Reduced plasma ghrelin levels on day 1 after esophagectomy: a new predictor of prolonged systemic inflammatory response syndrome

Effect of ghrelin administration on postoperative inflammatory response and bodyweight loss in patients with oesophageal cancer undergoing oesophagectomy: a systematic review and meta-analysis

OBJECTIVES

To investigate the effect of postoperative ghrelin therapy on postoperative inflammatory response and bodyweight loss in patients undergoing an oesophagectomy for oesophageal cancer.

METHODS

We conducted a systematic search using electronic information databases in accordance to PRISMA standards to identify studies comparing outcomes after oesophagectomy in patients who were and were not administered ghrelin in the postoperative period. Meta-analysis of the outcomes using random effects modelling was conducted. The Cochrane collaboration's tool and ROBINS-I tool were used for risk of bias assessment of the included studies.

RESULTS

Five studies including 192 patients were selected for analysis. Ghrelin therapy was associated with a significantly shorter duration of systemic inflammatory response syndrome (SIRS) (MD: - 2.72, P = 0.0001), lower CRP level on postoperative day 3 (MD: - 3.64, P < 0.0001), and less total bodyweight loss (MD: - 1.87, P = 0.14). There was no differences between the two groups in IL-6 level on postoperative day 3 (MD: - 19.65, P = 0.32), total lean body weight loss (MD: - 1.87, P = 0.14), total body fat loss (MD: 0.15, P = 0.84), pulmonary complications (OR: 0.47, P = 0.12), anastomotic leak (OR: 1.17, P = 0.78), wound complications (OR: 1.64, P = 0.63), postoperative bleeding (OR: 0.32, P = 0.33), arrhythmia (OR: 1.22, P = 0.77).

CONCLUSIONS

Administration of ghrelin following oesophagoectomy may reduce duration of postoperative SIRS and bodyweight loss. Whether shorter duration of SIRS and less bodyweight loss resulted from postoperative ghrelin therapy can translate into improved morbidity or mortality outcomes remains unknown. There is a need for randomised controlled trials with robust statistical power to investigate the role of postoperative ghrelin therapy on morbidity and mortality outcomes in patients undergoing oesophagectomy.

Diverse and Complementary Effects of Ghrelin and Obestatin

Ghrelin and obestatin are two “sibling proteins” encoded by the same preproghrelin gene but possess an array of diverse and complex functions. While there are ample literature documenting ghrelin’s functions, the roles of obestatin are less clear and controversial. Ghrelin and obestatin have been perceived to be antagonistic initially; however, recent studies challenge this dogma. While they have opposing effects in some systems, they function synergistically in other systems, with many functions remaining debatable. In this review, we discuss their functional relationship under three “C” categories, namely complex, complementary, and contradictory. Their functions in food intake, weight regulation, hydration, gastrointestinal motility, inflammation, and insulin secretion are complex. Their functions in pancreatic beta cells, cardiovascular, muscle, neuroprotection, cancer, and digestive system are complementary. Their functions in white adipose tissue, thermogenesis, and sleep regulation are contradictory. Overall, this review accumulates the multifaceted functions of ghrelin and obestatin under both physiological and pathological conditions, with the intent of contributing to a better understanding of these two important gut hormones.

Protective and Healing Effects of Ghrelin and Risk of Cancer in the Digestive System

Ghrelin is an endogenous ligand for the ghrelin receptor, previously known as the growth hormone secretagogue receptor. This hormone is mainly produced by endocrine cells present in the gastric mucosa. The ghrelin-producing cells are also present in other organs of the body, mainly in the digestive system, but in much smaller amount. Ghrelin exhibits a broad spectrum of physiological effects, such as stimulation of growth hormone secretion, gastric secretion, gastrointestinal motility, and food intake, as well as regulation of glucose homeostasis and bone formation, and inhibition of inflammatory processes. This review summarizes the recent findings concerning animal and human data showing protective and therapeutic effects of ghrelin in the gut, and also presents the role of growth hormone and insulin-like growth factor-1 in these effects. In addition, the current data on the possible influence of ghrelin on the carcinogenesis, its importance in predicting the risk of developing gastrointestinal malignances, as well as the potential usefulness of ghrelin in the treatment of cancer, have been presented.

Continuous ghrelin infusion attenuates the postoperative inflammatory response in patients with esophageal cancer

PURPOSE

The aim of this study was to clarify whether ghrelin infusion is useful for suppressing inflammatory responses after esophagectomy.

