Seroprevalence of Leishmania infantum in outdoor workers from southern Italian endemic regions

Visceral leishmaniasis is a zoonotic vector-borne disease caused by Leishmania infantum. The infection often remains asymptomatic, though clinical forms may occur in immunosuppressed individuals. Although data on leishmaniasis in humans are available worldwide, the exposure to L. infantum of workers conducting outdoor activities has been scantly investigated, and it is limited to military personnel operating in endemic regions. This study aimed to assess the seroprevalence of L. infantum in different groups of outdoor workers and the occupational risk factors. The cross-sectional study was performed on 229 workers including forestry guards, farmers, veterinarians, geologists and agronomists from three regions of southern Italy (i.e., Apulia, Basilicata and Campania). All serum samples were screened for L. infantum-specific IgG/IgM by using automated indirect chemiluminescent immunoassays. Overall, 5.7% (13/229) of workers was positive to anti-L. infantum antibodies, with the highest seroprevalence in veterinarians (13.6%). An increased occupational health surveillance for L. infantum infection in outdoor workers is essential to better understand the risk of exposure in specific jobs. Furthermore, guidelines and education along with a One Health collaboration among veterinarians, physicians, parasitologists and occupational health care professionals are crucial for the prevention of this disease.

An Epitope Platform for Safe and Effective HTLV-1-Immunization: Potential Applications for mRNA and Peptide-Based Vaccines

Human T-cell lymphotropic virus type 1 (HTLV-1) infection affects millions of individuals worldwide and can lead to severe leukemia, myelopathy/tropical spastic paraparesis, and numerous other disorders. Pursuing a safe and effective immunotherapeutic approach, we compared the viral polyprotein and the human proteome with a sliding window approach in order to identify oligopeptide sequences unique to the virus. The immunological relevance of the viral unique oligopeptides was assessed by searching them in the immune epitope database (IEDB). We found that HTLV-1 has 15 peptide stretches each consisting of uniquely viral non-human pentapeptides which are ideal candidate for a safe and effective anti-HTLV-1 vaccine. Indeed, experimentally validated HTLV-1 epitopes, as retrieved from the IEDB, contain peptide sequences also present in a vast number of human proteins, thus potentially instituting the basis for cross-reactions. We found a potential for cross-reactivity between the virus and the human proteome and described an epitope platform to be used in order to avoid it, thus obtaining effective, specific, and safe immunization. Potential advantages for mRNA and peptide-based vaccine formulations are discussed.

Efficacy of the Measures Adopted to Prevent COVID-19 Outbreaks in an Italian Correctional Facility for Inmates Affected by Chronic Diseases

Background: COVID-19 outbreaks in prisons and jails may affect both inmates and correctional workers. An observational study has been performed to investigate the efficacy of specific procedures and of a serial testing approach adopted for the COVID-19 prevention in an Italian correctional facility (Bari, Apulia) for inmates affected by chronic diseases.

Methods: Two SARS-CoV-2 antigen testing campaigns were carried out for all the prisoners and correctional workers, including correctional officers (CO), administrative staff (AS), correctional health care workers (HCW), and operators working with people completing their sentence outside the prison (OOP). Antigen testing was conducted on nasopharyngeal swab specimens, using a fluorescence immunoassay for the qualitative detection of nucleocapsid SARS-CoV-2 antigen. All subjects positive to the antigen test underwent confirmation by rRT-PCR test.

Results: In total, 426 new and residential inmates were tested during the first campaign and 480 during the second campaign. Only two new inmates resulted positive at the first campaign, while no positive cases were observed at the second campaign or outside of the testing campaigns. In total, 367 correctional workers were tested at the first campaign and 325 at the second. At the first, 4 CO and 2 HCW showed positive test results, while no new positive cases were observed at the second. Moreover, 1 CO and 1 HCW resulted positive outside of the testing campaigns for the onset of symptoms while at home.

