RARE PECAM1 VARIANTS IN THREE FAMILIES WITH LYMPHEDEMA

PECAM1 is a member of the immunoglobulin superfamily and is expressed in monocytes, neutrophils, macrophages and other types of immune cells as well as in endothelial cells. PECAM1 function is crucial for the development and maturation of B lymphocytes. The aim of this study was to link rare PECAM1 variants found in lymphedema patients with the development of lymphatic system malformations. Using NGS, we previously tested 246 Italian lymphedema patients for variants in 29 lymphedema-associated genes and obtained 235 negative results. We then tested these patients for variants in the PECAM1 gene. We found three probands with rare variants in PECAM1. All variants were heterozygous missense variants. In Family 1, the unaffected mother and brother of the proband were found to carry the same variant as the proband. Lymphoscintigraphy was performed to determine possible lymphatic malformations and showed that in both cases a bilateral slight reduction in the speed and lymphatic clearance of the lower limbs. PECAM1 function is important for lymphatic vasculature formation. We found variants in PECAM1 that may be associated with susceptibility to lymphedema.

Taste, olfactory and texture related genes and food choices: implications on health status

OBJECTIVE

The food choices are due to a mixture of sensory signals including gustatory, olfactory, and texture sensations. The aim of this quality review was to update data about studies concerning genetics of taste, olfactory and texture receptors and their influence on the health status in humans.

MATERIALS AND METHODS

An electronic search was conducted in MEDLINE, Pubmed database and Scopus, for articles published in English until December 2018. Two independent researches selected the studies and extracted the data.

RESULTS

The review confirms the importance of inter-individual variations in taste, olfactory and texture related genes on food choices and their implications in the susceptibility to nutrition-related conditions such as obesity, dental caries, diabetes, cardiovascular disease, hypertension, hyperlipidemia and cancer.

CONCLUSIONS

The knowledge of variants in taste, olfactory and texture related genes can contribute to the prevention of diseases related to unhealthy nutrition. Further studies would be useful to identify other variants in the genes involved in these systems.

CYP26B1 AND ITS IMPLICATIONS IN LYMPHANGIOGENESIS: LITERATURE REVIEW AND STUDY OF RARE VARIANTS IN TWO FAMILIES

CYP26B1 is a member of the cytochrome P450 family and is responsible for the breakdown of retinoic acid for which appropriate levels are important for normal development of the cardiovascular and lymphatic systems. In a cohort of 235 patients with lymphatic malformations, we performed genetic testing for the CYP26B1 gene. These probands had previously tested negative for known lymphedema genes. We identified two heterozygous missense CYP26B1 variants in two patients. Our bioinformatic study suggested that alterations caused by these variants have no major effect on the overall stability of CYP26B1 protein structure. Balanced levels of retinoic acid maintained by CYP26B1 are crucial for the lymphatic system. We identified that CYP26B1 could be involved in predisposition for lymphedema. We propose that CYP26B1 be further explored as a new candidate gene for genetic testing of lymphedema patients.

CYP26B1 and its implications in lymphangiogenesis: Literature review and study of rare variants in two families

CYP26B1 is a member of the cytochrome P450 family and is responsible for the break-down of retinoic acid for which appropriate levels are important for normal development of the cardiovascular and lymphatic systems. In a cohort of 235 patients with lymphatic malformations, we performed genetic testing for the CYP26B1 gene. These probands had previously tested negative for known lymphedema genes. We identified two heterozygous missense CY-P26B1 variants in two patients. Our bioinformatic study suggested that alterations caused by these variants have no major effect on the overall stability of CYP26B1 protein structure. Balanced levels of retinoic acid maintained by CYP26B1 are crucial for the lymphatic system. We identified that CYP26B1 could be involved in predisposition for lymphedema. We propose that CYP26B1 be further explored as a new candidate gene for genetic testing of lymphedema patients.