METHODS

A phase I study of ghrelin administration after esophagectomy was performed in 20 patients with esophageal cancer. The anti-inflammatory effect of ghrelin was compared with 20 consecutive patients who did not receive ghrelin infusion. Additionally, 10 patients with intermittent infusion for 10 days were compared with 10 patients with continuous infusion for 5 days. The primary endpoint was the duration of systemic inflammatory response syndrome (SIRS). Secondary endpoints included postoperative complications, serum C-reactive protein (CRP), interleukin-6 (IL-6), and growth hormone (GH) levels.

RESULTS

No adverse events of ghrelin administration occurred. Patients with ghrelin infusion had higher plasma ghrelin levels on postoperative day (POD) 3 (p = 0.003) and shorter SIRS duration (p = 0.007) than patients without ghrelin infusion. Although SIRS duration was similar (p = 0.19), patients with continuous ghrelin infusion had significantly higher plasma ghrelin (p < 0.001) and GH levels (p = 0.002) on POD 3 than patients with intermittent ghrelin infusion. Serum CRP and IL-6 levels on POD 3 tended to be lower in the continuous infusion versus intermittent infusion group.

CONCLUSIONS

Ghrelin was safely administered after esophagectomy and may reduce excess postoperative inflammatory responses. Continuous infusion is better for this purpose than intermittent infusion.

Acylated ghrelin protects against doxorubicin-induced nephropathy by activating silent information regulator 1

This study investigated the nephroprotective role of acylated ghrelin (AG) against DOX-induced nephropathy and examined whether the protection involves silent information regulator 1 (SIRT1). Rats were divided into control, control + AG, DOX, DOX + AG, DOX + AG + [D-Lys3]-GHRP-6 (a ghrelin receptor antagonist), and DOX + AG + EX-527 (a sirt1 inhibitor). DOX was given over the first 2 weeks. AG (10 ng/kg) and both inhibitors were given as 3 doses/wk for 5 weeks. AG improved the structure and the function of the kidneys; down-regulated the renal expression of TGF-β1, collagen 1A1 and α-SMA; and inhibited the renal collagen deposition in the kidneys of DOX-treated rats. Concomitantly, it reduced the renal levels of ROS, MDA, TNF-α, and IL-6 and protein levels of cytochrome-c, TGF-β1, Smad3 and α-SMA in these rats. In both the control and DOX-treated rats, AG significantly increased the renal levels of SOD and GSH, decreased the expression of cleaved caspase-3 and Bax, increased the total levels and the nuclear activity of SIRT1 and reduced the deacetylation of p53, NF-κB and FOXO-31. All the effects were abolished by the concurrent administration of EX-527 and [D-Lys3]-GHRP-6. In conclusion, AG prevents DOX-induced nephropathy in SIRT1 and GSHRa1-dependent mechanism.

Plasma ghrelin suppression as an early predictor for postoperative complications after pancreatoduodenectomy

BACKGROUND/OBJECTIVES

The gut peptide hormone ghrelin induces appetite and exhibits an anti-inflammatory effect. Serial perioperative changes in ghrelin have been examined in several surgical procedures, but few in pancreatectomy. The present study analyzed perioperative changes in plasma ghrelin levels after pancreaduodenectomy (PD).

METHODS

The study included 24 patients undergoing PD between May 2015 and January 2016 at Osaka University Hospital. Plasma ghrelin and interleukin-6 (IL-6) levels, as well as white blood cells (WBCs) and C-reactive protein (CRP), were measured preoperatively and on postoperative day (POD) 1, 3, 7, and 14 by enzyme-linked immunosorbent assay. The relationship between the individual ghrelin ratio relative to preoperative value (IGR) and the development of grade IIIa-V Clavien-Dindo (CD) complications was examined.

RESULTS

Twelve patients (50%) developed grade IIIa CD complications (n = 6 [25%] pancreatic fistula, n = 7 [29%] intraabdominal abscess, n = 3 [13%] post-pancreatectomy hemorrhage, n = 5 [21%] wound infection, and n = 1 [4%] lymphorrhea). The IGR on POD 1 was significantly lower (p = 0.014) in patients who developed the complications compared to those who did not, but no significant differences were found in terms of WBC, CRP, or IL-6 on POD 1. When the IGR cut-off was set to 82% by receiver operative curve analysis, the sensitivity was 83%, specificity 75% and area under the curve 0.80. The lower IGR group (≤82%) had more postoperative complications and longer hospital stay.

