highlighting the need for continued clinicopathologic and mechanistic studies of the neuropathology of obesity.

How to approach endocrine assessment in severe obesity?

The increasing numbers of severely obese patients (body mass index BMI >40 kg/m(2) ) represent a significant management challenge. These patients are at risk of obesity-related complications that may be driven by changes in endocrine function. Their care may potentially be complex at times, and therefore, an appropriate assessment strategy will be relevant to timely diagnosis and management. In this article, we discuss an approach to the endocrine assessment of the severely obese patient. We consider the clinical question in three categories that may also represent different complexities in terms of subsequent management: (i) obesity as a consequence of structural lesions at the hypothalamic-pituitary region; (ii) obesity as a consequence of inherited and genetic syndromes; and (iii) functional neuroendocrine hormone abnormalities relating to obesity. The first two categories are associated with hypothalamic dysfunction, of which hypothalamic obesity is a consequence. Additionally, the implications and difficulties associated with imaging severely obese patients are discussed from an endocrinological perspective and we provide practical guidance on which to base practice.

Hypothalamic obesity: prevalence, associations and longitudinal trends in weight in a specialist adult neuroendocrine clinic

OBJECTIVE

Obesity is highly prevalent among adults with acquired, structural hypothalamic damage. We aimed to determine hormonal and neuroanatomical variables associated with weight gain and obesity in patients following hypothalamic damage and to evaluate the impact of early instigation of weight loss measures to prevent or limit the severity of obesity in these patients.

DESIGN

Retrospective study of 110 adults with hypothalamic tumours attending a specialist neuroendocrine clinic. BMI was calculated at diagnosis and at last follow-up clinic visit. Endocrine data, procedures, treatments and weight loss measures were recorded and all available brain imaging reviewed.

RESULTS

At last follow-up, 82.7% of patients were overweight or heavier (BMI≥25 kg/m(2)), 57.2% were obese (BMI≥30 kg/m(2)) and 14.5% were morbidly obese (BMI≥40 kg/m(2)). Multivariate analysis revealed that use of desmopressin (odds ratio (OR)=3.5; P=0.026), GH (OR=2.7; P=0.031) and thyroxine (OR=3.0; P=0.03) was associated with development of new or worsened obesity. Neuroimaging features were not associated with weight gain. Despite proactive treatments offered in clinic in recent years (counselling, dietetic and physical activity advice, and anti-obesity medications), patients have continued to gain weight.

CONCLUSIONS

Despite increased awareness, hypothalamic obesity is difficult to prevent and to treat. Improved understanding of the underlying pathophysiologies and multicentre collaboration to examine efficacy of novel obesity interventions are warranted.

Integrating autoimmune risk loci with gene-expression data identifies specific pathogenic immune cell subsets

Although genome-wide association studies have implicated many individual loci in complex diseases, identifying the exact causal alleles and the cell types within which they act remains greatly challenging. To ultimately understand disease mechanism, researchers must carefully conceive functional studies in relevant pathogenic cell types to demonstrate the cellular impact of disease-associated genetic variants. This challenge is highlighted in autoimmune diseases, such as rheumatoid arthritis, where any of a broad range of immunological cell types might potentially be impacted by genetic variation to cause disease. To this end, we developed a statistical approach to identify potentially pathogenic cell types in autoimmune diseases by using a gene-expression data set of 223 murine-sorted immune cells from the Immunological Genome Consortium. We found enrichment of transitional B cell genes in systemic lupus erythematosus (p = 5.9 × 10(-6)) and epithelial-associated stimulated dendritic cell genes in Crohn disease (p = 1.6 × 10(-5)). Finally, we demonstrated enrichment of CD4+ effector memory T cell genes within rheumatoid arthritis loci (p < 10(-6)). To further validate the role of CD4+ effector memory T cells within rheumatoid arthritis, we identified 436 loci that were not yet known to be associated with the disease but that had a statistically suggestive association in a recent genome-wide association study (GWAS) meta-analysis (p(GWAS) < 0.001). Even among these putative loci, we noted a significant enrichment for genes specifically expressed in CD4+ effector memory T cells (p = 1.25 × 10(-4)). These cell types are primary candidates for future functional studies to reveal the role of risk alleles in autoimmunity. Our approach has application in other phenotypes, outside of autoimmunity, where many loci have been discovered and high-quality cell-type-specific gene expression is available.

