Weight loss in Alzheimer disease

BACKGROUND

Epidemiologic studies have shown that weight loss is commonly associated with Alzheimer disease (AD) and is a manifestation of the disease itself. The etiology of weight loss in AD appears multifactorial. Hypotheses to explain the weight loss have been suggested (eg, atrophy of the mesial temporal cortex, biological disturbances, and higher energy expenditure); however, none have been proven.

OBJECTIVE

In the first part of this article, we describe weight loss in AD (epidemiologic data and hypotheses to explain weight loss and anorexia in AD). In the second part we report the results of a longitudinal study of the changes in nutritional variables in a cohort of patients with a probable diagnosis of AD.

DESIGN

We followed subjects with AD (based on criteria of the National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association) who were recruited from the Alzheimer's Disease Center in Toulouse. All subject underwent a nutritional, neuropsychologic, and functional evaluation. The Zarit scales were used to assess caregiver burden and caregiver reactions to the patients' behavioral and autonomic disorders.

RESULTS

We showed that only results of the Burden Interview and the Memory and Behavior Problems Checklist, which explored caregiver burden, predicted weight loss in AD. It is possible that caregivers who consider themselves overburdened by the disease process are not willing to invest adequate resources to allow AD patients to properly nourish themselves.

CONCLUSION

Nutritional education programs for the caregivers of AD patients seem to be the best way to prevent weight loss and improve the nutritional status of these patients.

Brain Anatomy in Turner Syndrome: Evidence for Impaired Social and Spatial-Numerical Networks

Analysis of brain structure in Turner syndrome (TS) provides the opportunity to identify the consequences of the loss of one X chromosome on brain anatomy and to characterize the neural bases underlying the specific cognitive profile of TS subjects which includes deficits in spatial-numerical processing and social cognition. Fourteen subjects with TS and fourteen controls were investigated using voxel-based analysis of high resolution anatomical and diffusion tensor images and using sulcal morphometry. The analysis of anatomical images provided evidence for macroscopical changes in cortical regions involved in social cognition such as the left superior temporal sulcus and orbito-frontal cortex and in a region involved in spatial and numerical cognition such as the right intraparietal sulcus. Diffusion tensor images showed a displacement of the grey-white matter interface of the left and right superior temporal sulcus and revealed bilateral microstructural anomalies in the temporal white matter. The analysis of fiber orientation suggests specific alterations of fiber tracts connecting posterior to anterior temporal regions. Last, sulcal morphometry confirmed the anomalies of the left and right superior temporal sulci and of the right intraparietal sulcus. Our results thus provide converging evidence of regionally specific structural changes in TS that are highly consistent with the hallmark symptoms associated with TS.

Effect of physical training in humans on the response of isolated fat cells to epinephrine

Endurance training helps muscle tissue oxidize lipids and therefore helps conserve glycogen. It was thought interesting to find out if, in addition to this preferential use of fatty acids by muscle tissue, there is an increase in the capacity of adipose tissue to mobilize lipids. So the response to epinephrine of collagenase-isolated fat cells obtained after biopsies of fat performed in the periumbilical region of 10 trained marathon runners (T) and 10 sedentary subjects (S), all males, was studied in vitro. Glycerol release, chosen as adipocyte lipolysis indicator, was measured by bioluminescence. Lipolysis was studied with increased epinephrine concentration. This caused a significant increase in lipolysis only in the T subjects. The dose-response curves were significantly different for T and S subjects at 10(-6) M and above (P less than 0.05). To determine the modification mechanisms observed, lipolysis with isoproterenol and epinephrine plus propranolol were studied. Isoproterenol significantly increased lipolysis in both groups. The dose-response curves were significantly different at 10(-7) M (P less than 0.01) and above. In both groups, epinephrine plus propranolol significantly decreased lipolysis without distinction between T and S. It is concluded that in male subjects endurance training increases the sensitivity of subcutaneous abdominal adipose tissue to the lipolytic action of epinephrine; this effect seems to be related to an increased response of the beta-adrenergic pathways.

