understanding the changes occurring within an aging immune system is essential if public health authorities are to be equipped to deal with an aging population .
specifically , knowledge of altered immune responses to infectious agents is required if rational clinical interventions are to be tailored to these aging individuals .
aging is a continuous and slow process that compromises the normal functioning of various organs and systems . as the population ages ,
there is growing interest in understanding host - parasite interaction and eventual prevention of chronic parasitic diseases , including cysticercosis , in elderly individuals .
cysticercosis is emerging as a serious public health problem in many poor countries in latin america , africa and asia .
although theoretically easy to control , and declared eradicable , cysticercosis remains neglected in most endemic countries .
this parasitosis may be asymptomatic or it may cause a variety of clinical manifestations depending on the number , location , and stage of cysticercus lesions .
pleomorphic disease is a result of the presence of the parasite itself ( cysticerci ) , of the inflammatory process that surrounds the larvae , and of residual fibrosis and calcification [ 46 ] .
it is likely that the combination of several factors is responsible for such differences , one of which may be gender - related . the relevance of gender in host susceptibility has been explored in cysticercosis infection . in experimental murine taenia
crassiceps cysticercosis , female mice were found to be more susceptible than males in different syngeneic and congenic strains of mice .
the finding that gonadectomy equalized susceptibility between sexes , by reducing parasite loads in females and increasing it in males , first clearly indicated the relevance of sexual hormones . the cysticercus contains a large number of antigens that can elicit a host immune inflammatory reaction .
the inflammatory cellular infiltrate , if present , may be discrete with lymphocytes and eosinophils in the initial stage , or it may be a more intense lymphocyte infiltrate with giant multinucleated foamy macrophages in the necrotic stage .
recent evidence suggests that immunosenescence associated to an immunological alteration caused by cysticercosis leads to a favorable condition for neoplasia development in elderly individuals attacked by the parasitosis .
moreover , it is likely that the patients continue to be infected with cysticercosis as they age .
the aim of this study was to quantify the inflammatory infiltrate in the heart and in the encephalon of the elderly with cysticercosis .
our hypothesis is that it is possible to quantify the infiltrated inflammatory among male and female elderly patients , due to the fact that those individuals are undergoing immunosenescence .
this research paper was approved by triangulo mineiro federal university research ethics committee under protocol no . 486 .
as this research regards autopsy material , the only risk was the loss of confidentiality .
however , as a precautionary measure , the cases were identified by letters and numbers . also , consent for the autopsy
was given in writing by the next of kin after the death of the patient .
then the document was filed in the general hospital and the general pathology discipline records . a retrospective transversal study of 3639 autopsies of adults collected at the general hospital of triangulo mineiro federal university , located in uberaba , mg , brazil , from 1970 to 2008 , was carried out .
diagnosis of cysticercosis was made through histological demonstration or through direct visualization of the cysticercus , meeting the diagnostic criteria proposed by other authors , in 75 autopsies , 55 non - elderly , and 20 elderly patients .
information regarding age , gender , body weight , height , heart weight , brain weight , and the number , location , and evolutionary stage of the cysticercus was registered . in order to analyze the heart and brain inflammatory infiltration
, we obtained 33 ( 13 elderly and 20 non - elderly ) samples of heart and brain of patients with cysticercosis the 7 heart samples , amongst which 3 belonged to elderly patients and 4 belonged to non - elderly patients with cardiac cysticercosis , and 26 brains with neurocysticercosis , 10 of which belonged to elderly patients and 16 to non - elderly patients .
the other organs were not found at the anatomical specimens ' archives from the department of general pathology .
the brain and heart samples affected by cysticercosis were fixed in formaldehyde 10% and subjected to routine histological processing so as to obtain 4  m thick sections , stained with hematoxylin and eosin ( he ) , for general morphological analysis and for quantification of the inflammatory cell infiltrate . a video camera coupled to a standard light microscope and an interactive image analysis system ( ks 300 carl zeiss ) were used .
we analyzed ten fields per quadrant ; that is , 40 measurements were carried out in each slide .
the he - stained slides were examined using a standard light microscope with a 20x objective and 800x magnification range .
the digital image showed the field where the number of inflammatory cells was counted in absolute value .
quantification was carried out by the observer 's identification of such cells and through the staining performed by point - counting method .
the variables were tested in order to verify the type of distribution using the kolmogorov - smirnov test and variance analysis .