CONCLUSIONS

The IGR on POD 1 after PD is a useful marker for predicting postoperative complications.

Distribution patterns of metastases in recurrent laryngeal nerve lymph nodes in patients with squamous cell esophageal cancer

Esophageal cancers frequently metastasize to recurrent laryngeal nerve lymph nodes (RLNNs). Knowledge of anatomic metastatic RLNN (mRLNN) distributions is needed for lymph node dissection during esophageal cancer surgery. Among 189 patients with esophageal cancer who underwent esophagectomy between 2008 and 2010, 51 (27.0%) had mRLNN. Sixty-four mRLNNs (right, 31; left, 33) were identified via preoperative computed tomography (CT); more than 2 unilateral metastases and/or nodes with unclear boundaries were excluded. Anatomical characteristics, including vertical distance from the sternal notch level, circumferential angle to the mid-sagittal tracheal plane, and short and long axes, were measured via CT. Respective mean right and left vertical distances from the sternal notch were +2.0 ± 13.1 mm and -14.5 ± 23.8 mm (p = 0.0006). Left mRLNNs existed in vertically wider and inferior areas along recurrent laryngeal nerve, compared to right mRLNNs. The respective mean right and left circumferential angles around the trachea (from the anterior mid-sagittal plane) were 137.2 ± 11.2° and 94.3 ± 31.6° (p < 0.0001). Left mRLNNs were distributed more widely around the trachea, especially anteriorly. The short axes were larger for right mRLNNs than for left mRLNNs (8.6 mm vs. 6.8 mm, p = 0.026). Compared with the right side, left mRLNNs were smaller and had a vertically longer and circumferentially wider distribution. Careful attention should be given to the left side during curative RLNN dissection.

Physiology, pathophysiology and therapeutic implications of enteroendocrine control of food intake

With the increasing prevalence of obesity and its associated comorbidities, strides to improve treatment strategies have enhanced our understanding of the function of the gut in the regulation of food intake. The most successful intervention for obesity to date, bariatric surgery effectively manipulates enteroendocrine physiology to enhance satiety and reduce hunger. Areas covered: In the present article, we provide a detailed overview of the physiology of enteroendocrine control of food intake, and discuss its pathophysiologic correlates and therapeutic implications in both obesity and gastrointestinal disease. Expert commentary: Ongoing research in the field of nutrient sensing by L-cells, as well as understanding the role of the microbiome and bile acid signaling may facilitate the development of novel strategies to combat the rising population health threat associated with obesity. Further refinement of post-prandial satiety gut hormone based therapies, including the development of chimeric peptides exploiting the pleiotropic nature of the gut hormone response, and identification of novel methods of delivery may hold the key to optimization of therapeutic modulation of gut hormone physiology in obesity.

Cancer Recurrence After Esophagectomy: Impact of Postoperative Infection in Propensity-Matched Cohorts

BACKGROUND

Postoperative infection increases cancer recurrence and worsens survival in colorectal cancer, but the relationship for esophagogastric adenocarcinoma after esophagectomy is not well defined. We aimed to determine whether recurrence and survival after minimally invasive esophagectomy for esophagogastric adenocarcinoma were influenced by postoperative infection using propensity-matched analysis.

METHODS

We abstracted data for 810 patients (1997-2010) and defined exposure as at least 1 in-hospital or 30-day infectious complication (n = 206 [25%]). Using 29 pretreatment/intraoperative variables, patients were propensity-score matched (caliper = 0.05). Time to cancer recurrence and survival (Kaplan-Meier curves and the Breslow test), and associated factors (Cox regression with shared frailty) were assessed.

RESULTS

After propensity matching (n = 167 pairs), median bias across propensity-score variables was reduced from 12.9% (p < 0.001) to 4.4% (p = 1.000). Postoperative infection was not associated with rate (n = 60 versus 63; McNemar p = 0.736) or time to recurrence in those in whom disease recurred (median, 10.7 versus 11.1 months; Wilcoxon signed-rank p = 0.455) but was associated with shorter overall survival (n = 124 versus 102 deaths; median, 26 versus 41 months; Breslow p = 0.002). After adjusting for age, body mass index, neoadjuvant therapy, sex, comorbidity score, positive resection margins, pathologic stage, R0 resection, and recurrence, postoperative infection was associated with a 44% greater hazard for death (hazard ratio, 1.44; 95% confidence interval, 1.10-1.89).

