Plasma lipoproteins, glucose tolerance and insulin response in primary gout

Lipoproteins in patients with isolated hyperuricemia

BACKGROUND

There have been described abnormalities in the lipoprotein profile of hyperuricemic patients, it has not been clarified wether these abnormalities are due to the hyperuricemia or to the dyslipema often associated to these patients. Our aim is to study the apolipoprotein profile in hyperuricemic patients without dyslipemia compared to a control population.

PATIENTS AND METHODS

30 hyperuricemic patients and 26 healthy controls. Measurements were of blood uric acid, total cholesterol, total triglycerides, creatinine, HDL-C, and VLDL cholesterol, triglyceride, Apo B, Apo CII and Apo CIII (1 and 2). Uric acid clearance and fractionated excretion were measured in 24 h. urine samples.

RESULTS

No significant differences were found between hyperuricemic and control patients in cholesterol, triglycerides and apo B in VLDL, or LDL and HDL cholesterol. The levels of apo B, Apo AI levels and apo CIII/apo CII were similar in the hyperuricaemic and controls.

CONCLUSIONS

There are two types of hyperuricaemic patients, one group associated to hyperlipideamia and would be included in the X Syndrome. The other group not associated to other metabolic abnormalities. Is important to distinguish between these two groups to define the prognosis of a given patient because the greater cardiovascular risk linked hyperuricaemic patients could be related to the association to others cardiovascular risks factors.

Hyperlipoproteinaemia in primary gout: hyperlipoproteinaemic phenotype and influence of alcohol intake and obesity in Japan

Serum lipoprotein profiles were investigated in 108 male patients with primary gout before treatment to elucidate the prevalence of each individual phenotype of coexisting hyperlipoproteinaemia and pathogenic factors responsible for it. The mean serum triglyceride (TG) and total cholesterol (TC) levels in the patients with gout were 2.10 +/- 0.14 mmol/l and 5.26 +/- 0.10 mmol/l (mean +/- SEM) respectively, which were significantly higher (p less than 0.01 and p less than 0.05 respectively) than the levels in age matched controls without gout (1.30 +/- 0.07 mmol/l and 4.77 +/- 0.08 mmol/l respectively). Serum high density lipoprotein cholesterol (HDL-C) values were slightly decreased in patients with gout compared with controls (1.24 +/- 0.08 mmol/l v 1.40 +/- 0.03 mmol/l, p less than 0.05). Hyperlipoproteinaemia was seen in 61 patients (56%), of whom patients with type IIa, IIb, and IV hyperlipoproteinaemia formed 13, 15, and 69% respectively. Thus the prevalence of type IV hyperlipoproteinaemia was high in primary gout as compared with primary hyperlipoproteinaemia with primary hyperlipoproteinaemia (69% v 43%, p less than 0.01). The independent and relative influences of clinical data of the patients upon the concentrations of serum lipids were assessed by stepwise multiple regression analysis. Two major predictors of serum TG level were alcohol intake (p less than 0.01) and serum uric acid level (p less than 0.05). The most significant predictive variable was alcohol intake, but its influence was judged to be small (r2 = 0.067). None of the other variables, including obesity index, had any significant influence. The relationships between any of these variables and serum TC or HDL-C levels were not significant. In addition, serum lipid levels were investigated in patients with neither obesity (defined as 120% or more of ideal body weight) nor a history of alcohol intake. Their serum TG and TC concentrations were also significantly higher than the respective control levels. Thus hyperlipoproteinaemia in primary gout its unlikely to be secondary to excess alcohol intake or obesity, or both. Instead, it may result from genetic factors such as a combined hyperlipidaemic trait.

Serum lipids and lipoproteins in patients with primary gout

Serum lipid and lipoprotein values of 32 male patients suffering from gout were quantitated and compared with corresponding values of a random control group which did not differ significantly with regard to age, body weight index and socio-economic status. All patients were on therapy with allopurinol which lasted on average for 6 years. The most striking differences between patients and controls were the increased triglyceride and apo B values and the decreased HDL-cholesterol (HDL-C) and HDL-phospholipid (HDL-PL) values in the patient group. The values of total cholesterol, LDL-cholesterol, apo A-I and Lp (a) were not significantly different between patients and controls. The great differences in the ratios of apo B/LDL-C, apo A-I/HDL-C and apo A-I/HDL-PL values suggest that gout is connected with changes in the chemical composition of the major lipoprotein classes. In three normolipemic individuals who were treated for 3 weeks with allopurinol no changes in lipoproteins and apolipoproteins were apparent. The results are discussed in view of the atherosclerosis risk of patients suffering from gout.

Diffuse idiopathic skeletal hyperostosis and new bone formation in male gouty subjects. A radiologic study

Ninety-nine males with gout were identified and their radiographs examined for features of vertebral hyperostosis and entheseal changes (diffuse idiopathic skeletal hyperostosis, DISH). Of patients over the age of 45 years 43% fulfilled criteria for diagnosis of DISH. New bone formation in other regions of the skeleton was also common. The overhanging margin sign, seen in well developed tophi, was noted only in patients with prominent new bone formation elsewhere in their skeleton. Some of the radiologic manifestations of gout may be modified by a co-existent tendency, in these patients, to form new bone. It is suggested that a common metabolic factor, possibly hyperinsulinaemia, underlies the association of gout and hyperostosis.