student 's t - test ( t ) or mann - whitney ( t ) was used in the comparison of two groups , and anova ( f ) or kruskal - wallis ( h ) for comparison between three or more groups , followed by bonferroni or dunn test when necessary .
correlations between two variables were analyzed by pearson 's or spearman correlation coefficient ( r ) .
amongst the patients with cysticercosis , the average age of the non - elderly was 47.3 years , ranging from 23 to 58 years old , whereas the elderly had an average age of 66.7 years , ranging from 61 to 75 years old .
male and caucasian patients predominated in both groups , and analysis of nutritional status showed that the non - elderly had an average body mass index ( bmi ) of 21.2  4.4  kg / m and that the elderly with cysticercosis had an average bmi of 20.2  9.9 
kg / m . heart weight and brain weight of the non - elderly were found to be higher than those of the elderly with cysticercosis , and both elderly and non - elderly male patients had heart weight and brain weight higher than female patients ( table 1 ) .
it was possible to ascertain the evolutionary stage of the parasite in 8 cysticerci of elderly individuals , among whom 4 ( 50% ) were vesicular stage , 2 ( 25% ) colloidal vesicular stage , 1 ( 12.5% ) granular nodular stage and ( 12.5% ) nodular calcified stage . amongst the non - elderly , 4 ( 21.1% ) cysticerci
were in the first evolutionary stage , 5 ( 26.3% ) colloidal vesicular stage , 4 ( 21.1% ) granular nodular stage , and 6 ( 31.5% ) nodular calcified stage .
the elderly had an average of 3.1  2.5 cysticerci , whereas the non - elderly had 2.7  3.8 parasites . at all stages
was observed some degree of inflammatory reaction around the cysticercus , its intensity decreased with the succession of evolutionary stages .
the colloidal vesicular stage showed the highest inflammatory infiltrate , followed by the granular nodular stage in elderly and non - elderly groups ( table 2 ) .
analysis of the cardiac inflammatory infiltrate indicated that the non - elderly had significantly more inflammation than the elderly patients with cardiac cysticercosis ( figures 1 and 2 ) . in the non - elderly group , although men had more cardiac inflammation than women , this difference was not significant . nonetheless , elderly females had significantly more inflammation than the elderly males ( table 3 ) .
encephalic inflammation was more acute amongst the non - elderly when compared to the elderly with neurocysticercosis ( figure 1 ) . in the elderly group , female patients had significantly more encephalic inflammation than male patients .
when contrasting both genders of the non - elderly group , male patients had more inflammation , yet without any significant difference ( table 3 ) . a positive and not significant correlation between encephalic inflammation and cardiac inflammation was found ( r = 0 , 032 ; p = 0,247 ) , as well as a negative correlation between age and encephalic inflammation ( r = 0,518 ; p = 0,03 ) or cardiac inflammation ( r = 0,385 ; p = 0,186 ) in male group .
population aging , which has increased since the last decades of the twentieth century , has changed the demographic and epidemiological profiles of countries such as brazil .
the increase in chronic degenerative diseases , which have replaced infectious and parasitic diseases , has demanded that more emphasis be placed on the prevention and treatment of such diseases , which leads to the need to know about their pathological changes during the aging process . in the present study ,
heart and brain weights of non - elderly patients with cysticercosis were found to be higher than those of the elderly group with the parasitosis , without significant difference .
male patients had higher heart weight and brain weight , regardless of age . according to the literature , heart weight ranges from 347  g to 487  g in individuals over 60 years old , and brain weight ranges from 1105  g to 1264  g [ 1416 ] . in an experimental study , not only
did adult male rats have higher heart weight , but they also had larger myocardiocytes compared with female rats , which might be related to a higher risk of cardiovascular disease in males .
studies involving patients without encephalopathy showed that the brain weight and the volume and density of the cell undergo a steady decrease with age , whereby male patients have higher brain weight than female patients .
analysis of the inflammatory infiltrate showed that the non - elderly had significantly more cardiac and encephalic inflammation than the elderly , and that such inflammatory infiltrate decreases with age and depends upon the evolutionary stage of the cysticercus .
the inflammatory process caused by cysticerci in the cerebral parenchyma and in the myocardium comprises mononuclear and polymorphonuclear cells , mainly eosinophils , macrophages , and lymphocytes [ 19 , 20 ] . during the aging process
, changes in the expression of functionally important cell receptors , reduction in the population of polymorphonuclear cells , and reduction in the capability of producing antibodies are verified , and these factors may lead to immune dysfunction [ 21 , 22 ] . therefore
, our data might be related to changes in the immune response , mainly in t cells , which were found in the elderly individuals .
