Aberrant expression of calcitonin gene-related peptide and its correlation with prognosis in severe childhood pneumonia.

OBJECTIVES: The purpose of this study was to evaluate the relationship between the serum levels of calcitonin gene-related peptide (CGRP) and the prognosis of pediatric patients with severe pneumonia. METHODS: Children diagnosed with severe pneumonia (n=76) were stratified into the survival (n=58) and non-survival groups (n=18) according to their 28-day survival status and into the non-risk (n=51), risk (n=17) and high-risk (n=8) categories based on the pediatric critical illness score (PCIS). Demographic data and laboratory results were collected. Serum CGRP levels were determined by enzyme-linked immunosorbent assay (ELISA). A receiver operating characteristic (ROC) curve was generated to determine the cutoff score for high CGRP levels. RESULTS: Serum CGRP levels were significantly higher in the survival group than in the non-survival group and were significantly higher in the non-risk group than in the risk and high-risk groups. The ROC curve for the prognostic potential of CGRP yielded a significant area under the curve (AUC) value with considerable sensitivity and specificity. CONCLUSION: Our findings show that CGRP downregulation might be a diagnostic marker that predicts the prognosis and survival of children with severe pneumonia.

Aberrant expression of calcitonin gene-related peptide and its correlation with prognosis in severe childhood pneumonia

OBJECTIVES: The purpose of this study was to evaluate the relationship between the serum levels of calcitonin gene-related peptide (CGRP) and the prognosis of pediatric patients with severe pneumonia. METHODS: Children diagnosed with severe pneumonia (n=76) were stratified into the survival (n=58) and non-survival groups (n=18) according to their 28-day survival status and into the non-risk (n=51), risk (n=17) and high-risk (n=8) categories based on the pediatric critical illness score (PCIS). Demographic data and laboratory results were collected. Serum CGRP levels were determined by enzyme-linked immunosorbent assay (ELISA). A receiver operating characteristic (ROC) curve was generated to determine the cutoff score for high CGRP levels. RESULTS: Serum CGRP levels were significantly higher in the survival group than in the non-survival group and were significantly higher in the non-risk group than in the risk and high-risk groups. The ROC curve for the prognostic potential of CGRP yielded a significant area under the curve (AUC) value with considerable sensitivity and specificity. CONCLUSION: Our findings show that CGRP downregulation might be a diagnostic marker that predicts the prognosis and survival of children with severe pneumonia.

Renal sodium handling and blood pressure changes in gestational protein-restricted offspring: Role of renal nerves and ganglia neurokinin expression.

BACKGROUND: Considering long-term changes in renal sodium handling and blood pressure in maternal protein-restricted (LP) offspring, we assumed that the development of LP hypertension results from abnormal dorsal root ganglia (DRG) neurokinin expression associated with impaired responsiveness of renal sensory receptors, promoting a reduced urinary excretion of sodium. The present study investigates whether increased blood pressure in protein-restricted offspring would be associated with changes in the DRG cells and in renal pelvic wall expression of NK1R, SP and CGRP when compared to NP offspring. In addition, we assessed the tubular sodium handling, estimated by creatinine and lithium clearances before and after bilateral renal denervation in conscious LP offspring relative to age-matched NP counterparts. METHODS: Dams received a normal (NP) or low-protein diet (LP) during their entire pregnancy period. Male NP or LP offspring underwent bilateral surgical renal denervation before the 8-week renal functional test and blood pressure measurements. Immunofluorescence staining in DRG cells was assessed in optical sections by confocal laser scanning microscope. RESULTS: The current data demonstrated a sustained rise in blood pressure associated with a decrease in fractional excretion of sodium (FENa) by reducing post-proximal tubule sodium rejection in 16-wk old LP rats relative to age-matched NP counterparts. According to this study, bilateral renal denervation attenuated blood pressure and increased FENa in LP offspring. Furthermore, an immunohistochemical analysis showed a reduced expression of SP and CGRP in DRGs of LP when compared with NP rats. Renal pelvis of LP rats did not show a strong CGRP expression related to NP rats, whereas there was no change in SP immunostaining. CONCLUSIONS: These observations raise the possibility that impaired DRG and pelvic neurokinin expression associated with responsiveness of renal sensory receptors in 16-wk old LP offspring are conducive to excess renal reabsorption of sodium and development of hypertension in this programmed model.