Obesity, metabolic syndrome, and insulin dynamics in children after craniopharyngioma surgery

INTRODUCTION

Children after craniopharyngioma surgery often develop rapid weight gain and hyperphagia. We investigate the metabolic syndrome features, risk factors, and the insulin dynamics in these patients.

MATERIALS AND METHODS

Standard oral glucose tolerance tests (OGTT) were performed in 12 subjects, aged 7.7-18.1 years, after surgical removal of craniopharyngioma and their healthy age-, sex-, body mass index-, and pubertal stage-matched controls. Blood samples were obtained for measurement of levels of plasma glucose, insulin, lipids, liver enzymes, baseline hormonal profiles with calculation of insulin secretion, and insulin sensitivity indices derived from OGTT.

RESULTS AND DISCUSSION

Nine of 12 subjects were severely obese. All patients exhibited significant weight gain after surgery. The waist to hip ratio was higher in subjects compared to controls (P = 0.023). Subjects had higher fasting triglycerides (P = 0.019) and lower HDL/total cholesterol ratio (P = 0.012). Five of 12 subjects met the criteria for the metabolic syndrome, compared with one of 12 in controls. One patient had prediabetes and another patient had overt type 2 diabetes. Six of 12 subjects had nonalcoholic steatohepatitis. No significant risk factors were found between each group of patients with and without the metabolic syndrome. There were no differences of insulin secretion and insulin sensitivity indices between craniopharyngioma and control subjects.

CONCLUSION

Children after craniopharyngioma surgery are at risk of rapid weight gain and the development of metabolic syndrome. Further studies to better understand the mechanism are required to design effective treatment and prevention.

Somnolence in adult craniopharyngioma patients is a common, heterogeneous condition that is potentially treatable

CONTEXT AND OBJECTIVE

Somnolence and obesity are prevalent in craniopharyngioma patients. We hypothesized that somnolence was because of obstructive sleep apnoea in craniopharyngioma patients.

DESIGN, PATIENTS AND MEASUREMENTS

We assessed prevalence of somnolence and sleep apnoea in 28 craniopharyngioma and 23 obese controls attending a tertiary referral centre, by means of the Epworth Sleepiness Score (ESS) and polysomnography. All subjects with sleep apnoea were offered continuous positive airway pressure therapy (CPAP) or modafinil. All craniopharyngioma patients, with unexplained somnolence, were offered modafinil.

RESULTS

Somnolence was reported by 20/28 (71·5%) craniopharyngioma patients and 4/23 (17%) obese subjects (P < 0·001). Median ESS was 7·5 (IQR 6, 10·7) in craniopharyngioma patients and 4·0 (4,8) in controls, P < 0·01. Eleven somnolent craniopharyngioma patients had obstructive sleep apnoea, in whom treatment led to a reduction in ESS by 6·4 ± 1·4, P = 0·01. Among the remaining nine patients, five were offered modafinil therapy, of whom four had benefit, three were not compliant with hormone replacement, and one died before intervention. There was no difference in the prevalence of obstructive sleep apnoea between craniopharyngioma (n = 13, 46%) and obese subjects (n = 14, 61%, P = 0·4). Body mass index (BMI) does not correlate with apnoea hypopnoea index [apnoea - hypopnoea index (AHI), r = 0·25, P = 0·08], which suggests that obesity alone does not explain the prevalence of sleep apnoea in craniopharyngioma patients.

CONCLUSIONS

Somnolence is common in craniopharyngioma patients and in the majority is because of obstructive sleep apnoea. An additional group of somnolent craniopharyngioma patients benefits from modafinil.

Risk factors for obesity in childhood survivors of suprasellar brain tumours: a retrospective study

AIM

To characterize postdiagnosis changes in body mass index (BMI) among childhood survivors of suprasellar brain tumours, and to determine the risk factors associated with obesity.

METHODS

We conducted a retrospective analysis of 46 children (16 boys and 30 girls) with median (IQR) age of 7.49 (3.47-11.59) years at tumour diagnosis, and followed up for 3.93 (1.68-7.27) years. Survival analyses were used to identify risks of developing obesity.