Conclusion: The implementation of a full risk management plan in a correctional facility, including both a strict protocol for the application of preventive measures and a serial testing approach, seems to be able to prevent COVID-19 outbreaks in both inmates and correctional workers.

Infliximab therapy restores adiponectin expression in perivascular adipose tissue and improves endothelial nitric oxide-mediated vasodilation in mice with type 1 diabetes

Increased TNFα-mediated JNK signaling in the perivascular adipose tissue (PVAT) may contribute to the pathogenesis of vascular complications in T1DM by reducing adiponectin (Ad) synthesis and therefore impairing Ad-mediated activity in the contiguous blood vessel system. We evaluated whether in vivo treatment with the TNFα blocking antibody infliximab normalized expression of Ad and Ad receptors in various fat depots, and whether this effect correlated with improved endothelial activity and vasodilator function in streptozotocin (STZ)-induced diabetic mice. STZ mice were studied at 1 and 2weeks after diabetes onset, and compared to age-matched infliximab-treated diabetic (I-STZ) and control animals (CTRL) (n=10 each group). In STZ mice, activation of pro-inflammatory JNK signaling was faster in PVAT (P<0.01) than in visceral (VAT), epididymal (EAT) and subcutaneous (SAT) adipose depots, and associated with decreased Ad synthesis and dysregulated AdipoR1/R2 levels. In parallel, activation of JNK in aortic endothelial cells and mesenteric arteries was associated with decreased expression/phosphorylation of eNOS and impaired ACh-mediated vasodilation (P<0.05 vs. CTRL). Treatment with infliximab abrogated JNK activation, ameliorated Ad protein expression, and normalized expression of both AdipoR1 and AdipoR2 in PVAT, concomitantly improving eNOS expression and vessel relaxation in mesenteric arteries from I-STZ mice (P<0.01 vs. STZ). These observations underline the early susceptibility of PVAT to activation of pro-inflammatory JNK signaling, and highlight its potential importance in early vascular changes of T1DM. Further elucidation of the role of PVAT in cardiovascular complications may allow for the design of novel therapeutic strategies directly addressing PVAT pathophysiology.

Elevated endothelin-1 (ET-1) levels may contribute to hypoadiponectinemia in childhood obesity

CONTEXT

Pediatric obesity is associated with endothelial dysfunction and hypoadiponectinemia, but the relationship between these two conditions remains to be fully clarified. Whether enhanced release of endothelin-1 (ET-1) may directly impair adiponectin (Ad) production in obese children is not known.

OBJECTIVE

The aim of the study was to explore whether and how high circulating levels of ET-1 may contribute to impair Ad production, release, and vascular activity.

DESIGN AND PARTICIPANTS

Sixty children were included into obese (Ob; n = 30), overweight (OW; n = 11), and lean (n = 19) groups. Total and high-molecular-weight Ad, ET-1, vascular cell adhesion molecule-1, and von Willebrand factor levels were measured in serum samples. Adipocytes were stimulated with exogenous ET-1 or with sera from lean, OW, and Ob, and Ad production and release measured in the absence or in the presence of ETA (BQ-123) and ETB (BQ-788) receptor blockers, p42/44 MAPK inhibitor PD-98059, or c-Jun NH2-terminal protein kinase inhibitor SP-600125. Vasodilation to Ad was evaluated in rat isolated arteries in the absence or in the presence of BQ-123/788.

RESULTS

Total and high-molecular-weight Ad was significantly decreased and ET-1 levels significantly increased in OW (P < .01) and Ob (P < .001) children. A statistically significant linear regression (P < .01) was found between Ad and ET-1. Exposure of adipocytes to exogenous ET-1 or serum from OW and Ob significantly decreased Ad mRNA and protein levels (P < 0.001). The inhibitory effect of ET-1 on Ad was reverted by BQ-123/788 or PD-98059 but not SP-600125. Ad-mediated vasodilation was further increased in arteries pretreated with BQ-123/788.