CONCLUSIONS

In patients with esophagogastric adenocarcinoma, infections after esophagectomy were not associated with an increased rate or earlier time to recurrence when baseline characteristics associated with infection risk were balanced using propensity-score matching. Despite this, overall survival was shorter in patients with infectious complications. After adjusting for other important survival predictors, infections after esophagectomy continued to be independently associated with worse survival.

Improvement of cisplatin-related renal dysfunction by synthetic ghrelin: a prospective randomised phase II trial

Background:

Ghrelin, a 28-amino acid peptide predominantly produced by the stomach, exerts powerful renal protective effects by increasing levels of insulin-like growth factor-1 (IGF-1). The aim of this study was to evaluate the effects of ghrelin on the incidence of renal dysfunction in patients receiving cisplatin-based chemotherapy.

Methods:

Forty patients with oesophageal cancer receiving cisplatin-based chemotherapy were assigned to either the ghrelin group (n=20), which received ghrelin (0.5 μg kg⁻¹ h⁻¹) for 5 days, or a placebo group (n=20). The primary endpoint was serum creatinine. Secondary endpoints were serum cystatin C, chemotherapy-related adverse events, changes in serum ghrelin-related hormone levels, correlation between markers of renal injury and hormone concentrations, and effects on the second cycle of chemotherapy.

Results:

Blood acyl ghrelin, total ghrelin, and IGF-1 concentrations on day 4 were significantly higher in the ghrelin group. The renal dysfunction, serum creatinine and cystatin C levels, dose reduction, and delay in the initiation of the second cycle of chemotherapy were lower in the ghrelin group than in the control group. Serum creatinine levels were significantly correlated with serum IGF-1 levels.

Conclusion:

Continuous synthetic ghrelin administration during cisplatin-based chemotherapy attenuated renal dysfunction and harmful effects on subsequent chemotherapy, possibly by increasing IGF-1 levels.

Cachexia in patients with oesophageal cancer

Oesophageal cancer is a debilitating disease with a poor prognosis, and weight loss owing to malnutrition prevails in the majority of patients. Cachexia, a multifactorial syndrome characterized by the loss of fat and skeletal muscle mass and systemic inflammation arising from complex host-tumour interactions is a major contributor to malnutrition, which is a determinant of tolerance to treatment and survival. In patients with oesophageal cancer, cachexia is further compounded by eating difficulties owing to the stage and location of the tumour, and the effects of neoadjuvant therapy. Treatment with curative intent involves exceptionally extensive and invasive surgery, and the subsequent anatomical changes often lead to eating difficulties and severe postoperative malnutrition. Thus, screening for cachexia by means of percentage weight loss and BMI during the cancer trajectory and survivorship periods is imperative. Additionally, markers of inflammation (such as C-reactive protein), dysphagia and appetite loss should be assessed at diagnosis. Routine assessments of body composition are also necessary in patients with oesophageal cancer to enable assessment of skeletal muscle loss, which might be masked by sarcopenic obesity in these patients. A need exists for clinical trials examining the effectiveness of therapeutic and physical-activity-based interventions in mitigating muscle loss and counteracting cachexia in these patients.

Randomized Phase II Study of the Anti-inflammatory Effect of Ghrelin During the Postoperative Period of Esophagectomy

OBJECTIVE

A prospective randomized phase II trial was conducted to evaluate the efficacy of ghrelin administration in reducing systemic inflammatory response syndrome (SIRS) duration after esophagectomy.

BACKGROUND

Esophagectomy for esophageal cancer is highly invasive and leads to prolonged SIRS duration and postoperative complications. Ghrelin has multiple effects, including anti-inflammatory effects.

METHODS

Forty patients undergoing esophagectomy were randomly assigned to either the ghrelin group (n = 20), which received continuous infusion of ghrelin (0.5 μg/kg/h) for 5 days, or the placebo group (n = 20), which received pure saline for 5 days. The primary endpoint was SIRS duration. The secondary endpoints were the incidence of postoperative complications, time of a negative nitrogen balance, changes in body weight and composition, and levels of inflammatory markers, including C-reactive protein (CRP) and interleukin-6 (IL-6).

RESULTS

The ghrelin group had a shorter SIRS duration and lower CRP and IL-6 levels than did the placebo group. The incidence of pulmonary complications was lower in the ghrelin group than in the placebo group, whereas other complications did not differ between the groups. Although time of the negative nitrogen balance was shorter in the ghrelin group than in the placebo group, changes in total body weight and lean body weight did not differ significantly.