Nutritional support in acute pancreatitis: from physiopathology to practice. An evidence-based approach

Acute Pancreatitis (AP) is a potentially fatal syndrome, associated with a hyper-catabolic state as well as early and late complications that may lead to multi-organ failure and death. Clinical researches produced in recent years suggest that acute pancreatitis may benefit from early oral or enteral nutrition. Nevertheless, many clinicians still believe erroneously that fasting - particularly in the early phase - may reduce AP complications and mortality. The goal of our review is to demonstrate that such false belief may harm the patients and that the whole management paradigm must change, adopting a more rational, evidence-based approach. First, we will describe AP physiopathology and the clinical assessment of its severity. Then we will discuss evidence-based data supporting early oral or enteral nutrition in AP. Finally, we will offer some practice recommendations as regards nutritional support.

[Diet and nutrition in nephrolitiasis]

Nephrolitiasis is a frequent metabolic disease, with a high rate of recurrences. Epidemiological studies reveal that about 80% of all kidney stones are composed of calcium salts (75% calcium oxalate), while about 5% are pure uric acid. Urolithiasis is a multifactorial disease with several underlying disorders of metabolism: that is why diet is an important treatment, especially in the prevention of recurrences. Nutritional intervention is based on a high water intake, physiological calcium intake, modest sodium and animal protein restriction and vitamin C intake <2 gr daily. In case of diagnosed disorders of specific metabolic pathways, a low oxalate, low purine-diet should be advisable.

[Diabetes and diet revisited]

In the treatment of diabetes the diet has an important role complementary to the pharmaceutical treatment. The diet must provide the right amount of nutrients and calories in order for the individual to reach and maintain the ideal weight, stabilize the blood glucose levels close to the norm, and attain an optimal lipid profile. The daily caloric intake is represented by 55-60% of carbohydrates with a preference for nutrients rich in fiber and with a low blood glucose index. Of the daily caloric intake 10% may include sucrose as long as it is consumed in the context of a balanced meal. A moderate use of fructose is allowed, and an increased intake of fiber is encouraged. The consumption of proteins represents about 10-15% of the daily caloric intake. A consumption close to the lower limits of the range (about 0,8 gr/kg of body weight) is required for diabetes patients with nephropathy, while a daily intake of 0,6 gr/kg of body weight is considered to be the malnutrition risk factor for lower levels. The total intake of fats required is < or = 30%, of which saturated fatty acids are less than 8-10% (with a further restriction to 7-8% for individuals with LDL cholesterol of > or = 100mg/dl and other cardiovascular risk factors), the polyunsaturated fatty acids less than 10%, and the monounsaturated fatty acids at 10-15% of the total caloric intake. The intake of cholesterol through the diet should be <300 mg/die and still lower (< 200 mg/die) for individuals with high levels of LDL cholesterol. Multivitamin supplements are recommended only for certain categories of diabetic patients that may be at risk of micronutrient deficiency. A moderate quantity of alcohol (5-15 gr/die) is allowed in the case of stabilized diabetes and lack of hypertrigliceridemia. Although the diet may determine a ponderal decrease of up to 10% of the initial weight, it is good to insert a correct nutritional program into a well defined behavioral program that, other than a reduced caloric intake, takes into consideration an increased energetic expenditure through physical activity.

[Nutritional genomics: toward a personalized diet]

Nutrigenomics is the application of high-throughput genomics tools to the study of diet-gene interactions in order to identify dietetic components having beneficial or detrimental health effects. Nutrition becomes indeed one of the environmental factors influencing gene expression. We can consider nutrigenomics as a multidisciplinary science that comes after the human genome characterization and that put the genomic techniques besides the biochemical and epidemiological aspects, with the aim to understand the etiologic aspects of chronic diseases such as cancer, type 2 diabetes mellitus (T2DM), obesity, cardiovascular diseases (CVD), metabolic syndrome, etc. Nutrigenomics is linked to nutrigenetics, which studies the genetic basis of the different individual response to the same nutritional stimulus. This phenomenon arises from gene polymorphism. As a consequence genes are important in determining a function, but nutrition is able to modify the degree of gene expression. These are however theories only at an early stage, but a perspective in the change of dietetic intervention is emerging. A really personalized diet will be a diet considering the nutritional status, the nutritional needs based on age, body composition, work and physical activities, but also considering the genotype. The integration of all these information and in particular the ones arising from genomic, proteomic and metabolomic analyses will be useful to define the "nutritional phenotype".