CONCLUSIONS

ET-1-mediated inhibition of Ad synthesis via p42/44 MAPK signaling may provide a possible explanation for hypoadiponectinemia in pediatric obesity and contribute to the development of cardiovascular complications.

Globular adiponectin counteracts VCAM-1-mediated monocyte adhesion via AdipoR1/NF-κB/COX-2 signaling in human aortic endothelial cells

Adiponectin (Ad) is an insulin-sensitizing adipocytokine with anti-inflammatory and vasoprotective properties. Cleavage of native full-length Ad (fAd) by elastases from activated monocytes generates globular Ad (gAd). Increased gAd levels are observed in the proximity of atherosclerotic lesions, but the physiological meaning of this proteolytic Ad fragment in the cardiovascular system is controversial. We compared molecular and biological properties of fAd and gAd in human aortic endothelial cells (HAEC). In control HAEC, both fAd and gAd acutely stimulated nitric oxide (NO) production by AMPK-dependent pathways. With respect to fAd, gAd more efficiently increased activation of NF-κB signaling pathways, resulting in cyclooxygenase-2 (COX-2) overexpression and COX-2-dependent prostacyclin 2 (PGI(2)) release. In contrast with fAd, gAd also increased p38 MAPK phosphorylation and VCAM-1 expression, ultimately enhancing adhesion of monocytes to endothelial cells. In HAEC lacking AdipoR1 (by siRNA), both activation of NF-κB as well as COX-2 overexpression by gAd were abrogated. Conversely, gAd-mediated p38MAPK activation and VCAM-1 expression were unaffected, and monocyte adhesion was greatly enhanced. In HAEC lacking COX-2 (by siRNA), reduced levels of PGI(2) further increased gAd-dependent monocyte adhesion. Our findings suggest that biological activities of fAd and gAd in endothelium do not completely overlap, with gAd possessing both AdipoR1-dependent ability to stimulate COX-2 expression and AdipoR1-independent effects related to expression of VCAM-1 and adhesion of monocytes to endothelium.

Fluvastatin modulates renal water reabsorption in vivo through increased AQP2 availability at the apical plasma membrane of collecting duct cells

X-linked nephrogenic diabetes insipidus (XNDI), a severe pathological condition characterized by greatly impaired urine-concentrating ability of the kidney, is caused by inactivating mutations in the V2 vasopressin receptor (V2R) gene. The lack of functional V2Rs prevents vasopressin-induced shuttling of aquaporin-2 (AQP2) water channels to the apical plasma membrane of kidney collecting duct principal cells, thus promoting water reabsorption from urine to the interstitium. At present, no specific pharmacological therapy exists for the treatment of XNDI. We have previously reported that the cholesterol-lowering drug lovastatin increases AQP2 membrane expression in renal cells in vitro. Here we report the novel finding that fluvastatin, another member of the statins family, greatly increases kidney water reabsorption in vivo in mice in a vasopressin-independent fashion. Consistent with this observation, fluvastatin is able to increase AQP2 membrane expression in the collecting duct of treated mice. Additional in vivo and in vitro experiments indicate that these effects of fluvastatin are most likely caused by fluvastatin-dependent changes in the prenylation status of key proteins regulating AQP2 trafficking in collecting duct cells. We identified members of the Rho and Rab families of proteins as possible candidates whose reduced prenylation might result in the accumulation of AQP2 at the plasma membrane. In conclusion, these results strongly suggest that fluvastatin, or other drugs of the statin family, may prove useful in the therapy of XNDI.