The rheumatologic manifestations of diabetes mellitus

The rheumatologic disorders associated with diabetes mellitus have been reviewed. From the evidence presented, it can be concluded that neuroarthropathy and osteolysis are definitely assoicated with diabetes. Ankylosing hyperostosis and periarthritis probably represent valid associations, and possible, but still unproven associations exist for gout, pseudogout, the carpal tunnel syndrome, osteoarthritis, Dupuytren's contracture and joint contractures. Despite the lack of a proven pathophysiologic basis these interrelationships may be clinically relevant. The discovery of one of these disorders may provide a clue to underlying glucose intolerance, and idabetics should be followed with the knowledge that they are at risk for the development of certain musculoskeletal problems.

Effect of increased serum urate levels on virgin rats with no arteriosclerosis versus breeder rats with preexistent arteriosclerosis

Healthy virgin and breeder rats (Sprague-Dawley) with naturally occurring hypertension and arteriosclerosis were fed 5% oxonic acid and 1% uric acid added to their regular diet for 30 days. Although rats are able to convert uric acid into excretable allantoin, abnormal urinary and serum urate levels appeared. Males and females, virgins and breeders, differed in the severity of their increased urate levels. Animals with elevated urate levels developed hypertension, hyperglycemia, and hypertriglyceridemia, with only slight changes in cholesterol and free fatty acids. The kidneys were greatly enlarged and manifested medullary streaking indicative of urate deposits but were free of significant damage; BUN levels in these animals were abnormally high. Adrenal glands were reduced in size and depleted of lipid, circulating corticosterone levels were subnormal, and thymi were involuted. Serum enzymes CPK and LDH were greatly increased, whereas SGOT and SGPT levels were not elevated. The abnormal urate levels did not induce de novo arterial disease in the formerly healthy virgin rats and did not cause exacerbation of the pre-existing, naturally occurring arteriosclerosis characteristic of repeatedly bred rats. It is suggested that Sprague-Dawley rats are endowed with an especially efficient hepatic and renal capacity to metabolize uric acid. Increased urate levels in rats may have some direct metabolic relationship to the production of hypertension, hyperglycemia, and hypertriglyceridemia.

The effect of weight loss on plasma and urinary uric acid and lipid levels

Plasma uric acid levels in 35 obese gouty and non-gouty subjects showed a highly significant mean fall of 0.6 mg/100 ml after weight reduction on a low-calorie diet. Urinary urate also fell by a mean value of 87 mg/100 ml. Serum cholesterol and triglyceride levels have been studied in 20 of the subjects. Both have shown some overall fall with weight loss. So far the degree of change of plasma urate has shown a correlation with that of cholesterol but not that of triglyceride, but further data are needed on these inter-relationships.

Gout disease. Its natural history based on 1,000 observations

Gout disease in our country as both exogenous factors (dietary habits, professions, etc.) and endogenous factors (sex, inheritance, etc.) play a polygenic role in its incidence. Those conditions resulting in hyperuricemia (diseases, drugs, etc.) facilitate the clinical manifestations. But a genetic determinant in the articular reaction in front of an accumulation of uric acid crystals or in the development of such crystallization is a fundamental factor in the manifestation of the disease. In our series we were able to confirm the high incidence of arterial hypertension, renal lithiasis and renal participation in gout. The role of lead and of certain professions in favouring the hyperuricemia is suggested. A classification of gout, from a functional point of view, must include both the clinical form and the analysis of the whole renal function, and the renal handling of uric acid. This is mandatory not only for the diagnosis and prognosis of the disease but to set the basis of its adequate management.

Gout in Maoris

Historical evidence suggests that the Maori people of New Zealand were virtually untroubled by gout or obesity at a time when these disorders, along with other elements of the gouty diathesis, were rife in the best fed and hardest drinking sections of the Northern European population. By the mid 20th century, however, the apparent decline of the gout in Europe and North America and the breakup of the gouty diathesis in those lands had been more than compensated by their large-scale reappearance in the Maori and in other indigenous inhabitants of the Pacific Basin who, at first sight, appeared to have become one large gouty family. Half the Polynesian population of New Zealand, Rarotonga, Puka Puka, and the Tokelau Islands proved to be hyperuricemic by accepted European and North American standards, the associated gout rate reaching 10.2% in Maori males aged 20 and over. The trends towards hyperuricemia and gout, on the one hand, and towards obesity, diabetes mellitus, hypertension, and associated degenerative vascular disorders, on the other hand, which manifest themselves separately in some Polynesian Pacific Islanders, run together in the Maori and Samoan people, presenting a combined problem of considerable importance to the public health. The appearance of these traits under conditions of plenty in the descendants of hardy and wide-ranging Polynesian voyagers, suggests the emergence of a formerly favorable ancestral polygenic variation through selection for survival under harder conditions. This may now have lost its primitive survival value with a paradoxic shift towards increased prevalence of obesity and the gouty diathesis in more affluent environmental conditions. This may now constitute a genetic load, with recent environmentally determined increase in morbidity and mortality rates from degenerative vascular disorders. There is no satisfactory evidence that overproduction of uric acid differs in mechanism from its European counterparts, although more work remains to be done to determine whether there is any difficulty in renal handling of an increased uric acid load. A high Maori morbidity rate from gout and morbidity and mortality rates from associated components of the gouty diathesis in the face of readily available skilled medical advice and care, indicate the need for greater future attention to help education and health care delivery, at least while conditions of plenty continue. Continuation of previous epidemiologic surveillance may then be required in order to provide a continuing index of the effectiveness of these measures, as well as an opportunity for further research into the interrelationships of these associated disorders.