Lipolytic response of adipocytes to epinephrine in sedentary and exercise-trained subjects: sex-related differences

Adipose tissue lipolytic activity is increased in endurance-trained subjects, but little is known about the mechanisms of this increase. To understand more fully the mechanisms involved and to discover whether sex-related differences exist, biopsies of fat were performed in the periumbilical region of 20 sedentary subjects (10 women (W) and 10 men (M)) and 20 trained subjects (10 W, 10 M); the in vitro response to epinephrine of the collagenase-isolated fat cells was studied. Glycerol release, chosen as an adipocyte lipolysis indicator, was measured by bioluminescence. Dose-response curves with epinephrine (alpha 2 and beta agonist), with isoproterenol (beta agonist) and epinephrine + propranolol and adenosine deaminase, were studied. Epinephrine-induced lipolysis was enhanced in trained subjects and this was due to an increased efficiency of the beta-adrenergic pathway. However, differences were found between the two sexes. In trained men, the lipolysis increase resulted from the enhancement of the beta-adrenergic pathway efficiency without any significant decrease in the alpha 2-adrenergic pathway efficiency. In trained women, the lipolysis increase was not only due to the enhancement of the beta-adrenergic pathway efficiency (which was greater than in trained men), but also to a significant decrease in the alpha 2-adrenergic pathway efficiency. Despite the decrease, the alpha 2-adrenergic pathway remained more efficient in trained women than in trained men, as was the case in sedentary subjects. It is concluded that endurance training led to better lipid mobilization and that this effect seemed greater in women than in men.

Lipolytic response of fat cells to catecholamines in sedentary and exercise-trained women

It has been shown that adipose tissue lipolytic activity is increased in endurance-trained subjects. In women, adipose tissue is extensive and it was thought interesting to confirm that endurance training increases the capacity of female adipose tissue to mobilize lipids, and moreover to more fully understand the mechanisms involved. So, biopsies of fat were obtained from the periumbilical region of 13 trained female runners (T) and 17 sedentary women (S) and the in vitro response to catecholamines of the collagenase-isolated fat cells was studied. Glycerol release, chosen as adipocyte lipolysis indicator, was measured by bioluminescence for various epinephrine and norepinephrine concentrations. In both groups, these substances provoked an increase in lipolysis, but the response was significantly higher in T. In both groups, isoproterenol increased the lipolytic activity above basal concentrations at 10(-8) M and above. Lipolytic activity in T was significantly higher (P less than 0.01) than the S control at 10(-7) M and above. Epinephrine plus propranolol decreased lipolysis in both groups, but at 10(-5) M, lipolytic activity was significantly lower in S than in T (P less than 0.05). It is concluded that in female subjects, endurance training increases the sensitivity of subcutaneous abdominal adipose tissue to the lipolytic action of catecholamines; this effect seems to be related both to a decreased efficiency of the alpha 2-adrenergic pathway and to an increased efficiency of the beta-adrenergic pathway. This latter effect seems to take place at a step beyond the receptor-adenylate cyclase system in the lipolytic cascade.

Effect of carbohydrate ingestion on adipose tissue lipolysis during long-lasting exercise in trained men

To study whether sucrose administration acts on lipid mobilization during prolonged exercise, we used subcutaneous abdominal adipose tissue microdialysis in eight well-trained subjects submitted at random to two 100-min exercises (50% maximal aerobic power) on separate days. After 50 min of exercise, the subjects ingested either a sucrose solution (0.75 g/kg body wt) or water. By using a microdialysis probe, dialysate was obtained every 10 min from the subjects at rest, during exercise, and during a 30-min recovery period. During exercise without sucrose, plasma and dialysate glycerol increased significantly. With sucrose, the response was significantly lower for dialysate glycerol (P < 0.05). Plasma free fatty acid level was lower after sucrose than after water ingestion (P < 0.05). With water ingestion, plasma catecholamines increased significantly, whereas insulin fell (P < 0.05). With sucrose ingestion, the epinephrine response was blunted, whereas the insulin level was significantly increased. In conclusion, the use of adipose tissue microdialysis directly supports a lower lipid mobilization during exercise when sucrose is supplied, which confirms that the availability of carbohydrate influences lipid mobilization.