Neurochemical effects of photobiostimulation in the trigeminal ganglion after inferior alveolar nerve injury.

Orofacial pain is associated with peripheral and central sensitization of trigeminal nociceptive neurons. Nerve injury results in release of chemical mediators that contribute to persistent pain conditions. The activation of the transient receptor potential vanilloid 1 (TRPV1), promotes release of calcitonin gene-related peptide (CGRP) and substance P (SP) from trigeminal nerve terminals. CGRP and SP contribute to the development of peripheral hyperalgesia. The expression of SP and CGRP by primary afferent neurons is rapidly increased in response to peripheral inflammation. CGRP receptor activation promotes activation of AMPA receptors, leading to increased firing of neurons which is reflected as central sensitization. In this study we investigated whether inferior alveolar nerve (IAN) injury influences AMPA receptors, CGRP, SP and TRPV1 expression in the trigeminal ganglion (TG). The relative expression of the protein of interest from naive rats was compared to those from injured rats and animals that received low level laser therapy (LLLT). IAN-injury did not change expression of GluA1, GluA2 and CGRP, but increased the expression of TRPV1 and SP. LLLT increases GluA1 and GluA2 expression and decreases TVPV1, SP and CGRP. These results, together with previous behavioral data, suggest that IAN-injury induced changes in the proteins analyzed, which could impact on nociceptive threshold. These data may help to understand the molecular mechanisms of pain sensitization in the TG.

Expression of TRPM8 in diabetic rats and its relationship with visceral pain stimulation.

Transient receptor potential cation channel, subfamily M, member 8 (TRPM8) is a nonselective cation channel and a candidate for cold sensation signaling, but the relationship between TRPM8 and diabetes remains unclear. In the present study, we determined the expression levels of TRPM8 messenger RNA (mRNA) and the levels of the TRPM8 protein in the bladder tissue of diabetic rats. We also investigated the correlation between TRPM8 expression and the visceral pain stimulation-related factor, calcitonin gene-related peptide (CGRP) in diabetic rats. The rats were sacrificed 3, 5, 7, and 15 days after streptozotocin injection, and blood was collected from their tail veins to determine the blood glucose levels. Bladder tissue was removed to assess the expression of TRPM8 mRNA by reverse transcription-polymerase chain reaction, and the expression of the TRPM8 protein by western blotting. After administering electrical stimulation (5 V/1 Hz), the expression levels of TRPM8 and CGRP proteins were determined. Our results revealed that the blood glucose level, and TRPM8 mRNA and TRPM8 protein expression levels increased significantly in the diabetic rats. Spinal tissue protein expression levels of both TRPM8 and CGRP also increased significantly following electrical stimulation. This possibly indicates that TRPM8 is closely associated with visceral pain stimulation, and could be an independent prognostic biomarker for diabetes.

Measurement of calcitonin and calcitonin gene-related peptide mRNA refines the management of patients with medullary thyroid cancer and may replace calcitonin-stimulation tests.

BACKGROUND: Serum calcitonin (sCT) is the main tumor marker for medullary thyroid cancer (MTC), but it has certain limitations. Various sCT assays may have important intra-assay or interassay variation and may yield different and sometimes conflicting results. A pentagastrin- or calcium-stimulation calcitonin (CT) test may be desirable in some situations. Alternatively, or in the absence of the stimulation test, mRNA detection offers the advantages of being more comfortable and less invasive; it only requires blood collection and has no side effects. The objective of this study was to investigate the applicability of measuring calcitonin-related polypeptide alpha (CALCA) gene transcripts (CT-CALCA and calcitonin gene-related peptide [CGRP]-CALCA) in patients with MTC and in relatives diagnosed with a RET mutation and to test mRNA as an alternative diagnostic tool for the calcitonin-stimulation test. METHODS: Twenty-three healthy controls and 26 individuals evaluated for MTC were selected, including patients with sporadic or hereditary MTC and RET mutation-carrying relatives. For molecular analysis, RNA was extracted from peripheral blood, followed by cDNA synthesis using 3.5 µg of total RNA. Quantitative real-time polymerase chain reaction (RT-qPCR) was performed with SYBR Green and 200 nM of each primer for the two specific mRNA targets (CT-CALCA or CGRP-CALCA) and normalized with the ribosomal protein S8 as the reference gene. RESULTS: We detected CALCA transcripts in the blood samples and observed a positive correlation between them (r=0.946, p<0.0001). Both mRNAs also correlated with sCT (CT-CALCA, r=0.713, p<0.0001; CGRP-CALCA, r=0.714, p<0.0001). The relative expression of CT-CALCA and CGRP-CALCA presented higher clinical sensitivity (86.67 and 100, respectively), specificity (97.06 and 97.06), positive predictive value (92.86 and 93.75), and negative predictive value (94.29 and 100), than did sCT (73.33, 82.35, 64.71, and 87.50, respectively). In addition, the CALCA transcript measurement mirrored the response to the pentagastrin test. CONCLUSION: We demonstrate that the measurement of CALCA gene transcripts in the bloodstream is feasible and may refine the management of patients with MTC and RET mutation-carrying relatives. We propose considering the application of this diagnostic tool as an alternative to the calcitonin-stimulation test.

