The effect of long-term hypogonadism on body composition and morphometry of aged male Wistar rats.

Clinical studies show that hypogonadism in the aging male is associated with obesity and osteoporosis. Experimental studies are mostly conducted on relatively young adult animals and the induced hypogonadism lasts for a relatively short time. The present study aimed to describe the effect of long-term hypogonadism beginning in puberty on body composition, morphometry, and bone mineral density in aged male rats. Morphometric measurements and dual-energy X-ray absorptiometry were conducted at the age of 30 months on control and gonadectomized males. Long-term hypogonadism did not affect body weight, but led to a higher fat mass (by 26 %), lower lean mass (by 44 %), shorter body length (by 9 %), and anogenital distance (by 26 %), as well as to lower tail circumference (by 15 %) in comparison to control males. Lower bone mineral density (by 13 %) and bone mineral content (by 15 %) were observed in gonadectomized males. Results showing sarcopenic obesity and osteoporosis in this model of long-term hypogonadism might mimic the situation in aging males better than the widely used short-term hypogonadism induced in young animals. The morphometric analysis could potentially be a useful tool to study normal weight obesity without the need for specific equipment.

Insulin resistance and vitamin D deficiency in patients with chronic kidney disease stage 2-3.

Vitamin D status and the relationship between serum 25(OH) vitamin D concentrations and the components of insulin resistance were examined in 120 patients with chronic kidney disease stage 2 and 3. Insulin sensitivity/resistance was calculated by the quantitative insulin sensitivity check index (QUICKI). In this analysis, the prevalence of insulin resistance was 42 %. Only 17 % of patients had serum 25(OH) vitamin D concentration in the recommended range (>/=30 ng/ml), 42 % suffered from vitamin D insufficiency and 41 % had moderate vitamin D deficiency. Insulin resistance significantly correlated with serum 25(OH)D and 1,25(OH)(2)D concentrations, renal function and protein excretion rate. Our results support the increasing evidence that vitamin D deficiency may be one of the factors participating in the development of insulin resistance already in the early stages of chronic kidney disease.

Mitochondria and mitochondrial nitric oxide synthase alterations participate in energetical dysbalance, aging and age-related diseases.

Nitric oxide (NO) is a unique mediator of cellular regulations synthesized by nitric oxide synthases (NOS) present in cytoplasm of various cells. An additional Ca-dependent mitochondrial NOS (mtNOS) detected just recently synthesizes also NO inhibiting oxidative phosphorylation, i.e. mitochondrial energy producing metabolic process and protects mitochondria from oxygen radicals. Mitochondrial membrane possesses electrogenic uniporter transporting Ca into mitochondria (stimulation of mtNOS), while Na+/Ca2+ exchanger removes Ca from mitochondria. Mitochondrial disorders with low mtNOS activity participate in accelerated aging and age-related diseases. The direct NO balance determination is outside of the standard clinical facilities; Indirect alternatives, such as insulin resistance determination are accessible. Pharmacotherapy exploits effective therapeutic and preventive measures (NO donors, ACEI inhibitors, etc.) and pharmaceutical approach (development of mitochondriotropic drugs). We suggest, that mitochondrial disorders participate in aging and age related diseases and propose that the early diagnostics, preventive and therapeutic measures could prevent and even correct at least partially the development of age-related diseases (Tab. 4, Ref. 81).

Calcitriol load test in postmenopausal osteoporosis: a pilot study.

