Inflammatory markers in adults with Prader-Willi syndrome before and during 12 months growth hormone treatment

Prader-Willi Syndrome in Adults: An Update On Nutritional Treatment and Pharmacological Approach

PURPOSE OF REVIEW

Prader-Willi syndrome (PWS) is a rare and complex genetic disorder with multiple effects on the metabolic, endocrine, and neurological systems, as well as behavioral and intellectual difficulties. Despite advances in understanding the genetic basis of obesity in PWS, there are conflicting data on its management. Therefore, the present manuscript aims to provide an update on the nutritional treatment and pharmacological approach in adult patients with PWS.

RECENT FINDINGS

The management of obesity in patients with PWS is challenging and requires the cooperation of an experienced multidisciplinary team, including the nutritionist. An adequate clinical evaluation including nutritional and biochemical parameters should be performed to tailor the best therapeutic strategy. Both lifestyle and pharmacological interventions may represent useful strategies to prevent the high rate of morbidity and mortality related to PWS. The use of bariatric surgery is still controversial. Although it is imperative to adopt an obesity prevention strategy in childhood, there is promising evidence for the treatment of obesity in adulthood with current obesity medications in conjunction with lifestyle interventions.

The use of growth hormone therapy in adults with Prader-Willi syndrome: A systematic review

OBJECTIVE

Despite clear benefits in the management of children with Prader-Willi syndrome (PWS), the role of growth hormone (GH) in adults is unclear. The aim of this study was to conduct a systematic review to evaluate the effects of GH on body composition, bone health and cardiovascular health in adults with PWS.

DESIGN

A systematic computerized literature search of the PubMed database was conducted by two independent reviewers. Inclusion criteria were individuals over the age of 16 years with a genetic diagnosis of PWS who had received GH therapy, together with assessment of body composition, bone health or cardiovascular health.

RESULTS

Twenty full-text papers met the inclusion criteria, encompassing 364 unique patients. No differences in body mass index (BMI) were noted, although 2 studies reported increased BMI after GH cessation. Data demonstrated statistically significant increases in lean body mass and reductions in percentage fat mass. Studies reported inconsistent effects of GH on cholesterol and echocardiography parameters. No studies reported differences in bone mineral density, although one reported improved bone geometry. Minor adverse events including pretibial oedema, headache and transient impaired glucose tolerance were reported in 7 studies.

CONCLUSIONS

These data suggest that GH is safe and well tolerated in adults with PWS, with evidence of improvement in body composition. Further longitudinal studies are still required to investigate the effects of GH on bone and cardiovascular health. Where GH is used in adults with PWS, this should be managed by a specialist multidisciplinary team with regular monitoring initiated.

Phase Angle: Could Be an Easy Tool to Detect Low-Grade Systemic Inflammation in Adults Affected by Prader-Willi Syndrome?

Prader-Willi syndrome (PWS) is the most common genetic inherited obesity syndrome. Obesity-related complications, mostly related to chronic low-grade systemic inflammation (LGI), are the commonest cause of mortality and morbidity in PWS adults. Phase angle (PhA) is an easy tool to screen a state of LGI in healthy subjects and in subjects with obesity and is obtained from bioelectrical impedance analysis (BIA). The aim of this study was to validate the PhA in PWS adults as a potential biomarker of LGI. In this single-center, cross-sectional study, fifteen PWS adults (six males, aged 19-41 years, and body mass index (BMI) 31.0-68.0 Kg/m2) and fifteen control subjects matched by gender, age, and BMI were evaluated. PhA values were significantly lower (p < 0.001), while high-sensitivity C-reactive protein (hs-CRP) levels were significantly higher (p < 0.001) in PWS adults compared with controls (p < 0.001), without a gender difference in the latter. After adjustment for gender, BMI, and waist circumference, significant correlation was found between PhA and hs-CRP levels (r = -0.69, p = 0.01). At the ROC analysis, the threshold value of PhA predicting the highest hs-CRP levels above the median value was found at PhA ≤ 4.8° (p = 0.01; AUC, 0.82; standard error, 0.12; 95% CI, 0.58 to 1.00). These results suggest that PWS adults had a significant higher degree of LGI compared with their counterparts. Moreover, our finding suggest that PhA is a valid biomarker of LGI also in PWS adults.