[Diet, nutrition and rheumatoid arthritis]

Rheumatoid Arthritis (RA) is a chronic inflammatory disease resulting in diarthrodial joints inflammation (particularly joints of hands, wrists, feet, knees, cubitus, ankles, shoulder, etc.) that is manifested by swelling and functional impairment. The associated complications, osteoporosis and cardiovascular disease, make RA important in public health terms. During the active phase of disease, elevated plasma concentrations of inflammatory cytokines, such as interleukin-6 (IL-6), interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha) and acute-phase proteins, lead to reduction of fat free body mass (FFM) with a loss mean of 15% of cell body mass (CM) and consequent reduction of muscle strength. The pharmacological therapy (non steroidal anti inflammatory drugs (NSAIDs), slow acting antirheumatic drugs and corticosteroids), have the potential to cause side-effects, such as gastrointestinal bleeding, bone loss beyond to increase the requirement of some nutrients and reduce their absorption. The diet may play role in the management of RA, particularly in alleviating the symptoms of the disease, combating the side-effects of therapy and reducing the risk of complications. The increase of the caloric and proteic intake is not sufficient to offset a increased metabolic rhythm and important proteic catabolism but a diet balanced may warrant an adequate intake of nutrients. The carbohydrates of the diet provide 55-60% of the caloric intake, the diet is normo-proteinic or hyper-proteinic in the active phase of disease, and lipids represent 25-30% of the caloric intake (saturated, monounsaturated, polyunsaturated fatty acids in the ratio 1:1:1). omega-3 fatty acids supplementation, in combination with reduction of fatty acids omega-6 and adequate intake of monounsaturated fatty acids induce improvement in symptoms and sometimes a reduction in NSAIDs usage. Proper antioxidant nutrients (Vitamin A, Vitamin C, selenium) may provide an important defence against the increased oxidant stress and a supplementation of folate and vitamin B12, in patients treated with methotrexate (MTX), reduce the incidence of side effects and offset the elevation in plasma homocysteine frequent in these patients. Calcium and vitamin D, in patients treated with corticosteroids, reduce the bone loss, while a supplementation with iron may prevent anaemia. Finally, elimination diets may be feasible therapy only in patients with positive skin prick test.

[Diet, nutrition and bone health]

Nutrition is an important "modifiable" factor in the development and maintenance of bone mass and in the prevention of osteoporosis. The improvement of calcium intake in prepuberal age translates to gain in bone mass and, with genetic factor, to achievement of Peak Bone Mass (PBM), the higher level of bone mass reached at the completion of physiological growth. Individuals with higher PBM achieved in early adulthood will be at lower risk for developing osteoporosis later in life. Achieved the PBM, it is important maintain the bone mass gained and reduce the loss. This is possible adopting a correct behaviour eating associated to regular physical activity and correct life style. The diet is nutritionally balanced with caloric intake adequate to requirement of individual. This is moderate in protein (1 g/kg/die), normal in fat and the carbohydrates provide 55-60% of the caloric intake. A moderate intake of proteins is associated with normal calcium metabolism and presumably does'nt alter bone turnover. An adequate intake of alkali-rich foods may help promote a favorable effect of dietary protein on the skeleton. Lactose intolerance may determinate calcium malabsorption or may decrease calcium intake by elimination of milk and dairy products. Omega3 fatty acids may "down-regulate" pro-inflammatory cytokines and protect against bone loss by decreasing osteoclast activation and bone reabsorption. The diet is characterized by food containing high amount of calcium, potassium, magnesium and low amount of sodium. If it is impossible to reach the requirement with only diet, it is need the supplement of calcium and vitamin D. Other vitamins (Vit. A, C, E, K) and mineral (phosphorus, fluoride, iron, zinc, copper and boron) are required for normal bone metabolism, thus it is need adequate intake of these dietary components. It is advisable reduce ethanol, caffeine, fibers, phytic and ossalic acid intake. The efficacy of phytoestrogens is actually under investigation. Some drugs may interfere with calcium and other nutrients and produce an unfavourable effect on bone health.