BACKGROUND: Calcium and vitamin D balance is of critical importance in both, prevention and treatment of osteoporosis. The evaluation of this balance is difficult under steady state conditions, therefore the effect of a single oral calcitriol load in postmenopausal women with osteopenia/osteoporosis was used. METHODS: Mineral and hormone concentrations were determined under basal conditions and after the administration of a single 0.5 microg calcitriol dose (Rocaltrol, Roche). RESULTS: Single oral calcitriol dose was administered to 36 postmenopausal women. Increased calciuria (p < 0.001) and calcium fractional excretion (p < 0.001) 24 hours after drug administration indicated kidney participation in calcium homeostasis. Urinary calcium excretion after the calcitriol load correlated with basal urinary calcium excretion (r = 0.772; p < 0.001). On the basis of calciuric response, women could be separated to responders and non-responders; in responders, increase in calciuria was >1.0 mmol/d, while in non-responders < 1.0 mmol/d (p < 0.001). Neither plasma calcium nor plasma 25-hydroxycholecalciferol concentrations increased after the calcitriol load. Both basal (r = -0.361; p < 0.03) and calcitriol stimulated urinary calcium excretion correlated inversely with age (r = -0.425; p < 0.01). No significant changes in measured mineral and hormone parameters were found in women with osteopenia in comparison to women with osteoporosis, with the exception of plasma intact parathormone concentration, which was significantly higher in osteoporotic women (p < 0.05) and significantly decreased (p < 0.001) after the calcitriol load. CONCLUSION: Postmenopausal women suffered from calcium and vitamin D imbalance which could be elucidated by a simple calcitriol test. The reference range, significance and differentiation from other abnormalities are to be defined in an extensive study. (Tab. 4, Ref. 19.).

[Intensive vitamin D supplementation in the treatment of osteoporosis]. / Intenzifikovaná suplementácia vitamínom D v liecbe osteoporózy.

Vitamin D deficiency is not possible to correct with the nutritional vitamin D doses in postmenopausal women with decreased bone mineral density. The aim of study was to evaluated the effectivity and safety of 15,000 IU/week vitamin D administrated in 52 postmenopausal women with osteopenia or osteoporosis. Patients were divided into two groups. Treated group was supplemented by calcium 0.5 g/d and 25-hydroxycholecalciferol 15,000 IU/week and control group was supplemented by calcium and placebo for two months. Plasma calcium concentration did not change in the vitamin D treated group while it decreased (p < 0.001) in the control group. Neither calciuria nor fractional excretion of calcium changed during the treatment period. Plasma inorganic phosphate concentration did not change in any group, but urinary inorganic phosphate excretion increased in the vitamin D treated group (p < 0.001). The starting 25-hydroxycholecalciferol plasma concentrations were almost at the deficiency range in both groups. The 25-hydroxycholecalciferol plasma concentration increased substantially (p < 0.001) in the treated group, but it remained at the starting level in control group during the treatment period. Similar plasma concentration increase (p < 0.001) was apparent also in 1.25-dihydroxycholecalciferol. Plasma intact parathormone concentration did not change in the vitamin D treated patients, while it increased (p < 0.01) in the control group. None of the vitamin D treated women suffered from hypercalcemia and mild hypercalciuria was observed in one patient. In conclusion, the study presents an evidence on the effectiveness and safety of 15,000 IU/week 25-hydroxycholecalciferol dosage schedule.

Insulin resistance in kidney disease patients with mild to moderate kidney disease.

BACKGROUND: Insulin resistance is a very early sign of atherosclerosis and an increased risk of cardiovascular morbidity and mortality. Insulin resistance detection by the fasting plasma insulin and glucose determination enables early detection, follow-up, treatment and the search for accelerating factors in kidney disease patients threatened by atherosclerosis. PATIENTS AND METHODS: Insulin resistance was evaluated by the Quantitative Insulin Sensitivity Check Index from fasting glucose and insulin plasma concentrations in 66 kidney disease patients with a mild to moderate decrease in kidney function. RESULTS: Forty patients were insulin sensitive and 26 suffered from insulin resistance. These groups of patients did not differ significantly in age, gender, clearance of creatinine and cholesterol concentrations. However, patients with insulin resistance suffered from increased BMI (p < 0.001), fasting plasma glucose (p < 0.01), insulin (p < 0.001) and triglyceride (p < 0.01) concentrations. Insulin resistance correlated with BMI (r = -0.417, p < 0.001) and with plasma triglycerides concentration (r = -0.307, p < 0.01). The absent relationship between insulin resistance and age (r = -0.154, NS) or creatinine clearance (r = -0.061, NS) suggests the need for screening of insulin resistance even in young patients with mild kidney function reduction. CONCLUSION: A considerable number of renal patients in the early stages of kidney function reduction suffers from insulin resistance. They need to improve their life style and take medication (i.e. antihypertensive drugs) improving insulin sensitivity and to omit medications which harm it. (Fig. 2, Tab. 1, Ref. 20.)