Myokine levels after resistance exercise in young adults with Prader-Willi syndrome (PWS)

Individuals with PWS require marked caloric restriction and daily exercise to prevent morbid obesity. Lower energy expenditure, hypotonia, decreased muscle mass, and cognitive impairment make exercise challenging for this population. Exercise guidelines include resistance training as an important component. Myokine responses to resistance exercise may mediate beneficial metabolic effects. We aimed to determine if young PWS adults can perform a resistance exercise program and to measure myokine responses in PWS versus age- and BMI-matched controls. Each group included 11 participants (7M/4F). Ages and BMI for PWS and controls were 30.7 ± 4.6 versus 30.1 ± 4.3 years and 28.3 ± 4.3 versus 28.2 ± 4.2 kg/m² , respectively. Glucose, creatine kinase (CK), lactate, and myokines were measured before, after, 30, and 60 min after completing eight resistance exercises. Myokines were assayed using a multiplex myokine panel (Merck Millipore). CK was lower in PWS versus controls (62 ± 16 vs.322 ± 100 U/L, p < .04). Peak lactate was 3.7 ± 0.7 in PWS versus 7.3 ± 0.7 mmol/Lin controls (p < .001). The increase in interleukin-6 was similar in PWS and controls (41 ± 16% and 35 ± 10%, respectively). Pre- and post-exercise levels of the six myokines assayed showed no consistent differences between the PWS and control participants. PWS young adults are capable of performing resistance/strength-building exercise. The lower CK and peak lactate levels in PWS may reflect decreased muscle mass in this population. Further studies are needed to determine optimal exercise regimens and assess the role of myokines incontributing to the metabolic phenotype of PWS.

Body composition, adipokines, bone mineral density and bone remodeling markers in relation to IGF-1 levels in adults with Prader-Willi syndrome

Background

In patients with Prader-Willi syndrome (PWS) body composition is abnormal and alterations in appetite regulating factors, bone mineral density and insulin-like growth factor-1 (IGF-1) levels have been described. Studies in PWS adults are limited. In this study, we investigated body composition, appetite regulating peptides, bone mineral density and markers of bone remodeling in an adult PWS population. Furthermore, we investigated the association between these different parameters and IGF-1 levels because of the described similarities with growth hormone deficient patients.

Methods

In this cross-sectional observational cohort study in a university hospital setting we studied fifteen adult PWS patients. Anthropometric and metabolic parameters, IGF-1 levels, bone mineral density and bone metabolism were evaluated. The homeostasis model assessment of insulin resistance (HOMA2-IR) was calculated. Fourteen healthy siblings served as a control group for part of the measurements.

Results

In the adult PWS patients, height, fat free mass, IGF-1 and bone mineral content were significantly lower when compared to controls; body mass index (BMI), waist, waist-to-hip ratio and fat mass were higher. There was a high prevalence of osteopenia and osteoporosis in the PWS patients. Also, appetite regulating peptides and bone remodelling markers were aberrant when compared to reference values. Measurements of body composition were significantly correlated to appetite regulating peptides and high-sensitive C-reactive protein (hs-CRP), furthermore HOMA was correlated to BMI and adipokines.

Conclusion

In adults with Prader-Willi syndrome alterations in body composition, adipokines, hs-CRP and bone mineral density were demonstrated but these were not associated with IGF-1 levels. Further investigations are warranted to gain more insight into the exact pathophysiology and the role of these alterations in the metabolic and cardiovascular complications seen in PWS, so these complications can be prevented or treated as early as possible.