Activation of antilipolytic alpha(2)-adrenergic receptors by epinephrine during exercise in human adipose tissue

The involvement of the antilipolytic alpha(2)-adrenergic pathway and the specific role of epinephrine in the control of lipolysis during exercise in adipose tissue (AT) were investigated in healthy male subjects (age: 24.1 +/- 2.2 yr; body mass index: 23.0 +/- 1.6). An in vitro study carried out on isolated adipocytes showed that the weak lipolytic effect of epinephrine was potentiated after blockade of alpha(2)-adrenergic receptor (AR) by an alpha(2)-AR antagonist and reached that of isoproterenol, a beta-AR agonist. The effect of the nonselective alpha(2)-AR antagonist phentolamine on the response of the extracellular glycerol concentration (EGC) in AT during two successive bouts of aerobic exercise (50% maximum O(2) uptake, 60 min duration) was evaluated using the microdialysis method. The metabolic responses measured in perfused probes with Ringer solution were compared with those obtained in perfused probes with Ringer plus 0.1 mmol/l phentolamine. Plasma norepinephrine level was not different during the two exercise bouts, whereas that of epinephrine was 2.5-fold higher during the second exercise. EGC in AT was twofold higher in the second compared with the first exercise, and the same response pattern was found for plasma glycerol. The exercise-induced increase in EGC was higher in the probe perfused with phentolamine compared with the control probe in both bouts of exercise. However, the potentiating effect of phentolamine on EGC was significant during the second exercise bout but did not reach a significant level during the first. These results suggest that epinephrine is involved in the control of lipid mobilization through activation of antilipolytic alpha(2)-AR in human subcutaneous AT during exercise.

A single bout of exercise induces beta-adrenergic desensitization in human adipose tissue

This study was designed to assess whether physiological activation of the sympathetic nervous system induced by exercise changes adipose tissue responsiveness to catecholamines in humans. Lipid mobilization in abdominal subcutaneous adipose tissue was studied with the use of a microdialysis method in 11 nontrained men (age: 22. 3 +/- 1.5 yr; body mass index: 23.0 +/- 1.6). Adipose tissue adrenergic sensitivity was explored with norepinephrine, dobutamine (beta(1)-agonist), or terbutaline (beta(2)-agonist) perfused during 30 min through probes before and after 60-min exercise (50% of the maximal aerobic power). The increase in extracellular glycerol concentration during infusion was significantly lower after the exercise when compared with the increase observed before the exercise (P < 0.05, P < 0.02, and P < 0.01, respectively, for norepinephrine, dobutamine, and terbutaline). In a control experiment realized without exercise, no difference in norepinephrine-induced glycerol increase between the two infusions was observed. To assess the involvement of catecholamines in the blunted beta-adrenergic-induced lipolytic response after exercise, adipose tissue adrenergic sensitivity was explored with two 60-min infusions of norepinephrine or epinephrine separated by a 60-min interval. With both catecholamines, the increase in glycerol was significantly lower during the second infusion (P < 0.05). The findings suggest that aerobic exercise, which increased adrenergic activity, induces a desensitization in beta(1)- and beta(2)-adrenergic lipolytic pathways in human subcutaneous adipose tissue.

Lack of desensitization of catecholamine-induced lipolysis in fat cells from trained and sedentary women after physical exercise

A study was designed to assess whether a period of physical exercise (100 min; 60% of maximal aerobic power), known to promote sympathetic nervous system activation, had a functional impact on human fat cell responsiveness to catecholamines and beta-agonists. The lipolytic activity of isolated sc fat cells was measured before and after a period of exercise in trained and sedentary women with a similar body mass index values [20.4 +/- 0.5 (+/- SE) and 21.3 +/- 0.5 kg/m2] and an equivalent mean fat cell volume (0.216 +/- 0.022 vs. 0.278 pm 0.026 nL). Before exercise, compared with those of sedentary women, the adipocytes of trained women had greater lipolytic responsiveness to catecholamines and beta-agonists; moreover, dibutyryl cAMP had greater lipolytic efficiency on the adipocytes of the trained women. These results suggest that the differences in responsiveness of the adipocytes from sedentary and trained women are due to functional differences at a postreceptor level of the lipolytic cascade. The lipolytic (beta-adrenergic) and antilipolytic (alpha 2-adrenergic) responses of the adipocytes from both groups did not change after the period of physical activity. These results demonstrate, whatever the physical condition of the subjects, that desensitization of beta- and alpha 2-adrenergic responsiveness does not occur after a period of intense physical activity which promotes physiological activation of the sympathetic nervous system.