Kidney function and age related mineral imbalance in postmenopausal women with osteopenia/osteoporosis.

BACKGROUND: Negative mineral balance in postmenopausal women appears to be an important risk factor for osteoporosis and subsequent bone fractures. Its pathogenesis has not been elucidated. OBJECTIVES: To elucidate the participation of the kidney and ageing on mineral balance in postmenopausal women. METHODS: 36 postmenopausal women with osteopenia or osteoporosis, aged 46-75 years were evaluated by determination of mineral balance, kidney functions, 25(OH)-cholecalciferol [25(OH)D], 1,25(OH)2-cholecalciferol [1,25(OH)2D] and intact parathormone plasma levels. RESULTS: Plasma calcium (Ca) concentrations were low and they did not decrease further with ageing. Urinary Ca excretion decreased (r = -0.425, p < 0.01) with age without changes in the fractional excretion of Ca. A similar decrease of urinary excretion was found in the urinary excretion of phosphorus (Pi) (r = -0.335; p < 0.03) and magnesium (Mg) (r = -0.355; p < 0.03). All patients' kidney functions were in the age-related reference range. Plasma 25(OH)D concentrations were in the range of moderate to severe deficiency, related inversely to age (r = -0.357; p < 0.03) and Ca urinary excretion (r = 0.343; p < 0.04) and to plasma creatinine concentration (r = 0.381; p < 0.02). Plasma 1,25(OH)2D concentrations were also low, they did not change with age and were highly correlated with Ca urinary excretion (r = 0.458; p < 0.005). The intact parathormone (iPTH) plasma concentrations were in the reference range, without any changes during aging. CONCLUSIONS: Pi, Mg and dominantly Ca imbalance in postmenopausal women with osteopenia or osteoporosis accentuates with age and besides their insufficient intake the vitamin D deficiency takes part. These data support the need for increased supplementation of Ca and vitamin D with increasing age. (Tab. 3, Fig. 4, Ref. 18.).

Does magnesium dysbalance participate in the development of insulin resistance in early stages of renal disease?

We investigated the potential role of magnesium (Mg) dysbalance in the pathogenesis of insulin resistance (IR) in patients with mildly-to-moderately decreased renal function (creatinine: 142.8+/-11.0 mmol/l). The data were compared to those of 8 age- and sex-matched healthy controls (CTRL). The standard oral glucose tolerance test (oGTT) was performed in 61 patients. Twenty-two patients were classified as IR according to their values on fasting and after-load immunoreactive insulin concentrations. Serum and total erythrocyte Mg (tErMg) (atomic absorption spectro-photometry) and free erythrocyte Mg (fErMg) concentrations ((31) P NMR spectroscopy) were determined prior to and two hours after the glucose load. Ten out of 39 insulin-sensitive (IS) patients, but only one out of 22 insulin-resistant (IR) patients, had a low basal fErMg concentration (<162.2 micromol/l, chi2, p<0.01). IR patients had higher serum Mg, total erythrocyte Mg and bound erythrocyte Mg (bErMg) concentrations (both before and after glucose load) when compared with the IS group. Both groups responded to the glucose load with a significant decrease in serum Mg concentration (within the normal range), while the IR group also exhibited a decline in tErMg and bErMg. The mean sum of insulin needed to metabolize the same glucose load correlated positively with tErMg (r=0.545, p<0.01) and bErMg (r=0.560, p<0.01) in the IR patients. It is concluded that, at an early stage of renal dysfunction, IR is not associated with the decline in free erythrocyte Mg concentration, but the magnesium handling in red blood cells is altered.