Impairment of adipose tissue in Prader-Willi syndrome rescued by growth hormone treatment

BACKGROUND

Prader-Willi syndrome (PWS) results from abnormalities in the genomic imprinting process leading to hypothalamic dysfunction with an alteration of growth hormone (GH) secretion. PWS is associated with early morbid obesity and short stature which can be efficiently improved with GH treatment.

OBJECTIVES

Our aims were to highlight adipose tissue structural and functional impairments in children with PWS and to study the modifications of those parameters on GH treatment.

SUBJECTS AND METHODS

Plasma samples and adipose tissue biopsies were obtained from 23 research centers in France coordinated by the reference center for PWS in Toulouse, France. Lean controls (n=33), non-syndromic obese (n=53), untreated (n=26) and GH-treated PWS (n=43) children were enrolled in the study. Adipose tissue biopsies were obtained during scheduled surgeries from 15 lean control, 7 untreated and 8 GH-treated PWS children.

RESULTS

Children with PWS displayed higher insulin sensitivity as shown by reduced glycemia, insulinemia and HOMA-IR compared with non-syndromic obese children. In contrast, plasma inflammatory cytokines such as TNF-α, MCP-1 and IL-8 were increased in PWS. Analysis of biopsies compared with control children revealed decreased progenitor cell content in the stromal vascular fraction of adipose tissue and an impairment of lipolytic response to β-adrenergic agonist in PWS adipocytes. Interestingly, both of these alterations in PWS seem to be ameliorated on GH treatment.

CONCLUSION

Herein, we report adipose tissue dysfunctions in children with PWS which may be partially restored by GH treatment.

Metabolic syndrome in adult patients with Prader-Willi syndrome

BACKGROUND AND AIMS

Prader-Willi syndrome (PWS), the most common genetic cause of obesity, is characterized by elevated morbility and mortality in all ages. In this context, non-obese PWS children showed low frequency of metabolic syndrome (MetS), while a comparable prevalence was observed in obese PWS and obese controls. Aim of this study was to estimate the occurrence of MetS and its components in a large group of PWS adults, according to obesity status.

METHODS AND RESULTS

A cross-sectional study was performed in 108 PWS aged 18.0-43.2 years (87 obese and 21 non-obese) and in 85 controls with nonsyndromic obesity matched for age, gender, and BMI with obese PWS. Non-obese PWS showed lower waist circumference, insulin, HOMA-index, triglycerides, diastolic blood pressure, and higher HDL-C than both obese PWS and obese controls (p < 0.017). Obese PWS showed higher glucose and systolic blood pressure than both non-obese PWS and obese controls (p < 0.017). MetS was found in 1/21 (4.8%) non-obese PWS, 36/87 (41.4%) obese PWS and 39/85 (45.9%) obese controls. Non-obese PWS showed lower frequency for each MetS component as compared with obese PWS and obese controls. PWS patients with deletion of the chromosome 15q11-13 showed a lower risk for low HDL-C (p < 0.01) and a trend towards a lower MetS risk (p < 0.06) compared to subjects without deletion.

CONCLUSION

Our findings suggest the main role that obesity status plays on the individual metabolic risk clustering in PWS adults. Early identification of MetS could be helpful to improve morbidity and prevent mortality in such patients.

GrowthHormone Research Society workshop summary: consensus guidelines for recombinant human growth hormone therapy in Prader-Willi syndrome

CONTEXT

Recombinant human GH (rhGH) therapy in Prader-Willi syndrome (PWS) has been used by the medical community and advocated by parental support groups since its approval in the United States in 2000 and in Europe in 2001. Its use in PWS represents a unique therapeutic challenge that includes treating individuals with cognitive disability, varied therapeutic goals that are not focused exclusively on increased height, and concerns about potential life-threatening adverse events.

OBJECTIVE

The aim of the study was to formulate recommendations for the use of rhGH in children and adult patients with PWS.

EVIDENCE

We performed a systematic review of the clinical evidence in the pediatric population, including randomized controlled trials, comparative observational studies, and long-term studies (>3.5 y). Adult studies included randomized controlled trials of rhGH treatment for ≥ 6 months and uncontrolled trials. Safety data were obtained from case reports, clinical trials, and pharmaceutical registries.

