BackgroundThis study aimed to evaluate the prevalence of sedentarism, and to assess physical capacity and nutritional status in a cohort of older patients on peritoneal dialysis (PD), with respect to age-matched non-dialysis CKD population, using highly accessible, simple methods, namely the Rapid Assessment of Physical activity (RAPA) test and the 30″ Sit-to-stand (STS) test.MethodsThis cross-sectional multicenter study included 151 renal patients older than 60 years; 71 pts. (44 m, age 72 ± 7 yrs) were on PD and 80 pts. (63 m, age 74 ± 7 yrs) were affected by 3–4 stage CKD.ResultsThe prevalence of sedentary/underactive patients was double of that of the active patients as assessed by RAPA test, both in the PD (65.3%) and in the CKD (67.5%) cohort.The 30"STS test showed a reduced physical performance in both groups: 84.5% of PD patients and 87.5% of CKD patients did not reach the expected number of stands by age and gender. A malnutrition-inflammation score (MIS) ≥ 6 occurred in 37 % of PD patients and in 2.5 % of CKD patients. In PD patients, an independent significant association was observed between 30”STS test and MIS (beta -0.510, p = 0.013), as well as between RAPA and MIS (beta -0.544, p = 003) and phase angle (beta -0.506, p = 0.028).ConclusionsA high prevalence of low- performance capacity and sedentarism has been detected among elderly patients on PD or with CKD stage 3–4. Apart from age, a condition of malnutrition-inflammation was the major determinant of poor physical activity and capacity in PD patients. Better body composition seems to be positively associated with physical activity in PD and with physical capacity in CKD patients. Routine clinical management should include a close evaluation of nutritional status and evaluation of physical activity and capacity which can be easily assessed by RAPA and 30″STS tests.
The aim of the present study was to test whether the serotoninergic system may be involved in the well known reduced growth hormone (GH) response to insulin-induced hypoglycaemia (IIH) in obese patients. Ten obese women and 10 normal-weight control women underwent three IIH tests, at 14-day intervals: the first in basal conditions, the other two after randomized administration of a serotoninergic drug, fenfluramine (FF, 120 mg/day for 7 days) and FF plus ritanserin (RIT, 30 mg/day for the first 2 days and 20 mg/day on the following days). Ritanserin is a new selective 5-HT2 blocker receptor agent. Both controls and obese patients showed similar normal basal GH levels before each test and insulin administration always effectively reduced glucose levels to values lower than 2-2 mmol/l. In the controls, the expected GH increase to IIH (peak value 56 f 13.4 mU/1, AUC 234.4 f 55 mU/min/ml) was unaffected by FF administration (peak value 43 f 11.4;AUC 216.8 f 34.8). In response to the first IIH, the obese patients showed a significantly lower GH increase than in the case of the controls (peak valut 2 1 -4 f 4.6 mU/1, P < 0.02; AUC 93.2 f 18.6, P < 0.02). However, in comparison with the basal test, FF administration significantly ( P < 0.00 1) enhanced GH response to insulin hypoglycaemia (peak value 33.4 f 4; AUC 150 f 14.6), reaching values not significantly different from those of the controls. This effect was completely antagonized by RIT administration (peak value 18 f 5; AUC 85.6 f 2 1). In conclusion, the reduced GH response to insulin hypoglycaemia in obese women has been confirmed in the present study. However, the restoration of the hormonal response obtained after FF administration in obese patients only, which is effectively antagonized by RIT, strongly suggests the involvement of the serotoninergic system in this impaired
In order to demonstrate the suggested failure of the serotoninergic system in human obesity and to evaluate the role of central serotoninergic activity in prolactin (PRL) and thyroid stimulating hormone (TSH) release in this condition, 13 euthyroid obese and 9 healthy women of normal weight were studied. A TRH test (200 micrograms i.v.) was performed before and after administration of fenfluramine (FF) 60 mg b.d. for 14 days. In the controls, FF did not modify the expected significant increase in PRL induced by TRH. In obese patients, however, the PRL levels was significantly increased after TRH, but the increase was less than in the controls. After FF, the PRL response to TRH was larger than in the pretreatment phase, with values similar to those observed in normal subjects. In neither group FF did change the TSH-stimulating effect of TRH, but the hormonal response in obese patients was greater than in the controls. The restoration of the responsiveness of PRL to TRH after central serotoninergic stimulation confirms the hypothesis that a failure of the serotoninergic system may occur in human obesity. Since FF does not interfere with the secretory pattern of basal and stimulated TSH in normal or obese subjects, the serotoninergic system does not seem to play a major role in the control of TSH secretion.
These findings confirm that there is a physiological relationship between the serotoninergic and the opioidergic systems in the control of PRL secretion and show that this interaction is not present in obese subjects. Our data provide indirect proof of the functional impairment of these two systems in human obesity.
In order to study the hypothesized impairment of the serotoninergic system in human obesity, an insulin tolerance test (ITT) was carried out on 12 obese normoprolactinemic women and on 6 normal-weight women before (A) and after (B) the administration of a serotoninergic drug, fenfluramine (60 mg twice a day per os for 7 days). After a washout period, a new ITT (C) followed the administration of fenfluramine at the same dose, associated with a specific S2 blocker receptor agent, ritanserin (30 mg/day for the first 2 days and 20 mg/day for a further 5 days). In obese subjects, the prolactin (PRL) response to ITT A was reduced as compared to the controls: in 6 patients (‘nonresponders’) the PRL levels did not change, while in the other 6 (‘responders’) they increased (p < 0.003) but less than in the controls (p < 0.02). In normal-weight subjects, the administration of fenfluramine alone or with ritanserin did not modify the PRL response to ITT. In the responders, the serotoninergic drug normalized the PRL response to ITT while significantly improving it in the nonresponders; these effects were not antagonized by ritanserin. In conclusion, our data suggest that the serotoninergic system of obese patients is impaired and that the different secretory pattern observed in the two groups before and after fenfluramine may reflect differing degrees of this impairment.
The mechanism of prolactin (PRL) unresponsiveness to repeated sulpiride (SUL) administration was investigated by means of two experimental protocols. The first one was carried on in seven male volunteers (age 24 to 34 yr) and consisted of two phases separated by a 5-day interval. In both phases 1 mg/kg of SUL was given im and repeated, 24 h later, together with either placebo (PL, 2 ml saline iv) or TRH (200 micrograms iv). 7-10 days later a standard TRH test (200 micrograms iv) was performed. In the second protocol the usual dose (1 mg/Kg im) of SUL was administered alone and, 24 h later, together with 0.1 U/Kg iv of insulin (insulin tolerance test: ITT) to six male volunteers (age 20 to 32 yr). A control standard ITT (0.1 U/Kg iv) was also performed 7-10 days later. Plasma samples for the evaluation of PRL were taken in basal conditions and at regular intervals after each drug administration. In the first protocol, PRL showed a significant increase (peak values at 30 min) after SUL administration in both phases (phase A: 54.8 +/- 5.6 ng/ml, mean +/- SE vs 6.4 +/- 0.3, p less than 0.001. Phase B: 77.5 +/- 3.9 vs 7.0 +/- 0.6, p less than 0.001). Twenty-four h later, PRL levels were still higher than basal and were not affected by the administration of SUL + PL or SUL + TRH. Also in the second protocol, SUL alone induced a significant PRL increase (peak values at 30 min: 47.1 +/- 7.2 vs 4.2 +/- 0.5, p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)
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