[Validation of the Italian version of the "Neuropathic Pain Scale" and its clinical applications]

BACKGROUND

The Neuropathic Pain Scale is the first specific tool to measure and analyse pain due to a lesion in the nervous system; this kind of pain is usually difficult to describe for the patient because it is characterized by unusual qualities. Aim of this study is to evaluate a possible relation between pain descriptions and underlying pathogenetic mechanisms.

METHODS

The Italian version of the Neuropathic Pain Scale has been administered to 145 patients with neuropathic pain due to chronic radiculopathy, diabetic neuropathy, post-traumatic neuropathy, Complex Regional Pain Syndrome or postherpetic neuralgia. As it has been done in Galer's study, the predictive validity and the items' correlation have been evaluated; moreover, the structure validity of the scale has been studied.

RESULTS

Pain values were high in all pain syndromes with the prevalence of certain items in particular pathologies. The correlation of some items with "deep pain" and others with "superficial pain" was also observed.

CONCLUSIONS

The results have confirmed the statistical validity of the Italian version of the scale; they also pointed out the usefulness of the scale to distinguish between superficial pain, typical of neuropathic pain, and deep pain, typical of somatic pain.

Low insulin resistance and preserved beta-cell function contribute to human longevity but are not associated with TH-INS genes

Tyrosine Hydroxylase (TH) and Insulin (INS) genes lie extremely close in the 11p15.5 chromosomal region. An STR marker of the TH gene had revealed this locus associated with longevity. Thus, it seemed of interest to investigate the association between the TH-STR and INS gene variability (FokI-RFLP) with a phenotypic trait, such as the degree of insulin resistance (IR) and beta-cell function in centenarians (C). We analyzed age-related trajectories of IR and beta-cell function in a large sample (n=466) of individuals whose age ranged from 28 to more than 100 years; furthermore, allele average effects on IR and beta-cell function relevant to TH-STR and INS-FokI polymorphisms were estimated in C. Both IR and beta-cell function increased with advancing age and declined in subjects older than 90 years (p for trend <0.001). C had lower IR (1.5+/-0.7 vs. 3.9+/-1.7, p<0.001) and beta-cell function (26.1+/-8.5 vs. 55.4+/-16, p<0.001) than nC. In nC, but not in C, IR and beta-cell function correlated with the main anthropometric and metabolic confounders. Nevertheless, significant allele average effects by TH-STR and INS-FokI polymorphisms on IR and beta-cell function were not observed in C. In conclusion, C has a lower degree of IR and a preserved beta-cell function in comparison to nC, but the cause of such metabolic differences, which are likely does not lie in this genomic region.

New aspects of the insulin resistance syndrome: impact on haematological parameters

AIM/HYPOTHESIS

Previous studies have shown that insulin has an important in vitro role in the regulation of human erythropoiesis. We investigated whether in vivo hyperinsulinaemia/insulin resistance affects haematological parameters.

METHODS

A total of 608 subjects between 22 and 99 years of age were enrolled in the Chianti study, an epidemiological study of factors affecting mobility in old age. The degree of insulin resistance was assessed using the homeostasis model.

RESULTS

We found a correlation between insulin resistance and red blood cell count, (r = 0.14 p < 0.001), plasma haemoglobin (r = 0.16 p < 0.001), haematocrit (r = 0.15 p < 0.001) and plasma iron (r = 0.1 p < 0.05) concentrations. Red blood cell count was also associated with the other biological markers of insulin resistance syndrome. Subjects with higher insulin resistance (4 degrees quartile) had higher red blood cell count, plasma triglycerides and low density lipoproteins (LDL) cholesterol concentrations and lower high density lipoproteins (HDL) cholesterol concentrations then subjects at the lowest quartiles of insulin resistance. Insulin resistance and BMI were significant and independent predictors of red blood cell count even when the analysis was adjusted for age, sex, waist-to-hip ratio, plasma iron and drug intake.