Prenatal diagnosis of del(15)(q11q13)

A case of del(15)(q11q13) was detected in amniotic fluid cell cultures and confirmed by cordocentesis in a 27-year-old woman with a low maternal serum alpha-fetoprotein level. The fetus was shown to have a short femoral length on ultrasonography. This structural chromosome abnormality associated with the prenatal ultrasonographic findings and the morphological characteristics visualized after termination of pregnancy strongly suggest Prader-Willi syndrome.

Gonadal tumor and H-Y antigen in 46,XY pure gonadal dysgenesis

Six cases of Swyer's syndrome (46,XY pure gonadal dysgenesis) are reported. Three patients, without gonadal tumor, had female H-Y antigen. Three patients, after gonadal tumor ablation, had intermediate H-Y antigen levels. Repeated blood samples were obtained from two siblings. H-Y antigen level in the first sibling, who presented with a gonadoblastoma and underwent a gonadectomy before the H-Y assays, was intermediate, and did not show any significant variation for 21 months. H-Y antigen level in the second sibling showed an increase in the male range, presumably due to the presence of gonadoblastomas. After resection of the tumors, H-Y antigen level became intermediate. These findings suggest a relation between the tumorization potentiality of the gonadal remnants and the H-Y antigen levels in 46,XY pure gonadal dysgenesis.

Effect of long-term rhGH administration in GH-deficient adults on fat cell epinephrine response

Besides exerting its own lipolytic effect, growth hormone (GH) has been reported to potentiate the lipolytic response of adipose tissue to epinephrine. It was thought interesting to find out whether long-term recombinant human growth hormone (rhGH) administration modifies epinephrine-induced lipolysis in isolated adipocytes of GH-deficient adults. In a double-blind protocol, GH-deficient subjects received either 6 mo placebo (controls, n = 5) or 6 mo rhGH (treated, n = 5). Biopsies of fat were obtained from the periumbilical region before and after placebo or rhGH administration. The response of the collagenase-isolated fat cells to various concentrations of epinephrine was assessed by glycerol release, measured by bioluminescence. Epinephrine-induced lipolysis was not altered by 6 mo placebo, while it was significantly increased by 6 mo rhGH. A similar response was obtained with isoproterenol, but no significant differences occurred in either group with UK 14304, an alpha 2-adrenoreceptor agonist. Thus, in GH-deficient adults, long-term rhGH administration improves the lipolytic response of isolated adipocytes to epinephrine, essentially by increasing the efficiency of the beta-adrenergic pathway.

Effects of physiological and pharmacological variation of sympathetic nervous system activity on plasma non-esterified fatty acid concentrations in man

1. The consequence of the sympatholytic effect of clonidine (alpha 2-adrenoceptor agonist) was compared with the effect of a physiological inhibition of sympathetic nervous system activity (change from upright to supine position) on plasma catecholamine and non-esterified fatty acid (NEFA) concentrations in overnight fasting healthy men. 2. Clonidine (150 micrograms orally) administered in upright position induced a significant reduction of plasma noradrenaline and NEFA concentrations. A change from upright to supine position which provoked a more marked decrease in plasma noradrenaline concentrations induced a weak increase in plasma NEFA concentrations. 3. The modification of plasma NEFA and catecholamine concentrations brought about by standing up was studied after placebo or yohimbine (alpha 2-adrenoceptor antagonist) administration. With placebo, standing up promotes a 100% increase in plasma noradrenaline concentrations (measured 5 and 15 min after rising) and a weak transient decrease in plasma NEFA concentrations (5 min after rising). In the supine position, yohimbine increased plasma noradrenaline and NEFA concentrations by about 100% and 55% respectively. Standing after yohimbine administration promoted large increases in plasma noradrenaline and NEFA concentrations. 4. These results indicate that a reduction of sympathetic nervous activity is not associated with a decrease of plasma NEFA concentrations and argue for a role of alpha 2-adrenoceptors in the NEFA mobilization from adipose tissue after sympathetic nervous system activation in man.

