Helena Vala

Dr. Helena Vala

orcid

Research Focus & Metrics

Academic Career Length

26Years (2001-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 January 2017 in Environmental Pollution
Verified
Journal Article
Closed access
Andres Rodríguez-SeijoAndres Rodríguez-Seijo
Andres Rodríguez-Seijo
Joana LourençoJoana Lourenço
Joana Lourenço
Teresa Rocha-SantosTeresa Rocha-Santos
Teresa Rocha-Santos
Joao Pinto da CostaJoao Pinto da Costa
Joao Pinto da Costa
Armando C. DuarteArmando C. Duarte
Armando C. Duarte
Ruth PereiraRuth Pereira
Ruth Pereira

1 January 2010 in Mediators of Inflammation
Verified
Journal Article
Open access
PDF file
LFLiliana Ferreira
Liliana Ferreira
Edite Teixeira-LemosEdite Teixeira-Lemos
Edite Teixeira-Lemos
FPFilipa Pinto
Filipa Pinto
BPBelmiro Parada
Belmiro Parada
CMCristina Mega
Cristina Mega
Flávio ReisFlávio Reis
Flávio Reis
The purpose of this paper is to evaluate the chronic effect of sitagliptin on metabolic profile, inflammation, and redox status in the Zucker Diabetic Fatty (ZDF) rat, an animal model of obese type 2 diabetes. Diabetic and obese ZDF (fa/fa) rats and their controls (ZDF +/+) were treated during 6 weeks with vehicle (control) and sitagliptin (10 mg/kg/bw). Glucose, HbA1c, insulin, Total-c, TGs, IL-1β, TNF-α, CRPhs, and adiponectin were assessed in serum and MDA and TAS in serum, pancreas, and heart. Pancreatic histology was also evaluated. Sitagliptin in diabetic rats promoted a decrease in glucose, HbA1c, Total-c, and TGs accompanied by a partial prevention of insulinopenia, together, with a decrease in CRPhsand IL-1β. Sitagliptin also showed a positive impact on lipid peroxidation and hypertension prevention. In conclusion, chronic sitagliptin treatment corrected the glycaemic dysmetabolism, hypertriglyceridaemia, inflammation, and hypertension, reduced the severity of the histopathological lesions of pancreatic endocrine and exocrine tissues, together with a favourable redox status, which might be a further advantage in the management of diabetes and its proatherogenic comorbidities.

30 November 2011 in Experimental Diabetes Research
Verified
Journal Article
Open access
PDF file
CMCristina Mega
Cristina Mega
Edite Teixeira-LemosEdite Teixeira-Lemos
Edite Teixeira-Lemos
HVHelena Vala
Helena Vala
Rosa FernandesRosa Fernandes
Rosa Fernandes
Jorge OliveiraJorge Oliveira
Jorge Oliveira
Flávio ReisFlávio Reis
Flávio Reis
This study was performed to assess the effect of chronic low-dose sitagliptin, a dipeptidyl peptidase 4 inhibitor, on metabolic profile and on renal lesions aggravation in a rat model of type-2 diabetic nephropathy, the Zucker diabetic fatty (ZDF) rat. Diabetic and obese ZDF (fa/fa) rats and their controls ZDF (+/+) were treated for 6 weeks with vehicle (control) or sitagliptin (10 mg/kg/bw). Blood/serum glucose, HbA1c, insulin, Total-c, TGs, urea, and creatinine were assessed, as well as kidney glomerular and tubulointerstitial lesions (interstitial fibrosis/tubular atrophy), using a semiquantitative rating from 0 (absent/normal) to 3 (severe and extensive damage). Vascular lesions were scored from 0–2. Sitagliptin in the diabetic rats promoted an amelioration of glycemia, HbA1c, Total-c, and TGs, accompanied by a partial prevention of insulinopenia. Furthermore, together with urea increment prevention, renal lesions were ameliorated in the diabetic rats, including glomerular, tubulointerstitial, and vascular lesions, accompanied by reduced lipid peroxidation. In conclusion, chronic low-dose sitagliptin treatment was able to ameliorate diabetic nephropathy, which might represent a key step forward in the management of T2DM and this serious complication.