Treatment of spontaneously hypertensive rats with rosiglitazone ameliorates cardiovascular pathophysiology via antioxidant mechanisms in the vasculature

Oxidative stress contributes to cardiovascular complications of diabetes, in part, by reducing the bioavailability of nitric oxide (NO). We investigated the mechanisms whereby the insulin sensitizer rosiglitazone may ameliorate oxidative stress in the vasculature of spontaneously hypertensive rats (SHR). Nine-week-old SHR were treated by gavage for 7 wk with rosiglitazone (5 mg x kg(-1) x day(-1)) or vehicle control. Treatment of SHR with rosiglitazone lowered systolic blood pressure, reduced fasting plasma insulin and asymmetrical dimethylarginine, and increased insulin sensitivity (when compared with vehicle treatment). In vessel homogenates and serum from rosiglitazone-treated SHR, SOD activity was enhanced, while 8-iso-PGF(2alpha) (lipid peroxidation product) was reduced (when compared with samples from vehicle-treated SHR). Moreover, expression of p22phox (catalytic subunit of NADPH oxidase) as well as nitrotyrosine and superoxide content were all reduced in the aortas of rosiglitazone-treated SHR. In mesenteric vascular beds (MVB) isolated ex vivo from rosiglitazone-treated SHR, NO-dependent vasodilator actions of insulin were improved when compared with MVB from vehicle-treated SHR. Acute pretreatment of MVB from vehicle-treated SHR with apocynin (NADPH oxidase inhibitor) enhanced vasodilator actions of insulin (results comparable to those in MVB from rosiglitazone-treated SHR). In Langendorff heart preparations from rosiglitazone-treated SHR, ischemia/reperfusion injury caused infarcts 40% smaller than in hearts from vehicle-treated SHR. Acute pretreatment of hearts from vehicle-treated SHR with apocynin produced similar results. Finally, rosiglitazone treatment of endothelial cells in primary culture reduced superoxide induced by insulin-resistant conditions. We conclude that rosiglitazone therapy in SHR increases SOD activity and decreases p22phox expression in the vasculature to reduce oxidant stress leading to an improved cardiovascular phenotype.

Multiple pathological events in exercised dystrophic mdx mice are targeted by pentoxifylline: outcome of a large array of in vivo and ex vivo tests

The phosphodiesterases inhibitor pentoxifylline gained attention for Duchenne muscular dystrophy therapy for its claimed anti-inflammatory, antioxidant, and antifibrotic action. A recent finding also showed that pentoxifylline counteracts the abnormal overactivity of a voltage-independent calcium channel in myofibers of dystrophic mdx mice. The possible link between workload, altered calcium homeostasis, and oxidative stress pushed toward a more detailed investigation. Thus a 4- to 8-wk treatment with pentoxifylline (50 mg·kg−1·day−1 ip) was performed in mdx mice, undergoing or not a chronic exercise on treadmill. In vivo, the treatment partially increased forelimb strength and enhanced resistance to treadmill running in exercised animals. Ex vivo, pentoxifylline restored the mechanical threshold, an electrophysiological index of calcium homeostasis, and reduced resting cytosolic calcium in extensor digitorum longus muscle fibers. Mn quenching and patch-clamp technique confirmed that this effect was paralleled by a drug-induced reduction of membrane permeability to calcium. The treatment also significantly enhanced isometric tetanic tension in mdx diaphragm. The plasma levels of creatine kinase and reactive oxygen species were both significantly reduced in treated-exercised animals. Dihydroethidium staining, used as an indicator of reactive oxygen species production, showed that pentoxifylline significantly reduced the exercise-induced increase in fluorescence in the mdx tibialis anterior muscle. A significant decrease in connective tissue area and profibrotic cytokine transforming growth factor-β1 was solely found in tibialis anterior muscle. In both diaphragm and gastrocnemius muscle, a significant increase in neural cell adhesion molecule-positive area was instead observed. This data supports the interest toward pentoxifylline and allows insight in the level of cross talk between pathogenetic events in workloaded dystrophic muscle.