RESULTS

There were no sex differences in age at tumour diagnosis, duration of follow-up, tumour types, endocrinopathies, treatment modalities or baseline BMI SDS. In the first year after tumour diagnosis, ΔBMI SDS (median; IQR) was greater in girls (1.32; 0.07-2.08) than in boys (0.48; -0.40 to 0.89) (p = 0.01). At diagnosis, 3/46 children (6%) were obese; this increased to 20/46 (43%) by last follow-up (p < 0.001) and was more common in girls (17/30; 57%) than in boys (3/16; 19%). Female gender (hazard ratio 5.0, 95% CI 1.2-21.7; p = 0.04) and greater than average baseline BMI (hazard ratio 4.7, 95% CI 1.1-20.8; p = 0.02) were risk factors for subsequent obesity.

CONCLUSION

Accurate prediction of obesity risk is important and would allow early targeted intervention in high-risk patients.

Hypothalamic lipoma associated with severe obesity. Report of 2 cases

The association between hypothalamic dysfunction and obesity is well documented in both clinical and experimental models. The authors describe 2 children who developed obesity that could not be explained by endocrinological, genetic, or eating disorders. In both cases, cranial MR imaging revealed the typical appearance of a lipoma in the paramedian hypothalamus. In the absence of other etiologies, the authors hypothesized that in these 2 children obesity was caused by their hypothalamic lipomas. To the authors' knowledge, these are the first cases of hypothalamic lipomas likely to be causing obesity that have been described in children. These cases highlight the importance of performing cranial MR imaging in children with otherwise unexplained obesity.

The use of sibutramine in the management of obesity and related disorders: an update

Aims:

To review the major trials that evaluated the efficacy and safety of the use of sibutramine for weight loss and the impact of this agent on obesity-related disorders.

Methods and results:

The most important articles on sibutramine up to January 2009 were located by a PubMed and Medline search. Sibutramine reduces food intake and body weight more than placebo and has positive effects on the lipid profile (mainly triglycerides and high density lipoprotein cholesterol), glycemic control and inflammatory markers in studies for up to one year. Preliminary studies showed that sibutramine may also improve other obesity-associated disorders such as polycystic ovary syndrome, left ventricular hypertrophy, binge eating disorder and adolescent obesity. The high discontinuation rates and some safety issues mainly due to the increase in blood pressure and pulse rate have to be considered. Additionally, it has not yet been established that treatment with sibutramine will reduce cardiovascular events and total mortality.

Conclusions:

Sibutramine, in conjunction with lifestyle measures, is a useful drug for reducing body weight and improving associated cardiometabolic risk factors and obesity-related disorders. Studies of longer duration are required to determine the precise indications of the drug, to evaluate safety issues and to assess its efficacy on cardiovascular mortality.

Contributions of the hippocampus and medial prefrontal cortex to energy and body weight regulation

The effects of selective ibotenate lesions of the complete hippocampus (CHip), the hippocampal ventral pole (VP), or the medial prefrontal cortex (mPFC) in male rats were assessed on several measures related to energy regulation (i.e., body weight gain, food intake, body adiposity, metabolic activity, general behavioral activity, conditioned appetitive responding). The testing conditions were designed to minimize the nonspecific debilitating effects of these surgeries on intake and body weight. Rats with CHip and VP lesions exhibited significantly greater weight gain and food intake compared with controls. Furthermore, CHip-lesioned rats, but not rats with VP lesions, showed elevated metabolic activity, general activity in the dark phase of the light-dark cycle, and greater conditioned appetitive behavior, compared with control rats without these brain lesions. In contrast, rats with mPFC lesions were not different from controls on any of these measures. These results indicate that hippocampal damage interferes with energy and body weight regulation, perhaps by disrupting higher-order learning and memory processes that contribute to the control of appetitive and consummatory behavior.

