Effects of vitamin E deficiency on autonomic neuroeffector mechanisms in the rat caecum, vas deferens and urinary bladder

Gene expression analysis of neuropeptides in oral mucosa during periodontal disease in non-human primates

BACKGROUND

Neuropeptides (NPs) are innate pivotal regulators of the immunoinflammatory response. Nevertheless, their role in the pathogenesis of periodontal disease remains unknown. Changes in gene expression of 10 NPs and 16 NP receptors (NPRs) coincident with the initiation, progression, and resolution of periodontitis were determined.

METHODS

The ligature-induced periodontitis model was used in rhesus monkeys (n = 18). Gingival tissue samples were taken at baseline (preligatures), at 2 weeks and at 1 month (initiation), and at 3 months (progression) postligation. Ligatures were removed and samples taken 2 months later (resolution). Total RNA was isolated from tissues and NP/NPR gene expression microarray analysis was performed. Gene expression changes were validated by quantitative polymerase chain reaction and immunohistochemistry.

RESULTS

Unexpectedly, the expression of pro-inflammatory NPs/NPRs did not change during periodontitis or with resolution. However, increased expression of the anti-inflammatory NPs adrenomedullin (ADM) and galanin (GAL), and the NPRs calcitonin receptor-like (CALCRL) and receptor activity-modifying protein-2 and -3 (RAMP2 and RAMP3) were observed during initiation and progression of disease. The expression of the same NPs/NPRs exhibited a significant positive correlation with both molecular (interleukin-1ß, matrix mettaloproteinase-9, and receptor activator of nuclear factor-kappa B ligand) and clinical measures of gingival inflammation and tissue destruction.

CONCLUSION

Initiation and progression of periodontitis involve significant overexpression of ADM, GAL, CALCRL, RAMP2, and RAMP3. These anti-inflammatory NPs/NPRs could play a role in the unresolved infection and inflammation that normally drives tissue destruction in periodontitis. Both ADM and GAL potentially are new candidates to consider as biomolecules associated with periodontal disease activity.

Purinergic signalling in the urinary tract in health and disease

Purinergic signalling is involved in a number of physiological and pathophysiological activities in the lower urinary tract. In the bladder of laboratory animals there is parasympathetic excitatory cotransmission with the purinergic and cholinergic components being approximately equal, acting via P2X1 and muscarinic receptors, respectively. Purinergic mechanosensory transduction occurs where ATP, released from urothelial cells during distension of bladder and ureter, acts on P2X3 and P2X2/3 receptors on suburothelial sensory nerves to initiate the voiding reflex, via low threshold fibres, and nociception, via high threshold fibres. In human bladder the purinergic component of parasympathetic cotransmission is less than 3 %, but in pathological conditions, such as interstitial cystitis, obstructed and neuropathic bladder, the purinergic component is increased to 40 %. Other pathological conditions of the bladder have been shown to involve purinoceptor-mediated activities, including multiple sclerosis, ischaemia, diabetes, cancer and bacterial infections. In the ureter, P2X7 receptors have been implicated in inflammation and fibrosis. Purinergic therapeutic strategies are being explored that hopefully will be developed and bring benefit and relief to many patients with urinary tract disorders.

Effect of chronic vitamin E deficiency on sympathetic and sensorimotor function in rat mesenteric arteries

1. Mesenteric arterial beds from male rats deprived of vitamin E for 12 months postweaning were isolated and perfused at 5 ml min-1. 2. The basal perfusion pressure of vitamin E-deficient preparations was significantly higher (34.0 +/- 1.9 mmHg, n = 15) than in age-matched controls (26.1 +/- 2 mmHg, n = 14; P < 0.01). 3. At basal tone, vasoconstrictor responses to electrical field stimulation (EFS) were not attenuated by vitamin E deficiency; at high stimulation frequencies, responses were enhanced. According to dose-response curves, exogenous noradrenaline was significantly more efficacious in preparations from vitamin E-deficient rats (P < 0.05). 4. In preparations with tone raised by methoxamine (6-20 microM) and in the presence of guanethidine (5 microM), EFS of perivascular sensorimotor nerves elicited frequency-dependent vasodilatation which was significantly attenuated by vitamin E deficiency. There was no difference in relaxation to calcitonin gene-related peptide (CGRP; 1.5 x 10(-11) mol), or to the sensory neurotoxin capsaicin (5 x 10(-11) mol). 5. Immunohistochemical analysis of CGRP-containing nerves in the superior mesenteric artery showed no differences in density of innervation. 6. In conclusion, chronic vitamin E deficiency impairs sensorimotor vasodilatation in rat mesenteric arteries; this does not appear to be due to changes in postjunctional receptors, or to a depletion of transmitter (CGRP) content of the superior mesenteric artery. Sensorimotor nerves appear to be more vulnerable than sympathetic nerves to chronic vitamin E deficiency.

Effects of chronic vitamin E deficiency on vascular function--a study of sympathetic nerves, smooth muscle and endothelium of the mesenteric arterial bed of the rat

1. Male rats were deprived as weanlings of dietary vitamin E for 2, 4, 6, 10 and 12 months. Mesenteric arterial beds from these rats and from age-matched controls were isolated and perfused with Krebs solution at a constant flow rate (5 ml min-1). The function of perivascular sympathetic nerves, smooth muscle and endothelium was assessed. 2. At 12 months vitamin E deficient rats exhibited the characteristic symptoms of vitamin E deficiency, namely poor coat condition, muscle wasting, kyphoscoliosis and impaired gait. In the isolated mesenteric arterial bed electrical field stimulation (EFS) of perivascular nerves (4-32 Hz, 90 V, 1 ms, for 30 s) elicited frequency-dependent vasoconstrictor responses which were unaffected by vitamin E deficiency except at 12 months, at which age responses were significantly greater than those of the controls at 24 and 32 Hz (P < 0.01). 3. Exogenous noradrenaline (NA; 0.15-500 nmol) elicited dose-dependent vasoconstriction which was similar in vitamin E-deficient and control preparations at all ages. Potassium chloride (0.15 mmol) also produced similar vasoconstrictor responses in vitamin E-deficient and control preparations at each age. 4. Tone of the preparations was raised by continuous perfusion with methoxamine (4-70 microM), producing similar increases in perfusion pressure in vitamin E-deficient and control preparations at each age. Endothelium-dependent dose-dependent vasodilatation to adenosine 5'-triphosphate was significantly impaired in mesenteric arterial beds from 12 month-old vitamin E-deficient rats compared with the controls (P < 0.05). Relaxation to acetylcholine was not significantly different at any age. 5. Endothelium-independent vasodilatation to sodium nitroprusside was similar in vitamin E-deficient rats and age-matched controls. 6. These results suggest that long term (12 months) deprivation of dietary vitamin E may impair endothelial function in mesenteric arteries of the rat. Sympathetic perivascular nerve constrictor function was increased at 12 months. There were no functionally expressed changes in the vascular smooth muscle, which appears to be more resilient to the effects of oxidative stress in vitamin E deficiency.