[Vitamin K-controlled diet: problems and prospects]

Different natural (phylloquinone and menaquinone) and synthetic (menadione) compounds carry out the same action of Vitamin K in the human body. Vitamin K is a substrate for the enzyme catalysing the posttranslational conversion of specific glutamyl residues to gamma-carboxyglutamyl residues in certain proteins connected with the coagulation (Factors II, VII, IX, X), the anticoagulation (Proteins C and S) and other organic functions (osteocalcin). Foods rich in Vitamin K (1/4) and the action of gut bacteria (3/4) can give rise to changes in Vitamin K status. Dietary factors, alterations of gut bacteria or/and troubles in the absorption of this vitamin can cause a lack, which at first interferes in the normal hemostatic function and later on it leads to modifications in the bone structure. Therefore, it is necessary to pay a lot of attention to dietary intake, adequacy, bioavailability, absorption and metabolism of Vitamin K and compounds with an action similar to it for understanding the signs of lack, choosing the most suitable therapy and managing accurately the coumarin-based oral anticoagulants.

[Dietetic management of cystic fibrosis: intervention strategies]

Cystic fibrosis is a systemic disease whose prognosis has improved thanks multidisciplinary researches and above all better knowledges and care of nutritional problems. It is important, for a good therapy, considering each case singularly, with a differentiated and individualized dietetic approach, which focuses on its specific needs and features. A "step by step" process could be useful to manage patient suffering from cystic fibrosis; it is based on 5 different patterns of possible nutritional dietetic methods. The development of the nutritional techniques of treatment for this kind of desease both with the individualized and differentiated approach have led to improve prognosis and especially the patient's standard of life.

[Dietetic indications for obesity treatment in childhood]

A growing organism needs to have a steady availability of nutrients, in suitable quantities and in correct ratios, in order to achieve its genetic potential. Overweight and obesity in growing individuals may conceal lack of one or more nutrients. Obesity in childhood is the consequence of an excess of calories compared with the energetic waste because of the interlacing of genetic factors, metabolic factors (cellularity of the adipose tissue, deficit of thermogenesis), excessive food intake, alteration of some neuro-endocrine mechanisms which regulate bodily weight (set point theory), lack of suitable physical exercise; therefore a complicity of endogenous, exogenous, biological, psychological and social factors to which we cannot ascribe singularly a primary role. It is however necessary to start, since the first year of a child's life, a food education program as the latest acquisition shows that degenerative pathologies of metabolism start in a very precocious age and unbalanced nutrition starts since childhood. The most suitable therapeutic approach is that which takes in consideration all the aspects of obesity. This requires an intervention on several aspects: food, psychological mechanisms which sometimes are the cause of hypernutrition, attitude towards physical exercise, and also family and social behaviors concerning the patient. The traditional diet approach towards childhood obesity is based on balanced hypochaloric diets which provide about 1200-1800 kcal per day, distributed in 4 or 5 daily meals. The correct meal division educates the child to self-control and it is advantageous from a metabolic point of view because it avoids both high instability of glyco-insulin, caused by an excess of food, and because improving thermogenesis, induced by the diet, the result will consist in an increase of energetic waste. For the main meals it is advantageous to apply to a main course.

