Kallikrein and Antibiotics in the Treatment of Infertile Men with Genital Tract Infections

Management of male factor infertility: position statement from the Italian Society of Andrology and Sexual Medicine (SIAMS) : Endorsing Organization: Italian Society of Embryology, Reproduction, and Research (SIERR)

PURPOSE

Infertility affects 15-20% of couples and male factors are present in about half of the cases. For many aspects related to the diagnostic and therapeutic approach of male factor infertility, there is no general consensus, and the clinical approach is not uniform.

METHODS

In the present document by the Italian Society of Andrology and Sexual Medicine (SIAMS), endorsed by the Italian Society of Embryology, Reproduction, and Research (SIERR), we propose evidence-based recommendations for the diagnosis, treatment, and management of male factor infertility to improve patient and couple care.

RESULTS

Components of the initial evaluation should include at minimum medical history, physical examination, and semen analysis. Semen microbiological examination, endocrine assessment, and imaging are suggested in most men and recommended when specific risk factors for infertility exist or first-step analyses showed abnormalities. Full examination including genetic tests, testicular cytology/histology, or additional tests on sperm is clinically oriented and based on the results of previous investigations. For treatment purposes, the identification of the specific cause and the pathogenetic mechanism is advisable. At least, distinguishing pre-testicular, testicular, and post-testicular forms is essential. Treatment should be couple-oriented, including lifestyle modifications, etiologic therapies, empirical treatments, and ART on the basis of best evidence and with a gradual approach.

CONCLUSION

These Guidelines are based on two principal aspects: they are couple-oriented and place high value in assessing, preventing, and treating risk factors for infertility. These Guidelines also highlighted that male infertility and in particular testicular function might be a mirror of general health of a man.

Kinin-enhancing drugs for unexplained subfertility in men

BACKGROUND

Oligo-astheno-teratospermia (sperm of low concentration, reduced motility and increased abnormal morphology) of unknown cause is common and the need for treatment is felt by patients and doctors alike. As a result, a variety of empirical, non-specific treatments have been used in an attempt to improve semen characteristics and fertility. One suggested treatment for idiopathic oligo- and/or asthenospermia is the administration of kallikrein (kallidinogenase), a kinin-releasing enzyme (or kininogenase). The kinin biological system is complex and involves kininogen (the substrate), kininogenases (the activating enzymes), kinins (the effectors) and kininases (the inactivating enzymes). All four components of the kinin system have been found in the genitalia and in semen. Kallikrein releases 2 major kinins, kallidin and bradykinin, from seminal plasma kininogens. Activated kinins in semen affect sperm motility and metabolism. In vitro addition of kallikrein to semen has been shown to have a positive effect on sperm motility, sperm velocity, cervical mucus penetration, penetration of zona-free hamster eggs and post-thaw survival and motility rate after semen cryopreservation. The latter observation, however, was not confirmed in a more recent comparison of motility stimulants for cryopreserved semen using computerised sperm motion analysis. In vitro treatment of semen with kallikrein has been employed in a clinical context during sperm preparation prior to insemination. Although the kinin system may also be involved in the regulation of spermatogenesis in vivo, a clear mechanism of action is missing. Multiple suggestions on how an increase in kinin levels in the genital tract influences spermatogenesis at the testicular levels have been made by various authors.

OBJECTIVES

To determine whether treatment of the male with drugs enhancing kinin levles increases pregnancy rates among couples where failure to conceive has been attributed to idiopathic oligo- and/or asthenospermia. Effects on sperm parameters and sex hormones were studied as secondary outcomes.

SEARCH STRATEGY

The Cochrane Subfertility Review Group specialised register of controlled trials was searched".

SELECTION CRITERIA

SIxteen RCTs on the therapeutic use of androgens (clomiphene citrate or tamoxifen) in subfertile men were identified. Six trials were excluded.