Endothelial dysfunction in mice with streptozotocin-induced type 1 diabetes is opposed by compensatory overexpression of cyclooxygenase-2 in the vasculature

Cardiovascular complications of diabetes result from endothelial dysfunction secondary to persistent hyperglycemia. We investigated potential compensatory mechanisms in the vasculature that oppose endothelial dysfunction in diabetes. BALB/c mice were treated with streptozotocin (STZ) to induce type 1 diabetes (T1D). In mesenteric vascular beds (MVBs), isolated ex vivo from mice treated with STZ for 1 wk, dose-dependent vasorelaxation to acetylcholine (ACh) or sodium nitroprusside was comparable with that in age-matched control mice (CTRL). By contrast, MVBs from mice treated with STZ for 8 wk had severely impaired vasodilator responses to ACh consistent with endothelial dysfunction. Pretreatment of MVBs from CTRL mice with nitric oxide synthase inhibitor nearly abolished vasodilation to ACh. In MVB from 1-wk STZ-treated mice, vasodilation to ACh was only partially impaired by L-N(omega)-arginine methyl ester. Thus, vasculature of mice with T1D may have compensatory nitric oxide-independent mechanisms to augment vasodilation to ACh and oppose endothelial dysfunction. Indeed, pretreatment of MVBs isolated from 1-wk STZ-treated mice with NS-398 [selective cyclooxygenase (COX)-2 inhibitor] unmasked endothelial dysfunction not evident in CTRL mice pretreated without or with NS-398. Expression of COX-2 in MVBs, aortic endothelial cells, and aortic vascular smooth muscle cells from STZ-treated mice was significantly increased (vs. CTRL). Moreover, concentrations of the COX-2-dependent vasodilator 6-keto-prostaglandin F-1alpha was elevated in conditioned media from aorta of STZ-treated mice. We conclude that endothelial dysfunction in a mouse model of T1D is opposed by compensatory up-regulation of COX-2 expression and activity in the vasculature that may be relevant to developing novel therapeutic strategies for diabetes and its cardiovascular complications.

AQP2 exocytosis in the renal collecting duct -- involvement of SNARE isoforms and the regulatory role of Munc18b

Vasopressin regulates the fusion of the water channel aquaporin 2 (AQP2) to the apical membrane of the renal collecting-duct principal cells and several lines of evidence indicate that SNARE proteins mediate this process. In this work MCD4 renal cells were used to investigate the functional role of a set of Q- and R-SNAREs, together with that of Munc18b as a negative regulator of the formation of the SNARE complex. Both VAMP2 and VAMP3 were associated with immunoisolated AQP2 vesicles, whereas syntaxin 3 (Stx3), SNAP23 and Munc18 were associated with the apical plasma membrane. Co-immunoprecipitation experiments indicated that Stx3 forms complexes with VAMP2, VAMP3, SNAP23 and Munc18b. Protein knockdown coupled to apical surface biotinylation demonstrated that reduced levels of the R-SNAREs VAMP2 and VAMP3, and the Q-SNAREs Stx3 and SNAP23 strongly inhibited AQP2 fusion at the apical membrane. In addition, knockdown of Munc18b promoted a sevenfold increase of AQP2 fused at the plasma membrane without forskolin stimulation. Taken together these findings propose VAMP2, VAMP3, Stx3 and SNAP23 as the complementary set of SNAREs responsible for AQP2-vesicle fusion into the apical membrane, and Munc18b as a negative regulator of SNARE-complex formation in renal collecting-duct principal cells.

Activation profile of the F3/Contactin gene in the developing mouse cerebellum

In this study, we address the activation profile of the gene encoding the mouse axonal glycoprotein F3/Contactin. Promoter sequences previously characterized in vitro are used to drive an Enhanced Green Fluorescent Protein reporter in transgenic mice. In developing cerebellum, differential transgene expression occurs within distinct cell populations. At P0 the transgene is activated in postmitotic granule neurons undergoing radial migration, a sharp upregulation occurring at P6-P8, with a gradual decline from this stage onward. In Purkinje cells, promoter activation, first detected at P3, peaks at around P6 and is fully downregulated by P16. The transgene is also expressed in Ng2- and O4-positive cells, mostly at the end of the first postnatal week, suggesting correlation with early oligodendrocyte differentiation. These data indicate that the complex organization of the regulatory region of the F3/Contactin gene is necessary for directing its articulated expression in different neural cells types and for its developmental function.