Use of somatostatin analogues in obesity

Obesity is a condition that results from dysregulation of energy balance. Insulin, a component of the efferent pathway of the energy-regulatory circuit, promotes storage of energy substrates in adipose tissue and is, therefore, a potential target for pharmacotherapy. Somatostatin and its analogues (octreotide and lanreotide) bind to somatostatin subtype 5 receptors on the beta-cell membrane, which limits insulin release and, consequently, may decrease adipogenesis. Somatostatin and its analogues have been used in trials in patients with paediatric hypothalamic obesity. These children have hypothalamic dysfunction, mainly due to brain tumours such as craniopharyngiomas, which are thought to generate increased vagal output, leading to hyperinsulinaemia and weight gain. Two small trials, each of 6 months' duration, in children with paediatric hypothalamic obesity showed either a minimal weight loss or stabilization of bodyweight. In children with Prader-Willi syndrome, the most common genetic hypothalamic disorder associated with hyperphagia, hyperghrelinaemia, massive obesity and other endocrine disturbances, somatostatin failed to control hyperphagia and weight gain in a small number of patients, although it lowered the levels of the anorexigenic hormone ghrelin. Long-acting release octreotide was recently used in hyperinsulinaemic obese adults without cranial pathology. Insulin suppression was associated with small decreases in the body mass indexes of obese subjects receiving the higher dosages of the drug, with an acceptable safety profile, similar to that in previous studies. In conclusion, somatostatin and its analogues, by suppressing beta-cell insulin secretion, can retard weight gain in children with hypothalamic obesity and induce a small amount of weight loss in some adults with hyperinsulinaemic obesity.

Association of monosodium glutamate intake with overweight in Chinese adults: the INTERMAP Study

Animal studies indicate that monosodium glutamate (MSG) can induce hypothalamic lesions and leptin resistance, possibly influencing energy balance, leading to overweight. This study examines the association between MSG intake and overweight in humans. We conducted a cross-sectional study involving 752 healthy Chinese (48.7% women), aged 40-59 years, randomly sampled from three rural villages in north and south China. The great majority of participants prepared their foods at home, without use of commercially processed foods. Diet was assessed with four in-depth multipass 24-h recalls. Participants were asked to demonstrate MSG amounts added in food preparation. Amounts shaken out were weighed by trained interviewers. Overweight was defined as BMI > or =25.0 or > or =23.0 kg/m(2)(based on World Health Organization recommendations for Asian populations). Eighty-two percent of participants were MSG users. Average intake was 0.33 g/day (s.d. = 0.40). With adjustment for potential confounders including physical activity and total energy intake, MSG intake was positively related to BMI. Prevalence of overweight was significantly higher in MSG users than nonusers. For users in the highest tertile of MSG intake compared to nonusers, the multivariable-adjusted odds ratios of overweight (BMI > or =23.0 and > or =25.0) were 2.10 (95% confidence interval, 1.13-3.90, P for trend across four MSG categories = 0.03) and 2.75 (95% confidence interval, 1.28-5.95, P = 0.04). This research provides data that MSG intake may be associated with increased risk of overweight independent of physical activity and total energy intake in humans.

Clinical insights into adipsic diabetes insipidus: a large case series

OBJECTIVE

Adipsic diabetes insipidus (DI) causes significant hypernatraemia. Morbidity and mortality data for patients with adipsic DI have been previously published as single case reports, rather than as formal trials or case series from units with established management protocols. Our objective was to describe morbidity and mortality in patients with adipsic DI attending a tertiary referral centre, representing the largest reported series of adipsic DI, and to suggest management protocols for such patients, based on our extensive experience of this condition.

DESIGN

Arginine vasopressin (AVP) responses to hypotension were recorded during trimetaphan infusion. Sleep abnormalities were identified using overnight oximetry or polysomnography. Case-note analysis defined other clinical abnormalities including seizures and thrombotic episodes. Important clinical points for the management of these patients are highlighted.

PATIENTS

Thirteen patients with adipsic DI defined by thirst and plasma AVP responses to hypertonic saline infusion.

RESULTS

All patients had absent AVP and thirst responses to osmotic stimulation, with subnormal water intake. Five patients had absent AVP responses to hypotension; the remainder had normal responses. Eight patients were obese [body mass index (BMI) > 30 kg/m(2)], and three were overweight (BMI > 25 kg/m(2)). Seven patients had sleep apnoea, of whom three died at 36 years or younger. Four patients developed venous thrombosis during episodes of hypernatraemia. Two patients had thermoregulatory dysfunction and seven patients had seizure activity.