CONCLUSION/HYPOTHESIS

Our findings provide in vivo evidence of a relation between hyperinsulinaemia/insulin resistance, the main variables of insulin resistance syndrome and erythropoiesis. Increased red blood cell count could be considered as a new aspect of the insulin resistance syndrome that could contribute to the increased risk of developing cardiovascular problems.

[Delayed diagnosis of benign paroxysmal vertigo: economic impact]

Some time has passed since the early 1980's when a group of vestibologists with the same singular passion introduced in Italy the concept of Paroxysmal Positional Vertigo (PPV). Since then great advances have been made, but, despite the energy focused on improving and expanding the knowledge on this common disorder, PPV still frequently goes unrecognized. The direct consequence of delayed diagnosis is prolonged patient discomfort and the execution of useless, costly clinical examinations. Today, in most cases, delayed diagnosis is unjustified. Within the modern concept of health care economics, such delay is costly to the health care provider and has obvious psycho-physical repercussions for the patient who has to undergo a fruitless series of examinations and treatments of all types without reaping any benefits. In this light the Authors have performed a study to identify and quantify the relative costs of the most common errors made in the diagnosis of PPV. For a sample population of 100 patients, the clinical-instrumental tests performed before the disorder was correctly diagnosed were gathered and analyzed. Then the costs for the management of PPV patients diagnosed late were compared with those for patients whose diagnosis was reached early on. The results indicate that for each delay in PPV diagnosis the average cost was Euro 317.66 vs. Euro 64.04 for early diagnosis: a difference of Euro 253.06. The Authors underline how in this brief period of time (March-September 2000) the prescription of excessive testing led to a significant waste of money (Euro 10137.01).

Inverse association between free insulin-like growth factor-1 and isovolumic relaxation in arterial systemic hypertension

Several trials have suggested that insulin-like growth factor-1 (IGF-1) may have a pathophysiological role in the development of arterial essential hypertension. To verify the possible association of IGF-1 with left ventricular morphological and functional echocardiographic parameters in hypertension, we studied 40 male patients with newly diagnosed hypertension and 15 normotensive control subjects. Doppler echocardiography was performed and circulating free IGF-1 levels were determined in all subjects. Circulating free IGF-1 levels were higher in hypertensives than in control subjects (P<0.01). A significant inverse correlation was observed between free IGF-1 and isovolumic relaxation time in the overall population (r=-0.37, P<0.01) and in hypertensives (r=-0.57, P<0.0001), whereas this relation disappears in normotensives. These results were confirmed by multivariate analysis. The present study confirms that arterial essential hypertension represents a clinical condition associated with an increased synthesis of IGF-1. The observation of an inverse, independent association between free IGF-1 and isovolumic relaxation time suggests 2 alternative hypotheses: a possible beneficial effect of IGF-1 to diastolic relaxation or a resistance to IGF-1 in hypertension.

Conflict of interest in industry-sponsored economic evaluations: real or imagined?

As industry sponsorship of pharmacoeconomic studies has increased, concerns have been raised about potential biases, owing to the conflicts of interest that this sponsorship creates. A review of the literature indicates that there are some causes for concern, given the fact that most pharmacoeconomic studies report positive findings for the sponsor's drug. However, a more detailed analysis suggests that, although the methodologic quality of some published studies may be poor, the main reason for positive results is that companies only sponsor economic studies where a positive outcome is likely. Therefore, it is concluded that the best way of dealing with perceptions of sponsorship bias is not increased rhetoric, but rather increased public funding for economic evaluation of medicines, thereby creating a true mixed economy for research funding in this field.