[Endocrine obesity: bioelectric profiles (biotypes) detected in the body composition]

136 patients were selected (16 men and 120 women with non-specific menstrual disturbances) with a BMI (Body Mass Index) between 25 and 45 kg/m2, which were diagnosed with "disendocrinia" (GH deficit, hyperadrenocorticism, hypothyroidsm, hyperandrogenism, menstrual cycle disorders). The proposed approach, based on the visualization of the value distribution of the electric measures in different graphics, is able to immediately explain the bioelectric state of the individual's lean-mass. Subjects with hypothyroidism present, along with their overweight, less bio-conducting mass, with an altered fluid intra/extra-cellular distribution. Patients with hyperadrenocorticism show instead an hyperhydratation of the body mass, especially in the extracellular level. Patients with menstrual disorders (amenorrea, polycystic ovary syndrome, anovulatory cycle etc...) present a lean mass reduction (elevated Rs) and an increase of the intra-cellular compartment (elevated-Xc). Patients with hyper-androgenism (and hirsutism) show a characteristic bioelectric "pattern", with low Rs levels and high Xc levels. Subjects with GH deficit (men and women), has a trend of documenting bioelectric measures with lower lean mass and higher fat-mass. Different electric biotypes seem to characterize the body composition in the several endocrine disorders.

[Diet and management of degenerative diseases of the retina (retinitis pigmentosa)]

Considerable progress has been made in the understanding and management of degenerative diseases of the retina. The dietetic intervention has been favourably proposed in the most common forms of retinitis pigmentosa, a condition potentially leading to blindness. Vitamin A has been shown to be effective in delaying progression of the disease. In these patients such treatment is the only possible therapy, to date, and a lifetime generous supplementation of retinol is advisable, together with a vitamin A-rich diet and/or a dietary supplement (e.g. carrot flour) or pharmacologic supplement of vitamin A. Supply of vitamin A in doses up to 25000 IU (7500 igr/day), even for several years, has so far proved safe from risk of occurrence of liver disease. A possible effect on hypercholesterolemia related to a very prolonged treatment in predisposed individuals can be avoided by using a special diet, particularly enriched with beta-carotene. Guidelines for preparing a diet, specially formulated to provide an elevated weekly supply of vitamin and/or its precursor (equal to 15000 IU or 5000 microg of RE, retinol equivalent) and to control possible risk factors related to dietetic manipulation (supply of fat lower than 30% of total calories, variable levels of cholesterol and polyunsaturated fatty acids n-3, n-6) are presented. As long as resolutive therapy is lacking, dietetic intervention plays a primary role, although underestimated, in the management of the patients suffering from retinitis pigmentosa. The diet is specifically characterized by presence of food with a high content of carotenoids, substances with a favourable and additive effect.

[Malnutrition detected by "bioelectrical status" of total and segmental body mass to nutritional management of patients]

We examined 182 controls with Body Mass Index (BMI) between 20 and 25 kg/m2 and 246 hospitalised patients divided into 3 groups: the first one consisted of 70 severe malnourished with (BMI) < 20 kg/m2, the second one of 43 light malnourished with BMI between 20 and 25 kg/m2 and the last one of 133 obese with BMI > 25 kg/m2. The Resistance (Rs) and Reactance (Xc), with the Phase angle ((phi), are detected from total and segmental (Arm and "Trunk + Leg") body. We analysed electric parameters plotting them on 4 different graphs which reported the values of: 1) total Rs vs total Xc; 2) segmental Rs vs segmental Xc; 3) total Rs/height vs weight/ height; 4) total Xc/height vs weight/height. Rs and Xc were different in all groups: the severe malnourished patients (1st group) gave evidence of a paradoxical increase of Rs and a decrease of phi. The mean values decreased for the patient of the 2nd and 3rd group (the (phi reduced especially for the 2nd group). Referring to the segmental measures, "Trunk + Leg" biases total Rs and Xc much more than Arm. In addition the phi of "Trunk + Leg" is more similar to the total o than the Arm one. If compared with the total, this last one highly decreases in the patients of the 1st and 2nd group. We conclude that segmental bioelectrical values (Rs, Xc, phi) integrate the total one, because they allow to find out the correlation between total parameters and a specific body segment. Total and segmental Rs, Xc (and phi) values and segmental phi ratio are related to the malnutrition. The approach together with the analysis of the Graphics result to a prompt inspection of the individual bioelectrical status in subjects.