METHODOLOGY

Forty-three international experts and stakeholders followed clinical practice guideline development recommendations outlined by the AGREE Collaboration (www.agreetrust.org). Evidence was synthesized and graded using a comprehensive multicriteria methodology (EVIDEM) (http://bit.ly.PWGHIN).

CONCLUSIONS

Following a multidisciplinary evaluation, preferably by experts, rhGH treatment should be considered for patients with genetically confirmed PWS in conjunction with dietary, environmental, and lifestyle interventions. Cognitive impairment should not be a barrier to treatment, and informed consent/assent should include benefit/risk information. Exclusion criteria should include severe obesity, uncontrolled diabetes mellitus, untreated severe obstructive sleep apnea, active cancer, or psychosis. Clinical outcome priorities should vary depending upon age and the presence of physical, mental, and social disability, and treatment should be continued for as long as demonstrated benefits outweigh the risks.

Altered inflammation, paraoxonase-1 activity and HDL physicochemical properties in obese humans with and without Prader-Willi syndrome

Prader-Willi syndrome (PWS) represents the most common form of genetic obesity. Several studies confirm that obesity is associated with inflammation, oxidative stress and impairment of antioxidant systems; however, no data are available concerning PWS subjects. We compared levels of plasma lipids and C-reactive protein (CRP) in 30 subjects of 'normal' weight (18.5-25 kg/m(2)), 15 PWS obese (>30 kg/m(2)) subjects and 13 body mass index (BMI)-matched obese subjects not affected by PWS. In all subjects, we evaluated the levels of lipid hydroperoxides and the activity of paraoxonase-1 (PON1), an enzyme involved in the antioxidant and anti-inflammatory properties exerted by high-density lipoproteins (HDLs). Furthermore, using the fluorescent molecule of Laurdan, we investigated the physicochemical properties of HDLs isolated from normal weight and obese individuals. Altogether, our results demonstrated, for the first time, higher levels of lipid hydroperoxides and a lower PON1 activity in plasma of obese individuals with PWS with respect to normal-weight controls. These alterations are related to CRP levels, with a lower PON1:CRP ratio in PWS compared with non-PWS obese subjects. The study of Laurdan fluorescence parameters showed significant modifications of physicochemical properties in HDLs from PWS individuals. Whatever the cause of obesity, the increase of adiposity is associated with inflammation, oxidative stress and alterations in HDL compositional and functional properties.

Effects of recombinant human growth hormone therapy in adults with Prader-Willi syndrome: a meta-analysis

OBJECTIVE

Prader-Willi syndrome (PWS) is associated with GH deficiency, deleterious changes in body composition and function. As the effects of recombinant human GH (rhGH) in PWS adults have not been well established, we sought to conduct a meta-analysis of pertinent studies.

DESIGN

Meta-analysis of studies examining the effects of rhGH therapy in PWS adults.

PATIENTS

One hundred and thirty four PWS adults (75 men, 59 women).

MEASUREMENTS

Literature searches, including publications (PubMed, EMBASE and the Cochrane Register), and abstracts presented at meetings through July 2011 describing studies of rhGH therapy in PWS adults; 8/1194 articles, describing unique cohorts, were included. Two authors independently extracted data and examined study quality.

RESULTS

rhGH therapy for 12 months led to [weighted mean difference (95% CI)] decreased body fat [-2·91% (-3·90, -1·91)], visceral [-32·97 cm(2) (-55·67, -10·26)] and subcutaneous adiposity [-55·24 cm(2) (-89·05, -21·44)], and increased lean body mass (LBM) [2·41 Kg (1·32, 3·49)]. Similar changes in body fat [-2·89% (-4·69, -1·07)] and LBM [2·82 Kg (1·31, 4·33)] were found in longer studies. There were no changes in body mass index (BMI) or lipids. There was a small increase in fasting glucose [0·27 mmol/l (0·05, 0·49)] and trends towards higher fasting insulin [20·24 pmol/l (-0·55, 41·02)] and insulin resistance [HOMA: 0·60 (-0·04, 1·24)] after rhGH therapy for 12 months.