Voltage-dependent antagonist/agonist actions of taurine on Ca(2+)-activated potassium channels of rat skeletal muscle fibers

Emerging evidence supports the idea that taurine exerts some of its actions through inhibition of inward rectifier K(+) channels, ATP-sensitive K(+) channels, and voltage-dependent K(+) channels. However, to date not much is known about the effects of this sulfonic amino acid on Ca(2+)-activated K(+) (K(Ca(2+))) channels, which are widely expressed in various tissues, including skeletal muscle. In the present work, the effects of taurine on K(Ca(2+)) channels of rat skeletal muscle fibers were investigated using the patch-clamp technique. The application of the amino acid to the internal side of the excised macropatches induced a dose-dependent decrease in the outward K(Ca(2+)) currents recorded at positive membrane potentials in the presence of 8 to 16 microM concentrations of free Ca(2+) ions in the bath with an IC(50) of 31.9. 10(-3) +/- 1 M (slope factor = 1.2) (n = 11 patches). In contrast, at negative membrane potentials taurine caused an enhancement of the muscular inward K(Ca(2+)) currents with a DE(50) (drug concentration needed to enhance the current by 50%) of 46.7. 10(-3) +/- 2 M (slope factor = 1.3) (n = 9 patches). Single channel analysis revealed that this effect was mediated by changes in the reversal potential of the K(Ca(2+)) channel for K(+) ions with no changes in the gating properties or in the sensitivity of the channel to Ca(2+) ions. Taurine also did not affect the single channel conductance. In conclusion, taurine shows a voltage-dependent dualistic action on K(Ca(2+)) channels, being an inhibitor of the channel at positive membrane potentials and an activator at negative membrane potentials.

Should we recommend the therapeutical use of vitamin E in diabetic patients?

The therapeutic application of vitamin E was initially restricted to thrombocytopenic purpura and later extended to coronary artery diseases and peripheral vascular arteriosclerosis due to the potency of its effects. Several recent studies have pointed out that vitamin E supplementation is useful for reducing low-density lipoprotein oxidation and thus might be protective towards coronary heart disease. Such data has been confirmed in many in vitro data, while in vivo results of reports from epidemiological studies are much more controversial. More consistent is the evidence showing vitamin E to improve endothelial function especially in diabetic patients. Finally, chronic vitamin E has been demonstrated to improve the metabolic control in diabetic patients. Whether chronic vitamin E administration at pharmacological doses and for long time, is safe is still debated. A sure response to such a query will open the possibility for recommending vitamin E as a therapeutic agent in diabetic patients.

Oral administration of collagen conjugated with cholera toxin induces tolerance to type II collagen and suppresses chondritis in an animal model of autoimmune ear disease

B10.RIII (H-2r) mice were orally administered cyanogen bromide peptide 11 (CB11) or cholera toxin B (CTB)-conjugated CB11 to induce tolerance in collagen-induced autoimmune ear disease. Oral administration of a high dosage of CB11 provided partial protection from chondritis. However, administration of a tiny amount of CTB-CB11 conjugate effectively suppressed chondritis. Oral administration of CTB-CB11 conjugate did not alter the stimulation of T cells in vitro or the fine specificities of B cells. The oral administration of CTB-CB11 caused a higher level of type II collagen-specific IgG and its subclass. Interestingly, increases of TH1 cytokine (interferon-gamma) in Peyer's patches and of TH1/TH2 cytokines (interleukin-2 and interleukin-4) in lymph nodes were detected in mice that had been fed CTB-CB11. An increase of CD8+ T cells in the Peyer's patches with a decrease of CD8+ T cells in lymph nodes was seen in mice that had been fed CTB-CB11. These results suggest that protection from chondritis by oral administration of minute amounts of CTB-CB11 conjugate can be achieved by a mechanism distinct from that of conventional oral tolerance induction.

Absence of mutations involving the LIM homeobox domain gene LHX9 in 46,XY gonadal agenesis and dysgenesis

The etiology of most cases of 46,XY gonadal dysgenesis in the absence of extragenital anomalies is not accounted for by mutations in the genes known to date to be involved in sex determination. We have investigated the possibility that mutations in the gene LHX9, whose murine ortholog causes isolated gonadal agenesis when inactivated, might be responsible for gonadal dysgenesis and agenesis in humans. We isolated a human LHX9 complementary DNA (cDNA), mapped the gene to the long arm of human chromosome 1, and determined its genomic structure. We found that LHX9 is highly conserved between species, sharing in particular over 98% amino acid identity. A mutational screen was performed in a sample of patients with a range of gonadal maldevelopment, including bilateral gonadal agenesis in two sisters with an opposite sex karyotype. We did not detect mutations in the open reading frame of LHX9 in the patients studied. However, the extent of between-species structural conservation suggests that LHX9 deserves further consideration as a determinant of gonadal function in humans.