the vesicular stage was more prevalent among the elderly and nodular calcified stage among non - elderly , and colloidal vesicular stage showed higher inflammatory infiltrate in both groups .
researches show that a more intense inflammation with lymphocyte and macrophage infiltrate can be found around the cysticercus in colloidal vesicular stage [ 10 , 24 , 25 ] . with
cysts degenerates , the inflammatory reaction tends to decrease in the granular nodular stage , denoting continuity in the host reaction against the parasite remnants without , however , having an association with the type or intensity of the inflammatory response [ 24 , 26 ] .  
the duration of each of the progressive stages in the natural history of cysticercosis has not been established because there are considerable differences between individuals , particularly in relation to the intensity of the endogenous immune response .
whereas the parasite typically dies few years after infection stimulating a vigorous inflammatory response , probably the acquisition of the parasite occurred most recently in the elderly than in non - elderly patients , or the elderly , due to changes in the immune system with aging , preserve the cysticercus in the initial phase for a long time .
there are also some indications that , in human neurocysticercosis caused by t. solium , women show a more intense inflammatory profile in the cerebrospinal fluid than men do and , likewise , are more prone to develop a severe and generalized encephalitic process .
these observations are in accordance with previous studies in which gender has been associated with the intensity of the inflammatory response against the parasite , possibly promoted by the female sex - steroid levels [ 7 , 9 , 2832 ] .
therefore , our data showed that even during senescence , when a decrease in the levels of female sex steroids is noticed , women have a more intense immune response towards cysticercosis in comparison with men .
studies have showed that the presence of multiple parasites is more common in older individuals .
encephalic inflammation and cardiac inflammation were more commonly found in the analyzed material , and most of the individuals had cysticercosis in more than one location .
it was found that multiple cysticerci lesions and multiple vesicular cysts were more frequently observed in the elderly without an increase in severity of the clinical symptoms .
this observation could indicate that susceptibility to become infected increases with age , whereas susceptibility to follow a pathogenic course of the infection decreases .
the reverse effect of age upon susceptibility to infection and to resistance against severe disease has been found in other parasite infections such as schistosomiasis [ 33 , 34 ] and it suggests that susceptibility and pathogenicity involve distinct physiological pathways that are independently regulated .
this study presents important findings on the influence of gender on cardiac and encephalic inflammation in the elderly with cysticercosis , although it has some limitations , such as small number of samples for analyses , particularly of the gender influence , loss of many biopsies and retrospective design .
future researches are needed to determine the mechanisms of the differences related to gender and immunosenescence associated to immunological alteration caused by cysticercosis .
in this study , we showed that the non - elderly had significantly more cardiac and encephalic inflammation than the elderly , and that such inflammatory infiltrate decreases with age and depends upon the evolutionary stage of the cysticercus .
furthermore , there are differences , concerning gender , in the intensity of the inflammatory response due to cysticerci in the heart and brain parenchyma during senescence . even during this period , women continue to have a more intense response to the parasitosis .
 
 background . 
 the present study explores the influence of the host 's age and gender upon the inflammatory infiltrate . 
 we aimed to quantify the inflammatory infiltrate caused by cysticercosis , which is related to aging , in the heart and in the encephalon . 
 methods . 75 autopsy protocols with cysticercosis diagnosis from department of pathology at a university hospital from 1970 to 2008 were reviewed . 
 two groups were formed : elderly with cysticercosis and nonelderly with cysticercosis . 
 we used ks-300 ( kontron - zeiss ) software for morphometric analysis of the inflammation . results . 
 the elderly had an average of 3.1  2.5 cysticerci , whereas the non - elderly had 2.7  3.8 parasites . 
 the non - elderly group with cysticercosis had significantly more inflammation , both cardiac and encephalic , than the elderly group . 
 the elderly females with cysticercosis had more cardiac and encephalic inflammation . 
 conclusions . in this study 
 , we showed that the non - elderly had significantly more cardiac and encephalic inflammation than the elderly , and that such inflammatory infiltrate decreases with age and depends upon the evolutionary stage of the cysticercus . 
 furthermore , there are differences concerning gender in the intensity of the inflammatory response due to cysticerci in the heart and brain parenchyma during senescence . even during this period , women continue to have a more intense response to the parasitosis . 