Benign prostatic hyperplasia: a new metabolic disease of the aging male and its correlation with sexual dysfunctions

Abstract

Metabolic syndrome (MetS) is a well-recognized cluster of cardiovascular (CV) risk factors including obesity, hypertension, dyslipidemia, and hyperglycaemia, closely associated with an increased risk of forthcoming cardiovascular disease and type 2 diabetes mellitus. Emerging evidence indicates that benign prostate hyperplasia (BPH) and its related lower urinary tract symptoms (LUTS) represent other clinical conditions frequently observed in subjects with MetS. Several modifiable factors involved in MetS determinism, such as inadequate diet, lack of physical exercise, and smoking and drinking behaviours are emerging as main contributors to the development of BPH. The pathogenetic mechanisms underlying the connection between MetS and BPH have not been completely clarified. MetS and its components, hypogonadism, and prostate inflammation probably play an important role in inducing BPH/LUTS. Although historically considered as a "normal" consequence of the aging process, BPH/LUTS should now be faced proactively, as a preventable disorder of the elderly. Type of diet and level of physical activity are now considered important factors affecting prostate health in the aging male. However, whether physical exercise, weight loss, and modifications of dietary habit can really alter the natural history of BPH/LUTS remains to be determined. Further research is advisable to better clarify these points.

Figure 1

Association between insulin levels and prostate total or transitional zone volume. Association between insulin levels and prostate total (a) or transitional zone (b) volume. Insulin levels are reported as quartiles. All data are adjusted for age and total testosterone. Data are derived from a series of subjects seeking medical care for coupler infertility at our unit. The number of subjects with available parameters is reported in the inset. Note that the statistical analyses have been performed using insulin levels as a continuous variable, even if grouped in quartiles for graphical purposes.

Figure 2

Gene expression of sex steroid receptors (upper panel) and inflammatory markers (middle and lower panels) in prostate of rabbits fed a regular diet (RD) or a high fat diet (HFD), according to metabolic syndrome (MetS severity). MetS severity was categorized as previously described [138], according to the number of factors present (abscissa). Ordinate axis indicates level of mRNA expression in arbitrary unit, as derived from quantitative RT-PCR analysis of the indicated prostate samples. Level of significance was derived from Kruskall-Wallis analysis of the data.

Figure 3

Weighted differences (with 95% confidence interval (CI)) of International Prostate Symptom Score (IPSS; (a)) and maximum flow rate (Q _max⁡; (b)), for the studies on phosphodiesterase type 5 inhibitors (PDE5-Is) versus placebo. § no erectile dysfunction; §§ erectile dysfunction.

Figure 4

Graphical representation of a proposed multifactorial pathogenesis of benign prostatic hyperplasia/low urinary tract symptoms (BPH/LUTS). Symptomatic or asymptomatic prostate inflammation (very common in young individuals), in the presence of permissive factors such as metabolic syndrome (MetS), and in particular dyslipidemia, or an altered sex steroid milieu, can progress through prostate enlargement (BPE). The latter can or cannot be associated with LUTS, in particular in the presence of bladder dysfunction. Recent data indicates that MetS itself can also favour bladder alteration.