[Nephrologic manifestations of mitochondrial diseases]. / Nefrologické manifestácie mitochondriálnych chorôb.

Mitochondrial diseases, rated as rarities in paediatrics and neurology, become more and more often diagnosed in various body systems. In nephrology, mitochondrial defects play an important role in the pathogeny of tubular syndromes, interstitial nephritis, focal and segmental glomerulosclerosis, and probably also some other diseases. Review is aimed to point out such defects and to form conditions for their diagnosis and therapy.

Acute effect of hydrochlorothiazide on renal calcium and magnesium handling in postmenopausal women.

A single 50 mg dose of hydrochlorothiazide (HCTZ) decreases the urinary excretion of calcium (U(Ca)V), clearance (C(Ca)) and fractional excretion (FE(Ca)) of calcium. This is accompanied by an increase of total calcium and ionized calcium (Ca2+) concentrations in the serum. On the other hand, HCTZ increases fractional excretion of magnesium (FE(Mg)) and decreases serum Mg2+ concentrations. Moreover, HCTZ decreases markedly clearance of phosphate (C(Pi)) and fractional excretion of phosphate (FE(Pi)) and increases serum phosphate (Pi) concentrations in healthy postmenopausal women. It is concluded that intrinsic renal cellular control promptly uncouples calcium and magnesium tubular reabsorption even without K+ depletion.

31P NMR investigation of free intracellular magnesium, pH and energy balance in striated muscle of patients with kidney disease: relation to insulin resistance.

BACKGROUND: High prevalence (48%) of insulin resistance (IR) in patients with mild to moderate kidney function reduction, and the potential pathogenetic role of magnesium (Mg) deficiency in IR prompted us to study skeletal muscle free Mg (fMg) concentration in patients with impaired kidney function. METHODS: fMg concentration, intracellular pH (pHi) and parameters of energy balance were determined employing 31P NMR spectroscopy in the calf muscle of the dominant leg of 18 healthy controls (C) and 22 patients (P) with decreased kidney function. 10 patients suffered from insulin resistance (IR). RESULTS: No difference in fMg concentration in skeletal muscle was observed (C: 0.929 +/- 0.075; P: 0.948 +/- 0.062 mmol/l; x +/- SEM). In patients a slight shift of pHi towards acidic values was found (C: 7.036 +/- 0.0.004; P: 7.013 +/- 0.004; p < 0.004), which was even more expressed in IR patients (7.008 +/- 0.005). Serum creatinine levels and creatinine clearance correlated with pHi in the patient's group. Adenosintriphosphate (ATP) to inorganic phosphate (Pi) ratio in skeletal muscle was lower, phosphocreatine (Pcr)/ATP ratio was higher, while that of Pcr/Pi showed only a trend towards an increase in the patient's group. CONCLUSION: In patients with reduction of kidney function IR does not associate with a change in skeletal muscle free magnesium concentration, or deficiency in macroergic phosphate levels. Shift in intracellular pH towards acidic values may participate in IR. Decreased activity of Na+/H+ antiporter is suggested. (Fig. 5, Tab. 2, Ref. 22.)

[New perspectives of treatment of osteoporosis with thiazides]. / Nové perspektívy liecby osteoporózy tiazidmi.

Thiazides inhibit calcium and magnesium excretion, the basic substrates of bone mineralization. Clinical investigations pointed already previously to their effectiveness in the prevention and treatment of osteoporosis despite a relatively small effect on the balance. This aroused some distrust and prevented their acceptance among preparations with this indication. They were indicated mainly in patients with hypercalciuria. The results of recent research indicate however their direct inhibition of osteoclasts and in particular stimulation of osteoblasts. This confirms results of clinical investigations which could not be explained previously. It may be foreseen that within a short time thiazides will become an important member in the spectrum of drugs used for the treatment of osteoporosis.