Role of free fatty acids on cardiac autonomic nervous system in noninsulin-dependent diabetic patients: effects of metabolic control

Decreased heart rate variability (HRV) is a risk factor for cardiovascular mortality. Elevated plasma free fatty acid (FFA) levels decrease HRV in healthy subjects. Thus, we investigated the effect of changes in plasma FFA levels on HRV, in non-insulin-dependent diabetes (NIDDM) patients. Thirty NIDDM patients free from diabetic neuropathy volunteered for a study made by two phases. In study A, changes in HRV along a 10% lipid emulsion infusion + heparin (n = 15) or saline infusion (control study; n = 15) were investigated. In study B, all patients (n = 30) underwent further determination of HRV after 3 months of improved metabolic control achieved by intensified insulin treatment. In study A, lipid emulsion infusion increased plasma FFA (P < 0.001) and catecholamine concentrations (P < 0.005), mean arterial blood pressure (P < 0.005), low frequency/high frequency (LF/HF) ratio (P < 0.001). Delta plasma FFA levels correlated with delta LF/HF ratio (r = 0.57; P < 0.02). Along with saline infusion, metabolic and cardiovascular parameters remained unchanged throughout the test. In study B, improved metabolic control lowered fasting plasma glucose (P < 0.005), FFA (P < 0.001), norepinephrine (P < 0.02), epinephrine (P < 0.04), and glycosylated hemoglobin levels (P < 0.001), mean arterial blood pressure(P < 0.05), and LF/HF ratio (P < 0.001). Again percent decline in plasma FFA correlated with the percent change in LF/HF ratio (r = 0.72; P < 0.001). In a multivariate analysis, percent changes in LF/HF ratio were associated with percent changes in plasma FFA independently of gender and percent changes in body mass index, waist/hip ratio, plasma norepinephrine, epinephrine, glycosylated hemoglobin, and daily insulin therapy. Our study demonstrates that changes in plasma FFA levels may have a parallel effect on cardiac sympathetic/parasympathetic nervous system balance in NIDDM patients.

Chronic administration of pharmacologic doses of vitamin E improves the cardiac autonomic nervous system in patients with type 2 diabetes

BACKGROUND

Type 2 diabetes is associated with elevated oxidative stress and declines in antioxidant defense. The disease is also characterized by an imbalance in the ratio of cardiac sympathetic to parasympathetic tone. Antioxidants, vitamin E in particular, may have beneficial effects on the cardiac autonomic nervous system through a decline in oxidative stress.

OBJECTIVE

We investigated the possible effects of vitamin E on the cardiac autonomic nervous system, as assessed by analysis of heart rate variability, in patients with type 2 diabetes and cardiac autonomic neuropathy.

DESIGN

In a double-blind randomized controlled trial, 50 patients with type 2 diabetes were assigned to treatment with vitamin E (600 mg/d) or placebo for 4 mo.

RESULTS

The anthropometric characteristics of the patients remained unchanged throughout the study. Chronic vitamin E administration was associated with decreases in concentrations of glycated hemoglobin (P < 0.05), plasma insulin (P < 0.05), norepinephrine (P < 0.03), and epinephrine (P < 0.02); a lower homeostasis model assessment index (P < 0.05); and improved indexes of oxidative stress. Furthermore, vitamin E administration was associated with increases in the R-R interval (P < 0.05), total power (P < 0.05), and the high-frequency component of heart rate variability (HF; P < 0.05) and decreases in the low-frequency component (LF; P < 0.05) and the ratio of LF to HF (P < 0.05). Finally, change in the plasma vitamin E concentration was correlated with change in the LF-HF ratio (r = -0.43, P < 0.04) independently of changes in the homeostasis model assessment index and plasma catecholamines concentrations.