DATA COLLECTION AND ANALYSIS

Methodological characteristics of trials Baseline characteristics of the studied groups Outcomes: Pregnancy rates, semen parameters (sperm concentration, motility and morphology), endocrinology (serum FSH, testosterone and oestradiol)

Pharmacological characterization of kinin-induced relaxation of human corpus cavernosum

OBJECTIVE

To characterize the kinin receptor subtype involved in the relaxation of human isolated corpus cavernosum (HCC) induced by bradykinin (BK), Lys-bradykinin (Lys-BK), Met-Lys-bradykinin (Met-Lys-BK) and des-Arg9-bradykinin, and to investigate whether the kinin-induced relaxation of HCC results from the stimulation of nonadrenergic, noncholinergic (NANC) neurons supplying the cavernosal tissue.

MATERIALS AND METHODS

Excised HCC tissues were immediately placed in Krebs solution and kept at 4 degrees C until use (never > 24 h after removal). HCC was cut in strips of approximately 2 cm, suspended in a cascade system and superfused with oxygenated and warmed Krebs solution at 5 mL/min. After equilibration for approximately 90 min, noradrenaline (3 micromol/L) was infused to induce a submaximal contraction of the HCC strips. The release of cyclo-oxygenase products was prevented by infusing indomethacin (6 micromol/L). HCC strips were calibrated by injecting a single bolus of the nitrovasodilator glyceryl trinitrate (GTN) and the sensitivity of the tissues adjusted electronically to be similar. The agonists (kinins, histamine and acetylcholine) were injected as a single bolus (up to 100 microL) and the relaxation of HCC expressed as a percentage of the submaximal relaxation induced by GTN.

RESULTS

Bradykinin, Lys-BK and Met-Lys-BK significantly relaxed the HCC tissues; on a molar basis, there was no statistical difference among the degrees of relaxation induced by these peptides. The B1 kinin receptor agonist des-Arg9-bradykinin had no effect on the HCC. The infusion of the B2 kinin receptor antagonist Hoe 140 (50 nmol/L) virtually abolished the relaxation induced by BK, Lys-BK and Met-Lys-BK without affecting those induced by acetylcholine and histamine. The infusion of the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester increased the tone of the HCC tissues and significantly reduced (P < 0.01) the relaxation induced by BK (74%), Lys-BK (90%), Met-Lys-BK (87%) and acetylcholine (89%) without affecting those induced by GTN. The subsequent infusion of L-arginine (300 micromol/L) partially reversed the increased tone and significantly (P < 0.01) restored the relaxation induced by BK, Lys-BK and Met-Lys-BK. The results were similar with the novel guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo[4,3,-alquinoxalin-1-one] which reduced by > 95% (P < 0.01) the relaxation induced by BK, Lys-BK, Met-Lys-BK, acetylcholine and GTN. The infusion of the sodium-channel blocker tetrodotoxin had no significant effect on the BK-, GTN- and acetylcholine-induced relaxation of HCC.

CONCLUSION

This study clearly showed the existence of functional B2 kinin receptors in human erectile tissues that when activated lead to the release of NO and hence relaxation of the HCC tissues. As tetrodotoxin failed to affect the kinin-induced relaxation of HCC strips, it is likely that these peptides release NO from the endothelium of sinusoidal capillaries rather than from neuronal sources supplying the cavernosal tissue. Although tissue kallikreins and their components have been found in the male reproductive system, the physiopathological importance of these findings has yet to be elucidated.

Effect of antibiotic therapy in asthenozoospermic men associated with increased agglutination and minimal leukospermia

Thirteen patients with asthenozoospermia and semen analysis suggestive of infection were studied and divided at random into 2 groups according to the antibiotic treatment they received: (I) ciprofloxacine 250 mg every 12 hours by 14 days per os (n = 7) and (II) trimethoprim 160 mg and sulfamethoxazole 800 mg every 12 hours by 14 days per os (n = 6). Their couples received the same treatment. Changes in sperm density, morphology, viability, motility, agglutination, pH, and presence of leukocytes were analyzed before and after treatment. The average of morphologically normal sperms significantly decreased after treatment in the ciprofloxacine group; sperm with grade III motility increased in the trimethoprim-sulfamethoxazole group, but without statistical significance. With these preliminary results, it can be concluded that antibiotic administration modifies some of the spermatic parameters, particularly motility and morphology, in patients whose semen analysis parameters suggested infection.