Nodal metastases distribution in laryngeal cancer requiring total laryngectomy: Therapeutic implications for the N0 Neck

OBJECTIVES

Neck dissection is a controversial surgical procedure in patients with squamous cell carcinoma of the Larynx free of any node metastasis detected in preoperative staging. The aim of this study was to investigate the distributions of lymph node metastases in laryngeal squamous cell carcinoma and improve the rationale for elective treatment of N0 neck.

MATERIAL AND METHODS

Retrospective single-center series of Seventy-eight successive patients with laryngeal squamous cell carcinoma who underwent neck dissection between 2008 and 2015.

RESULTS

Surgery was first-line treatment in 37 patients (47%) and for recurrent disease in 41 (53%). The rate of occult nodal metastasis was 14% (n=11): levels IIa and/or III were affected in 9 cases (11.5%) compared with single cases of IIb and IV involvement (1.3% each). The rate of occult nodal metastasis was significantly lower among patients operated on for recurrent disease after radiotherapy than in patients who never had any radiotherapy of the cervical lymph nodes (0% vs. 16.7%, P=0.03).

CONCLUSIONS

Selective cervical lymph node dissection in levels IIa and III sparing levels IIb and IV seems to be ideal in total laryngectomy in patients with cN0 laryngeal squamous cell carcinoma. Omitting lymph node dissection altogether may be considered in total laryngectomy on a cN0 patient showing recurrence after radiotherapy.

[The congenital central hypoventilation syndrome (CCHS): a late presentation]

BACKGROUND

The congenital central hypoventilation syndrome (CCHS) or Ondine's curse is a rare autosomal dominant disease, characterized by disorders of the autonomic nervous system, with abnormal ventilatory responses to hypercapnia and hypoxia. PHOX2B has been identified as the major gene causing CCHS. It results from polyalanine repeat expansion mutations. It typically presents in the newborn period but some cases have been described in adults (late onset CCHS) reflecting the variable penetrance of PHOX2B mutations.

CASE REPORT

A 48 year-old woman presented, after ovarian cyst surgery, with severe hypoventilation requiring intubation. Arterial blood gases revealed a PaO2 of 6.6kPa (50mmHg), a PaCO2 of 10kPa (80mmHg) and a pH of 7.22. The past medical history revealed nocturnal symptoms for a few years. These included apnoeas, fitful sleep and awakening with headaches. Physical examination, pulmonary function tests, lung tomography and magnetic resonance imaging of the brainstem were all normal. Polysomnography revealed numerous central and obstructive apnoeas and hypopnoeas, with severe hypoxaemia and hypercapnia. Hypoxic and hypercapnic stimulation tests showed no adaptation of the ventilatory responses. Genetic analysis showed a heterozygous five alanine expansion mutation of the 20-residue polyalanine tract in exon 3 of the PHOX2B gene.

CONCLUSION

The diagnosis of late onset CCHS should be considered in patients with unexplained hypoventilation, and physiological evaluation should be undertaken to document the abnormal ventilatory responses. The presence of a PHOX2B mutation confirms the diagnosis.

Prenatal diagnosis of a fetus with partial monosomy 7(q34-->qter) and partial trisomy 18(q21-->qter)

Ultrasound examination of a 31-year-old woman at 27 weeks' gestation revealed fetal growth retardation, a bilateral cleft lip and palate, and the absence of median cerebral structures. Chromosome analysis after cordocentesis showed an abnormal karyotype with a structural abnormality of the long arm of chromosome 7: 46,XX,-7,+der(7),t(7;18) (q34;q21.3)mat. The pregnancy was terminated at week 29. The ultrasound findings were confirmed by post-mortem examination, which also revealed a semilobar holoprosencephaly.

Response of fat cells to growth hormone (GH): effect of long term treatment with recombinant human GH in GH-deficient adults

GH deficiency impairs lipid metabolism in adults, but little is known about the direct effect of GH on adipose tissue in humans. First, the in vitro response of fat cells to GH in five GH-deficient adults was studied; second, it was investigated whether 6-month recombinant human GH (rhGH) administration modifies this response. Biopsies of fat were obtained from the periumbilical region before and after rhGH administration. The response of the collagenase-isolated fat cells to various concentrations of GH was assessed by glycerol release, measured by bioluminescence. Before treatment, GH induced a lipolytic activity from the adipocytes, which became significantly higher after 6 months of treatment. Thus, this study provides evidence for an intrinsic lipolytic activity of GH in GH-deficient adults and for its improvement after long term rhGH administration.