CONCLUSIONS

Chronic vitamin E administration improves the ratio of cardiac sympathetic to parasympathetic tone in patients with type 2 diabetes. Such an effect might be mediated by a decline in oxidative stress.

Depression of windup of spinal neurons in the neonatal rat spinal cord in vitro by an NK3 tachykinin receptor antagonist

The effects of the NK3 tachykinin receptor antagonist SR 142801 on synaptic transmission and spike windup induced by trains of stimuli applied to a dorsal root were investigated with intra- and extracellular recording from the neonatal rat spinal cord in vitro. SR 142801 (10 microM) reduced the depolarization (recorded from lumbar ventral roots) induced by senktide (an NK3 agonist) more strongly than the one evoked by substance P methyl ester (SPMeO; an NK1 agonist). Nevertheless, after a long (>2 h) application time, SR 142801 largely depressed the response to SPMeO as well. When NK1 or NK3 receptors were blocked by >50% in the presence of SR 142801, there was also a significant reduction in the cumulative depolarization induced by repeated stimuli to a single dorsal root. This blocking action by SR 142801 was also observed in the presence of the N-methyl-D-aspartate (NMDA) receptor antagonist D-aminophosphonovalerate (APV) and the calcium channel blocker nifedipine. Intracellular data from lumbar motoneurons showed that the spike windup was the first and most sensitive target for the SR 142801 blocking effect. Increasing stimulus strength to dorsal root fibers could partly surmount such a block. SR 142801 per se had no direct action on fast synaptic transmission, membrane potential, or input resistance. These findings indicate that SR 142801 could lead to an early, large reduction in the windup of action potential discharge by motoneurons, suggesting its ability to suppress the reflex component of central sensitization evoked by repeated dorsal root stimuli.

[Nursing diagnoses in women attending a family planning service]

The purpose of this study was to identify nursing diagnoses in women enrolled in a family planning program. An instrument of data collection was elaborated according to the Functional Health Patterns. The sample consisted of 100 adult women. Forty-nine nursing diagnoses, of which 9 with a frequency equal or higher to 45.0% were identified. Further studies are still needed in institutions that offer assistance in the area of family planning in order to examine if the nursing diagnoses found in these women can be generalized to the population.

The BB-paraoxonase genotype is associated with impaired brachial reactivity after acute hypertriglyceridemia in healthy subjects

The possible relationship between paraoxonase (PON) gene polymorphism and brachial reactivity in healthy adult subjects in the presence of acute hypertriglyceridemia (HT), as a prooxidant factor, was investigated. In 101 healthy subjects the response to flow- induced vasodilatation was measured before and after Intralipid infusion. In the same subjects the A/B PON polymorphism was detected. The frequency was 0.545 for AA genotype, 0.356 for the AB genotype, and 0.099 for the BB genotype. At baseline all genotype groups had a similar increase in brachial artery diameter and flow. After Intralipid infusion, subjects sharing the BB genotype had a significant decrease vs. baseline values in changes in brachial artery diameter (P for trend < 0.001 vs. the other genotypes), but not in flow. In a subgroup of 55 subjects distributed among the 3 PON genotypes the same study protocol was repeated by buccal nitroglycerine administration to study the endothelium-independent vasodilatation. Again, subjects with the BB genotype had the worse vasodilation (P for trend < 0.001). Furthermore, subjects sharing the BB genotype had the lowest endothelium-independent and -dependent changes in diameter (P for trend < 0.001 vs. the other genotypes) independently of gender ratio, basal plasma triglycerides concentrations, and changes in plasma triglycerides concentrations. In conclusion, our study demonstrates that transient HT decreases vascular reactivity more in subjects with the PON BB genotype than in those with the other PON genotypes.

