Short-Term Daily Intake of Polydextrose Fiber Does Not Shorten Intestinal Transit Time in Constipated Adults: A Randomized Controlled Trial.

Chronic constipation (CC) remains a common gastrointestinal (GI) disorder that conveys a substantial healthcare burden. Expert guidelines recommend increasing fiber intake, yet the clinical evidence to support this needs strengthening for specific fibers. The aim was to evaluate changes in intestinal transit time and GI symptoms in CC patients who consumed polydextrose. In a randomized, double-blind, placebo-controlled trial, 128 adults with CC received 8 g or 12 g polydextrose, or placebo, daily for 4 weeks. Transit time, as primary outcome, was assessed by radiopaque marker distribution after 2-weeks intervention. Bowel habits, GI symptoms and quality of life (QOL) were assessed by questionnaire, including the Patient-Assessment of Constipation (PAC) Symptoms (SYM), and PAC-QOL. Following 2-weeks intervention, no reduction was seen in transit time in any group and following 2- or 4-weeks intervention, no improvements were seen in stool frequency or consistency in any group. After 2-weeks intervention with 8 g/day polydextrose an improvement was seen in the PAC-SYM rectal score (p = 0.041). After 4-weeks intervention both rectal (p = 0.049) and stool (p = 0.029) scores improved while improvement in the QOL satisfaction score did not reach significance (p = 0.071). Overall, the results suggest that 2-weeks consumption of 8 or 12 g/day polydextrose does not significantly improve physiological measures of gut function in CC adults. Longer term consumption may improve clinical measures, but further studies will be required to substantiate this.Nestec SA

Identification and Functional Characterization of a Novel Activation Cascade of the KLK Family in Seminal Plasma

Proteolytic processes are often mediated by highly orchestrated cascades, through which protease enzymes function coordinately to ensure a stepwise activation. This thesis presents experimental data which supports and complements the previously postulated mechanism of KLK (kallikrein-related protease) activation through proteolytic cascades. Further examination of the seminal KLK cascade has revealed several of its key (patho) physiological roles in human reproductive system. Multiple members of the seminal KLK cascade, in particular KLK14, were shown to play a pivotal role in regulating semen liquefaction. The cascade was further shown to be tightly regulated through a series of highly orchestrated feedback loops, to prevent deleterious effects due to aberrant protease activation. Accordingly, a strong association was observed between the expression level of several seminal KLKs, delayed liquefaction, and other markers of semen quality, including semen hyperviscosity. Furthermore, a strong association was found between delayed liquefaction and abnormal sperm motility. Therefore, dysregulated KLK expressions and/or activities were proposed as an underlying cause of male subfertility. Finally, this thesis has provided initial insights into a novel potential function of multiple members of the seminal KLK cascade in activation of the key immune-deviating agent, TGFβ1, in seminal plasma. TGFβ1 activation is postulated to be mediated directly through complete fragmentation or indirectly through partial cleavage and conformational changes of the LAP propeptide motif of the latent TGFβ1. KLK- mediate proteolytic cleavage of the TGFβ1 binding protein, LTBP1, is also suggested as a potential physiological mechanism for release of the membrane-bound latent TGFβ1. Overall, the data provided here may suggest a common regulatory mechanism, involved co-temporally in the two key processes of semen liquefaction and immune-suppression. This might be critical in protecting motile sperms following their release from semen coagulum. Understanding KLK-mediated proteolytic events in seminal plasma can shed light not only on the physiological role of this family of enzymes, but also on some of causes of male subfertility. Accordingly, therapeutic induction of this cascade may be utilized to supplement the current clinical treatment of male subfertility. Conversely, targeted inhibition of key components of the cascade may have potential pharmaceutical utility as a novel topical contraceptive strategy.Ph

Major role of human KLK14 in seminal clot liquefaction

Liquefaction of human semen involves proteolytic degradation of the seminal coagulum and release of motile spermatozoa. Several members of human kallikrein-related peptidases (KLKs) have been implicated in semen liquefaction, functioning through highly regulated proteolytic cascades. Among these, KLK3 (also known as prostate-specific antigen) is the main executor enzyme responsible for processing of the primary components of semen coagulum, semenogelins I and II. We have recently identified KLK14 as a potential activator of KLK3 and other KLKs. This study aims to elucidate the cascade-mediated role of KLK14 ex vivo. KLK14 expression was significantly lower (p = 0.0252) in individuals with clinically delayed liquefaction. Concordantly, KLK14 expression was significantly (p = 0.0478) lower in asthenospermic cases. Specific inhibition of KLK14 activity by the synthetic inhibitor ACT(G9) resulted in a significant delay in semen liquefaction, a drop in the "early" (30 min postejaculation) "chymotrypsin- like" and KLK1 activity, and an increase in the "late" (90 min postejaculation) chymotrypsin-like activity. Conversely, the addition of recombinant active KLK14 facilitated the liquefaction process, augmented the early chymotrypsin-like activity, and lowered late chymotrypsin-like activity. Given that the observed chymotrypsin-like activity was almost completely attributed to KLK3 activity, KLK3 seems to be regulated bidirectionally. Accordingly, a higher level of KLK3 fragmentation was observed in KLK14-induced coagula, suggesting an inactivation mechanism via internal cleavage. Finally, semenogelins I and II were directly cleaved by KLK14. Semenogelins were also able to reverse KLK14 inhibition by Zn2+, providing a novel regulatory mechanism for KLK14 activity. Our results show that KLK14 exerts a significant and dose-dependent effect in the process of semen liquefaction