CONCLUSIONS

Postoperative ghrelin administration was effective for inhibiting inflammatory mediators and improving the postoperative clinical course of patients with esophageal cancer.

Perturbation of acyl ghrelin profile after liver transplantation

BACKGROUND

A significant problem to be solved for patients after liver transplantation (LT) is malnutrition with anorexia in the early posttransplant period. We hypothesized that this problem was due to the change in ghrelin metabolism during LT. The aim of this study was to examine the balance of acyl ghrelin (AG) and desacyl ghrelin and the dependence of the regulation mechanism on hepatic-related enzymes in patients during LT.

MATERIALS AND METHODS

AG, desacyl ghrelin, and acyl/total ghrelin (A/T) concentrations in blood samples were measured in 15 patients with liver failure (LF), 15 patients after LT, and 10 controls. The correlations between the participants' ghrelin profiles and hepatic function-related data, including liver enzymes, were evaluated. In vitro assays using synthetic AG for assessment of deacylation activity in serum were performed.

RESULTS

AG and A/T ratio were significantly higher in the LF patients than the patients after LT and controls (AG: 25.9 ± 12.6 versus 16.4 ± 12.6 and 9.8 ± 7.6 fmol/mL, P < 0.05; A/T ratio: 17.4 ± 4.1 versus 12.2 ± 5.5 and 11.8% ± 5.9%, P < 0.05). The serum cholinesterase level was inversely correlated with AG and A/T ratio (P < 0.01). In vitro assays showed that deacylation activity was significantly lower in patients with LF than controls (10.5% versus 42.4%, 90 min; P < 0.01). Degradation of AG was partially suppressed by a cholinesterase inhibitor.

CONCLUSIONS

Deacylation activity was lower in LF patients, which could cause elevation of AG levels. Serum cholinesterase may be responsible for deacylation in humans.

Clinical application of ghrelin in the field of surgery

Ghrelin was discovered as an intrinsic ligand for the growth hormone (GH)-secretagogue receptor (GHS-R) in 1999. The endogenous production of ghrelin occurs mainly in the stomach. Ghrelin has multiple functions; it has orexigenic action, stimulates GH secretion, has anti-inflammatory activities, stimulates gastrointestinal activity, stabilizes heart function and has other metabolic roles. Moreover, ghrelin is the only gastrointestinal hormone known to stimulate appetite. In the past decade, clinical applications of ghrelin have been attempted for various pathologies, based on its anabolic function, including applications for patients with anorexia nervosa and cachexia due to chronic heart, renal or pulmonary diseases. In the field of surgery, we have conducted several clinical trials using exogenous ghrelin in patients undergoing total gastrectomy, esophagectomy and neoadjuvant chemotherapy, including cisplatin treatment, and consistently obtained unique and striking benefits in these patients. Ghrelin comprehensively improves the patients' general conditions and quality of life via its pleiotropic physiological functions. This characteristic is unique and different from the existing drugs; therefore, ghrelin may be an indispensable supplement to prevent surgical stress and postoperative sequelae. This review summarizes the recent advances toward the clinical application of ghrelin.

Clinical application of ghrelin administration for gastric cancer patients undergoing gastrectomy

Loss of body weight is a common (and the most serious) sequela after gastrectomy. It impairs quality of life, increases various diseases including infection, and may affect long-term survival. Ghrelin, an intrinsic ligand of the growth hormone secretagogue receptor, was discovered in the stomach in 1999. In addition to growth hormone secretion, ghrelin has pleiotropic functions including appetite stimulation, increasing bowel movement and absorption, and anti-inflammatory reactions. In consequence, ghrelin comprehensively leads positive energy balance and weight gain. The fundic gland of the stomach produces the majority of ghrelin, and plasma ghrelin declines to 10-30 % of the preoperative level after total gastrectomy and 50-70 % after distal gastrectomy. Although plasma ghrelin is never restored after total gastrectomy, it gradually recovers to the preoperative level within a few years after distal gastrectomy. Chronic gastritis due to Helicobacter pylori infection and vagotomy are additional factors that perturb the ghrelin secretion of gastric cancer patients after gastrectomy. A randomized clinical trial that revealed that recombinant ghrelin administration successfully increased both food intake and appetite, and ameliorated weight loss after total gastrectomy. Ghrelin administration could thus be a promising strategy to transiently improve the nutritional status of patients who who have undergone gastrectomy, but its effect in the long term remains unclear. Further studies are warranted to elucidate the mechanism of ghrelin and to create and evaluate the analogs that could be administered orally or subcutaneously.