Repression of calcitonin gene-related peptide expression in trigeminal neurons by a Theobroma cacao extract.

ETHNOPHARMACOLOGICAL RELEVANCE: Cocoa bean preparations were first used by the ancient Maya and Aztec civilizations of South America to treat a variety of medical ailments involving the cardiovascular, gastrointestinal, and nervous systems. Diets rich in foods containing abundant polyphenols, as found in cocoa, underlie the protective effects reported in chronic inflammatory diseases. Release of calcitonin gene-related peptide (CGRP) from trigeminal nerves promotes inflammation in peripheral tissues and nociception. AIM OF THE STUDY: To determine whether a methanol extract of Theobroma cacao L. (Sterculiaceae) beans enriched for polyphenols could inhibit CGRP expression, both an in vitro and an in vivo approach was taken. RESULTS: Treatment of rat trigeminal ganglia cultures with depolarizing stimuli caused a significant increase in CGRP release that was repressed by pretreatment with Theobroma cacao extract. Pretreatment with Theobroma cacao was also shown to block the KCl- and capsaicin-stimulated increases in intracellular calcium. Next, the effects of Theobroma cacao on CGRP levels were determined using an in vivo model of temporomandibular joint (TMJ) inflammation. Capsaicin injection into the TMJ capsule caused an ipsilateral decrease in CGRP levels. Theobroma cacao extract injected into the TMJ capsule 24h prior to capsaicin treatment repressed the stimulatory effects of capsaicin. CONCLUSIONS: Our results demonstrate that Theobroma cacao extract can repress stimulated CGRP release by a mechanism that likely involves blockage of calcium channel activity. Furthermore, our findings suggest that the beneficial effects of diets rich in cocoa may include suppression of sensory trigeminal nerve activation.

Decreases in the expression of CGRP and galanin mRNA in central and peripheral neurons related to the control of blood pressure following experimental hypertension in rats.

Calcitonin gene-related peptide (alpha CGRP) and galanin (GAL) are peptides known to participate in central mechanisms of blood pressure control. Nonetheless, variations in the synthesis of the peptides in response to a hypertensive challenge are not well described, specially using a model, which allows acute and chronic analyses. In this study, we have employed in situ hybridization to analyse changes in mRNA expression of alpha CGRP and GAL in the nucleus tractus solitarii (NTS), hypothalamic paraventricular nucleus (PVN) as well as petrosal and nodose ganglia after aortic coarctation-induced hypertension in rats. Acute (2h) and chronic (3 and 7 days) analyses were performed in order to evaluate the involvement of both peptides in different periods of hypertension. The analysis of relative mRNA levels showed significant differences between sham-operated and aortic coarcted hypertensive rats. alpha CGRP mRNA expression was decreased 2h (40%) and 3 days (42%) in nodose and petrosal ganglia, respectively, after coarctation. No changes in CGRP mRNA signal were seen in the NTS and PVN in the analysed periods. GAL mRNA expression was decreased in the NTS (19%) and PVN (55%), 3 and 7 days, respectively, after coarctation-induced hypertension. No changes in GAL mRNA expression were observed in petrosal and nodose ganglia following aortic coarctation. Data suggest that alpha CGRP and GAL may participate in the mechanisms involved in the establishment/maintenance of hypertension induced by aortic coarctation. Acute changes might be involved with the adaptation to the hypertensive state, while changes at the chronic phase might be related to counteraction of hypertension.