1 March 2009 in Nutrition
Verified
Journal Article
Closed access
Edite Teixeira-LemosEdite Teixeira-Lemos
Edite Teixeira-Lemos
Flávio ReisFlávio Reis
Flávio Reis
SBS. Baptista
S. Baptista
RPRui Manuel Pinto
Rui Manuel Pinto
BSBruno Sepodes
Bruno Sepodes
UDU.N. Das
U.N. Das

13 April 2015 in PLOS ONE
Verified
Journal Article
Open access
PDF file
PGPatrícia Garrido
Patrícia Garrido
SRSandra Ribeiro
Sandra Ribeiro
JFJoao Fernandes
Joao Fernandes
HVHelena Vala
Helena Vala
EBElsa Bronze-Da-Rocha
Elsa Bronze-Da-Rocha
Flávio ReisFlávio Reis
Flávio Reis
Anemia is a common complication of chronic kidney disease (CKD) that develops early and its severity increases as renal function declines. It is mainly due to a reduced production of erythropoietin (EPO) by the kidneys; however, there are evidences that iron metabolism disturbances increase as CKD progresses. Our aim was to study the mechanisms underlying the development of anemia of CKD, as well as renal damage, in the remnant kidney rat model of CKD induced by 5/6 nephrectomy. This model of CKD presented a sustained degree of renal dysfunction, with mild and advanced glomerular and tubulointerstitial lesions. Anemia developed 3 weeks after nephrectomy and persisted throughout the protocol. The remnant kidney was still able to produce EPO and the liver showed an increased EPO gene expression. In spite of the increased EPO blood levels, anemia persisted and was linked to low serum iron and transferrin levels, while serum interleukin (IL)-6 and high sensitivity C-reactive protein (hs-CRP) levels showed the absence of systemic inflammation. The increased expression of duodenal ferroportin favours iron absorption; however, serum iron is reduced which might be due to iron leakage through advanced kidney lesions, as showed by tubular iron accumulation. Our data suggest that the persistence of anemia may result from disturbances in iron metabolism and by an altered activity/function of EPO as a result of kidney cell damage and a local inflammatory milieu, as showed by the increased gene expression of different inflammatory proteins in the remnant kidney. In addition, this anemia and the associated kidney hypoxia favour the development of fibrosis, angiogenesis and inflammation that may underlie a resistance to EPO stimuli and reduced iron availability. These findings might contribute to open new windows to identify putative therapeutic targets for this condition, as well as for recombinant human EPO (rHuEPO) resistance, which occurs in a considerable percentage of CKD patients.

4 September 2020 in Veterinary Sciences
Verified
Journal Article
Open access
PDF file
Maria Aires PereiraMaria Aires Pereira
Maria Aires Pereira
RSRute Santos
Rute Santos
RORicardo Oliveira
Ricardo Oliveira
LCLina Costa
Lina Costa
APAna Prata
Ana Prata
Gabriela Santos-GomesGabriela Santos-Gomes
Gabriela Santos-Gomes
Canine leishmaniosis (CanL) is a chronic and potentially fatal disease. The prognosis of CanL depends on the severity of the clinical signs and clinicopathological abnormalities presented by the dog at the time of diagnosis. This study aims to estimate the survival time of dogs with CanL, determining the prognostic value of different clinical and clinicopathological parameters. Medical records of 99 dogs diagnosed with CanL in five veterinary centers of the Alentejo region (Portugal) were examined retrospectively. The majority of dogs presented hyperproteinemia, moderate normocytic normochromic anemia, normal blood urea and creatinine levels and were classified as stage 1 according to the International Interest Society (IRIS) guidelines at the time of diagnosis. The severity of anemia, presence of concomitant infectious diseases at the time of diagnosis and the anti-Leishmania therapy were correlated with the survival time. The influence of renal dysfunction was evaluated by Receiver Operating Characteristic (ROC) curve and survival analysis. Survival analysis demonstrated that patients classified as IRIS 1 at the time of diagnosis survived more than four years, in contrast with dogs classified as IRIS 2 that survived around two and half years and dogs classified as IRIS 3–4 that survived around one month. IRIS stage deteriorated during the course of CanL in one third of the dogs and was the principal cause of death or euthanasia in a high proportion of animals. In some cases, dogs did not receive anti-Leishmania treatment or abandoned the veterinary follow-ups, which may have considerable repercussions for animal wellbeing and public health. This study reinforces the value of blood urea and creatinine levels as prognostic factors in CanL.