CONCLUSIONS

In PWS adults, rhGH therapy led to decreased body adiposity and increased LBM without changes in BMI or lipids. There was a small increase in fasting glucose and trends towards higher insulin and insulin resistance.

The metabolic phenotype of Prader-Willi syndrome (PWS) in childhood: heightened insulin sensitivity relative to body mass index

CONTEXT

Insulin sensitivity is higher in patients with Prader-Willi syndrome (PWS) than in body mass index-matched obese controls (OCs). Factors contributing to the heightened insulin sensitivity of PWS remain obscure. We compared the fasting levels of various hormones, cytokines, lipids, and liver function tests in 14 PWS patients and 14 OCs with those in 14 age- and gender-matched lean children (LC). We hypothesized that metabolic profiles of children with PWS are comparable with those of LC, but different from those of OCs.

RESULTS

Leptin levels were comparable in PWS patients and OCs, suggesting comparable degrees of adiposity. Glucose levels were comparable among groups. However, fasting insulin concentrations and homeostasis model assessment insulin resistance index were lower in PWS patients than in OCs (P < 0.05) and similar to LC. Moreover, high-density lipoprotein levels were lower and triglycerides higher in OCs (P < 0.05) but not PWS patients. Total adiponectin, high-molecular-weight (HMW) adiponectin and the HMW to total adiponectin ratio were higher in PWS patients (P < 0.05) than in OCs and similar to LC. High-sensitivity C-reactive protein and IL-6 levels were higher in OCs than in PWS patients or LC (P < 0.05). Nevertheless, PAI-1 levels were elevated in both OC and PWS patients. There were no group differences in glucagon-like peptide-1, macrophage chemoattractant protein-1, TNFα, IL-2, IL-8, IL-10, IL-12p40, IL-18, resistin, total or low-density lipoprotein cholesterol, aspartate aminotransferase, or alanine aminotransferase.

CONCLUSIONS

The heightened insulin sensitivity of PWS patients relative to OCs is associated with higher levels of adiponectin and lower levels of high-sensitivity C-reactive protein and IL-6. Future studies will determine whether PWS children are protected from obesity comorbidities such as type 2 diabetes, hyperlipidemia, and nonalcoholic fatty liver disease.

Adult subjects with Prader-Willi syndrome show more low-grade systemic inflammation than matched obese subjects

AIM

Adult subjects with Prader-Willi syndrome (PWS) may show several conditions that are associated with an activation of innate immunity such as obesity, deficient GH secretion or hypogonadism. Our aim was to study whether obese adult PWS subjects show an additional low-grade systemic inflammation (LGSI) in relation to obese adult non-PWS subjects and lean healthy control subjects before and after a standardized liquid meal.

METHODS

Seven obese adult PWS subjects, 7 matched obese non-PWS subjects and 7 lean healthy control subjects were studied for 6 h from the administration of a standard liquid meal.

RESULTS

Compared to non-PWS, PWS subjects showed higher plasma concentrations of C-reactive protein (CRP) (p=0.030), complement component C3 (p=0.018), interleukin(IL)-18 (p=0.048), and IL-6 (p=0.041) that persisted post-prandially elevated for CRP (p<0.0001), C3 (p=0.015), and IL-18 (p=0.003). Tumor necrosis factor(TNF)-alpha did not differ between the 3 groups. These results were independent from IGF-I levels, homeostasis model assessment index, and body mass index (BMI). In male subjects with PWS, testosterone levels correlated to IL-18 (r=-0,646, p=0.041).

CONCLUSIONS

Compared to matched non-PWS subjects, the obese PWS subjects in this study showed an additional LGSI that persisted postprandially and was independent from BMI, insulin resistance, and deficient GH secretion. However, in PWS males, high IL-18 levels were related to low testosterone concentrations.