[Diet and chronic corticosteroid therapy]

Corticosteroid therapy is widely used in the acute and chronic treatment of different diseases, with consequent possible onset of typical side effects on multiple systems of the organism, including also energy metabolism and metabolism of water and minerals (sodium, potassium, calcium and phosphorus). Clinical signs, related to the type and dosage of the steroidal drug, may lead to secondary illnesses with variable degrees of severity, depending on proneness of the individual patient and on the underlying disease that motivated the treatment. The role of dietetic intervention in the management of a patient chronically receiving corticosteroid therapy is not ancillary, although often underestimated, its aim being the reduction of some long-term therapy related side effects, and the correction of major metabolic derangements. In particular, the diet shall be moderately rich in protein (1.5 g/Kg/day of proteins) and low in fat (< 30% of calories, obtained mostly from unsaturated fatty acids), based mainly on complex carbohydrates (80%), providing 50% of the caloric intake. Diet has to be specifically characterized by food containing little sodium and yielding high amounts of water, calcium, magnesium and potassium. Minor directions concern the reduced intake of ethanol and purines. The efficacy of supplementation with antioxidant vitamins (vitamin C and E) and selenium is currently under investigation.

[Strategy for safe nutrition in swallowing disorders]

Swallowing deficits may affect the ability of patients to feed properly and sufficiently, therefore inducing malnutrition. In order to provide effective and durable treatment, a team of experts should evaluate the swallowing function of each individual patient. Treatment protocols must be carefully analyzed, and adapted to progression of the disease. We refer paradigmatically to patients with Huntington disease, although indications may be conveniently extended to other patients with impaired transit of food.

[Dietetic management of patients with impaired swallowing]

Swallowing deficits may be present in patients with neurological, otolaryngoiatric or internal medicine diseases. These deficits impair their feeding capability, thus inducing malnutrition. Diet therapy in these conditions involves specific instructions for properly choosing, handling and eating food, in order to allow patients to preserve their autonomy and safety while eating, thus preventing malnutrition. We refer paradigmatically to patients with Huntington disease, which is the main neurologic cause of swallowing deficits, although these guidelines may be conveniently extended to other patients with impaired transit of food.

[Use of unconventional lipid substrates in parental nutrition]

In addition to the classic soybean oil fat emulsion, developed more than 40 years ago and still widely used, emulsions with other lipid substrates are available today for parenteral nutrition; these substrates implement the benefits offered by soybean oil when mixed with it in given proportions. Soybean oil triglycerides are rich in linoleic acid, a long chain omega-6 polyunsaturated fatty acid, which is essential and is an indispensable component of parenteral nutrition. However, very high doses of omega-6 polyunsaturated fatty acids should be avoided, particularly in some critical illnesses. Medium chain triglycerides, long well known to nutritionists and dietitians for their easy intestinal absorption, have become available in parenteral nutrition emulsions in a mixture with soybean oil. Medium chain triglycerides are completely and readily used for energy production and do not interfere significantly in the production of inflammatory mediators, in the composition of cell membranes and in body organ and system functions. Omega-3 polyunsaturated fatty acids, essential fatty acids derived from fish oil, permeate cell structure and affect cell activity with different mechanisms, playing also an important role in the modulation of inflammatory processes. Omega-3 emulsions in parenteral nutrition are currently added as a supplement to other fat emulsions. Knowledge of these "non-conventional" fat emulsions is being continuously improved by investigative work and clinical experience.

[Non-obese obese-like subjects: a new patient to be treated with diet]

Decreased insulin sensitivity patients, although normal-weight, are treated with a "prudent" hypocaloric diet and exercise, in order to reduce insulin resistance. Metabolic (glycolipidic) alterations can be easily diagnosed by combination of clinic and laboratory tests. A diet model aimed at controlling insulin levels and inducing a light weight loss is proposed.