Age-related insulin resistance: is it an obligatory finding? The lesson from healthy centenarians

It is widely known that advancing age is associated with impaired glucose handling. A unifying hypothesis explaining the relationship between aging and insulin resistance might encompass four main pathways, namely: (a) anthropometric changes (relative and absolute increase in body fat combined with a decline in fat free mass) which could be the anatomic substrate for explaining the reduction in active metabolic tissue; (b) environmental causes, mainly diet style and physical activity; (c) neuro-hormonal variations [decline in plasma dehydroepandrosterone sulphate (DHEAS) and IGF-1]; and finally (d) the rise in oxidative stress. Indeed previous studies have also investigated the occurrence and the degree of insulin resistance in healthy centenarians. Such data demonstrated that age-related insulin resistance is not an obligatory finding in the elderly and that healthy centenarians have a preserved insulin action compared to aged subjects. Why insulin action is preserved in centenarians is still not known. Nevertheless, a possible approach to the question is to outline the centenarians' anthropometric, endocrine and metabolic characteristics in order to design a clinical picture of such metabolic "successful aging". According to the remodeling theory of age, the preserved insulin action in centenarians might be the net result of the continuous adaptation of the body to the deleterious changes that occur over time. Nevertheless, only future longitudinal studies specifically designed to investigate the relationship between extreme old age and degree of insulin sensitivity will provide a conclusive answer with regard to the pathophysiology of adaptive metabolic changes occurring in the elderly.

Oxidative stress and a thrombophilic condition in alcoholics without severe liver disease

BACKGROUND AND OBJECTIVES

The degree of oxidative stress and its association with a thrombophilic condition, if any, were investigated in alcoholics before the onset of severe liver disease.

DESIGN AND METHODS

Reactive oxygen species and total antioxidant capacity were evaluated using two new kinetic spectrophotometric methods in a selected group of 45 consecutive chronic alcohol abusers and 42 apparently healthy moderate drinkers, used as controls. The hemostatic system was explored by detecting the plasma levels of prothrombin fragment 1+2 (F1+2) and thrombin-antithrombin complexes (TAT) with enzyme-linked immunosorbent assays, while D-dimer plasma levels were measured with a turbidimetric immunoassay.

RESULTS

Reactive oxygen species were significantly higher (p<0.001) in heavy drinkers than in controls: 328.1 (143.4-847.2) U.CARR vs 250 (200.7-366.8) U.CARR, respectively. The total antioxidant capacity was similar in chronic alcohol abusers and in moderate drinkers: 360.2 (336.8-374.4) microMol HClO/mL vs 369 (362-378.4) microMol HClO/mL, respectively. All molecular markers of hemostatic system activation were significantly increased in chronic alcohol abusers in comparison with those in moderate drinkers, as follows: TAT: 2.5 (1.4-13) microg/L vs 1.5 (1-4.1) mocrog/L, respectively (p<0.001); F1+2: 1.7 (0.5-5.2) nMol/L vs 0.9 (0.4-1.1) nMol/L, respectively (p<0.01); D-dimer: 235.5 (208-462) ng/mL vs 163.5 (71-233) ng/mL, respectively (p<0.001).

INTERPRETATION AND CONCLUSIONS

Our results suggest that oxidative stress and a thrombophilic condition can be observed in heavy drinkers without severe liver disease. The new test available for measuring reactive oxygen species in serum proved to be reliable and useful as an early marker of tissue damage.

Neoadjuvant chemotherapy with ifosfamide, cisplatin, and vinorelbine in advanced squamous cell carcinoma of the cervix