Simulated microgravity increases beta-adrenergic lipolysis in human adipose tissue

The effect of a sustained decrease in sympathetic nervous activity, achieved through 5-day head-down bed rest (HDBR), on the beta-adrenergic lipolytic activity of s.c. adipose tissue was studied in eight healthy men. The in situ beta-adrenoceptor (AR) sensitivity was studied using the microdialysis method. Local perfusion of increasing concentrations of isoprenaline showed an increased beta-AR sensitivity to lipolysis (assessed by extracellular glycerol concentration) and to vascular tone (assessed by the ethanol clearance). The adrenergic sensitivity of isolated adipocytes was studied in vitro. Basal lipolysis and the response to nonselective (isoprenaline) or selective (dobutamine, terbutaline, and CGP 12177) beta-AR agonists were increased after HDBR as was the lipolytic effect of dibutyryl cAMP. When data were expressed as a percentage of the dibutyryl cAMP effect to rule out the postreceptor events, basal and lipolytic responses to beta-AR agonists where similar before and during HDBR. The alpha 2-AR-mediated antilipolytic effects of adrenaline were not modified. Lymphocyte beta-AR number was unchanged during HDBR. Our results demonstrate that a sustained sympathoinhibition induces an increase in the lipolytic beta-adrenergic response in adipose tissue and suggest that this hypersensitization is linked to an increase in the postreceptor steps of the lipolytic cascade in the adipocyte rather than to changes in beta-adrenoceptors.

Determination of appendicular muscle mass by dual energy X-ray absorptiometry method in women with sarcopenia and Alzheimer's disease

OBJECTIVES

To study appendicular muscle mass in women with Alzheimer's disease (AD) to investigate the association between sarcopenia and AD. To examine the AD associated changes in body fat distribution.

DESIGN

a cross-sectional study of 32 women with AD and 32 healthy age and bone mineral density matched women.

SETTING

Toulouse, France.

RESULTS

No differences were noted in fat free soft tissue mass or Appendicular Skeletal Muscle (ASM) mass between AD women and control women. The difference of ASM (kg) /height2 (m)2, used as an index of relative skeletal muscle mass, was not statistically significative between the two groups. The prevalence of sarcopenia increased from 21.9 % in healthy elderly women to 40.6 % in AD women but the difference was not statistically significant. No statistically significant relationship emerged between sarcopenia and AD (OR= 0.41, CI 0.12-1.4). Moreover, total body fat mass was significantly lower in women with AD than in the age -, sex - and bone mineral density - matched controls.

CONCLUSION

AD are not necessary linked to sarcopenia. The decrease in adipose tissue in women with AD could be one more factor involving estrogen deficiency in the etiology of the disease.

Platelet alpha 2-adrenoceptors and adrenergic adipose tissue responsiveness after moderate hypocaloric diet in obese subjects

Platelet alpha 2-adrenoceptor number was studied in obese subjects treated by a moderate hypocaloric diet (1000-1200 kcal/day = 4200-5000 kg/day) for 21-25 days. Spontaneous lipolysis and adrenergic responsiveness of isolated subcutaneous abdominal adipocytes, collected by a biopsy procedure, were studied before and after treatment on the same subjects. The number of alpha 2-adrenoceptor binding sites (Bmax values) of the platelets was increased after the hypocaloric diet, while there was no change in the equilibrium dissociation constant. Basal lipolytic activity of the adipocytes was increased after the hypocaloric treatment, whereas neither the beta-dependent lipolytic effect of isoproterenol nor the alpha 2-dependent antilipolytic effect of epinephrine were affected. It is concluded that moderate hypocaloric diet induces an up-regulation of platelet alpha 2-adrenoceptors. No modification occurs in alpha 2- and beta-adrenergic responsiveness of the subcutaneous adipocytes. Although alpha 2-adrenergic receptor binding studies on platelets have been widely used as an index for alpha 2-adrenoceptor function in other tissues, it is suggested by this study that platelet alpha 2-adrenoceptors cannot be used for prediction of alpha 2-adrenoceptor function in adipose tissue.