Dietary protein restriction in combination with angiotensin converting enzyme inhibitor improves insulin resistance in patients with chronic renal disease.

Insulin resistance (IR) and secondary hyperinsulinaemia are major risk factors of atherosclerosis and probably also of related glomerulosclerosis. Angiotensin converting enzyme inhibitors (ACEI), while improving IR in essential hypertension, do not improve it in patients with chronic renal disease. Thus, the combination of ACEI and low protein diet was evaluated. Thirty-eight patients with various kidney diseases and mild to moderate impairment of kidney function were included in the study. Thirteen of them suffered from IR. Their dietary protein intake was decreased from > or = 1.0 g/kg/d to 0.6-0.7 g/kg/d. Moreover, they were treated by ACEI enalapril at dosages of 2-10 mg/d depending on the absence/presence and severity of hypertension. The patients were followed for 8 months. No clinically relevant kidney disease progression (KDP) was found. IR patients improved remarkably. IR was examined by the oral glucose tolerance test and glucose, insulin and C-peptide determinations. Their increased plasma triglyceride, VLDL concentrations and proteinuria decreased, HDL concentration increased. Acid-base balance and anaemia did not change. It is concluded that protein restriction in combination with ACEI treatment improve IR and the associated dyslipoproteinaemia and proteinuria.

[A protein-restricted diet combined with ACE inhibitors does not improve insulin sensitivity in renal hypertension]. / Diéta s obmedzeným prívodom bielkovín v kombinácii s ACEI nezlepsuje inzulínovú senzitivitu pri nefrogénnej hypertenzii.

Hypertension is one of the most important accelerating factors for progression of nephropathies. Its prevalence is about 35% in patients with nephropathies, even in minor or medium severe functional impairment. This is evidence that it is essential to select an optimal therapeutic regimen as soon as possible. A group of 38 patients (14 hypertensive patients) with a minor or medium severe functional impairment were included in a controlled trial. The patients were served a low-protein diet--0.6-0.7 g/kg/day and 2-10mg enalapril/day divided into two doses. The amount of enalapril depended on the blood pressure and enalapril was given also to normotensive patients. The investigation lasted 8 months. In the course of 8 months the authors did not reveal progression of the renal disease, as apparent from results of assessment of the creatinine level and clearance, assessment of uric acid and urea. The authors did not find deterioration of metabolic acidosis, nor of nephrogenic anaemia. Hypertensive patients had a tendency to deteriorating of insulin sensitivity while in normotensive patients a decline of triacylglycerols, VLDL and rise of HDL was recorded. The total cholesterol and LDL cholesterol level did not change. The authors conclude that the combination of a low-protein diet with ACEI in hypertensive and normotensive patients with mild to medium severe functional disorders inhibits the progression of nephropathies, but in hypertensive patients it does not prevent deterioration of insulin sensitivity.

[Insulin resistance in kidney diseases]. / Inzulínová rezistencia pri chorobách obliciek.

Insulin resistance (IR) is found in different kidney diseases in almost half the patients with mild to medium severe disorders of renal functions; in advanced renal failure it is almost constant. In addition to pathogenetic mechanisms known in other diseases of Reaven's syndrome it has some specific features: Already in the early stages calcitriol production is impaired, and if the calcium intake is not increased and calcitriol is not substituted, secondary hyperparathyroidism with osteodystrophy develops. The intracellular concentration of free Ca increases and the intracellular concentration of free Mg declines. Activation of the renin angiotensin system (RAS) stimulates Ca release from intracellular reserves and potentiates thus the cumulation of free Ca in the cytoplasm. Magnesium plays a special part as it influences glucose utilization by several mechanisms. Diagnosis, prevention and therapy of IR are an essential part of comprehensive prevention of progressing nephropathies with a predicted decline of patients requiring dialysis by cca 30% by the year 2000. This calls, however, for concentrated efforts of all health professionals.