CONCLUSION

Adipsic DI is associated with significant morbidity and mortality. Physicians should be aware of associated, treatable hypothalamic abnormalities such as obesity, sleep apnoea, seizures and thermoregulatory disorders when managing adipsic DI.

Craniopharyngiomas

Craniopharyngiomas are rare, mainly sellar/parasellar, epithelial tumors diagnosed during childhood or adult life. Histologically, two primary subtypes have been recognized (adamantinomatous and papillary) with an as yet, unclarified pathogenesis. They may present with a variety of manifestations (neurological, visual, and hypothalamo-pituitary). Despite their benign histological appearance, they often show an unpredictable growth pattern, which, combined with the lack of randomized studies, poses significant difficulties in the establishment of an optimal therapeutic protocol. This should focus on the prevention of recurrence(s), improvement of survival, reduction of the significant disease and treatment-related morbidity (endocrine, visual, hypothalamic, neurobehavioral, and cognitive), and preservation of the quality of life. Currently, surgical excision followed by external beam irradiation, in cases of residual tumor, is the main treatment option. Intracystic irradiation or bleomycin, stereotactic radiosurgery, or radiotherapy and systemic chemotherapy are alternative approaches; their place in the management plan remains to be assessed in adequately powered long-term trials. Apart from the type of treatment, the identification of clinical and imaging parameters that will predict patients with a better prognosis is difficult. The central registration of patients with these challenging tumors may provide correlates between treatments and outcomes and establish prognostic factors at the pathological or molecular level that may further guide us in the future.

Looking to the future: electrical stimulation for obesity

Among all classes of therapies for morbid obesity-behavioral, drugs, devices, and surgery-devices for electrical stimulation are a relatively new approach. This article reviews the history of electrical therapies for the gastrointestinal tract with an emphasis on the development of stimulation for obesity. Based on similar animal work, electrical stimulation of the gastrointestinal tract has been applied to treat morbid obesity much in the way it has been used to treat nausea and vomiting. The current status of gastrointestinal electrical stimulation for the treatment of morbid obesity is reviewed, with an emphasis on human studies. The physics of electrical stimulation and the possible mechanism of stimulation in the gastrointestinal tract, including for the treatment of morbid obesity, are also discussed. Future work on stimulation for obesity offers the opportunity for better understanding of possible mechanisms of action.

Dexamphetamine use for management of obesity and hypersomnolence following hypothalamic injury

Unrelenting weight gain, morbid obesity and disturbance of the sleep-wake cycle are well-recognized sequelae of hypothalamic injury. These health problems and their risk of significant associated co-morbidity drive the search for potential treatment modalities.

OBJECTIVE

To report effects on weight change and wakefulness in a cohort of 12 patients with structural hypothalamic lesions treated with low-dose dexamphetamine.

METHOD

Retrospective review of case notes.

RESULTS

Twelve patients received dexamphetamine 5 mg twice daily (median duration 13 months in males, 15 months in females). Ten of 12 patients experienced either stabilisation of weight or weight loss on treatment (median loss -0.7 SDS in males, -0.44 SDS in females). Eleven patients reported improvement in daytime wakefulness and/or concentration and exercise tolerance.

CONCLUSION

Low-dose dexamphetamine therapy has a positive impact on inexorable weight gain and daytime somnolence following hypothalamic injury.

The rise, fall, and resurrection of the ventromedial hypothalamus in the regulation of feeding behavior and body weight