Penetration capacity of spermatozoa from patients with oligoasthenoteratozoospermia into bovine cervical mucus before and after therapy with kallikrein

Due to the high degree of subjectivity involved in quantifying sperm motility by light microscopy, it appeared of interest to compare the results obtained with a bovine mucus penetration test (Penetrak) to those of routine laboratory measurement before and after therapy with kallikrein (600 U/day). The study included 45 patients with oligoasthenoteratozoospermia (OAT syndrome) in the absence of genitourinary pathology or abnormal serum hormone levels. Infertile partnership has lasted for a mean of 3.2 years. Analysis of spermiograms and the penetration test were performed before and after 3 months of treatment. Neither of these techniques revealed significant alteration after treatment, nor was there a demonstrable success during the observation period in terms of pregnancy. Judging from these results, (1) kallikrein has no effect in patients with OAT syndrome and (2) the penetration test provides no additional information on the biological quality of ejaculate.

Infertility treatment: from cookery to science. The epidemiology of randomised controlled trials

OBJECTIVES

To review the epidemiology of published randomised controlled trials in infertility treatment over the last 25 years, with special emphasis on the number and quality of trials.

DESIGN

Computer literature review by MEDLINE backed up by a manual search of 41 journals. Each trial was classified according to the methodology described and quality criteria. The results were recorded in a computer database. Odds ratios (OR) and confidence intervals (CI) were calculated where the data were sufficient.

SUBJECTS

Couples suffering from primary or secondary infertility. The trials studied 33,761 patients overall.

SETTING

Institute of Epidemiology and Health Services Research, Leeds.

RESULTS

Five hundred and one randomised trials in male and female infertility treatment were identified between 1966 and 1990. Pregnancy was an outcome in 291 (58%) and these were the subject of detailed analysis. Two hundred and twenty-four (77%) and 67 (23%) 'pregnancy trials' were concerned, respectively, with female and male infertility. Four per cent of the trials were preceded by a sample size calculation, and the average sample size was 96 patients (range 5-933); 700 patients per group would be required to demonstrate plausible success rates for most treatments. The method of randomisation was unstated or pseudo-randomised in 206 (71%) of trials where pregnancy was an outcome. Only 29 (5.8%) of studies were multicentre. The method of confirmation of pregnancy was omitted for 70% of papers. Cross-over design was used in 103 (21%) of cases. Meta-analysis is possible for selected topics such as the use of anti-oestrogens in idiopathic oligospermia and unexplained female infertility. Eight cases of double reporting were identified.

CONCLUSIONS

Trials using randomised methodology were relatively few in comparison with other branches of medicine, although their use is important in the evaluation of treatment for infertility as treatment-independent pregnancy is common. It was encouraging to note that an exponential increase in the use of this methodology occurred during the last three years, especially in association with assisted conception techniques, and meta-analysis has become possible for selected topics. However, many trials suffer from an unrealistically small sample size, inappropriate use of cross-over design or pseudo-randomisation. The trend towards properly controlled studies should be encouraged but these studies should be of improved quality and organised on a multicentre or even international basis.

Molecular cloning and sequence analysis of the monkey and human tissue kallikrein genes

Cynomolgus monkey renal kallikrein cDNA and genomic human tissue kallikrein gene were cloned. The monkey gene encodes a 257 amino acid (aa) preprokallikrein and exhibits 95% and 92% homology to the human at nucleotide (nt) and aa level, respectively. The monkey gene encodes a 233-aa mature kallikrein versus a 238-aa in human. The human kallikrein gene and urinary kallikrein both contain a Lys-162 instead of the reported Glu-162. Human, monkey and rat renal/pancreatic kallikrein genes evolve with a N-glycosylation containing domain (aa 81-87) which is absent in porcine and is non-glycosylable in mice. Only human kallikrein evolves with an additional Thr-108 and with a N-glycosylation site at aa-141.