[Insulin resistance: its clinical importance and trends in modern research]. / Inzulínová rezistencia: klinický význam a smery súcasného výskumu.

Insulin resistance is the major pathogenetic link of atherosclerosis development and progression. The clinical diagnosis is made on the basis of analysis of glycemic and insulinemic response during the oral glucose tolerance test. Insulin resistance prevalence is constant in NIDDM and advanced renal failure, and almost 50% in early stages of essential hypertension and kidney diseases. Its prevention and therapy are effective. The increase of free Ca and decrease of free Mg concentrations participate both in insulin resistance and hemodynamic changes in diseases of the Reaven's syndrome. The intracellular mineral dysbalance is caused by the alteration of Na+,H(+)-antiporter. (Fig. 1, Tab. 4, Ref. 51.).

The prevalence of insulin resistance in essential hypertension.

The prevalence of insulin resistance and/or glucose intolerance (IR/GI) was evaluated in 98 patients with essential hypertension of various stages: a) Almost 35% of them had an abnormal or diabetic glucose tolerance test and 47% of the total number suffered from either/both IR/GI. b) The prevalence was high from stage I essential hypertension, which pointed to an early development of IR/GI, and no further increase during the development of hypertension was found if no antihypertensive drugs influencing IR/GI were taken by the patients. c) Obesity doubled the prevalence of IR/GI. d) No changes in total and HDL cholesterol or triglycerides were found in patients with IR/GI or stage-dependent. e) The presented criteria could be used for the diagnosis of IR/GI in clinical practice.

Magnesium deficiency impairs rat soleus muscle glucose utilization and insulin sensitivity.

Insulin resistance (IR), probably a common pathway of atherosclerosis development in various diseases, was suggested to be related to magnesium (Mg) deficiency. The in vivo observations required an in vitro extension. The study was performed on isolated rat soleus muscle incubated in Ringer bicarbonate with/without Mg. Mg deficiency inhibited basal, insulin- and tolbutamide-stimulated glucose utilization. Insulin-stimulated glucose utilization was inhibited even in the case that insulin was given to rats before sacrifice. Similar inhibition of glucose utilization was found in Ca deficiency and the simultaneous lack of Mg had no additive effect. It is concluded that Mg deficiency inhibits glucose utilization at the level of Ca mediation of glucose transport regulation.

[Enalapril in the treatment of nephrogenic hypertension]. / Enalapril v liecbe nefrogénnej hypertenzie.

In a half-year open clinical study the authors investigated the antihypertensive action of enalapril--an inhibitor of the angiotensin converting enzyme--and its action on renal functions in a group of 11 patients with nephrogenic hypertension. In seven patients monotherapy, using a mean dose of 12 mg, was sufficiently effective. In the remaining four patients treatment was combined with diuretics. It was revealed: that: 1. a significant drop of systolic and diastolic pressure occurred with a concurrent decline of the total peripheral vascular resistance, 2. a slight (statistically not significant) reduction of the glomerular filtration as well as quantitative proteinuria with a decline of glomerular hypertension. 3. In this group of patients without left ventricular hypertrophy no signs of regression of its mass were present. 4. Even in patients with nephrogenic disease no negative effect on the lipid, carbohydrate and purine metabolism was observed. The subjective tolerance of the preparation was very satisfactory.

Metabolic effects of enalapril in the treatment of essential hypertension.

In an open two-month study with an initial placebo period, the effect of enalapril on glucose tolerance, insulin (IRI) sensitivity and lipid profile was evaluated in 20 patients with mild to moderate essential hypertension. The following results were obtained: 1. Enalapril produced a favourable effect of blood pressure both in monotherapy and if combined with a diuretic. 2. Therapy did not lead to significant differences in blood glucose, IRI or IRI/glucose increase at 1 or 2 hours of oral glucose tolerance test either in patients with monotherapy or combination therapy, and with normal or disturbed glucose tolerance, respectively. 3. Serum lipids (total and HDL-cholesterol and triglycerides) did not change significantly in any group of patients.