Early researchers found that lesions of the ventromedial hypothalamus (VMH) resulted in hyperphagia and obesity in a variety of species including humans, which led them to designate the VMH as the brain's "satiety center." Many researchers later dismissed a role for the VMH in feeding behavior when Gold claimed that lesions restricted to the VMH did not result in overeating and that obesity was observed only with lesions or knife cuts that extended beyond the borders of the VMH and damaged or severed the ventral noradrenergic bundle (VNAB) or paraventricular nucleus (PVN). However, anatomical studies done both before and after Gold's study did not replicate his results with lesions, and in nearly every published direct comparison of VMH lesions vs. PVN or VNAB lesions, the group with VMH lesions ate substantially more food and gained twice as much weight. Several other important differences have also been found between VMH and both PVN and VNAB lesion-induced obesity. Concerns regarding (a) motivation to work for food and (b) the effects of nonirritative lesions have also been addressed and answered in many studies. Lesion studies with weanling rats and adult pair-tube-fed rats, as well as recent studies of knockout mice deficient in the orphan nuclear receptor steroidogenic factor 1, indicate that VMH lesion-induced obesity is in large part a metabolic obesity (due to autonomic nervous system disorders) independent of hyperphagia. However, there is ample evidence that the VMH also plays a primary role in feeding behavior. Neuroimaging studies in humans have shown a marked increase in activity in the area of the VMH during feeding. The VMH has a large population of glucoresponsive neurons that dynamically respond to blood glucose levels and numerous histamine, dopamine, serotonin, and GABA neurons that respond to feeding-related stimuli. Recent studies have implicated melanocortins in the VMH regulation of feeding behavior: food intake decreases when arcuate nucleus pro-opiomelanocortin (POMC) neurons activate VMH brain-derived neurotrophic factor (BDNF) neurons. Moderate hyperphagia and obesity have also been observed in female rats with damage to the efferent projections from the posterodorsal amygdala to the VMH. Hypothalamic obesity can result from damage to either the POMC or BDNF neurons. The concept of hypothalamic feeding and satiety centers is outdated and unnecessary, and progress in understanding hypothalamic mechanisms of feeding behavior will be achieved only by appreciating the different types of neural and blood-borne information received by the various nuclei, and then attempting to determine how this information is integrated to obtain a balance between energy intake and energy output.

Current knowledge in the neurophysiologic modulation of obesity

Obesity is today one of the commonest of life-threatening diseases in developed countries and generally results from an imbalance between energy intake and energy expenditure. Although there is increasing evidence for a genetic basis of obesity in some clinical syndromes, this seems to be the cause only in a limited number of patients and obesity is far from being considered as a gene-related disease. Eating is a complex and multifactorial process involving autonomous pathways that transfer sensory and motor information between the entire length of the digestive tract and the central nervous system. Modulation of the amount of energy that we take in as food involves several mechanisms and networks that connect the brain with the gut, this process being key to the regulation of body weight over time, as well as to the modification of long-term eating behaviors. Furthermore, this axis is closely coupled to other systems that are involved in energy homeostasis, namely, food preference, energy expenditure, and lifestyle. The identification of several neuropeptides that modulate eating behavior in various ways, along with studies performed in animal models, have focused attention on the role of these molecules and their clinical implications in the development of obesity in humans.

Endocrine late effects of cancer treatment

Endocrinopathies are significant consequences of the treatment of childhood cancers. The risk of developing these adverse events is related to the underlying disease and its treatment with cytotoxic agents and radiation therapy. This article reviews hypothalamic-pituitary, thyroid, and gonadal dysfunction, as well as osteopenia-osteoporosis and obesity.

Aspects cliniques des syndromes hypothalamiques idiopathiques : étude rétrospective et revue de la littérature

Hypothalamic obesity is usually induced by tumoral or genetic alterations such as craniopharyngioma or Prader-Willi syndrome, respectively. However, few cases have been reported without recognized etiology, this syndrome is also called idiopathic hypothalamic syndrome.

OBJECTIVES

To improve definition and frequency of complications associated with this syndrome.

POPULATION AND METHODS

A retrospective cohort study was performed in French endocrine paediatric departments and was associated with a literature review.

RESULTS

We report five cases of idiopathic hypothalamic syndrome. This syndrome is correlated with a high mortality (one of our five cases, 25% in the literature) by neurovegetative dysfunction (breathing or thermal alteration). Obesity began before six years old because of compulsive eating and resulted in social behaviour disorders. Abnormal endocrine secretions were characterized by early hyperprolactinemia, permanent but later somatotrope deficiency and 80% of thyreotrope deficiency. Puberty abnormalities included hypogonadotropic hypogonadism as well as precocious (one of our cases, three cases including literature) or normal puberty. Neurogenic hypernatremia and water and electrolytic disorders were also responsible of acute neurological alterations.

CONCLUSION

This largest study ever reported of idiopathic hypothalamic syndrome emphasizes the need of a multidisciplinary coordination to provide the best care of these patients.