A phase II trial was performed to assess the efficacy and toxicity of a combination of ifosfamide (IFX), cisplatin (CDDP), and vinorelbine (VNB) as neoadjuvant chemotherapy (NAC) for untreated advanced cervical carcinoma (ACC). Between October 1995 and February 1998, 40 patients were entered in this study. Their median age was 43 years (range: 23-74 years). International Federation of Gynecology and Obstetrics stages were: IIB, 23; IIIB, 13; and IVA, 4. Therapy consisted of: IFX 2,000 mg/m2 1-hour (H) IV infusion days 1 to 3; 2-mercaptoethanesulfonic acid sodium salt (mesna) 400 mg/m2 IV bolus H 0 and 4, and 800 mg/m2 by mouth H 8, days 1 to 3; VNB 25 mg/m2 20-minute IV infusion days 1 and 8; and CDDP 75 mg/m2 IV day 3. Cycles were repeated every 28 days for a total of three courses. Both staging and response (R) assessment were performed by a multidisciplinary team. An objective response (OR) was observed in 24 of 40 patients (60%; 95% confidence interval, 45-75%). Four patients achieved complete response (CR) (10%); 20 partial response (50%); 12 patients stable disease (30%); and 4 progressive disease (10%). Eight of 24 patients (33%) with OR underwent radical surgery, and histologic CRs were recorded in 2 of them. The remaining patients received definitive radiotherapy after NAC. The dose-limiting toxicity was myelosuppression. Leukopenia occurred in 32 patients (80%) and was grade III or IV in 14 patients (36%). Peripheral neuropathy occurred in 9 patients (22%), whereas myalgias occurred in 10 (25%). Constipation was observed in 9 patients (23%); emesis occurred in 35 patients (88%). There were no therapy-related deaths. These results indicate that IFX/CDDP/VNB is an active combination for ACC with moderate toxicity. Implementation of this regimen in a multimodal therapy protocol deserves further study.

Metabolic age modelling: the lesson from centenarians

Evolutionary theories of ageing, and data emerging from cellular and molecular biology of ageing, suggested that animals and humans capable of reaching an age close to the extreme limit of the life span should be equipped with a very efficient network of anti-ageing mechanisms. Indeed several evidences have demonstrated that starting from young to very old subjects, ageing is associated with a progressive remodelling. Thus, a new paradigm, the remodelling theory of age, was proposed. This theory, focusing on the human immune system, suggested that immunosenescence is the net result of the continuous adaptation of the body to the deteriorative changes occurring over time. According to this hypothesis, body resources are continuously optimized, and immunosenescence must be considered a very dynamic process including both loss and gain. Whether the metabolic pathways and the endocrine functions are also part of the age remodelling is not investigated. The aim of this review is to focus on the age-related changes in metabolic pathways and endocrine functions and to demonstrate that healthy centenarians (HC) represent the best living example of successful age-remodelling in whom the age remodelling has occurred without problems. In order to design the clinical picture of such successful ageing, anthropometric, endocrine and metabolic characteristics of healthy centenarians (HC), compared with aged subject, have been outlined.

Elevated plasma fatty acid concentrations stimulate the cardiac autonomic nervous system in healthy subjects

BACKGROUND

Fatty acids have been shown to stimulate the sympathetic nervous system in rats. Power spectral analysis of heart rate variability (HRV) is a safe and useful tool with which to evaluate cardiac autonomic nervous system (ANS) activity. Whether changes in plasma fatty acid concentrations affect the sympathetic nervous system or HRV in humans is unknown.

OBJECTIVE

We investigated the possible changes in HRV after a significant increase in plasma fatty acid concentration.

DESIGN

Subjects were randomly assigned to receive an infusion of lipid emulsion (10% triacylglycerol emulsion for 180 min) + heparin (a bolus of 200 U followed by 0.2 U*min(-)(1)*kg body wt(-)(1); n = 20) or 0.9% NaCl (for 180 min; n = 10).

RESULTS

Lipid emulsion + heparin infusion was associated with a rise in plasma epinephrine and norepinephrine concentrations. The rise in plasma fatty acid concentration was associated with a significant decline in the RR interval (P: < 0.03) and in total power (P: < 0.03). Analysis of the different components of HRV showed that lipid emulsion + heparin infusion stimulated low- frequency (LF) components (P: < 0.03 at the second hour and P: < 0. 01 at the third hour) and inhibited high-frequency (HF) components (P: < 0.03 at the second and third hours). Consequently, the LF-HF ratio was significantly stimulated (P: < 0.03 at the second hour and P: < 0.01 at the third hour). Such results persisted, although attenuated, when the study was repeated in association with a propranolol infusion (n = 8).

CONCLUSION

Elevated plasma fatty acid concentrations may stimulate cardiac autonomic nervous system activity.