Endocrine and neuroanatomic features associated with weight gain and obesity in adult patients with hypothalamic damage

PURPOSE

Obesity is a common consequence in patients with tumors of the hypothalamic region and of related treatment in children. Much less information is available on adult patients and long-term survivors. The aims of this study were to estimate the prevalence of obesity in adult patients with acquired structural hypothalamic damage and to define the characteristics of patients at greatest risk of obesity.

METHODS

A retrospective study was conducted of 52 patients (25 women; median age at diagnosis, 44 years; range, 17 to 78 years) with tumors involving the hypothalamic region. These included 22 craniopharyngiomas, 24 pituitary adenomas, and six other hypothalamic tumors. Changes in body mass index were determined, magnetic resonance imaging scans were scored by a radiologist for tumor size and the extent of involvement of the hypothalamus, and current hormone replacement therapy was recorded, to identify possible features associated with new or worsened obesity (defined as a body mass index > or =30 kg/m(2) at the latest follow-up, which had increased by at least 2 kg/m(2) since diagnosis of the tumor).

RESULTS

Serial body mass index data from diagnosis to the latest follow-up were available for 42 patients. After a median of 5 years (range, 1 to 19 years) of follow-up, most patients with hypothalamic damage were obese (52% [n = 22] vs. 24% [n = 10] at the time of diagnosis, P < 0.0001). In a multivariate model, use of desmopressin (odds ratio [OR] = 13; 95% confidence interval [CI]: 2.0 to 86; P = 0.007) and growth hormone replacement (OR = 7.6; 95% CI: 1.1 to 51; P = 0.04) were associated with new or worsened obesity during follow-up. No correlation was found between the initial size or location of the tumor and subsequent weight gain.

CONCLUSION

Obesity is highly prevalent in adult survivors of hypothalamic tumors. Use of desmopressin and growth hormone therapy, but not size or location of the tumor, were associated with weight gain and obesity following diagnosis. These findings may be helpful in identifying patients at increased risk of obesity, to whom earlier intervention could be offered.

Nonalcoholic fatty liver disease among patients with hypothalamic and pituitary dysfunction

Patients with hypopituitarism develop a phenotype similar to metabolic syndrome with central obesity and diabetes. Similarly, patients with hypothalamic damage may develop central obesity, insulin resistance, and hyperphagia. We sought to examine the clinical associations between hypopituitarism, hypothalamic dysfunction, and nonalcoholic fatty liver disease (NAFLD). A case series of patients seen at our institution with diagnoses of hypopituitarism, hypothalamic obesity, or craniopharyngioma and NAFLD was undertaken. Clinical, laboratory, and liver biopsy features were reviewed. Twenty-one patients were identified. NAFLD was diagnosed 6.4 +/- 7.5 years (median 3 years) after the diagnosis of hypothalamic/pituitary dysfunction. Mean gain in body mass index (BMI) between diagnoses of hypothalamic/pituitary disease and NAFLD was 11.3 +/- 8.9 kg/m(2) at an average yearly rate of 2.2 +/- 2.2 kg/m(2). The majority of patients developed elevated glucose levels and dyslipidemia by time of diagnosis of NAFLD. Of the 10 patients biopsied, six were cirrhotic, two had nonalcoholic steatohepatitis (NASH) with fibrosis, and two had simple steatosis. Long-term follow-up of 66 +/- 33 months (range 12-120) was available for 18 patients. Two required liver transplantation. Six patients died, two from liver related causes. In conclusion, patients with hypothalamic and/or pituitary disease are at risk of excessive weight gain, impaired glucose tolerance, and dyslipidemia with subsequent development of NAFLD. This group has a high prevalence of cirrhosis placing them at risk for liver-related death. The novel evidence that hypothalamic/pituitary dysfunction may be accompanied by progressive NAFLD has important implications for the work-up and management of patients with hypothalamic/pituitary disease.

Endocrine late effects of cancer treatment

Endocrinopathies are significant consequences of childhood cancers and their treatments. The risk of developing these adverse events is related to the underlying disease and its treatment with cytotoxic drugs and radiation therapy. This article will explore the current literature about endocrine late effects of hypothalamic-pituitary, thyroid, and gonadal dysfunction, as well as osteoporosis and obesity.